Cervical intraepithelial neoplasia (CIN) has a natural history of bidirectional transition between different states. Therefore, conventional statistical models assuming a unidirectional disease progression may oversimplify CIN fate. We applied a continuous-time multistate Markov model to predict this CIN fate by addressing the probability of transitions between multiple states according to the genotypes of high-risk human papillomavirus (HPV). This retrospective cohort comprised 6022 observations in 737 patients . Patients were followed up or treated at the University of Tokyo Hospital between 2008 and 2015. Our model captured the prevalence trend satisfactory, particularly for up to two years. The estimated probabilities for 2-year transition to CIN3 or more were the highest in HPV 16-positive patients  compared with those in the other genotype-positive patients . Approximately 40% of HPV 52- or 58-related CINs remained at CIN1 and CIN2. The Markov model highlights the differences in transition and progression patterns between high-risk HPV-related CINs. HPV genotype-based management may be desirable for patients with cervical lesions. Cervical cancer is the second most commonly diagnosed type of cancer, and the third leading cause of cancer-related death among females in developed countries . In 2012Worldwide, patients with a high-grade squamous intraepithelial lesion (HSIL) undergo surgical interventions , regardless of the HPV genotype ,11. In JAmong the hrHPVs, HPVs 16 and 18 are the most frequently observed genotypes in patients with cervical cancer, and approximately 70% of cervical cancers are HPV 16 or 18 positive ,16. SeveThe Cox proportional hazards model is most frequently used to predict the risk of transition from one state to another. However, the natural history of CIN shows a bidirectional transition between different states, and patients intricately move between a series of states. For example, CIN2 can progress to CIN3 or regress to CIN1 during the follow-up period. A model capable of estimating the risks of transitions from and to multiple states is more suitable for assessing the fate of CIN patients compared with the traditional Cox proportional hazards model, accounting only for the transition between two states. A solution is the use of multistate Markov models that enable investigators to estimate the transitions between multiple states ,24,25. UIn the present study, we retrospectively analyzed a cohort of patients with HPV genotype-confirmed CIN to investigate the relationship between HPV genotypes and clinicopathological features in CIN/cervical cancer. We applied a continuous-time multistate Markov model to independently estimate the prognosis of cervical lesions for designated HPV categories.Among the 1417 patients, 737 patients were enrolled with the following diagnoses at the time of entry: normal, 195 patients; CIN1, 259 patients; and CIN2, 283 patients. The median age was 37.6 years (interquartile range [IQR]: 31.8–44.5 years), the median number of visits was seven (IQR: 4–12), and the median duration of the follow-up was 3.03 years (IQR: 1.21–4.91 years). This study is the first to estimate the parameters of the continuous-time multistate Markov model from one data set to shed light on the prognosis of cervical lesions based on the infected HPV types. The results indicated that the prognosis of hrHPV-infected cervical lesions differs according to the types of HPV and the grades of CIN.The Markov model revealed that the rate of progression to CIN3 from any condition was highest in HPV 16-positive patients, followed by HPV 18-positive patients. These results are consistent with those reported in previous studies. In addition, our Markov model also revealed that HPV 52/58-positive patients tend to remain between CIN1 and CIN2. The Markov model clarifies the characteristics of HPV 52- and HPV 58-related lesions, as it demonstrates the probabilities of transitioning from state to state. Contrary to HPV 16-positive lesions, which highly progress to CIN3/cancer, HPV 52- and 58-related lesions were characterized by their stability between CIN1 and CIN2. In this study, we estimated the 2-year prognosis of patients with CIN using two types of models. The main model reflects transitions based upon objective results, and it is not always in line with clinical practice, because some patients with CIN2 undergo treatment without a final diagnosis of CIN3. On the other hand, the alternative model well reflects the trajectory of clinical practice. However, treatment is occasionally affected by the physicians’ decision and patients’ choice; therefore, the alternative model may lack objectivity. Admitting that our models both have advantages and disadvantages, we consider the results for the 2-year prognosis of CIN patients to be reasonably robust, as both models essentially yielded identical results.The continuous-time multistate Markov model is more capable of reflecting the features of HPV-infected cervical lesions than the frequently used Cox proportional hazards model. Most of the previous studies have focused on the risk of progression to CIN3 or cervical cancer according to the types of HPV or grades of CIN, implicitly assuming a unidirectional disease progression. Considering the bidirectional nature of CIN, the Markov model has the potential to more accurately estimate the fates of HPV-infected cervical lesions than the standard Cox proportional hazards model. Indeed, the Markov model and the Cox model led to quite different predicted 2-year transition probabilities from CIN1 to CIN2 or more severe lesions. Notably, we could not detect higher disease progression risk in HPV 16-positive patients than in HPV 52/58-positive patients in the Cox model. The Markov model can estimate the transition between multiple states besides the probability of the customarily used endpoint, e.g., CIN3 and cervical cancer. The use of this model highlighted the difference between the natural history of cervical lesions infected with the focused four HPV types. We conclude that the model may improve our understanding of the natural history of cervical lesions and aid in the management of hrHPV-related lesions.The Markov model was suitable for HPV-infected cervical lesions because the virus–host interaction (virus vs. host immune system) leads to bidirectional transitions between states. Activated host immune responses contribute to CIN regression, whereas immunosuppressive conditions promote CIN progression ,37,38. LIn this study, we could not fully estimate the transitions of HPV 18-positive patients with the present Markov model due to the limited sample size. HPV 18 is the second most frequently observed HPV genotype in patients with cervical cancer, whereas it is not frequently detected in those with precancer lesions . In addiThis study has several limitations. First, we performed the HPV genotyping test once for each patient. Therefore, the change to negative for the HPV test (latent infection or clearance) was not taken into account. Previous reports demonstrate that patients with HPV clearance tend to regress compared with those with persistent HPV infection ,41. PatiSecond, in this study, we did not evaluate the effect of concurrent multiple HPV infections. In previous reports, coinfections with multiple α9 species were associated with an increased risk of CIN2 or more severe lesions compared with single infections ,43. BecaThird, the evaluation of model fitness uncovered that the simulated prevalence of the normal state (CIN3/cancer) was overstated (understated) compared with the observed prevalence. These discrepancies imply a violation of the Markov property, i.e., the distribution of the next states depends only upon the present state. Misclassification and omitted covariates, such as age, can be a potential source of the violation. The application of a hidden Markov model that can incorporate the possibility of misclassification through the information from the previous or more distant visits may be an intriguing direction for further research. Fourth, we have not assessed the validity of our model with the use of a test set separate from the training set, which is the dataset used for parameter estimation. Instead, we prioritized improving the parameter estimation accuracy by using all data for parameter estimation. This is currently a common practice in the literature ,32,33,34Lastly, this study was based on data obtained from a single institute with some censoring. Especially, there is a selection bias; for example, patients enrolled in this study previously had abnormal cytology. In addition, some patients with relatively severe CIN2 were censored because of the treatment according to the physician’s decision. However, by conducting the sensitivity analysis, we confirmed that the impact on the results was limited. Nevertheless, as we have not assessed the external validity of our model in the general population, care must be taken when extrapolating the present results to the entire population, unless similar results are yielded from other institutes.This study was performed in accordance with the Declaration of Helsinki. Approval was obtained from the internal institutional review board  for this study.This study was a retrospective cohort analysis of data extracted from the electronic health records of a teaching hospital in Japan. Since 2008, human papillomavirus (HPV) genotyping has been performed in the University of Tokyo Hospital  for outpatients. The patients who had abnormal cytology in the population-based screening, or whose abnormal cytology was found in the outpatient visits at the Obstetrics and Gynecology Department of the University of Tokyo Hospital or other hospitals, were enrolled. At the first visit, we confirmed the diagnosis by performing punch biopsy under colposcopic examination . As follow-up screening, we routinely performed combination examinations of cytology and colposcopy because these examinations are non-invasive. We performed histological diagnosis only when the disease progressed. We reviewed the electronic health records of 1417 patients for whom genotyping was performed between October 1, 2008, and March 31, 2015, to construct a retrospective cohort. Patients were included in the study if they were (i) diagnosed with normal cervical lesion, CIN1, or CIN2 and (ii) observed for at least two visits during the study period. Patients were excluded if they had HPV 6- or HPV 11-single-positive lesions with only the diagnosis of condyloma during their follow-up period, or had only glandular lesions. Patients were followed up until they were diagnosed