It is unclear how much low clearance of, or frequent reinfection with HPV accounted for the study prevalence of infection in different age groups.To investigate the prevalence of, and the risk factors for, cervical infection with 44 types of human papillomavirus (HPV) in a rural area in the Dindigul District, Tamil Nadu, India, we interviewed and obtained cervical cell samples from 1891 married women aged 16–59 years. HPV prevalence was 16.9% overall and 14.0% among women without cervical abnormalities, or 17.7 and 15.2%, respectively, age-standardised to the world standard population. In all, 21.9% of infections involved more than one HPV type. High-risk HPV types predominated, particularly HPV 16 (22.5% of women infected), followed by HPV 56, HPV 31, HPV 33 and HPV 18. Unlike most populations studied in developed countries, HPV prevalence was constant across the age groups. HPV positivity was inversely associated with education level (odds ratio (OR) among women with high school  The prevalence of human papillomavirus (HPV) is low in some populations in Asia  and the International Agency for Research on Cancer (IARC). The study area is rural, at an average elevation of 600 m above sea level in the foothills of the Western Ghats and consists of 324 village panchayats . The study goal was to assess the prevalence of cervical HPV infection and cytological abnormalities in a sample of 2000 married, nonpregnant women aged 16–59 years, but we searched for an approximately two-fold larger population to compensate for ineligibility and refusals. We therefore randomly selected a few villages in the study district, as follows.ad hoc trained nurses, and three healthcare workers, stayed in each selected village for 2–5 days and visited each household to invite eligible women. Women who agreed to participate signed informed consent forms as recommended by the ethics committees of the CFCHC and IARC, both of which approved this study. A structured questionnaire including information on sociodemographic characteristics, reproductive factors and use of contraceptive methods was administered in the local language (Tamil) in women's homes and an appointment was arranged in the temporary clinic that had been installed in each village during the survey.After excluding the 113 village panchayats that participated in a concurrent IARC randomised trial of cervical visual screening . All samples were stored at +4°C until shipment to the Department of Pathology at the Vrije University Medical Center, Amsterdam, The Netherlands, for HPV testing and liquid-based cytology. In order to meet the immediate screening needs of participating women, visual inspection with acetic acid and, in the presence of suspicious lesions, colposcopy, were performed (Trichomonas (T.) vaginalis was reported systematically.Liquid-based ThinPrep cytology slides were prepared from PreservCyt vial specimens according to the manufacturer's standard protocol. Results were classified by cytotechnicians according to the CISOE-A classification (β)-globin gene-specific primers. HPV positivity was assessed by general primer-mediated GP5+/GP6+-PCR and by hybridisation of PCR products in an enzyme immunoassay (EIA) using two HPV oligoprobe cocktails that, together, detect the following 44 HPV types: HPV 6, 11, 16, 18, 26, 30, 31, 32, 33, 34, 35, 39, 40, 42, 43, 44, 45, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 64, 66, 67, 68, 69, 70, 71 , 72, 73, 81 , 82 (IS39 and MM4 subtypes), 83 , 84 , cand85, 86, cand89  and JC9710. PCR products that were positive in the EIA were subsequently subjected to further typing by reverse line blot hybridisation, as described previously  testing, cervical specimens were screened with beta  for HPV positivity with 95% confidence intervals (CIs) by various women's characteristics were calculated using unconditional, multiple logistic regression adjusted for age group . The statistical significance of trends for ORs was assessed by giving increasing scores to successive categories of appropriate variables in the logistic model.Of the 2884 women invited, 154 could not be enrolled in the study because they were pregnant, 31 because of illness and 13 because of heavy menstrual bleeding, thus leaving 2686 eligible candidates. There were 743 refusals (27.7%) mainly because of lack of time (372) and reluctance to undergo a gynaecological examination (331). Women who refused to participate were similar to the participating ones in relation to their occupation, husband's occupation, religion, marital status, age at marriage, number of pregnancies and use of contraceptive methods. The only characteristics that were associated with refusals were age (highest below age 25 and above age 54) and education (with the minority of women with high school or college having a participation 10% lower than less educated women).β-globin-negative HPV samples. Of the 1891 women with valid cytology and HPV results, 92 (4.9%) had abnormal cytological findings, including 46 with borderline dyskaryosis, 26 with mild dyskaryosis, 13 with moderate dyskaryosis and seven with severe dyskaryosis. Whereas the frequency of borderline dyskaryosis was similar in different age groups, moderate or severe dyskaryosis was never found in women under age 25, and steadily increased from age 25–34 (1.0%) to age 45–59  than low-risk types (6.0%). Most commonly found in either single- or multiple-type infections were HPV 16 (3.8%), HPV 42 , HPV 56 (1.5%), HPV 31 (1.2%), HPV 33 (1.2%) and HPV 18 (1.0%), but HPV type distribution varied by cytological results. High-risk types were found in 70.7% of women with cytological abnormalities and in 17 out of 20 (85.0%) women with moderate or severe dyskaryosis (including HPV 16 or 18 in nine women). Details of HPV types found in women with multiple HPV infections are given in vs illiterate women=0.6; 95% CI: 0.4–1.0), whereas women working outside the house (the vast majority as farm labourers) had an excess of HPV positivity of borderline statistical significance , and separated or divorced  showed a higher proportion of HPV positivity than married women . The medWhen education level, marital status, number of pregnancies, and contraceptive methods were included, in addition to age, in the same multiple logistic regression, the corresponding ORs did not change materially.The main findings of our large survey in Dindigul District in rural India are the high overall prevalence of HPV infection, the similar prevalence across different age groups, and the marked predominance of HPV 16 among HPV types.All-age HPV prevalence in Dindigul District is similar to that found in high-risk areas for cervical cancer in Latin America  was found in previous IARC surveys  or indirectly (high school or college degree) associated with HPV positivity involved a small, and sometimes very small, proportion of study women.The uniformity of living standards and lifestyle in rural India provides some reassurance in respect of selection bias. Two main groups of women accounted for nonparticipation in our study: those who were not traced during the few days that the gynaecological clinic stayed in each village (approximately 25% of women), and those who were contacted but refused to participate  mainly out of a lack of familiarity with gynaecological examinations. However, we were able to obtain some basic information from almost all women during the survey, or in subsequent repeated visits to the same villages. The three main groups  were similarly distributed by sociodemographic and reproductive factors.


The HPV Vaccine Controversy is a testimony of the amazing uprise of interest and discussion that accompanied this recommendation and the arrival of the first HPV vaccine, and follows it through 2008, up to the time when the book was published. The author, Dr Shobha Krishnan, explains that the book's target audience is parents, women, men and teenagers.In June 2006, the United States Centers for Disease Control first recommended the administration of the human papillomavirus (HPV) vaccine to 11–12-year-old girls. Overall, Dr Krishnan provides a well-balanced view of the strengths and weaknesses of the currently available prophylactic HPV vaccines, including the need to continue screening efforts, and to avoid feelings of fear and guilt on the part of a woman when a HPV infection is detected during cervical cancer screening. The book, however, is very long and is full of technicalities. It made me wonder if, in order to make up their mind, the lay public was anxious to know so many details on HPV types that are not included in the current vaccines, or on the cervical cancer staging system. It is true that when ‘…sex, science, and morals of society intersect.’ , everybody has something to say, but other lines of reflection could have been, in my view, more fecund for the lay public.How was it, for instance, that after 13 years of deliberation, both Merck and Glaxo Smith Kline signed royalty agreements with four, mainly tax-payer-supported, institutes (pages 97–98) so that their original research could be applied to developing and manufacturing ‘a vaccine that was released at the highest price in history’? Why is there so much insistence on sexually transmitted diseases when the HPV vaccine has been conceived, and should have been promoted, as the vaccine against cervical cancer?An obvious side effect of the length of the book is the increase in the scope for inaccuracies and already out-of-date scientific statements. For instance, some myths are presented as facts, for example, ‘The teenage cervix is most vulnerable to HPV…’ (page 23), or ‘Men should be equal players in reducing the viral load in society’ (page 134). The first statement is often heard, but it has no clear scientific support. The second is the result of a misunderstanding . In reality, good vaccine coverage of one sex is enough to curb HPV infection for the same reason Dr Krishnan believes the contrary, that is, because transmission is mainly from one sex to another. Women, however, have a stronger need to be vaccinated than men as it is they who develop the most severe and frequent disease associated with HPV, that is, cervical cancer.Appropriately, the book ends not in the United States, but in India, with a touching expression of gratitude from a 37-year-old woman whose life was saved in the 1990 s by the early detection of cervical cancer (pages 187–188). Almost certainly, her daughters have already missed the chance to benefit from the vaccine against cervical cancer. Will her granddaughters miss it too?