with cervical cancer, underwent treatment, transferred to another hospital, or until the date March 31, 2018, whichever came first. In our practical management, most patients with CIN2 were followed up without any treatment. Patients diagnosed with CIN3 underwent surgical intervention, such as conization and loop electrosurgical excision or laser vaporization.The date of birth was extracted for each patient. Patient age was defined as their age at the time of entry. Follow-up interval was defined as the length of time between two consecutive visits.Patient cytological and histological results and the date were recorded for each visit. Cytological and histological results were combined to classify the results into any of the following four diagnoses: normal, CIN1, CIN2, and CIN3/cancer. The investigators (experts in gynecologic oncology) convened and determined the criteria for pathological diagnosis as follows: (1) CIN1–2 was classified into CIN2; (2) CIN2–3 and carcinoma in situ were classified into CIN3; (3) uncertain diagnoses  were excluded from the study due to concerns regarding diagnostic reliability; and (4) in the presence of histological and cytological examinations, the most severe classification was adopted as the final diagnosis.The results of the HPV genotyping in cervical samples collected using swabs were recorded. Genotyping was performed once for each patient; thus, the HPV type assigned to a patient did not change over time. It was permitted to assign multiple genotypes to a single patient. On the basis of the classification of the International Agency for Research on Cancer, we defined HPVs classified in Group 1 or Group 2A  as “high-risk HPVs (hrHPVs)”. Of these, HPVs 16, 18, 52, and 58 were separately categorized. hrHPVs other than HPVs 16, 18, 52, and 58 were classified as “other hrHPVs.” Patients who were not infected with any hrHPVs were referred to as “no hrHPVs” patients. Patients without HPV infection were also categorized in this group.Cervical samples were tested for HPV DNA using PGMY line-blot hybridization, as previously described . DNA wasWe used the continuous-time multistate Markov model to estimate the prognosis of each patient with HPV-infected cervical lesions ,24,25. Wij is interpreted as an “instantaneous risk” of transition from state i to j [Each transition parameter λ in e i to j . IdentifInitially, an unbalanced panel data with the unit of observation being one visit was constructed on the basis of the chart review. We truncated observations after the diagnosis of CIN3 or cancer to make the data used in the estimation compatible with the model in Summary statistics are reported for the combination of defined HPV categories  and diagnoses at the time of entry . In cases of observed coinfection with different HPV genotypes, it was possible to include the same patient in the summary statistics of multiple HPV categories.msm package in R [A maximum likelihood estimation was performed to estimate the parameters using the age in R . Intuitiage in R . The CoxAdditionally, we simulated the change in the prevalence of each state over the five years for the HPV categories. To make it easier to compare the observed and the simulated prevalence, the initial prevalence of each state was set to be the same as the data used for parameter estimation. The fit of the model was assessed on the basis of the comparison of the observed and the simulated prevalence.Some patients with CIN2 underwent treatment without a final diagnosis of CIN3. Some patients with CIN3 were observed without any treatment if the lesion immediately regressed to CIN2 or a lower state. Therefore, we specified an alternative model that encompasses these situations with the following four states: normal (state 1), CIN1 (state 2), CIN2/CIN3 (state 3), and treatment (state 4) . The arrIn this study, we applied a continuous-time multistate Markov model to predict the prognosis of patients with HPV-infected cervical lesions. We demonstrated that the Markov model is a promising analytical method considering the bidirectional nature of these lesions. The study revealed that the natural history of hrHPV-related cervical lesions differed among the focused four HPV types: HPV 16-positive lesions were likely to be upgraded to CIN states in a step-by-step manner; HPV 52/58-positive lesions were likely to be maintained between CIN1 and CIN2; lesions positive for the other hrHPVs were most likely to regress to the normal state and least likely to progress to CIN3/cancer. On the basis of the present findings, HPV genotype-based management may be desirable for patients with cervical lesions.


Since March 2014, the quadrivalent HPV vaccine has been incorporated into the Brazilian Unified Health Care System and began to be offered, without direct costs, for girls from 9 to 13 years of age. Older female adolescents would have the option to be vaccinated at private health care system being responsible for the payment of HPV vaccine. The present study aimed to evaluate the coverage rates and predictors of HPV vaccination in Brazil among two groups of female adolescents: eligible and non-eligible for the HPV vaccination public program.We used data from the 2015 Brazilian National Adolescent School-Based Health Survey, which involved a probabilistic sample of 5404 female adolescents students at public and private schools. Using a questionnaire, we gathered information on sociodemographic characteristics, sexual behavior, and respondent perception of parental supervision and have been vaccinated for HPV. Age-specific vaccination rates were analyzed in girls aged 9 to 13 at the time of public vaccination (eligible for public policy), as well among those 14 to 17 years old not eligible by the Ministry of Health for vaccination. We used Poisson regression models to investigate associated factors.HPV vaccine coverage was 83.5 and 21.8% among eligible and non-eligible populations, respectively. In both populations, the chance of being vaccinated decreased with older age. In the eligible population there is a greater chance of being vaccinated among ethnic group “pardas” but not with other indicators of socioeconomic status. In the non-eligible population, there was a clear association between higher vaccine coverage and greater maternal education and living with the mother.Our findings highlight the importance of public policies to minimize inequities in access to cancer prevention measures in vulnerable adolescents. A public policy of HPV vaccination for older female adolescents would increase coverage with possible reduction of HPV-related diseases in this group of women. Excluding non-melanoma skin cancer, cervical cancer is the one of the most common tumors in females in Brazil, second only to breast cancer, and is the fourth leading cause of cancer-related death among women in the country . The NatVaccination against HPV is an effective primary prevention strategy to reduce HPV infection , 5. SincVaccination coverage varies widely among countries, being higher in high-income countries. A systematic review of studies conducted between 2006 and 2014, including data from 64 countries, showed that the proportion of females between 10 and 20 years of age who received a complete course (three doses) of the HPV vaccine was higher in high-income countries than in middle- and low-income countries (33.6% vs. 2.7%) .Various factors have been associated with non-vaccination, including national priorities and fundings, access to healthcare, socioeconomic factors, as well as the attitudes of and knowledge on the part of health care professionals and relatives or caregivers –13. In aIn the United States, studies on the association between HPV vaccination and family income and between HPV vaccination and the type of health care have produced controversial results. One such study showed that adolescents from lower-income families without health insurance are more likely to initiate the HPV vaccination process . HoweverStudying HPV vaccination coverage reached in various contexts is critical to assessing the benefits of different vaccination strategies and identifying possible disparities in access. The present study aimed to analyze HPV vaccination coverage in populations of adolescent girls to whom the vaccine was available via the Unified Health Care System, without direct costs (eligible), and those who were older and not eligible for the Brazilian HPV vaccination program. In both scenarios, we also evaluated the predictors of vaccination.The present study used data from the third edition of the Brazilian National Adolescent School-Based Health Survey—PeNSE 2015—conducted by the Brazilian Institute of Geography and Statistics, in partnership with the National Ministry of Health and Education  between N = 8269) were used in the present study.In this survey, a secondary data analysis, we employed a complex clustered sampling procedure, first selecting schools (primary sampling units) in each of the major regions and then selecting classes (secondary sampling units) in those schools. All of the students in those classes were invited to participate in the survey. The sampling weights for schools and students were adjusted on the basis of the 2015 school census, which contained up-to-date registry information. The response rate was 85.3%. The final sample included 16,608 students in 653 classes at 371 schools. Only data from girls (N = 8269), we selected a representative sample of those who were 13–17 years of age (n = 5404). Detailed information about the sampling strategy can be found in the report published by the Brazilian Institute of Geography and Statistics [From among all of the girls  for HPV vaccination were used in order to stratify the adolescents by the type of access to vaccination (eligible and non-eligible). Therefore, girls 9–13 years of age at the time of vaccination, who were the target population of the NMH, were considered eligible population, whereas females between 13 and 17 years of age at the time of vaccination were considered the non-eligible for the public vaccination. To calculate the age of the girls at the time of the vaccination, we took into consideration the months (March and September 2014 and 2015) that the NMH campaigns for to promote public vaccination and the day of the interview, together with the month and year of birth.The outcome measure was having received the vaccine against HPV, evaluated by means of the question “Have you been vaccinated against HPV?”On the basis of the PeNSE 2015 questionnaire data, the following sociodemographic factors were assessed: age of the respondent (13 to 17 