The association between HIV infection and invasive cervical cancer that has been reported may reflect differential prevalence of human papillomavirus (HPV) infection or uncontrolled confounding. We conducted a case-control study in a West African population to assess the relationship between HIV infection and invasive cervical cancer, taking into account HPV infection and other potential risk factors for cervical cancer.Women with invasive cervical cancer (cases) or normal cervical cytology (controls) were recruited in a hospital-based case-control study in Abidjan, Côte d'Ivoire. Odds ratios and 95% confidence intervals (CI) were estimated in logistic regression analyses controlling for important cofactors.HIV infection was noted in 22/132 (16.7%) cases and 10/120 (8.3%) controls (p = 0.048). High-risk HPV infection was detected in cervical tumor samples from 89.4% of case-participants and in cervical cytology samples in 31.1% of control-participants. In logistic regression analysis, HIV infection was associated with cervical cancer in women with HPV . Among women aged ≤ 40 years, risk factors for cervical cancer were high-risk HPV infection ; parity > 2  and HIV infection . Among women aged > 40 years, high-risk HPV infection  and parity > 2 , but association with HIV infection was not statistically significant.These data support the hypothesis that HIV infection is a cofactor for cervical cancer in women with HPV infection, and, as in all populations, the need for promoting cervical screening in populations with high prevalence of HIV infection. In sub-Saharan Africa, age-standardized incidence of cervical cancer is high, ranging from 29.3 (West Africa) to 42.7 (southern Africa) per 100,000 women , cigaretThe incidence of cervical cancer has been changing at a global level, with increasing incidence in women below 40 years of age ,10. ThisIn HIV-infected women, there is an increased risk of HPV infection and squamous intraepithelial lesions (SIL), the precursor of cervical cancer ,12. SincStudies of HIV infection and invasive cervical cancer to date have tended to be limited by lack of information on presence of HPV DNA in cervical samples of study participants, and focused on quantifying the effect of HIV infection relative to other cofactors in the presence of HPV infection. We conducted a case-control study in a West African population to assess the relationship between cervical cancer and HIV infection, taking into account the presence of high-risk HPV infection and other cofactors such as age, parity, and lifetime number of sexual partners. In Côte d'Ivoire, the study setting, the annual incidence of cervical cancer was approximately 24.2 per 100,000  during tOver a two-and-a half-year period, all women aged 18-70 years who presented with cervical lesions at the gynecology and oncology services at two tertiary hospitals in Abidjan, Côte d'Ivoire were asked to participate. These university teaching hospitals are the principal referral sites for patients with suspected malignancies in Abidjan. Controls were recruited from consecutive eligible women attending the oncology and general surgery outpatient clinics for post-surgery follow-up evaluation; the principal reasons for their admissions were trauma, abdominal surgery, or breast cancer. None of the patients had evidence of Kaposi sarcoma or non-Hodgkin lymphoma. Eligibility criteria included being aged 18-70 years, having an intact cervix, and having no current or past history of cervical disease. Cases and controls were not individually matched for age, place of residence, or economic status.All consenting women were interviewed and examined by study personnel, using a standardized questionnaire. Demographic, socioeconomic, reproductive and behavioral data were obtained. Blood samples were collected by venipuncture and a physician performed a complete physical and pelvic examination and collected cervical specimens after visualizing the cervix. For all participants, endocervical and ectocervical cells were collected with a Cytobroom  and transferred to PreservCyt™ liquid collection media (Cytyc). For women with suspected cancer, the cervical lesion was biopsied and clinical stage was determined using the 1986 International Federation of Gynecology and Obstetrics (FIGO) architectural staging system . InformeClinical and pathology data for all participants were reviewed to determine final inclusion into the study. Case-participants were required to have histologically confirmed primary cervical cancer. Advanced disease was defined as FIGO stage III or higher . ControlSerum was tested for HIV-1 and HIV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) according to a standardized algorithm ,25. SeroCervical samples and biopsy specimen were sent to the local reference pathology laboratory in Abidjan, and the Centers for Disease Control and Prevention (CDC) laboratory in Atlanta, Georgia. PreservCyt™ samples were shipped at ambient temperature to CDC and used to prepare ThinPrep™ . Pap smears were read in a diagnostic cytology laboratory using Bethesda 1988 criteria . Residuain situ hybridization (ISH) and polymerase chain reaction (PCR).Cervical biopsy tissue specimens were divided in half and transported in formalin. One half was sent to the local pathology laboratory for clinical diagnosis. The other half was transferred to 50% alcohol 1% formalin and shipped at ambient temperature to CDC for processing. At CDC, tissues were trimmed for processing to paraffin blocks, and serial sections were cut from each block. The first and last sections were H&E stained and reviewed to determine research diagnosis. Discrepancies  between clinical and research diagnoses were resolved through consensus after exchange of tissue blocks between the pathology labs. Intervening sections were used for HPV testing by HPV DNA was extracted from 0.5 ml of the stored cervical cytology samples and from two de-paraffinized 5-μ sections of tumor using the QIAmp DNA Mini Kit  and concentrated in a Centricon Centrifugal Filter Device YM-100  to 25 μL. A 5-μL aliquot was used in the L1 consensus PCR assay  software. The outcome was histologically confirmed cervical cancer, and the primary risk factor of interest was HIV infection, stratified into two main groups of seroreactivity including three categories of reactivity: HIV-1 positive, HIV-2 positive, and dually-reactive. Because HIV-2 is more indolent than HIV-1 in its effects on the immune system and related pathologies, those who were HIV-1 or dually reactive were combined into one group and association with cervical cancer assessed for the two main groups of seroreactivity, i.e., HIV-1-positive or dually reactive, and HIV-2-positive. Because of the small sample size in a final subgroup analysis by age group, HIV-positive sub-groups were pooled together in one group, and associations with cervical cancer were explored with HIV-negative as the reference. Other potential risk factors considered included age (included as continuous variable), socioeconomic status, number of lifetime sexual partners, parity,  and presence of high-risk HPV DNA .In univariate analysis, we compared the characteristics of women with cervical cancer from each of the two hospitals, and then the characteristics of cases and control participants. We then assessed HIV covariates among control participants and the association between HIV infection and presence of high-risk HPV DNA. Comparisons were made using Wilcoxon-rank sum tests for continuous variables, and for categorical variables, Chi Square or Fisher exact test where appropriate . The assMultivariate logistic regression analyses were performed to evaluate the independent association between cervical cancer and risk factors that had been identified in univariate analyses. The variables included in logistic regression models were those that were known to be associated with cervical cancer from previous studies and were found to be associated with both cervical cancer and HIV infection in these data. Different models were used in logistic regression analyses. First, we used a model that included age, socioeconomic status, and lifetime number of sexual partners, parity, and presence of high-risk HPV DNA and HIV infection to assess the independent effect of HIV infection taking into account all other cofactors. Second, because HPV sequences are found in more than 99% of cervical cancers worldwide , we assuFrom April 1997 to October 1999, 141 women with putative invasive cervical cancer seen at the hospitals during the study period were asked to participate. Of these, one woman declined and eight were excluded because of lack of histological confirmation, leaving 132 case participants with histologically confirmed cervical cancer. Of these 132, 114 had been recruited from the first hospital and 18 from the second hospital. No significant differences were observed between these two groups with respect to demographics, economic status, the number of lifetime sexual partners, parity or HIV infection status. A total of 135 consenting women were enrolled as potential controls, representing approximately 70% of those eligible from those recruited. Of these 135 women, 120 with normal cervical cytology results were retained as controls; 14 women with cervical dysplasia  and SIL) and one with missing cytology results were excluded.Table The five most prevalent types of HPV found in cervical cancer specimens were: HPV16 (45%), HPV18 (21%), HPV45 (10%), HPV35 (8%), and HPV31 (3%). Other high-risk HPV types found were: 33, 39, 51, 52, 53, 56, 58, 59, 66, and 68. The HPV types in cases and control specimens were similar. However, the prevalence of high-risk HPV infection was higher among women with cervical cancer than among controls .Table High-risk HPV types were detected in all (100%) of the HIV-positive women with cervical cancer and in 98/110 (89%) of HIV-negative women with cervical cancer (p = 0.1). In multivariate analysis, only HIV infection was associated with HPV infection among controls . A stronger association was observed among younger women, but the number of samples were small and the difference was not statistical significant .Table Of women aged ≤ 40 years, those with cervical cancer were similar to controls with respect to economic status and number of lifetime sexual partners. Table Table Although HIV-positive women with cervical cancer had lower median CD4 counts than did HIV-positive controls, the difference was not statistically significant (376 cells/μl vs. 572 cells/μl: p = 0.6).The results in this case-control study are consistent with established associations of cervical cancer with oncogenic types of HPV infection and with a potential association of cervical cancer with high parity both for older and younger women ,18,33. ARelatively unique to West Africa is the issue of HIV-2 infection. In this study, a higher prevalence of HIV-2 was observed among participants with cervical cancer than among controls; however, the small numbers of women with HIV-2 infection in the absence of HIV-1 infection limited the power of the study to achieve a statistically significant result. An association of cervical carcinoma and HIV-2 infection has been previously noted in studies conducted in West Africa ,35. AlthYoung age and advanced stage of cervical cancer in HIV-infected women in this study were consistent with published findings of rapidly progressive or more advanced forms of cervical cancer at a young age . A possiAlthough HIV infection itself has been reported as a risk factor for cervical cancer ,18,37, iper se in the presence of HPV infection, as well as the degree of HIV-induced immune suppression, are both contributory to development of invasive cervical cancer. HIV is present in vaginal cells, and there is amplification of HPV expression by HIV tat protein, which may explain a direct biologic interaction between HIV and HPV [Previous findings support the biological plausibility of an association between HIV infection and development of cervical cancer . It is p and HPV , with HI and HPV . Degree  and HPV . Althoug and HPV , in the In interpreting the results of this study, a few limitations should be noted. First, controls who were recruited in the oncology and surgical outpatient clinics may not have been representative of the general population with respect to the probability of having HIV infection; however, if the pathology that resulted in their seeking care at the clinic had been related to HIV infection, the measure of effect would be biased towards the null hypothesis of no association between HIV infection and cervical cancer. Second, women who were recruited in university hospitals may not have been representative of women with cervical cancer in the general population in terms of probability of having HIV infection; to adjust for this potential bias (Berkson bias), control participants were selected from oncology and surgical outpatient clinics of the same institutions from which the case patients were selected. Third, control-participants were on average younger and had a higher socioeconomic status than did case-participants; however, these differences were addressed in multivariate analysis, and therefore were unlikely to affect validity of results. Fourth, the few cervical cancer specimens in which high-risk HPV DNA was not identified were probably false negatives, but their number was sufficiently small that their inclusion in the case group would not have appreciably altered the conclusions of this study.The data presented here using confirmatory HIV testing, HPV DNA testing, and histologically confirmed biopsies support associations of cervical cancer with high-risk HPV infection and with parity observed in previous studies. In addition, strong association of HIV infection and cervical cancer was observed among young women, with a high prevalence of high-risk HPV DNA in women with HIV infection. In this study population, few participants had ever had a Pap smear, and cervical cancer was observed at a young age among women with HIV infection in the absence of extreme immunosuppression. The findings overall add support to the association of invasive cervical cancer among HIV-infected persons, an association on which the recommendation for annual cervical cytology screening in persons with HIV infection is based.The authors declare that they have no competing interests.GA-J conceived and designed the study, performed data analysis, and drafted the manuscript; ERU and SDV contributed to study design, and completed cytology and HPV testing; EB-O, KT-C, and CM contributed to study design, and performed clinical exams and HIV testing; AEG and SZW provided scientific support for design and contributed substantially to manuscript writing; TC contributed substantially to revising parts of the study and to manuscript writing. All authors read and approved the manuscript.The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2334/10/242/prepub


Cervical cancer is one of the most important cancers in African women. Polymorphisms in the Fas (FasR) and Fas ligand (FasL) genes have been reported to be associated with cervical cancer in certain populations. This study investigated whether these polymorphisms are associated with cervical cancer or human papillomavirus (HPV) infection in South African women.Participants were 447 women with invasive cervical cancer (106 black African and 341 women of mixed-ancestry) and 424 healthy women controls, matched by age, (101 black African and 323 women of mixed-ancestry) and domicile . Two polymorphisms in Fas gene  and one in FasL gene (FasL844T/C) were genotyped by TaqMan. None of the polymorphisms, or the Fas haplotypes, showed a significant association with cervical cancer. There was also no association with HPV infection in the control group. However, on analysis of the control group, highly significant allele, genotype and haplotype differences were found between the two ethnic groups. There were generally low frequencies of FasR-1377A alleles, FasR-670A alleles and FasL-844C alleles in black women compared to the women of mixed-ancestry.This is the first study on the role of Fas and FasL polymorphisms in cervical cancer in African populations. Our results suggest that these SNPs are not associated with cervical cancer in these populations. The allele frequencies of the three SNPs differed markedly between the indigenous African black and mixed-ancestry populations. Cervical cancer is caused by persistent infection with specific types of human papillomavirus (HPV). During their life-time, many women become infected with HPV but most are able to clear the infection and only a small fraction develop cervical cancer. This indicates that additional risk factors play an important role in the development of cervical cancer. These risk factors include host and viral genetic factors as well as environmental and life style factors .One of the most important mechanisms of the human immune system to control viral infection is to induce apoptosis of viral-infected cells . ApoptosSix studies in different populations have been published on the association of these SNPs with cervical cancer. One investigated the FasR-670A/G polymorphism in a case-control study in the Chinese population and reported an association of the A allele and A/A genotype with higher risk of developing cervical cancer . The samThe importance of host genetic susceptibility factors for cervical cancer development has been demonstrated by epidemiological studies. A hereditary component of cervical tumors was detected in twin studies  and in aParticipants were 447 women with invasive cervical cancer (106 black African and 341 women of mixed-ancestry) and 424 controls (101 black African and 323 women of mixed-ancestry) without cancer of the cervix recruited from hospitals or clinics in the Western Cape Province, South Africa. The control women were selected to be representative of the population from which the cases were selected, specifically similar to the cases with respect to age, ethnicity and domicile status , so that case-control status would not be associated with either of those. There were 264 (59%) urban cases and 183 (41%) rural cases compared to 247 (58%) urban controls and 177 (42%) rural controls. The cases and controls formed part of a study to investigate the association of oral contraceptives with cervical cancer [Blood was collected from cases and controls, following written informed consent and stored at -80°C. The study was approved by the University of Cape Town Research Ethics Committee (REC REF: 075/2009). The subject identifiers were permanently unlinked from the specimens. The HIV infection status was known for 98% (n = 437) of the cases and 94% (n = 398) of the controls and 5% of the cases and 4% of the controls were positive for HIV infections. 13% of the controls were positive for HPV by Digene Hybrid Capture II. 14.5% of the controls in our study had abnormal cervical cytology.The genomic DNA was extracted using TotalNucleicAcid Extraction kit for MagNA Pure Compact nucleic acid extractor .Reactions were conducted in 5 μl volumes and contained 10 ng DNA, 1.75 μl PCR MasterMix (Applied Biosystems), 0.087 μl TaqMan assay mix , FasR-670 , FasL844 ) (Applied Biosystems) and 1.16 μl distilled water. Cycling conditions on the ABI prism 7900 HT (Applied Biosystems) were 2 minutes at 50°C, 10 minutes at 95°C, followed by 40 cycles of 15 seconds at 92°C and one minute at 60°C. End point fluorescence was measured immediately after cycling. Alleles were assigned using SDS 2.0 software (Applied Biosystems) . The genThe genotype distributions were tested for Hardy-Weinberg equilibrium and linkage disequilibrium in cases and controls. Logistic regression was used to test for genotype, allelic and haplotype associations with cervix cancer status as well as baseline characteristics  and secondary outcomes such as HIV status, abnormal cytology (Pap smear) and high risk HPV according to Hybrid Capture II HPV Test in the control group.We inferred haplotypes from the two polymorphisms in FasR, and tested their association with cervix cancer status and between ethnicities in the controls.http://www.r-project.org, and R packages dgc-genetics http://www-gene.cimr.cam.ac.uk/clayton/software/ and haplo.stats http://CRAN.R-project.org/package=haplo.stats. Broadly, haplo.stats uses the expectation maximisation (EM) algorithm, to calculate maximum likelihood estimates of probabilities, of haplotype pairs  for each subject, as described in Schaid et al. [Statistical analyses were done with R, the freely available environment for graphics and statistics d et al. .The mean age for black cases was 43.8 yrs (SD 9.2) and for mixed-ancestry cases it was 45.9 yrs (SD 8.1). The mean age for black controls was 42.9 yrs (SD 9.0) and for mixed-ancestry controls it was 45.6 yrs (SD 8.2). No significant differences in age or HIV status were observed between cases and controls.The observed genotype frequencies of FasR-1377G/A, FasR-670A/G and FasL-844T/C in the controls were all in Hardy-Weinberg equilibrium . The two FasR polymorphisms were in tight linkage disequilibrium (LD) (P < 0.05), except in the black controls (P = 0.078).Neither the allelic, nor the genotype frequencies showed a significant association  with cervical cancer status  between ethnic groups  and hybrid capture high risk HPV) and any of the three SNPs in the control group, adjusted for ethnicity (results not shown here).Polymorphisms in the Fas or FasL genes that impair the apoptotic signals have been associated with susceptibility to a number of different cancers -27 incluWe observed statistically significant allele frequency differences for all the three Fas SNPs between ethnic groups in the control women. For FasR-1377G/A, the A allele frequency was 9% in the black Africans and 19% in women of mixed-ancestry, which were both markedly lower than the frequency in other populations, such as the 43% and 31% in Taiwanese and Chinese populations, respectively ,12. The The FasR-1377G/A and FasR-670A/G SNPs are in tight LD in our population. Both the AG and GA haplotypes were significantly more frequent in women of mixed-ancestry compared to GG, the most common haplotype, which was observed at a higher frequency in black women (Table Our study did not show a significant association of the FasR-1377G/A, FasR-670A/G and FasL-844T/C polymorphisms with cervical cancer. A statistically significant difference was found in the allele and genotypes frequencies of the three SNPs between women of black African and mixed-ancestry in the control population.The authors declare that they have no competing interests.KC participated in planning of the study, performed extraction of DNA, genotyping, analyzing the results and basic statistical analysis. ME helped in genotyping, analysis and interpretation of the results. CD helped in reporting and interpreting of the results. LM and UGA performed advanced statistical analysis and helped with reporting and interpretation of results. MH coordinated the collection of the biological samples. UGY helped in planning the study and supervised the genotyping part. ALW was responsible for the storage of the biological samples, helped in planning and supervising the study and helped in interpretation of the results. All authors critically read and took part in finalizing the manuscript.