years of age); ethnic group ; maternal level of education ; type of school (public or private); and consumer goods and services score for the family . The consumer goods and services score was based on whether the family had an automobile, a home telephone, a cell phone, a computer, or internet access, as well as whether there was a bathroom in the home and whether the family had a maid in five or more days per week. Each of those items were given a weight that was the inverse of the frequency of their possession or presence in the sample as a whole. The score for each adolescent was obtained by summing the weights of the respective items. We divided the distribution of the score into thirds, considering the effect of complex sampling . The sexMultiple imputation by chained equations was used in order to assign numerical values to the maternal level of education, for which 20% of the data were missing. The imputed data exhibited satisfactory statistical reproducibility according to error analysis by Monte Carlo simulation .We evaluated the following aspects of parental care among the respondents: living with parents  and perception about parental involvement .P < .05 were considered statistically significant. The models used in the analysis of the linear trend included the following as continuous variables: the maternal level of education; the consumer goods and services score of the family; and the number of sexual partners of the respondent. In all analyses, we took into consideration the sampling design, with the aid of the Stata statistical software package, version 15.1 .The HPV vaccination coverage, expressed as a proportion and its 95% CI, was estimated on the basis of the total number of respondents, by the variables studied and according to the type of access to vaccination (eligible population and non-eligible population). To estimate the association between HPV vaccination coverage and each of the selected variables, the prevalence ratios (PRs) and respective 95% CIs were calculated. Unadjusted and adjusted Poisson regression models, stratified by the type of access to HPV vaccination, were used in order to assess the associations between HPV vaccination coverage and each of the selected variables adjusted for the other independent variables. Poisson regression was used in order to prevent odds ratio overestimating risk considering the high rate of the outcome. In the bivariate Poisson regression models of the associations between the dependent variable (HPV vaccination coverage) and the independent variables, all covariates were included. In the multivariate analysis, values of The PeNSE was approved by the NMH National Committee for Ethics in Research (Protocol no. 1006467). Student participation was voluntary. All participants gave informed consent through a self-administered questionnaire. The questionnaire could be answered in whole or in part. All information was confidential and anonymous.The study included 5404 adolescent females between 13 and 17 years of age. In the sample as a whole, the proportions of respondents eligible and non-eligible for the public vaccination were 44.0 and 56.0%, respectively. In the eligible and non-eligible populations, public school students predominated , as did non-White students . In the eligible population, 47.7 and 33.9% of the respondents described their ethnic group as “parda” and White, respectively; 13.6% had had sexual intercourse at least once; 54.9% lived with both parents; and 65.8% reported having parents that were almost always/always aware of where their children were. In the non-eligible population, 46.2 and 36.8% of the respondents described their ethnic group as “parda” and White, respectively; 44.9% had had sexual intercourse at least once; 22.0% had had ≥2 sexual partners; and 27.0% had not used condoms in their most recent sexual encounter , who had first sexual intercourse after 15 years of age (73.6%) and among those who were 15 years old at the time of the vaccination campaign (74.0%). In contrast, vaccination rates among non-eligible population ranged from 32.4%, for the respondents whose mother had college degree to 11.5%, for those who lived with their father only . Among the interviewed girls, who were not eligible for the HPV vaccination public program, vaccine coverage reduced to 21.8% and was associated with parental care of the mother and higher schooling. In this group, girls were more likely to be vaccinated if they lived with their mothers and if their mothers had a higher level of schooling. These findings emphasize that, in the absence of universal public policies, adolescents living only with the father and inserted in a context of greater social vulnerability will have reduced access to vaccination and will be more subject to health problems, such as cervical cancer.In the eligible and non-eligible populations, our results showed a clear association between higher vaccination rates and younger age. One possible explanation for that is that the benefit of vaccination has become more evident in recent years in the light of scientific evidence and media campaigns. Therefore, younger generations are more likely to be vaccinated.Another important aspect common to both of the populations studied is the lack of association between HPV vaccination and indicators of perception of parental care. The chance of being vaccinated against HPV was not significantly different according to the perception of the respondents about parental concern and attention. Despite the large number of studies emphasizing the importance of parental attitudes and beliefs regarding HPV immunization, we identified no studies specifically addressing the perceptions that adolescents have of parental care.Nevertheless, our results show that mothers have a significant influence on the rates of vaccination among girls not covered by the public program. In this group, girls living only with their father were less likely to be vaccinated than were those living with both parents or those living only with the mother. These data suggest that mothers are more concerned than are fathers or have more influence on HPV vaccination of their daughters. That type of concern is enhanced by a higher maternal level of education. Having a more well-educated mother increases the chance that a daughter will be vaccinated. Mother’s higher education could also be associated with knowledge (and then concern) about HPV and ability to pay for the vaccine. To our knowledge, there are no other studies comparing mothers and fathers in terms of the role they play in HPV vaccination.Our data on vaccination coverage are quite encouraging, given that national and international studies have suggested that vaccination coverage above 70% is more cost-effective , 28, 29.However, the HPV vaccination coverage for young females who were not included in HPV vaccination public program is much less encouraging. Because they were not included in the national vaccination campaigns, only 21.8% of those girls were vaccinated against HPV, seeking vaccination spontaneously or being vaccinated because they were influenced by their parents and schools. It should be borne in mind that the Brazilian Unified Health Care System does not provide vaccination for individuals who are outside the recommended age ranges. Such individuals must seek vaccination at private clinics. Since their inception, campaigns promoting vaccination against HPV have been carried out in various media and at health care clinics, focusing on the general population and, specifically, girls 9–13 years of age, although also touting the benefits of immunization against HPV in older females, not only for the prevention of various types of cancer  but also for the prevention of genital warts.From a collective point of view, the HPV vaccination strategy, focusing only on girls between 9 and 13 years of age, accentuates a pattern of inequality in older females who do not receive adequate protection against HPV. It is of note that the new NMH guidelines, issued in 2017, are aimed at partially correcting this distortion, expanding the program to include 14-year-old girls who have not yet been vaccinated or who did not complete the three-dose cycle, as well as boys 12–13 years of age.In the non-eligible population, the only socioeconomic indicator found to be associated with higher HPV vaccination coverage was the maternal level of education. That suggests that a higher level of education enhances the care provided by the mother. One previous study showed that the daughters of women with a lower level of education are less likely to be vaccinated , which cIn the United States, the cost of vaccination is considered as an important barrier to the initiation and completion of the vaccination cycle , 36, 37 The results of the present study show that among young females with access to the HPV vaccine via a public health care system there was no association between vaccine rate and number of sexual partners. In the literature, there are divergent data on the relationship between vaccination and sexual behavior, reflecting differences across studies in terms of the characteristics of the samples, such as age, social status, and cultural norms, as well as different outcome measures for sexual behaviors and methodological differences. Some studies have suggested that young females who have been vaccinated against HPV have fewer sexual partners , 40 wherAmong the strengths of the present study are the fact that it involved a broad population-based sample, obtained through a probabilistic sampling process, and the unprecedented social, behavioral, and parental/school monitoring/care aspects. Another strength is the analysis of data from two different female populations, eligible and non-eligible.One limitation to be considered in the present study is that the HPV vaccination coverage was evaluated through a direct questionnaire, although it is common practice in studies of this type. That might have increased the risk of non-differential misclassification in the analysis of vaccination coverage rates, because young people could forget or be confused about which vaccine they have previously taken. However, 95.6% of the young women in our sample showed a high degree of knowledge about the HPV vaccine, as assessed with a specific question on the questionnaire (results not shown). In addition, the response rate was, in general, quite high (95%). However, for the maternal education variable, the non-response rate was 24% and the data were imputed. That increased the reliability and power of the analysis . AlthougThe present study presents an overview of HPV vaccination coverage in Brazil, providing elements to better understand the scope and possible limitations of universal public and non-universal access vaccination strategies. Monitoring the outcomes and coverage of the HPV immunization program, together with management of technology transfer and the development of electronic vaccination records, are key elements in the long-term success of the public policy . Public


Background: Kidney transplant (KT) recipients have higher incidence of malignancies, including Human Papillomavirus (HPV)-associated cancers. Thus, HPV vaccines may have an important role in preventing HPV-related disease in this population; however, immunogenicity and safety data are lacking.Objective: To examine the immunological response and tolerability to HPV vaccination in pediatric KT recipients compared to future KT candidates.Methods: The quadrivalent HPV vaccine was administered to girls and boys age 9–18 recruited from seven centers part of the Pediatric Nephrology Research Consortium. Subjects were recruited for three groups: (1) CKD: chronic kidney disease stages 3, 4, and 5 not on dialysis; (2) Dialysis; (3) KT recipients. The outcome consisted of antibody concentrations against HPV 6, 11, 16, and 18. Geometric mean titers (GMTs) and seroconversion rates were compared. Vaccine tolerability was assessed.Results: Sixty-five participants were recruited: 18 in the CKD, 18 in the dialysis, and 29 into the KT groups. KT patients had significantly lower GMTs after vaccination for all serotypes. The percentages of subjects who reached seroconversion were overall lower for the KT group, reaching statistical significance for HPV 6, 11, and 18. Comparing immunosuppressed subjects  with the non-immunosuppressed participants, the former had significantly lower GMTs for all the HPV serotypes and lower seroconversion rates for HPV 6, 11, and 18. KT females had higher GMTs and seroconversion rates for certain serotypes. There were no adverse events in either group.Conclusions: HPV vaccine was well-tolerated in this population. Pediatric KT recipients had in general lower GMTs and seroconversion rates compared to their peers with CKD or on dialysis. Immunosuppression played a role in the lack of seroconversion. Our results emphasize the importance of advocating for HPV vaccination prior to KT and acknowledge its safety post transplantation. Future studies are needed to investigate the effect of a supplemental dose of HPV vaccine in KT recipients who do not seroconvert and to evaluate the long-term persistence of antibodies post-KT. Solid organ transplant (SOT) recipients are at increased risk for malignancies in both pediatric and adult populations –3, with The efficacy and safety of the HPV vaccine in certain immunocompromised populations, such as pediatric chronic kidney disease (CKD), dialysis and KT recipients, has not been well-studied. This is a population at increased risk for infections and HPV related sequelae; in addition, they appear to also be at high risk for not getting vaccinated due to lack of data and less immediate concerns about sexual activity when ill and awaiting transplant, as has been shown in other patients with severe chronic illnesses , 26. TheMales and females ages 9–18 years were recruited from seven collaborating large medical centers in the Pediatric Nephrology Research Consortium: Riley Hospital for Children in Indianapolis, IN, Primary Children's Hospital in Salt Lake City, UT, Medical University of South Carolina Children's Hospital in Charleston, SC, University of Minnesota Masonic Children's Hospital in Minneapolis, MN, Kentucky Children's Hospital in Lexington, KY, C.S. Mott Children's Hospital in Ann Arbor, MI and Nationwide Children's Hospital in Columbus, OH. Subjects were recruited in three cohorts:2], 4 (GFR 15–29 mL/min per 1.73 m2) or 5 not on dialysis .– Group 1 (CKD) included patients with CKD stages 3 . For all AEs, subjects were instructed by the VRC to estimate the severity of AEs as mild (awareness of symptom but easily tolerated), moderate , or severe . Serious AEs were collected for the whole duration of the study regardless of causality and were followed for outcome. In addition, for KT recipients, data was specifically collected on any biopsy-proven acute rejection episodes after T1 up to 6 months after the last dose of the vaccine administration.p-0.0167 to control for inflated type I error rates. Similar analyses, for demographics and the two outcome variables, were also performed comparing those who were on immunosuppression medications vs. those who were not, with similar analyses, using Student's t-tests, Wilcoxon rank-sum tests, and Fisher's Exact tests. All analyses were performed using SAS v9.4  and all analytic assumptions were verified. Non-inferiority analyses were also performed, but all were non-significant due to the extremely low power due to our small sample size (results not presented).Basic demographic and clinical characteristics are presented as means [standard deviations (SD)] for age, median [interquartile range (IQR)] for eGFR due to non-linearity, and frequencies (percentages) for categorical variables , with analyses comparing groups performed with ANOVA, Kruskal–Wallis, and Chi–Square tests, respectively. The two main outcomes of serotiter and seroconversion were assessed to determine if there were significant differences between groups at T2. Serotiter values were analyzed using Kruskal–Wallis non-parametric tests and seroconversion proportions using Fisher's Exact tests, with descriptive statistics being given as medians (IQRs) and frequencies (percentages), respectively. Pairwise comparisons were made for serotiter levels using a Bonferroni adjusted N = 34, 54.8%). The majority of participants were white  or black . n = 29) the median (range) time since first transplant was 3.9 years , about half (51.9%) had received a kidney from a living donor, one individual had had two transplants; two KT recipients reported events of rejection during the study enrollment.A total of 72 subjects were enrolled: 28 from Riley Hospital for Children in Indianapolis; 15 from Primary Children's Hospital in Salt Lake City; 9 from University of Minnesota Masonic Children's Hospital in Minneapolis; 9 from Medical University of South Carolina Children's Hospital in Charleston; 5 from Kentucky Children's Hospital in Lexington; 5 from C.S. Mott Children's Hospital in Ann Arbor; 1 from Nationwide Children's Hospital in Columbus. A total of 65 participants completed the study: 18 participants in the CKD group, 18 participants in the dialysis group and 29 participants in the KT group . The average age of enrollment was 13.6 years (SD 2.6) and little over one half were males  and with higher seroconversion rates for HPV 18 only . Although statistically significant, this is difficult to interpret clinically with the inconsistencies among the various HPV types and small numbers for multiple analyses.All variables found to be different among the three treatment groups were examined directly with the two outcome variables, GMTs at T2 and seroconversion. Age, sex, race, and eGFR were found to have no association with GMTs at T2 or actual seroconversion. However, when only the KT population was examined, being a female KT-recipient was associated with greater GMTs at T2 for HPV 6 and 11 only  vs. not, the immunosuppression medication-using group had significantly lower serotiters for all four HPV serotypes at T2 and lower seroconversion rates for HPV 6, 11, and 18 . The immWithin the transplant population, neither the donor type, neither time since transplant, nor the number of transplants, made any difference in terms of GMTs at T2 or seroconversion rates.As for the AEs, they were minimal, limited to only mild local reactions. Two patients underwent acute rejection episodes within 6 months following the last dose of the vaccine. However, upon review of chart data, these events were considered to be likely related to medication non-adherence.American Society of Transplantation recommends that HPV vaccine be given to all SOT candidates and recipients in the recommended age-group . HoweverIt is important for the HPV vaccine to be given before HPV infection is acquired, meaning before the onset of sexual activity . This isOur study showed for the first time both in boys and girls that overall, transplant patients had a decreased response to the HPV vaccine compared to CKD and dialysis patients, likely related to their state of medication-induced immunosuppression. However, specifically for HPV 16, seroconversion rates were not found to be significantly lower for KT patients and neither were they found to be lower for patients taking immunosuppression medications. Although power may have biased this result, it is also somewhat reassuring since the majority of HPV cancers are associated with type 16. At the very least, the data supports ongoing vaccination in this group due to the fact that the majority of individuals did effectively respond to the vaccine. Review of literature revealed that the first studies to look into HPV vaccine responses in immunosuppressed populations was in HIV-positive cohorts, which showed promising results, as 95–100% of the subjects demonstrated seroconversion –38. ThusIn this study, it is likely that the entire population was affected by varying levels of immunosuppression, regardless of the study group. Indeed, patients with CKD and more so the ones on dialysis have been shown to have various degrees of immunosuppression, whether caused by defects in neutrophil function, antigen processing, cell-mediated immunity, or antibody-mediated immunity , 43. AntIt is possible that girls and boys who are KT recipients respond differently to the HPV vaccine. The quadrivalent HPV vaccine was approved in the US in 2006 for use in girls/women only. Subsequently, in 2009, the indication was extended to boys/men as well. The few studies that compared the seroconversion rates to HPV vaccine between males and females in the general population have not shown any differences , 48. OurAEs reported were similar to those noted in prior studies, limited to minor vaccine local skin reactions. Two patients underwent acute rejection episodes within 6 months following dose 3 of the HPV vaccine. In 2014, a study initiated HPV vaccination in 14 pediatric KT recipients; unfortunately six of them developed acute rejection shortly after the initiation of the vaccine series, which lead to an early termination of the study . In contWe acknowledge that our study has certain limitations. Like in many pediatric SOT studies, our study was