The human papillomavirus (HPV) is the major etiologic agent in the development of cervical cancer and its natural history of infection is altered in persons infected with the human immunodeficiency virus (HIV). The prevalence of HPV infection and cervical dysplasia in the HIV sero-positive females in the Bahamas is not known. Finding out the prevalence would allow for the establishment of protocols to optimize total care of this population and help prevent morbidity and mortality related to cervical cancer.The Objective of this study is to determine the prevalence of high risk HPV genotypes and the prevalence of cervical dysplasia in the HIV sero-positive females attending the Infectious Disease Clinic at the Princess Margaret Hospital, Nassau, Bahamas.One hundred consecutive, consenting, non-pregnant, HIV-sero-positive females from the Infectious Disease Clinic at the Princess Margaret Hospital in Nassau, Bahamas were screened for high-risk HPV infections and cervical cytology abnormalities using liquid-based pap smear and signal amplification nucleic acid method for HPV detection. A questionnaire was also utilized to gather demographic information and obtain information on known risk factors associated with HPV infections such numbers of partners.-1 and in women with cervical cytology abnormalities (97%). The most common cervical abnormality was low-grade squamous intraepithelial lesions.The prevalence of high-risk HPV was 67% and cervical abnormalities were noted in 44% of the study population. High-risk HPV types were more likely to be present in women with CD4+ cell counts less than 400 μlFindings suggest that HIV-sero positive females should have HPV testing done as part of their normal gynecology evaluation and these patients should be encouraged and provisions be made for ease of access having regular PAP smears and HPV testing. The human papillomavirus (HPV) is the major etiologic agent in the development of cervical cancer  with knoThe goal of the study is to determine the prevalence of high-risk HPV infections and associated cervical abnormalities in HIV sero-positive females in the Bahamas.One hundred (100) consecutive, consenting, non-pregnant, HIV sero-positive females (18) years or older were recruited from the Infectious Disease Clinic at the Princess Margaret Hospital in Nassau, Bahamas. The criteria for eligibility required all of the following: Females 18 years and older, a positive HIV via ELISA and Western Blot methods and HIV infectivity via sexual intercourse. All participants were interviewed, provided informed written consent and had a liquid based pap smeared performed after receiving consent. The study received ethical approval from the Ethics Committee of the Public Hospital Authority and the University of the West Indies – Bahamas Campus.Each participant had a vaginal examination performed by an Obstetrics and Gynaecology Resident. Cervical samples were collected using a cytobrush (cytobroom) and stored in Sure Path vials. A cytotechnologist screened the prepared slides. All positive results and fifteen percent (15%) of all negatives results were reviewed by a board certified cytopathologist. The cytology was reported as either negative, atypical squamous cells of unknown significance (ASCUS), low-grade squamous intraepithelial lesion (LGSIL) or high-grade squamous intraepithelial lesion (HGSIL). Additionally co-infections as well as presence of HPV changes were noted. The Obstetrics and Gynaecology Oncologist referred all patients with abnormal cytology results to Colposcopy Clinic for further evaluation, treatment and follow-up as determined.Each patient was interviewed and a questionnaire completed by the interviewer. Information on associated HPV risk factors such as parity, number of sexual partners, and birth control method, risky behavior such as drug use, sex under the influence of drugs and condom usage as well as demographic were obtained via the questionnaire. The medical records were reviewed to obtain patient's date of HIV testing and confirm sero-positivity, most recent CD4+ lymphocyte counts and viral load, and use of high active anti-retroviral therapy.Samples collected from patients were stained with FlowCARE PLG CD4 Reagent. CD4+ lymphocytes counts were determined by flow cytometry. White blood cell counts were obtained with a COULTER STKS Instrument. The values were expressed in terms of percentage (%) of total lymphocytes and absolute count (cells/μL).The DNA HIV viral load was tested using a quantiplex HIV-1 RNA 3.0 Assay. This assay is a nucleic acid hydridization procedure to directly quantify HIV-1 RNA in human plasma. The HIV-1 is concentrated from the plasma by centrifugation then the genomic RRNA is liberated from the virions and captured on a microwell by specific synthetic oligonucleotide capture probes. The probes bind to different regions of the pol gene of the viral RNA which is them amplified.Multiple copies of the alkaline phosphatase-labelled probe are then hybridized to an immobilized complex to amplify the signal. Detection is achieved by incubating the complex with a chemiluminescent substrate. The light emission generated by the bound alkaline phosphatase reacting with the chemiluminescent substrate is recorded as relative light units (RLUs). The light emission is directly proportional to the amount of HIV-1 present in each sample. A standard curve is defined by light emission from standards containing known concentrations of beta proiolactone (BPL)-treated virus. Concentrations of HIV-1 RNA in plasma specimens are determined form this standard curve.HPV was detected using the HPV Hybrid Capture II assay which is a signal amplification nucleic acid method for the qualitative detection of eighteen types of human papillomavirus (HPV) DNA in cervical specimens. The assay differentiates between high risk and low risk groups. High HPV types detected are 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68.Clinical and laboratory risk factors for the study population were imported to a statistical software package for analysis. Statistical analyses were performed using the Intercooled STATA (version SE 10.0) software . Factors associated with high-risk HPV status were selected based on cross-tabulations and univariate logistic regression analyses. Cross-tabulations were analyzed using the Fisher's exact test. Logistic regression was used to perform the analyses of associations between demographic, behavioral and clinical variables with high-risk HPV status. Crude odds ratios were first calculated. Potential confounders were identified based on p-values = 0.05. Logistic regression was used to calculate the relative odds of high-risk HPV status after adjusting for the potential confounders (age (continuous), marital status, number of pregnancies, Tobacco use, duration of HAART therapy, CD4 counts, viral load and cervical cytology).One hundred females ranging from ages 20–71 years were interviewed and had a PAP smear performed. The mean and median ages were 40.1 years and 39 years respectively. Fifty-six participants (56%) were single and twenty-four (24%) were married (Table Sixty-seven women (67%) tested positive for high-risk HPV genotypes. The proportion of high-risk HPV-positive women was significantly higher than those who are HPV-negative (p = 0.001). Forty-four women (44%) were found to have abnormal cervical cytology with 95% testing positive for high-risk HPV. Seven patients (7%) had ASCUS, LGSIL in 31 (31%) and HGSIL in six (6%) participants.Adjusting for potential confounders , one hundred percent of participants with HGSIL were high-risk HPV positive . Of note, participants with greater than ten lifetime sexual partners were four times more likely to have high-risk HPV infections than those with less than 10 lifetime sexual partners . This finding was not statistically significant.-1, 38 (38%) had CD4+ counts between 200 and 499 μl-1, and 39 (39%) had CD4+ counts less that 200 μl-1. After adjusting for potential confounders, subjects with CD4+ counts greater than 400 μl-1 were less likely to test positive for high-risk HPV  (Table The mean and median CD4+ lymphocyte counts were 339.15 and 260 respectively. Twenty-three participants (23%) had CD4+ counts ≥ 500 μlHigh-risk HPV is prevalent in the HIV sero-positive females attending the Infectious Disease Clinic at the Princess Margaret Hospital. Unfortunately, a comparison with the HIV sero-negative population could not be done as there is no published HPV prevalence study for the general population. The high prevalence reported in this study is not unusual with HPV infections being quoted as anywhere from 33–47% in other published studies -12. The Subjects living with HIV infection for two to six years were three times more likely to carry high-risk HPV infections than those infected for less than two years, however this association was not significant (p > 0.1). Similarly, women who lived with HIV infections for more than 6 years were almost two times more likely to carry high-risk HPV infections however; this also was not significant.1 were more likely to test positive for high-risk HPV genotypes. As CD4+ count is a reflection of the state of the immune system, it reasonable to assume that the immune dysfunction noted at lower CD4+ levels is responsible for the increased detection of high-risk HPV in these women.Individuals with a CD4+ lymphocyte count of less than 400 μl-An increased number of lifetime sexual partners was associated with an increased likelihood of testing positive for high-risk HPV. Other behavioral variables such as cocaine use, alcohol use and non-barrier method did not show the expected increased risk. This lack of increased risk could be the result of a relatively small study population.The high prevalence of high-risk HPV genotypes and cervical cytology abnormalities demonstrates the need to screen and monitor HIV sero-positive women and to implement preventative measures to decrease the numbers of females with high risk HPV infections. Most participants reported not having yearly PAP smears and unfortunately, routine HPV screening is not conducted at the public facilities where most of these patients receive their PAP smears. Screening for HPV infections in HIV sero-positive females should be an integral component of their routine gynaecological evaluation and these patients should be encouraged and provisions be made for ease of access to having regular PAP smears and HPV testing.The authors declare that they have no competing interests.DND conceived of the study, participated in its design and coordination and drafted the manuscript. CR performed the statistical analysis and reviewed the manuscript. AGB performed the Pap smears and cervical examination. RB sourced the funding, helped with coordination of the study, provided further management for patients with detected abnormalities and reviewed the manuscript.