limited by its small sample size. Unfortunately three subjects were missing information on medication use in the data collection form and some were not complete, thus impairing our ability to analyze the effect of specific immunosuppresion medications. Indeed, for specific vaccinations, for example influenza vaccination in KT recipients, it has been demonstrated that different imunosuppression regimens can influence the immune response . In addiIn conclusion, this study addresses the immune response to the HPV vaccine in pediatric KT recipients, CKD and dialysis patients, as well as its safety. The HPV vaccine was well-tolerated in these populations. Pediatric KT recipients had in general lower GMTs and seroconversion rates compared to their peers in the CKD and dialysis groups. In addition, immunosuppression (either due to the need to address immune-mediated diseases of the native kidneys or to prevent rejection in KT) played a role in the lack of seroconversion. Our results emphasize the importance of advocating for HPV vaccination prior to KT and acknowledge its safety post transplantation. However, questions still remain. Specifically, studies to identify factors associated with the lack of seroconversion in KT recipients are needed for targeted interventions. In addition, future studies should investigate the effect of a supplemental dose of HPV vaccine in KT recipients who do not seroconvert. It would also be important to evaluate the long-term persistence of antibodies post-KT and the possible need for re-immunization post-KT.All datasets generated for this study are included in the article/supplementary material.The studies involving human participants were reviewed and approved by Indiana University Office of Research Administration Institutional Board Review. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.CN generated the hypothesis, obtained funding, designed the study, recruited subjects at her institution, interpreted data, and wrote the manuscript. RN, PV, KT, AC, MM, and JM had solutions for improving design, recruited subjects at their respective institutions, and corrected the manuscript. JS analyzed and presented data, while also helping CN and MS write the statistics paragraph and interpret data. MS mentored and helped CN in all of the above endeavors.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Evidence suggested that vaginal microbiome played a functional role in the progression of cervical lesions in female infected by HPV. This study aimed at evaluating the influence of common vaginal infection on the carcinogenicity of high risk HPV (hr-HPV).From January 15, 2017 to December 31, 2017, 310,545 female aged at least 30 years old had been recruited for cervical cancer screening from 9 clinical research centers in Central China. All the recruited participants received hr-HPV genotyping for cervical cancer screening and vaginal microenvironment test by a high vaginal swab. Colposcopy-directed biopsy was recommended for female who were infected with HPV 16 and HPV 18, and other positive hr-HPV types through test had undertaken triage using liquid-based cytology, cases with the results ≥ ASCUS among them were referred to colposcopy directly, and cervical tissues were taken for pathology examination to make clear the presence or absence of other cervical lesions.Candida albicans and Gardnerella were not associated with the detection of cervical lesions. Positive trichomonas vaginitis (TV) was correlated with hr-HPV infection (p < 0.0001). Co-infection with TV increased the risk of CIN 1 among female infected with hr-HPV . Co-infection with TV increased the risk of CIN 2–3 among female infected with HPV 16 .Among 310,545 female, 6067 (1.95%) were tested with positive HPV 16 and HPV 18, 18,297 (5.89%) were tested with other positive hr-HPV genotypes, cervical intraepithelial neoplasia (CIN) 1, CIN 2, CIN 3 and invasive cervical cancer (ICC) were detected in 861 cases, 377 cases, 423 cases, and 77 cases, respectively. Co-infection of TV and HPV 16 is a significant factor for the detection of cervical lesions. Cervical cancer is a common malignant tumor of the female reproductive system, and it progresses rapidly with a high mortality rate . HPV is Under normal conditions, vaginal flora is composed of more than 20 kinds of microbes . InfectiCentral China is one of the regions with the highest incidence of cervical cancer , and theThis project had been conducted in Central China from January 15, 2017 to December 31, 2017. Female aged at least 30 years old were recruited to undergo cervical cancer screening from 9 clinical research centers  in Central China via media promotion and government notices. Female who received hysterectomy, were pregnant, without sexual history had been excluded. All the female had not been vaccinated against cervical cancer yet. All the participants received questionnaires, hr-HPV genotyping, and vaginal microbiota examination. The screening process was based on the interim clinical guidance of ASCCP in 2015 , female All the recruited participants were interviewed by a trained interviewer and filled out a questionnaire  assay was used for typing HPV DNA. The COBAS 4800 HPV test detected a total of 14 h-HPV types simultaneously: HPV-16 individually, HPV-18 individually, and pooled hr-HPV genotypes other than HPV 16 and 18 , in addition to a separate high b-globin control.Candida albicans, TV, Gardnerella, clue cells, and miscellaneous bacteria  density [Candida albicans. Candida was diagnosed using the KOH method (10% KOH), and vaginal trichomonas was examined according to conventional methods, the swimming trichomonas was observed under the microscope (× 400). Gardnerella, clue cells, and miscellaneous bacteria density (MBD) were observed by Gram staining. The scoring method of miscellaneous bacteria density was listed as follows, and no miscellaneous bacteria was scored as I, 1–5 miscellaneous bacteria/OML as II, 6–30 miscellaneous bacteria/OML as III, >30 miscellaneous bacteria/OML as IV [The high vaginal swab was processed for microscopic evaluation of vaginal microenvironment, including the presence of  density . A vaginML as IV .According to the manufacturer’s instructions, slides for liquid-based cytology were prepared. Bethesda System 2001 terminology was used for reporting the results [Female with positive HPV 16 and HPV 18 through the test or with other hr-HPV types through the test and the result of liquid-based cytology ≥ ASCUS underwent further cervical biopsy and/or endocervical curettage (ECC) by a local trained gynecologist in each hospital. The cervical tissues underwent the preparation of histological sections. Two pathologists made the diagnosis separately. The histological diagnoses of cervical lesions were divided into normal, CIN1, CIN2, CIN3 and ICC according to the WHO criteria for the pathological staging of cervical lesions , 22. CINCandida albicans, Gardnerella and TV) or not. Odds ratios and 95% confidence intervals (CIs) were calculated to study the specific risk among different HPV types. Next, social-demographic and reproductive characteristics were taken into consideration so as to improve the accuracy of the results. These characteristics of the participants were presented as proportions. Correlations between specific vaginal infection and hr-HPV genotype and CIN/ICC were assessed using stepwise logistic regression after adjusting for all potential risk factors. ORs and 95% CIs were calculated to analyze the correlation between possible risk factors and pathogenic infection. Data was analyzed with SPSS Software Version 20.0.Histological results  were distributed among respective hr-HPV types and then evaluated. Univariate analysis was used for comparing whether the risk of any cervical lesions  differed when female having a vaginal infection  female were infected with hr-HPV. Candida albicans were detected.In 13,763 (4.43%) female, Gardnerella were detected in 1050 (0.34%) female, and TV were tested positive in 5683 (1.83%) female, respectively.Three hundred seven thousand seventy-one female received complete screening process finally  6067(1.95%) female were tested positive for HPV 16 and HPV 18, including HPV 16 only, HPV 16+ other high risk (OHR), HPV 18 only, HPV 18+ OHR, HPV 16 + 18, and HPV 16+ 18+ OHR types. 4736 (1.53%) among them, received colposcopy, CIN1, CIN2, CIN3, ICC were detected in 480 (0.15%) cases, 265 (0.086%) cases, 346 (0.11%) cases, 75 (0.024%) cases, respectively. 18,297 (5.89%) female were tested positive only for other hr-HPV genotypes, and undertook triage using liquid-based cytology. 2350 (0.76%) cases with the results ≥ ASCUS were referred to colposcopy directly, and CIN1, CIN2, CIN3 and ICC were detected in 381 (0.12%) cases, 112 (0.036%) cases, 77 (0.025%) cases, 2 cases, respectively  and the histological results  among different hr-HPV types is displayed in Fig. Candida albicans, Gardnerella co-infection, and any cervical lesions.The distribution of potential risk factors among CIN/ICC and normal participants are shown in Additional file Among the overall participants, 5683 1.83%) participants were infected with TV; among them, 1952 (0.63%) female were co-infected with hr-HPV. Among the co-infection population, 1643 cases had normal cytology or histologic diagnosis, 171 cases had CIN 1, 60 cases had CIN 2, 67 cases had CIN3 and 11 cases had ICC , but it did not increase the risk of CIN2–3 and ICC. For different HPV types, TV increased the risk of CIN2–3 among the female infected with HPV16 (single HPV16 or simultaneous infection of HPV 16 and other high-risk HPV types) . For there were only 77 ICC female in this study, no efficient results were found among HPV 16 positive ICC female. No positive correlation were found between TV and CIN 1/CIN 2–3/ICC among none HPV16 positive female in this study , number of pregnancies ≥1 (p < 0.001), postmenopause (p < 0.01), poverty (p < 0.01), personal HPV history (p < 0.01), miscellaneous bacteria density (p < 0.0001), trichomonas (p < 0.0001), were positively associated with hr-HPV infection significantly; Education(p = 0.0154), was not associated with hr-HPV infection; Number of birth, and candida infection were negatively correlated with hr-HPV infection (p < 0.0001).To find the risk factors of hr-HPV infection, multivariate logistic regression analyses were utilized. The results are shown in Fig. Baseline features of the participants with hr-HPV and TV co-infection are shown in Table Though it is recommended to begin primary hrHPV screening at age 25 years in the interim clinical guidance of ASCCP in 2015 , it raisIn our study, the prevalence of hr-HPV in this region was lower than the hr-HPV prevalence from other parts of China (from 9.03 to 16.8%) . The cerIt was found that Candida spp. was not associated with the detection of cervical lesions in this study, consistent with previous studies , 13, 14.Several pieces of research had concerned the relationship between TV, HPV and CIN/ICC, but their conclusions were inconsistent. Gweneth’s study found that trichomonas vaginitis was associated with hr-HPV infection  significantly, but no correlation between trichomonas and cervical lesions . Ishita In this study, 5683 among the overall participants were TV positive and 1952 (34.35%) among these, were co-infected with hr-HPV. Co-infection with TV increased the risk of CIN 1 among female with hr-HPV, and increased the risk of CIN 2–3 among female with HPV 16. It was expected that TV was often associated with more severe inflammatory reaction and HPV persistence, and was likely closely related to the invasion, persistent infection of HPV 16. HPV including hr-HPV infections are mostly temporary. The virus can be cleared through host immune responses spontaneously, only a small number of infections persisted and progressed to cervical cancer . HPV 16 Both TV and genital tract HPV infection are sexually transmitted disease (STD). In the districts with lower economic levels, many people went out to the developed areas to work and couples usually work in different places, and sex act extramarital is common . Risk faAs it was known that, this research had the largest number of female who received COBAS human papillomavirus primary testing for cervical cancer screening up to now worldwide, and it was a multisite investigation with the most massive scale about the correlation between cervical hr-HPV infection, CIN/ICC and vaginal microenvironment. The detection methods of hr-HPV and vaginal microenvironment in this study were highly sensitive and recognized internationally.Of note, there were some limitations to our study. Because our study was a cross-sectional analysis of current hr-HPV and TV infections, one of its major limitations, which is inherent to the design, is that the association found does not imply causality. It was not clear whether there was a persistent infection among these female or not, so follow-up of TV-infected women to assess whether new CIN detection or CIN stage progression occurs would result in a much more clarifying study to support our findings. Besides, there are some participants who failed to be followed up for a variety of reasons in the screening process. Chlamydia has been detected less and less, so it was not included in this study. HIV-infection status and smoking habit has not been included in this study.From this large population-based study, it was found that Positive TV was correlated with hr-HPV infection and co-infection with TV increased the risk of CIN 1 among female infected with hr-HPV, co-infection with TV increased the risk of CIN 2–3 among female infected with HPV 16. From what has been discussed above, co-infection of TV and HPV 16 is a significant risk factor for the detection of cervical lesions. For our study was a cross-sectional analysis, there were some limitations, and follow-up of TV-infected women to assess whether new CIN detection or CIN stage progression occurs will be the next step of our work.Additional file 1. . The content of the questionnaire.Additional file 2.. Distribution of potential risk factors among CIN/ICC and normal participants.Additional file 3. Correlation between Candida albicans, Gardnerella, TV and the progression of cervical lesions stratified by different hr-HPV types


With millions of viewers globally, live streaming is a new social media that can deliver video content in real time and with many social interaction functions. Our research aims to understand the personality traits and the motivations of active live streaming viewers as well as their user behaviors in the general population in China. Our results indicate that extraversion was negatively associated with live streaming use, while openness was positively associated. The main motivations to watch live streaming were social interaction, information gathering, and entertainment, and they were associated with different frequencies of use and genre selection. Financial tipping behavior was positively associated with social interaction. Furthermore, motivations mediated the effects of personality traits on live streaming use. People high in openness were more likely to be motivated to chat by information needs. Among extraverts, those who were more social watched fewer streams. We demonstrated that personality traits and motivations can jointly predict live streaming use. The current study not only provides the first evidence of live streaming use with personality traits and motivations but also expands the perspective on individual difference with the mediation analysis. Practically, the person–situation joint interpretation can give industry a clear indication on how to design personalized user experience for people with different personality traits and motivations. Live streaming—a new way to deliver video content in real time—has attracted millions of users globally in recent years. The popularity of digital cameras and the increased availability of network access have facilitated the substantial growth of video transmission on the Internet. In 2016, live streaming ranked as the top application of mobile data traffic and accounted for over 34% of total mobile data . Since 2From a user’s perspective, we could draw more inferences about how personality traits and motivations can influence live streaming use. Furthermore, our study of live streaming use in China can contribute to the current body of social medial research from a cultural perspective, providing insights of how culture may influence the way people use live streaming. In addition, our study can offer practical implications for platforms to attract users based on individual needs and personality traits.via comments or emojis. Therefore, often there is an interesting cross-model discourse during online streaming  belong to the broad category of social network sites (SNSs), while featuring specific characteristics: synchrony, real-time broadcasting of user-generated content, interactions between the viewers and the streamers, and a gratification system . Throughtreaming . As suchA few studies have examined live streaming in the United States, mainly focusing on the Twitch platform . For exaHowever, research from individual perspectives concerning the factors leading to the use of live streaming in China has been limited. A growing body of evidence suggests that personality traits and motivations are influential in guiding online behavior . The coefficient of chat became smaller ; however, the mediation on chat was not significant. Interestingly, we also found an inconsistent mediation from extraversion to streams through social motivation (p < 0.01). This shows that the use of live streaming by extraverts is motivated by social needs. However, after controlling for the effect of social, extraversion had an even stronger negative relation with streams . Here social motivation acted as a suppressor variable. Among participants who were extraverted, those who were more socially motivated tended to use live streaming less. These evidences support our H7a and H7c that motivations mediate the effects of personality traits in live streaming use.To explore the mediation relationship between personality traits and viewers’ live streaming use, we conducted a regression analysis with the motivations controlled for tivation . After cp < 0.01) were more likely to spend money on tipping. However, whether to tip was not associated with viewers’ demographics (p ≥ 0.07). Then, we examined tipping behavior with motivations. The results showed that people who were motivated by social  were more likely to spend money on tipping. These results support H8 that social interaction is positively associated with tipping behavior.Finally, logistic regressions were conducted to analyze tipping behavior. First, we analyzed tipping behavior with viewing and chatting behavior. The results showed that people who chatted more  but also viewing frequency and tipping behavior. According to In general, personality traits have less influence on genre selection than motivations. Our results showed that entertainment was associated with preference In addition, we explained how motivations can mediate the effects of personality traits to influence user behaviors in live streaming. Douyu platform and found that viewers often follow others to send virtual gifts. If virtual gifting is the social norm in Chinese live streaming, viewers who want to find group identity need to adopt this practice. In this sense, virtual gifting could be a conformity behavior motivated by the group identity. On the other hand, in many Chinese live streaming platforms, there are a number of gift types with a wide range of values, from a 0.1 RMB “like” to a 500 RMB “rocket”. Sending high-value gifts to streamers can create special visual or audio effects, such as flashing lights through the browser window, and can attract attention from streamers and other viewers. The platforms also designed different badges and titles to distinguish viewers who send high-value gifts from other viewers who paid less and provided those high-value gift senders with privileges. These symbolically demonstrated that hierarchies attract people who seek status in live streaming and motivate them to enhance their presence through tipping behavior (Douyu platform, the 2.7% high-value gift senders contributed to 80.2% of the total gift value (One feature of live streaming is that users can directly provide financial support to streamers. According to survey, among 31.5% of users who spent money on Twitch, majority paid for subscription , whereasbehavior . On Douyft value . It seemOur current research provides a personality profile of Chinese live streaming users and corroborates previous evidence on the motivations of live streaming use. Importantly, our findings contribute novel insight into how person–situation jointly could be used in interpreting viewers’ livestreaming use. Theoretically, this expands the perspective on individual difference in livestreaming use. Viewers with different personality traits could be motivated by different needs, which together shape their livestreaming use.Practically, the findings of the current study suggest that strategies targeted to different viewer’s personality profile can be applied to