Effective prophylactic vaccines are available against human papillomavirus (HPV) types 6, 11, 16, and 18 which are licensed for routine use among young women. Monitoring is needed to demonstrate protection against cervical cancer, to verify duration of protection, and assess replacement frequency of non-vaccine types among vaccinated cohorts.Data from a population-based study were used to assess the type-specific prevalence of HPV in a non-vaccinated population in Estonia: 845 self-administered surveys and self-collected vaginal swabs were distributed, 346 were collected by mail and tested for HPV DNA from female participants 18-35 years of age.The overall HPV prevalence (weighted estimate to account for the sampling method) in the study population (unvaccinated women aged 18-35) was calculated to be 38% (95% CI 31-45%), with estimated prevalences of high- and low-risk HPV types 21% (95% CI 16-26%), and 10% (95% CI 7-14%), respectively. Of the high-risk HPV types, HPV 16 was detected most frequently  followed by HPV 53  and HPV 66 .We observed a high prevalence of total and high-risk type HPV in an Eastern European country. The most common high-risk HPV types detected were HPV 16, 53, and 66. Human papillomavirus (HPV) is thought to be the most common sexually transmitted infection in the world . GenitalAn age-stratified  random sample of 845 women aged 18-35 years was derived from the Estonian Population Registry list for Tartu city (the second largest city in the country) and county residents . The Estonian Population Registry is an electronic database containing personal data about people residing in Estonia.® Collection swab, Deltalab, S.L.I., Barcelona, Spain), collection instructions and an informed consent form attached to a 35-item questionnaire requesting socio-demographic characteristics, sexual behaviour, and health care utilization data. For specimen collection, participants were instructed to wash their hands before opening the swab, to hold the swab by the end of the handle, to insert the foam swab into the vagina as if inserting a tampon, to gently turn the swab during a count of 10, and to replace the swab in the plastic sleeve, avoiding contact with the external genitalia.Data collection was conducted from September 2005 to May 2006. Each participant was mailed a package containing a specimen collection kit  were mailed directly to the laboratory, in pre-stamped, pre-addressed envelopes. The swabs were transported in a dry state. Earlier studies have documented good performance of NAAT assays for the detection of HPV  using self-obtained vaginal swabs shipped in a dry state to a laboratory -10. SampThe vaginal swabs were held for up to three days at 4°C prior to DNA extraction. Material from swab specimens was suspended in PBS and collected by centrifugation at 16,060G for 20 minutes. The supernatant was discarded and the pellet was resolved in PBS. DNA was extracted using the High Pure PCR Template Preparation Kit  according to the manufacturer's instructions. Amplification of the human β-globin gene was performed to confirm the integrity of the DNA in the samples .Human papillomaviruses were detected by single-round PCR using the degenerated oligo primers MY09/11 and HMB01 as described by Gravitt et al.  using anThe HPV prevalence was calculated from the number of positive cases divided by the number of tested specimens. Weighted estimates of population prevalence were computed to adjust for the stratified sampling utilized in the study. Correlates of HPV prevalence were explored using the chi-square test for proportions, and multiple logistic regression analysis to assess confounding and interaction between variables. Factors with p < 0.05 in bivariate analysis were entered in a multivariate comparison. A conceptual framework approach was used for the multivariable analysis . All anaEthical approval was obtained from the Ethics Review Board of the University of Tartu and the Institutional Review Board of the State University of New York at Albany. The study followed data protection legislation requirements from the Estonian Data Protection Inspectorate. Study participants received no financial incentive for participation.Study invitations reached 86% (723/845) of the targeted sample but 122 individuals could not be reached because the packet was undeliverable . These subjects were excluded from the analysis.Women who returned the questionnaire or self-collected a vaginal sample (n = 346) were compared with those who did not (n = 377) using population registry data. There was no statistically significance difference in response proportion according to age, residency or ethnicity (data not shown) .Respondents ranged in age from 18 to 35 years . Two out of three participants were either married (23%) or living with a sexual partner (41%).Of the 326 adequate specimens available for HPV DNA testing, 37% 95% CI 31-44%) were positive for any HPV DNA. After weighting for the source population distribution, the prevalence estimate was 38% (95% CI 31-45%)  and 10% (95% CI 7-14%), respectively. The prevalence of unidentified HPV types was 7% (95% CI 4-10%). The most common HPV types detected were HPV 16, 53, 66 (high-risk types), and HPV 61, 81 (low-risk types) . However, HPV DNA was detected in 6% of females who reported never having had sex. The final multivariate model demonstrated that age , age above 18 years at first sexual intercourse , and increasing numbers of sexual partners in the last 12 months  were independently associated with HPV DNA detection Table .Cervical cancer is the second most common cancer in women worldwide. It is the sixth most frequent cancer among Estonian women of all ages, and the second most frequent cancer among young Estonian women (aged between 15 and 44 years) . The avaConsistent with published data, we found that HPV 16 was the most prevalent HPV type (6.4%). We found a relatively low HPV 18 prevalence. In the light of studies documenting similar prevalence of any high-risk HPV in paired cervical and vaginal specimens this finding is of importance ,29, and Based on the most recent studies Table  we surmiThe overall HPV prevalence in our study population was high with the highest overall HPV prevalence among those aged 21-25 years  and declining with age. It is well known that sexually active young adults are most at risk for acquiring HPV. Beside young age, predictors of HPV infection included younger age at first sexual intercourse and higher number of sexual partners in the 12 months before the study. Our results are also in line with existing information on HPV epidemiology ,33,34.Our study has several limitations. This study was not originally designed to assess HPV prevalence, thus we do not have data on cervical cytology from participating women. The degree to which the study is representative of the general population may be affected by the low response rate and selection factors associated with response. It is very probable that non-responders and women who were not reachable are at higher risk of exposure to HPV. However, in our study, the probability of not responding was not related to ethnicity, residency or age, despite the correlation between young age and infection. Also, we were unable to include preadolescent women as this would have been ethically unjustifiable and impractical from a logistical standpoint. While it is reasonable to assume that the prevalence estimates from this study are somewhat inflated due to selective participation, the estimate is probably better than that based on traditional clinic-based findings which are not representative in Estonia.Several factors affecting cervical cancer control are changing, including a better understanding of the natural history of HPV, reliable assays for detecting high-risk HPV infections, and the availability of effective preventive vaccines. However, there are important differences in the relevant policy questions for different settings. Local data including information on HPV (type specific) prevalence is needed for modeling in a decision analytic framework to identify those factors most likely to influence outcomes, provide insight into the cost-effectiveness of different strategies, and assist in early decision-making when weighed against equity, public preferences, and political and cultural constraints. Our study provides valuable baseline data about prevalence and type distribution of HPV prior to the introduction of HPV vaccination.The content of this paper has not been published elsewhere, nor is it being considered elsewhere, nor are there any conflicts of interest contained therein.AU, LAM and JD designed the study and outlined the analysis. MR performed the needed statistical analyses. LK was responsible for the laboratory work needed. AU wrote the first draft of the manuscript. All authors contributed to revising the manuscript and have approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2334/10/63/prepub


Objective To obtain large scale and generalisable data on the long term predictive value of cytology and human papillomavirus (HPV) testing for development of cervical intraepithelial neoplasia grade 3 or cancer (CIN3+).Design Multinational cohort study with joint database analysis.Setting Seven primary HPV screening studies in six European countries.Participants 24 295 women attending cervical screening enrolled into HPV screening trials who had at least one cervical cytology or histopathology examination during follow-up.Main outcome measure Long term cumulative incidence of CIN3+.Results The cumulative incidence rate of CIN3+ after six years was considerably lower among women negative for HPV at baseline  than among women with negative results on cytology ). By comparison, the cumulative incidence rate for women with negative cytology results at the most commonly recommended screening interval in Europe (three years) was 0.51% (0.23% to 0.77%). The cumulative incidence rate among women with negative cytology results who were positive for HPV increased continuously over time, reaching 10% at six years, whereas the rate among women with positive cytology results who were negative for HPV remained below 3%.Conclusions A consistently low six year cumulative incidence rate of CIN3+ among women negative for HPV suggests that cervical screening strategies in which women are screened for HPV every six years are safe and effective. Cytological screening has reduced the incidence of cervical cancer in countries with organised screening,9Several randomised controlled trials are currently being conducted to compare primary screening based on HPV detection with conventional cytology screening.Most of the cohort studies and the randomised trials, however, have observed only limited numbers of cases of CIN3+ on longer term follow-up, resulting in reduced statistical power for estimating the critical factor for deciding the appropriate screening interval: the rate of CIN3+ among women with negative results at screening. Furthermore, clinical and diagnostic practices vary between European countries, and different studies have often used different methods for evaluation, making meta-analyses difficult.To obtain large scale and generalisable data on long term predictive values for CIN3+, we obtained primary data from seven HPV screening studies in six EU countries, each investigating the predictive value of primary HPV screening for future CIN3+; assessed variability between studies; and estimated the overall long term predictive values for CIN3+.The seven prospective HPV studies supplied data to a common database for joint statistical analysis. Table 1 provides details of the design of the seven studies, inclusion and exclusion criteria, setting, and locationIn 1993-5 women in the general population were enrolled in a prospective cohort study of the clinical course of HPV and cervical neoplasia. They were interviewed and underwent a cervical smear tests for cytology and cervical swabs for detection of HPV DNA with hybrid capture II.In 1999-2000 women aged ≥30 were invited to the medical universities in Hannover or Tübingen for a prospective cohort study  on HPV screening.The UK study included women attending routine screening in west London to evaluate HPV based screening in women aged ≥35 during 1994-7.Women who participated in biennial or triennial routine screening in 1997-2002 in Reims, France, were invited to participate in a study to evaluate HPV testing with hybrid capture II in cervical cancer screening.In 1997-2000 women aged 32-38 who took part in organised cervical screening in five regions of Sweden  were invited to participate in a randomised population based trial of primary HPV screening with general primer GP5+/6+ polymerase chain reaction.In 1997-2001 women randomly selected from the general population of the Barcelona metropolitan area or who were attending one of nine family planning clinics for routine screening were enrolled.From the joint cohort, we included only women with adequate cytology and HPV tests at baseline and with at least one follow-up cytological or histological test. We regarded abnormal cytology as the equivalent of atypical squamous cells of uncertain significance (ASCUS) or worse for all the participating studies. Women were followed up from the date of the baseline test. Incidence depends on the number of person years of follow-up, and, for a disease detectable by screening, follow-up requires the person to have attended screening. Therefore, we censored follow-up at the date of diagnosis of the CIN3+ lesion  or at the last registered testing date.Firstly, we estimated the specific cumulative incidence rate of CIN3+ by original baseline group  for each country, with 95% confidence intervals, using the non-parametric Kaplan-Meier product limit estimator for log(hazard).Out of 24 295 women included in the pooled analyses, 381 developed histologically confirmed CIN3+ during six years’ of follow-up (table 2)Analysis with an alternative outcome definition that included all high grade lesions  showed essentially similar results but was based on a higher number of cases (n=585). For example, at six years of follow-up, the cumulative incidence rate of CIN2+ was 0.67% (0.39% to 1.11%) among women negative for HPV and 1.76% (1.00% to 2.47%) among women with negative cytology results. The rates at three years of follow-up were 0.19% (0.07% to 0.38%) and 0.79% (0.43% to 1.16%), respectively.As the prevalence of HPV infection is highly age dependent and as cytological performance also varies with age, we analysed positive and negative predictive values, sensitivity, and specificity of the screening tests stratified by age group The seven studies included in the pooled analyses had estimates of cumulative incidence rate for CIN3+ that were not significantly different among cytology−/HPV−, cytology−/HPV+, or cytology+/HPV− women . The cumulative incidence rate of CIN3+ among women with positive cytology and HPV test, however, was clearly different between studies  (fig 4)Using pooled data from seven HPV screening studies in six European countries we estimated a cumulative incidence rate for future histologically confirmed CIN3+ during six years of follow-up. The uniformly low rate among women with negative results on both cytology and HPV tests suggests that double negativity confers a long lasting protective effect that is remarkably robust, considering that the participating studies used several different types of HPV tests in several different settings and in several different age groups. The long lasting protective effect was similarly low in women negative for HPV and women with negative results on both tests.That several studies in different settings in different countries and with different infrastructure and intensity of follow-up gave largely similar results is a strength of the study, as it implies that the data are generalisable to various settings. Similarly, that we studied the actual cytological tests used in the different countries implies that the data are generalisable—for example, the largest study in the joint cohort (France) used the most modern cytology technique (liquid based cytology) and several other cohorts used the same routine conventional cytology as is used in organised programmes with a documented preventive effect on cancer.Our results agree with the results from a US cohort of 20 810 women that found that cytology−/HPV− women had a cumulative incidence rate of CIN3+ of 0.16% after 45 months and 0.79% after 122 months.28As expected, the HPV test was less specific than cytology. The higher specificity in women aged over 35 suggests that restricting HPV testing to older women would reduce overdiagnosis. With increasing length of follow-up, however, the cumulative incidence rate for CIN3+ increased more among women positive for HPV than among women with positive cytology results. This implies that the problem of HPV based screening resulting in increased overdiagnosis, with women unnecessarily referred for clinical procedures, is attenuated in evaluations with longer follow-up—some of the HPV positivity that seems to be false positivity in cross sectional evaluations will turn out to be true, but earlier, detection of CIN3+.Verification bias might overestimate the performance of screening tests when only women with a positive screening test result are referred for colposcopy. Only some of the included studies performed colposcopies in women with negative results on both tests. It is, however, rare to diagnose CIN3+ by colposcopy in such womenNevertheless, as assessment of the incidence of CIN3+ by baseline group during follow-up depends on the intensity of screening our estimates should be interpreted as relative rather than absolute.32In one study (Spain), no action was taken because of positive results of HPV tests at baseline whereas four studies mandated extra testing or colposcopy, or both . As we did not include Denmark and Tübingen in the follow-up of women with positive results on cytology or HPV tests, our cumulative incidence rate of CIN3+ is almost entirely based on active follow-up of HPV tests and should reflect the outcome of active HPV based screening strategies.As prevalence of CIN3+ is associated with prevalence of HPV some heterogeneity between studies might be explained by differences in prevalence of HPV—for example, Spain has a low prevalence of HPV.In conclusion, these joint European data suggest that screening intervals could safely be lengthened to six years among women with a negative result on an HPV test. This could at least partly compensate for the increased referral rate resulting from HPV based screening strategies.Cervical screening with HPV testing is more sensitive for detection of cervical intraepithelial neoplasia grade 3 or cervical cancer (CIN3+)Cost efficiencies of cervical screening strategies combining cytology with HPV testing depend on the duration of the protective effect of negative testing as this determines the optimal screening intervalA joint analysis of seven different studies in six European countries consistently found a low six year cumulative incidence rate of CIN3+ among women negative for HPVCervical screening strategies with HPV testing every six years is safe and effective


Human papillomavirus (HPV) infection, and in particularly infection with HPVs 16 and 18, is a central carcinogenic factor in the uterine cervix. We established and optimized a PCR assay for the detection and discrimination of HPV types 16 and 18 in archival formaldehyde fixed and paraffin embedded (FFPE) sections of cervical cancer.Tissue blocks from 35 cases of in situ or invasive cervical squamous cell carcinoma and surrogate FFPE sections containing the cell lines HeLa and SiHa were tested for HPV 16 and HPV18 by conventional PCR using type specific primers, and for the housekeeping gene β-actin. Using HPV 16 E7 primers, PCR products with the expected length were detected in 18 of 35 of FFPE sections (51%). HPV 18 E7 specific sequences were detected in 3 of 35 FFPE sections (9%).In our experience, the PCR technique is a robust, simple and sensitive way of type specific detection of HPV16 and HPV18 genes in FFPE tissue. That makes this technique applicable to routine practices of HPV detection. Human papillomavirus (HPV) infection is a central carcinogenic factor in the uterine cervix, and cervix cancer is a common malignancy in women worldwide . Most woThe new vaccination program should confer type specific immunity against HPV 16 and 18, and it is expected to be a valuable tool for reducing the incidence of cervical cancer [In the present study we aimed to establish sensitive, specific and simple assays for type specific detection of the presence of the E7 region of HPV 16 and 18 DNA in FFPE tissue, since fresh unfixed tissue is rarely available for routine diagnostics. Methods to this end, such as HPV detection by PCR using the MY09/MY11 and GP5+/GP6+ primer systems have been described, but have often been found to allow only the broad detection of a spectrum of HPVs [In general the sensitivity of PCR-based assays is lower in FFPE specimens compared with fresh, unfixed tissues as a result of degradation and fragmentation of the target DNA -12. TypiTissue blocks from 35 cases of loop excision or surgical excision of carcinoma in situ or of invasive cervical squamous carcinoma were randomly selected in the pathology database "Snomed" and obtained from the archives of the Institute of Pathology, Aarhus University Hospital. All were routine diagnostic surgical specimens that had been fixed in buffered formalin and embedded in paraffin. Specific fixation times were not known for individual specimens, but typically varied between 18 and 24 hours. Cases were classified on haematoxylin and eosin stained sections by a pathologist experienced in evaluation of gynaecological pathology according to standard World Health Organization diagnostic criteriaWe used the following cell lines as controls in our study: HeLa (contains about 50 copies of HPV 18 according to the supplier), SiHa (contains 2-5 copies of HPV 16 according to the supplier) and fetal kidney cell line 293-EBNA (does not contain HPV) . Cell lihttp://www.qiagen.com) according to the manufacturer's protocol.DNA isolation from unfixed Hela, SiHa and 293-EBNA cell lines was performed using a QIAmp DNA purification kit , then placed in 99% ethanol for 2 × 20 min at 60°C and air-dried. They were subsequently resuspended in 300 μl of digestion buffer  and incubated at 56°C under rocking conditions for 24 hours until the tissue was completely digested. The proteinase K was inactivated by incubating the samples for 20 min at 95°C. Phenol/chloroform/isoamyl alcohol  was added to each tube at a volume equal to that of the digestion mixture (300 μl). Tubes were then vortexed for 10-15 sec and centrifuged at 14,000 rpm for 5 min. The supernatant was transferred to new tubes and mixed with 1/10 volume of 3 M sodium acetate and 2.5 volume of 99% ice-cold ethanol, incubated at -20°C for 30 min, then centrifuged at 14,000 rpm for 5 min, and the supernatant was discarded. Pellets were washed with 1 ml of 70% ethanol, centrifuged for 5 min at 14,000 rpm, after which the ethanol was removed and the specimen air-dried. Dry pellets were then resuspended in water. The integrity and purity of the DNA extraction and the concentration of the extracted DNA was assessed by spectrophotometry.2, 100 nM of each dNTP, 300 nM of each primers, and 0.6 U AmpliTaq Gold polymerase. The DNA template concentrations varied from 5 ng to 500 ng per reaction. The primers used for the β-actin detection are listed in table DNA extracted from unfixed cells and from FFPE sections was used as template for PCR reactions. Amplification reactions were performed with an AmpliTaq Gold PCR kit . The reaction mixture with a total volume of 25 μL contained 1 × AmpliTaq Gold buffer, 5.5 mM MgCl2+, 3.0 mM MgCl2, 200 μM of each dNTP, 0.4 μM of each primers, and 2.5 U FastStart High Fidelity Taq polymerase. DNA template concentrations varied from 5 ng to 500 ng per reaction. The amplification was performed in two steps: PCR cycling 95°C 5 min,  10 cycles,  × 25, 72°C 5 min. Ten μl of PCR product were run in 1.5% agarose gel at 80 V for 90 min and stained with ethidium bromide.DNA extracted from both unfixed cells and FFPE sections was used as template for type specific HPV 16 and HPV 18 detection. Amplification reactions were performed with the FastStart High Fidelity PCR system (Roche). Primers are listed in table To evaluate the quality of the DNA extracted from the study specimens for amplification by PCR, all samples were tested for the housekeeping gene β-actin using PCR. β-actin DNA was detected in 32 of 35 91%) FFPE, in situ or invasive cervical squamous carcinoma samples whereas β-actin was detected in all cell line samples (table % FFPE, iAll samples and controls were tested for HPV 16 E7 and HPV 18 E7 using specific primers within the E7 regions of the two genomes. Primers were designed using the "Vector NTI" software. The HPV16, HPV18 and β-actin sequences were obtained from the NCBI database. Results are shown in table We designed and optimized our PCR assay for the detection of HPV in potentially damaged DNA templates. In accordance with previous studies showing that PCR-based detection assays in FFPE sections work best when the amplicon size is up to 200 bp, amplicon sizes from 99 bp to 196 bp were used ,15. To vWe chose to place the amplified region of HPV DNA in the E7 regions of HPV DNA, as the expression of the HPV 16 and HPV 18 oncogenes E6 and E7 shows a strong positive correlation with the development of invasive cervical carcinoma ,5. In orUsing HPV 16 E7 primers, PCR products were detected in 51% of sections, whereas HPV 18 E7 specific sequences were detected in 9% of sections. These frequencies correspond with Zur-Hausen et al. who reported that HPV 16 was found in approximately 50% of all cervical cancer and HPV 18 in close to 20% [We conclude that the yield and quality of the DNA extracted from the archival FFPE sections of cervical carcinoma was sufficient for PCR assays. Using our optimized PCR protocol, we were able to specifically detect the HPV types 16 and 18 in routine pathology archive specimens with a simple, reproducible and cheap method.The assay could be applied for post-vaccination typing of HPV types where a universal PCR for HPV identifies any HPV infection, whereas this assay identifies the subpopulation of infections caused by HPV 16 and 18.DNA: Deoxyribonucleic acid; FFPE: Formalin fixed paraffin embedded; HPV: Human papilloma virus; PCR: Polymerase chain reaction.The authors declare that they have no competing interests.IL obtained the diagnostic material from the archive of the Institute of Pathology, carried out molecular tests and drafted the manuscript. ML carried out pathological examination. SHD carried out pathological examination, participated in the coordination of the study and contributed to the preparation of manuscript. JK participated in the coordination of the study, coordination of the molecular tests, and the final preparation of manuscript. All authors read and approved the final manuscript.