attract users. For neurotics who cannot find enough social support in livestreaming, platforms could promote small-sized channels where a close interaction is allowed. Platforms could support economic and inclusion opportunities for streamers with disabilities, mental health issues, or physical health issues. These streamers can build up an inclusive community for people who encounter similar difficulties in life through sharing experiences and encouraging each other, which can be beneficial to both streamers and viewers . For extvia SSLSs but also by some other applications. For example, Taobao, the biggest online shopping platform, used live streaming for product sales. The relationship between viewers’ behaviors and personality traits and motivations can change as the context changes. Further research could examine specific platforms, content, and new application to understand the use of live streaming.Although this research offers new insight into the individual difference of livestream viewers, it has some limitations. First, viewers’ behavior can be defined in different ways. Besides the variables that we used, duration of streams watching and interaction behaviors can also describe different aspects of live streaming use. Regarding the tipping behavior, although we did not find an association between income level of viewers and whether they chose to spend, the findings could have been restricted by the measure. Determining how much users pay for tipping or how often they tip could provide more details to explain this behavior. Second, our study surveyed users across platforms and explored the general usage patterns of live streaming as a homogenous activity. However, platform and content differences were not included, which could be a noteworthy factor in determining user behaviors . AlthougThe current study is one of initial attempts to explore viewers’ personality traits and motivations related to live streaming use in the general population in China. Results indicated that extraversion and openness were two major personality traits, and social, information, and entertainment were the three motivations that associated with viewers’ live streaming use. Furthermore, we found that motivations can mediate the effects of personality traits, demonstrating that personality traits and motivations jointly influence live streaming use. It provides novel insight into understanding the various degrees of social interaction in live streaming from individual differences. The personality profile of Chinese viewers can also support a future cross-cultural study to understand live streaming user behaviors.The datasets generated for this study are available on request to the corresponding author.The studies involving human participants were reviewed and approved by USC-SJTU Institute of Cultural and Creative Industry Ethnic Board. The participants provide their written informed consent to participate in this study.YY was responsible for collecting data and part of the analysis. YX was responsible for part of the analysis and all other work including idea generation, analysis and writing. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The future photovoltaic technologies based on perovskite materials are aimed to build low tech, truly economical, easily fabricated, broadly deployable, and trustworthy solar cells. Hole transport material (HTM) free perovskite solar cells (PSCs) are among the most likely architectures which hold a distinctive design and provide a simple way to produce large-area and cost-effective manufacture of PSCs. Notably, in the monolithic scheme of the HTM-free PSCs, all layers can be printed using highly reproducible and morphology-controlled methods, and this design has successfully been demonstrated for industrial-scale fabrication. In this review article, we comprehensively describe the recent advancements in the different types of mesoporous (nanostructured) and planar HTM-free PSCs. In addition, the effect of various nanostructures and mesoporous layers on their performance is discussed using the electrochemical impedance spectroscopy (EIS) technique. We bring together the different perspectives that researchers have developed to interpret and analyze the EIS data of the HTM-free PSCs. Their analysis using the EIS tool, the limitations of these studies, and the future work directions to overcome these limitations to enhance the performance of HTM-free PSCs are comprehensively considered. A complete understanding of PSCs has turned out to be a challenge due to their dynamic behavior and complex multidimensional nanostructure. Recently, electrochemical impedance spectroscopy (EIS) has emerged as a useful tool in breaking down the complex dynamic processes occurring within the different layers of solid-state PSCs, which makes it easier to analyze the interfaces and charge dynamics of this type of solar cells. EIS technique has proven to be an effective tool in analyzing the processes occurring at the interface of different layers of the PSC ,2. For iDifferent architectures of PSCs have been studied and analyzed by the EIS technique in previous works. This includes the conventional n-i-p structure  and the This review provides an insight into the EIS technique and how it is essential to understand the complex behavior of HTM-free PSCs better. EIS analysis has been discussed based on Nyquist and Bode plots, which are the most common methods of analyzing EIS data. The relevant physical parameters that can be extracted from the EIS data by equivalent circuit modeling are also discussed. Furthermore, a comprehensive literature review on EIS analysis employed in previous works was also performed to analyze the trend of utilizing this tool in the field of HTM-free PSC research over the past years.2, beneficial for commercialization, and impressive PCEs. The overall PCE of carbon-based planar HTM-free PSCs is increasing, considering the active area (ive area e. The PCSome commonly employed HTM-free PSC structures in previous works are shown in A very compatible work function of Au with perovskite makes it an excellent choice as the back contact for HTM-free PSCs see g. There 2 heterojunction HTM-free PSC for the first time (in 2015) utilizing gold as the back contact and achieved a PCE of 5.5%. The Au layer was thermally evaporated onto the cell. Since then, various modifications have been performed by researchers to optimize it further. Laban et al. [2 junction, which aided in charge separation and prevented the recombination of electrons and holes and hence provided a PCE of up to 8%. Later on, to avoid the complex vacuum and energy-intensive deposition process of Au, Zhou et al. [2O3 in HTM-free PSC was also studied, and it was reported that the presence of Al2O3 increases the PCE because it prevents the recombination of electrons and holes at the TiO2 and nanoporous Au interface. Shi et al. [2 junction which can be estimated by Mott Schottky analysis. Furthermore, it was also analyzed that the width of the depletion layer could be controlled by the thickness of the mesoporous TiO2 film. It was observed that at 2 film was depleted, and hence the PCE obtained was the highest among the samples.Etgar et al.  introducn et al.  further u et al.  fabricati et al.  also desi et al. , who revInitial work on planar HTM-free PSCs with Au back contact was performed by Gamliel et al. , who depBesides an expensive energy-intensive vacuum deposition process of Au, it has also been reported that the Au could be a potential reason behind the degradation of the PSC devices by diffusing into the perovskite layer . Subsequ2 nanosheets [2 nanosheets, which enhanced the interfacial properties between the compact TiO2 and perovskite. Afterward, over 11% of PCE was achieved by optimizing the size of the graphite/carbon counter electrode [2 and ZrO2 was employed and covered by a porous carbon layer. 5-AVA additives were also incorporated to improve the PCE. In later research, ammonium chloride was incorporated into the perovskite precursor, which increased the PCE to 15.6% [The research on carbon-based HTM-free PCS is mostly concentrated on monolithic architectures. Han’s group provided a significant contribution to carbon-based HTM-free PSCs research, and they introduced a unique type of mesoporous HTM-free PSC; monolithic PSC, where all the layers are screen printed and stacked, as illustrated in nosheets . The implectrode . The inflectrode . A doublto 15.6% .oc was observed to be decreasing. This phenomenon was explained by a new approach, known as bridging and trapping effects. By analyzing the energy band diagrams illustrated in 2 interface due to bridging effect. Consequently, in polyaniline-based PSC, the carbon layer causes charge trapping due to mismatching energy levels of perovskite and polyaniline electrode resulting in trapping effect, and hence the Voc decreases. Ke et al. [2O3 mesoporous layer was also incorporated between perovskite and TiO2 layers to avoid direct contact, and hence electron–hole recombination was suppressed. The fabricated device is illustrated in Significant research on carbon-based HTM-free PSCs has been dedicated to mesoporous configurations. The multiple mesoporous layers in this type of architecture prevent the recombination of electrons and holes and also avoids pure ohmic shunts . Bhatt ee et al.  also rep3 was used, and carbon and TiO2 were used as the back counter electrode and ETL, respectively. Most of the research on this type of architecture is concentrated on low temperature processed SnO2, such as the ETL illustrated in 2, which require high temperature for processing and sintering. SnO2 has been consistently used in previous works as the ETL in HTM-based PSCs and has shown impressive electrical and chemical properties with a wide bandgap and high charge mobility [2 in a planar HTM-free PSC architecture, and achieved a PCE of 14.5%. This device was compared with the conventional high temperature processed TiO2-based HTM-free PSC device, and it was observed that the Voc of SnO2 (1.07 V)-based device was 100 mV higher than that of TiO2-based PSC. This is due to SnO2’s impressive hole blocking and electron transporting ability which is attributed to its enhanced fermi level owing to its wider bandgap, as illustrated in oc increases due to inhibition of charge recombination. Recently, Vijayaraghavan et al. [2 quantum dot as the ETL and achieved a PCE of 13.6%. SnO2 quantum dots were reported as superior to other solution-processed SnO2 and colloidal nanoparticles-based SnO2 due to their long-term stability, higher molar extinction coefficient, fast electron