Few large studies have evaluated concordance based on a broad spectrum of human papillomavirus (HPV) types in oral and genital specimens of mothers and their recently born infants. This information is important in determining whether HPV vaccines administered prior to pregnancy may be useful for preventing vertical transmission. HPV DNA was positive in 30% of mothers and 1.5% of newborns. Maternal/newborn concordance (HPV+/+ or HPV−/−) was 71%. Among HPV DNA+ mothers, only 3% of their infants were DNA+ and only 1 pair had the same HPV type. Among HPV− women, 0.8% of infants were HPV+. HPV DNA detected in hospitalized newborns reflects current infection transmitted to infants during pregnancy or delivery. None of the mother/baby HPV DNA+ concordance pairs detected viral types found in HPV vaccines suggesting that vaccination prior to pregnancy is unlikely to be efficacious in preventing vertical transmission. Human papillomavirus (HPV) is well recognized for causing laryngeal papillomatosis, genital warts, and cancer , 2. HPV Although the predominant mode of viral transmission occurs through sexual contact, HPV also has been found in virginal women prior to first coitus , 2, 4. Sn = 582) were recruited into the study at the University of Iowa Hospitals and Clinics, Department of Obstetrics/Gynecology. The study included only healthy women with normal pregnancies. Mothers were excluded if they were having complicated pregnancies, had a language barrier, were mentally unable to consent, or were not going to deliver at the research hospital site and thus would not be eligible for the aims of the study. All participants signed an approved Human Subjects Consent form. Not all women who were recruited could be included in the final analyses because some women delivered elsewhere or the cord blood was not available at delivery. Among 333 included pregnant women who were included in the study analyses, HPV results were evaluated by obtaining cervical and oral cell specimens and by collecting peripartum serology. Samples from the 333 newborns were obtained from oral and genital areas and from cord blood to test for HPV status. There were 193 male and 140 female newborns in the study. No same sex couples or nonbiologic partners were identified during the study recruitment.Between 1997 and 2000, all pregnant women, ages 18 and over, who were being seen in their third trimester of pregnancy during routine obstetric examinations . The procedures have been described elsewhere –21. The β-globin gene [β-globin gene. Two percent of the DNA  extracted from cell specimens was PCR-amplified with MY09 and MY11 primers [32P-labeled probes for a more sensitive detection of HPV DNA. Those samples positive only after the membrane hybridization underwent hemi-nested PCR-amplification with MY09 and GP5+ primers [Sample preparation, PCR analyses, DNA hybridization, and HPV typing procedures for assessment of exfoliated oral cells were based on a standard protocol described previously , 24. Eacbin gene  to verif primers  to detec primers . The PCR primers . DNA seq primers .Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for HPV seropositivity associated with mother and newborn characteristics adjusting for number of sexual partners and maternal history of an HPV-related disease. Concordance was examined using McNemar's test for matched pairs in 2 by 2 tables utilizing mother and newborn VLP and HPV DNA results. The Kappa statistic was used to measure agreement in HPV positivity status between mother and newborn sera samples. Statistical significance was noted at  .05 and all tests were 2-sided. All analyses were performed using the SAS statistical package .n = 86) and C-section (n = 13) deliveries were also 87% and 13%, respectively. For HPV DNA transmission, only 3 (1%) of the 86 vaginal deliveries were concordant and none of the 13 DNA positive C-sections . For serologic transmission, 35% (30/86) of the vaginal deliveries and 38% (5/13) of the C-sections were concordant. After adjusting for a history of HPV disease, the OR comparing vaginal to C-section deliveries was 1.1 (0.1–23.1) for DNA transmission and 0.9 (0.3–3.0) for serologic transmission. There were no significant associations between seropositivity to anti-HPV VLPs  in mothers and risk of HPV-HR DNA for these same four HPV types (data not shown).Risk factors included in n = 45), only in the cervix. The two most common HPV-HR types in mothers were HPV-16 (33%) and HPV-31 (29%) and these types were more frequent in both cervical and oral mucosa. Less common HPV-HR DNA types included 18, 33, 39, 51, 56, 58, 59, 66, and 70. The overall prevalence of HPV-16, 18, 31, and 33 DNA was 16% in mothers. The overall prevalence of HPV-LR DNA in mothers was 8% and the most common LR types were HPV-53 (19%), HPV-61 (14%), and HPV-83 (14%); other less frequently detected types were HPV-6, 11, 54, 69, 84, and several unnamed types. The table also shows the frequency of HPV-6, 11, 16, 18 types which are found in current HPV vaccines. Maternal and newborn data indicated that only about one-third of their HPV+ DNA infections included these four vaccine types. The prevalence of HPV DNA in newborns was 1.5% (P > .10). Three newborns were detected with HPV DNA in oral samples: 2 HPV-HR types (HPV-16 and 51) and 1 HPV-LR type (HPV-61). Two newborn HPV-LR vulvar samples also were positive for HPV-61 whereas none of the circumcision tissue samples was positive. No multiple infections were found in the HPV DNA of newborns.HPV frequency and types in mothers and newborns are shown in was 1.5%  and therThe seropositivity rate to VLPs 16, 18, 31, and 33 was 32% in mothers and 31% in newborns. The prevalence was similar in mother and infant for each VLP type tested . Among tP-value = .20). Based on DNA transmission, the mean intervals for HPV DNA-negative versus HPV DNA-positive transmission was 63 days and 49 days, respectively . The overall mean interval time (based on both serology and DNA) was not significantly related to the transmission rate. The mean HPV specimen collection interval between enrollment at the third trimester and delivery was 71.4 days. There was no significant association between the interval between the third trimester and delivery specimen collection period and subsequent risk of HPV transmission. Based on serology, the mean intervals between HPV seronegative versus HPV seropositive transmission was 74 days and 60 days, respectively, (adjusted P = .30) and high agreement in HPV seropositivity . Type specific concordance rates were between 96%–97%.Next we examined concordance between maternal and newborn samples for anti-HPV VLPs . There wP < .0001), mostly due to HPV– findings in both groups (n = 3) of their infants were HPV+ compared to 0.8% (n = 2) of infants in HPV– mothers. Although there were three mother/baby pairs that were both HPV+, HPV type-specific concordance occurred in only one case, for HPV-51 in the maternal cervix and oral mucosa of the newborn. The other two HPV+ mother/baby pairs were HPV-39/HPV-61 and HPV-99/HPV-61. The two HPV+ infants with HPV-mothers were detected with HPV-16 and HPV-61. Only one of the five DNA+ newborns had a type contained in current HPV vaccines (HPV-16). Thus the findings were substantially different from those of serology which were essentially those of the mother whereas the DNA findings represented current infection in both mother and infant.The HPV DNA+ concordance rate between mothers and newborns was 71%  maternal/newborn samples [P < .0001). Yet only one of the five HPV+ newborns was detected with an HPV vaccine type (HPV-16). Furthermore, in this study the genitals in newborns were as likely to be infected as the oral mucosa; thus concern that vertical transmission of HPV will primarily affect the oral mucosa  does not attend to the larger concern about transmission to genital mucosa areas. The risk of genital dysplasia and cancer in adolescents and young adults based on vertical transmission may be important, as it is for HPV-related oral papillomatosis.Since a comparison of maternal anti-HPV serologic findings does not provide a valid measure of transmission of infection to infants, the clinical focus is limited to concordance in DNA types from exfoliated cells. This source of HPV detection has the advantage of measuring current infection in the individual unlike serologic markers. Supported by our former , 11 and  samples , 13, verAlthough others suggest that the frequency of vertical transmission is much higher –16, thesn = 1/5) in this analysis, both studies using DNA sequencing to identify a wide variety of types. In contrast, Tseng et al [We are among one of the few to have examined HPV DNA type-specific maternal/newborn concordance in a large patient population –13. Amonng et al , detecteIt was surprising that the most common HPV DNA types that have been reported in the oral mucosa, HPV-16, 18, 31, and 33, and which are among the most frequent identified in the cervix –34 and VAmong the strengths of this study was the ability to evaluate type-specific concordance of DNA and serologic HPV results between mothers and newborns. In comparison with other studies which tested for less than six HPV DNA types, our study sequenced HPV DNA and thus tested for all types. The conclusion remains, however, that DNA concordance and thus vertical transmission is low between mother/newborn oral and genital sites. The large sample size in this study allowed investigating the concordance of HPV positivity in mothers and their newborns. The size also allowed not only an assessment of stable prevalence rates but also examination of maternal risk factors for HPV infection in the newborn as a potential method for identifying infants at high-risk of acquiring this viral infection. Based on the low HPV DNA positive maternal/neonate concordance, this suggests that prophylactic HPV vaccination during family planning prior to pregnancy is unlikely to be efficacious in preventing vertical transmission. More importantly, the findings suggest that because vertical transmission of HPV is low, the suggestion that women be vaccinated prior to pregnancy is unlikely to be efficacious.


The aim of this paper was to provide epidemiological evidence to support the notion that cervical intraepithelial neoplasia (CIN) without human papillomavirus (HPV) is a true entity. If a diagnosis of HPV-negative cervical neoplasia is erroneous, one would not expect there to be any differences in risk factors between HPV-positive and HPV-negative patients. Patients at a gynaecological outpatient clinic of a university hospital  completed a structured questionnaire regarding smoking habits and sexual history. Analysis of an endocervical swab for Chlamydia trachomatis, analysis of a cervical scrape for HPV, and morphological examination of cervical biopsy specimens were also performed. HPV was found in 205 (77.4%) out of the 265 women. Univariate analysis showed that current age (P=0.02), current smoking behaviour (P=0.002) and the number of sexual partners (P=0.02) were significantly associated with the presence of HPV. Age at first sexual intercourse, a past history of venereal disease or genital warts, and current infection with Chlamydia trachomatis were not associated with the presence of HPV. Using multivariate logistic regression analysis, the number of sexual partners and current smoking behaviour showed an independent significant association with HPV. HPV-negative and HPV-positive CIN patients differ with respect to the risk factors for HPV. These findings suggest that HPV-negative CIN is a separate true entity.


To predict the public health impact on cervical disease by introducing human papillomavirus (HPV) vaccination in the United Kingdom, we developed a mathematical model that can be used to reflect the impact of vaccination in different countries with existing screening programmes. Its use is discussed in the context of the United Kingdom. The model was calibrated with published data. The impact of vaccination on cervical cancer and deaths, precancerous lesions and screening outcomes were estimated for a vaccinated cohort of 12-year-old girls, among which it is estimated that there would be a reduction of 66% in the prevalence of high-grade precancerous lesions and a 76% reduction in cervical cancer deaths. Estimates for various other measures of the population effects of vaccination are also presented. We concluded that it is feasible to forecast the potential effects of HPV vaccination in the context of an existing national screening programme. Results suggest a sizable reduction in the incidence of cervical cancer and related deaths. Areas for future research include investigation of the beneficial effects of HPV vaccination on infection transmission and epidemic dynamics, as well as HPV-related neoplasms in other sites. Invasive cervical cancer (ICC) is the second most common cancer in women worldwide, with approximately 470 000 cases and 230 000 deaths annually , and efficacy was maintained over 4.5 years . Finally, there are additional health states corresponding to cervical cancer and noncervical cancer death.The natural history of cervical disease is modelled as a sequence of transitions, between mutually exclusive health states, occurring every 6 months. The transitions occur with probabilities that are age- and HPV type-specific. There are seven HPV categories in the model  and low-risk HPV), where each category is subdivided into health states corresponding to ‘normal’ (un-infected and disease-free), four cervical disease states  and four ICC states (Federation of Gynaecology and Obstetrics (FIGO) Stage 1, Stage 2, Stage 3, Stage 4). The four FIGO stages are subdivided according to whether cancer is diagnosed  of HPV-type distribution in normal cytology, low- and high-grade lesions and ICC for each HPV stratum  , 2005b.CIN prevalence: age-specific prevalence patterns of CIN 1 or less , CIN 2 and CIN 3 lesions  reported in Manchester study  from The following end points were used for calibration:Goodness-of-fit for HPV prevalence, cervical cancer incidence and mortality were measured using an average percentage deviation calculation /observed), weighted by: (1) age-specific disease rates and (2) age-specific number of cases expected. For CIN prevalence, goodness-of-fit was calculated using overall rates.We conducted an analysis to estimate the public health benefits associated with HPV-16/18 vaccination in the setting of cervical cancer screening in the UK, based on the conservative assumption that current screening practice does not change. For vaccinated and unvaccinated females, clinical events  were derived from the model for one birth cohort of girls from age of vaccination until a maximum of 110 years. Rates of screening events  were also estimated. A vaccination coverage rate of 100% was assumed.et al, 2004, To examine the protection afforded by vaccination, a cohort of 376 385 girls vaccinated at age 12 was modelled, representing one annual age cohort in the UK . The folvs 77% assumed for the UK).Alternative assumptions about vaccine efficacy and waning, vaccination coverage rate, vaccination age and HPV type distribution were explored using sensitivity analyses. Vaccine efficacy for HPV types 16 and 18 was varied from 90 to 100%. As cross-protection against types 31 and 45 has as yet only been demonstrated for incident infection, alternative scenarios where cross-protection was absent or waned were analysed. Waning of immunity against types 31 and 45 was assumed to occur in a linear manner to 0% of initial efficacy after 10 years, and was analysed with and without a booster at 10 years after initial vaccination. In the 4.5 years of follow-up in clinical trials, waning of efficacy against HPV types 16 and 18 have not been observed; therefore, it was assumed that waning would either not occur or would be addressed by boosters. The impact of vaccinating older and younger girls was also analysed (10 and 18 years). Also, as 100% vaccination coverage is likely not achievable in practice in the near term, an alternative vaccination coverage rate of 80% was explored, based on the coverage actually achieved in recent vaccination campaigns in adolescents  and 335 cancer deaths (76% reduction). Vaccination was also predicted to give a considerably high reduction in the prevalence of high-grade lesions  across all ages . In partIt was also predicted that vaccination would have benefits in relation to HPV prevalence and low-grade lesions (CIN 1), although to a lesser extent. When considering only oncogenic HPV, the estimated percentage reduction in HPV prevalence was 45% with vaccination . For allAs a consequence of the projected reductions in cervical disease owing to vaccination, clinical benefit is anticipated from a reduction in screening tests and treatments. Predicted numbers of abnormal cytology tests, diagnostic tests and treatments for precancerous lesions, occurring over the lifetime of a cohort of 12-year-old girls, with and without vaccination are shown in We investigated the impact of varying assumptions concerning vaccine efficacy and waning, vaccination coverage and age at vaccination, assuming 100% vaccination coverage. et al, 2004, ®). To facilitate such decisions, a detailed model of the natural history of HPV infection and cervical cancer was developed, capable of evaluating the long-term impact of a type-specific HPV vaccine in different countries with varying cervical cancer epidemiology and screening policies. The present study gives an example of this adaptation to the specific situation in the UK.The imminent global arrival of HPV vaccines with proven efficacy against HPV types 16 and 18 (Calibration achieved a consistently close fit to HPV and CIN prevalence, as well as ICC incidence and mortality for the UK. Further, the model reflects the prevalence of HPV types within different stages of cervical disease, including low- and high-grade lesions, and ICC. Calibrating simultaneously across the spectrum of cervical disease, which is not a new concept (see e.g. Perhaps the most striking model prediction is that 100% vaccination coverage of a 12-year-old cohort of girls would lead to a reduction of 66% in the prevalence of high-grade cervical lesions and a 76% reduction in cervical cancer deaths. These beneficial effects of vaccination are entirely plausible as they reflect the prevalence of HPV 16/18 in high-grade lesions and cervical cancer and the potential additional impact of prevention of HPV 45 and 31 infection . A compaResults also predict that approximately one-quarter of abnormal cytology tests and one-third of diagnostic tests and CIN treatments would be avoided with vaccination. This has important implications for reducing both NHS costs and the distress associated with positive tests (Results were sensitive to an increase in vaccination age, with projected benefits at 18 years reduced compared with 12 years. This is due to the pre-existing level of persistent HPV infection and related disease in the older adolescent and mature population and vaccination is predicted to provide maximum benefit at age 12, before sexual activity is initiated in most girls. Further, the projected benefit of vaccination was lower when assuming an 80% vaccination coverage rate, a rate similar to that observed in adolescent hepatitis B vaccination (There are limitations to our estimates of the beneficial effects of vaccination that should be considered. First, evidence suggests that HPV prevalence rates have increased in the UK since 1990 (In summary, mathematical models provide a means for extrapolating results beyond clinical trials and exploring the long-term impact of vaccination on outcomes. This analysis suggests that the public health benefits of HPV 16/18 vaccination, within the context of an effective screening programme, may be substantial in the UK, with large reductions not only in cervical cancer incidence and mortality, but also in the prevalence of precancerous lesions and associated diagnostic tests and treatments.