extraction, and hole blocking property, which results in an enhanced PCE.This type of architecture does not include mesoporous scaffold and insulating layers, as shown in mobility  and has mobility  were then et al.  fabricatPlanar carbon-based HTM-free PSCs are not very popular because the mesoporous scaffold and spacer layers, like in mesoporous and monolithic architectures e,f are n2 and Al2O3, which require high temperature (400–500 °C) for deposition. Hu et al. [3NH3PbI3/C60/Ag, and a PCE of 5.4% was achieved with a sequential vapor deposition technique for the growth of highly uniform perovskite film. The perovskite was deposited directly on the ITO substrate. Since then, impressive progress has been made on inverted HTM-free PSC research. Tsai et al. further enhanced the PCE to above 11% with an impressive open circuit voltage of 1.1 V by fabricating an HTM-free perovskite/fullerene heterojunction PSC with the configuration of ITO/MAPbI3/PC61BM/bis-C60/Ag, as illustrated in 3−xClx(CuSCN)/C60/BCP/Ag. CuSCN was incorporated in the perovskite to form a bulk heterojunction, where CuSCN played the role of hole conductor. Later on, there was a major breakthrough by Wu et al. [3:F4TCNQ/C60/BCP/Cu, by molecular doping of the perovskite film which improved its conductivity and its contact with the substrate. This resulted in a reduced series resistance and an enhanced PCE. Moreover, the doctor-blading deposition technique was acquired, enabling a scalable production.Most of the work on the inverted structure utilizes silver (Ag) as the back metal electrode instead of Au. Ag usually is not used in the standard architecture since the iodine in the perovskite can react with Ag. However, the inverted structure makes it possible to utilize Ag as the metal electrode. This architecture also avoids the need for mesoporous metal oxide layers such as TiOu et al.  were theu et al. , who many-axis and x-axis, respectively. The resultant spectra can exhibit one, two, three, or more semicircles (depends on the time constants within the applied frequency range). Each arch can be represented by an RC element in an electrical equivalent circuit (EEC) model. 4), intermediate frequency (IF) (10–104 Hz) and low frequency (LF) (<10 Hz) regions are evident, and these arcs are formed by a parallel combination of resistance and interfacial capacitance [Electrochemical impedance spectroscopy (EIS) refers to a technique that is utilized to gain insight into the bulk and interfacial properties of multijunction devices, and it can be used to study the devices under different in-situ conditions such as a function of different variables such as dc voltage, illumination intensity and temperature . It has acitance .2/perovskite interface or in the bulk of these layers. The LF region is related to ionic motion as well as recombination processes, and it is very complex to analyze due to hysteresis related to ionic motion [The HF region represents geometric capacitance, which is commonly provided by the carbon or gold electrode in HTM-free PSCs. The IF arc represents the recombination process in the mesoporous TiOc motion . Sometimc motion ,62,63. Ec motion  explainect that appears in the high-frequency region is typically attributed to the counter electrode, carbon or gold electrode, and their interface with the perovskite layer (in the case of PSCs). Another resistance element is required to represent the charge transfer at the electron transport layer (ETL) and perovskite interface in the lower frequency region. This is commonly the case when only two arcs appear in the Nyquist plot, [There are different configurations of electrical circuits that are employed for the fitting of the EIS data , recombination resistances (Rrec), and charge transfer resistance (Rct) , and PCE can be determined. Raminafshar et al. [s value in the absence of HTM. Similarly, Khan et al. [The first article employing the EIS tool to analyze HTM-free PSCs was demonstrated by Juárez-Pérez et al.  in 2014.Rct) see a and ther et al.  also pern et al.  also per2 or Al2O3, play a crucial role in separating the front and back electrodes to prevent ohmic shunts [The properties of ETL and mesoporous oxide layers have a significant impact on charge transfer and recombination processes. The better is the energy alignment of ETL with perovskite, the lower is the recombination rate. The spacer layers, ZrOc shunts . The por2 nanosheets (NSs) as an electron transport layer (ETL) was compared with TiO2 nanoparticles (NPs), and the EIS data showed better interfacial properties of the device with NSs. The Nyquist plot showed two well-defined arcs and the device with NSs provided a smaller arc in the HF region and a bigger arc in the low frequency (LF) region, indicating a smaller Rct at the counter electrode/perovskite interface and a higher Rrec at the perovskite/ETL interface, compared to NPs and hence improving the performance  on HTM-free mesoscopic PSC with a TiO2/spacer/carbon architecture and analyzed the spacer layer thickness to optimize the performance of the device [2/perovskite interface. To confirm the reported correlations of each semicircle with the physical processes at the interfaces, the EIS study was also performed with and without the mesoporous TiO2 layer.Hang’s group fabricated an HTM-free mesoscopic PSC and demonstrated a PCE of 10.64% . TiO2 naformance a. The exnterface . It was e device . The Nyq2 blocking layer in HTM-free PSCs, by optimizing the amount of DEA (diethanolamine) in the precursor solution, through EIS analysis. It was stated the conventional fabrication procedure of TiO2 is prone to cracking, which can create trapping sites for electrons and holes recombination. Consequently, the incorporation of DEA in the precursor solution revamps the cracks resulting in a higher performance of the PSCs by increasing the contact area. The EIS analysis confirmed the optimum DEA molar ratio (x) of 0.75. The Nyquist plot, as illustrated in ct kept decreasing by increasing the amount of DEA until x = 0.75, where Rct value was at its minimum. Any further increase in the DEA amount leads to an increase in Rct value. Consequently, the Rrec increased to a maximum at x = 0.75 followed by a decrease in further increasing the value of x  play a crucial role in determining the performance of PSCs. In HTM-free PSCs, it is required for the CE to play the role of HTM as well , which ie device . Carbon e device . Batmunke device  suggestee device  revieweds and Rct of the device and hence had a significant impact on increasing the PCE (up to 11%) of HTM-free cells. Next, they employed an ultrathin graphite-based carbon counter electrode for HTM-free mesoscopic fully printable PSC, analyzed its interfacial properties with the EIS tool, and compared it with bulk graphite counter electrode-based device, as shown in 2/perovskite interface as shown in Han’s group utilized the EIS tool to analyze the effect of the counter electrode (CE) on the photovoltaic performance of the fabricated HTM-free mesoscopic PSC device . Graphitrec, which was related to the recombination processes of the overall PCS, was reduced in CuS-C-based PSC, indicating better hole collection property of CuS-based carbon CE, as well as the better property of suppressing electrons and holes recombination, leading to an enhanced FF and Jsc. Zhou et al. [3 nanoparticles in it to function as the HTM. A PCE of 10.77% was achieved under ambient conditions. To analyze this HTM-free PSC, EIS analysis was performed in the range of 1 Hz to 1 MHz at −0.2 V DC biasing in the dark. As can be observed in 3 nanoparticles showed a lower Rs value compared to PSC without WO3, indicating higher hole extraction efficiency. Moreover, the Rrec was higher with WO3 embedded PSC, which means that the WO3 was acting as a passivating layer at the carbon and perovskite interface, inhibiting the recombination of charges. Later on, Bhandari et al. [3 embedded carbon in HTM-free PSC with the EIS technique. This time, the EIS tool was used to optimize the amount of WO3 and EIS results of the best performing device; 7.5% WO3 showed a lower Rs value, which is directly correlated to the PCE and a higher Rrec at TiO2/perovskite interface (BF4)x) and used EIS tool to compare it with the single anion perovskite-based HTM-free PSC device [oc of the device, as illustrated in oc.Han’s group fabricated HTM-free fully printable mesoscopic PSC with a mixed anion perovskite  materials. Although the carbon-based HTM-free PSCs can simply be prepared using printing methods, the low power conversion efficiency (PCE) of ~15% is leftover as an essential research question. Besides, the challenge is still under debate to achieve consistent and high integrity on the consecutive layer and perovskite layer deposition for the massive scale production. The PCE can be observed to be decreasing with an increase in the area. More research work is required to further enhance its performance by exploring more optimization strategies. In addition, the widespread production of the HTM-free PSCs requires improving the device stability, deep understanding of the interfaces between the different printed layers, and charge collection at the respective electrodes.2 or Al2O3, which are responsible for the additional features in the Nyquist plot. The charge transport processes from the perovskite confined in these spacer layers produce an additional feature in the Nyquist plot, which is commonly merged with the high-frequency arc and, therefore, is challenging to identify. In this respect, a well-supported electrical equivalent circuit (EEC) model can be developed to improve the accuracy of the analysis and hence can provide valid, relevant physical parameters. It is essential to acquire an in-depth understanding of EEC modeling of the impedance spectra since the underlying assumptions and applicability of this approach remains unclear in the literature.In this respect, electrochemical impedance spectroscopy (EIS) has emerged as a leading-edge tool for a systematic illustration of the charge accumulation, charge transfer, interfaces analysis, and degradation of the different layers in the PSCs research. It is widely utilized by researchers to study the behavior of HTM-free PSCs under various operating conditions. Even though EIS has proven to be an advanced tool, with the help of which the interfacial and bulk properties of PSCs can be comprehensively analyzed, many aspects of this tool are yet to be fully understood, for example, identifying the correlation of each interface of the multilayered HTM-free PSC with the different features in each frequency range of the Nyquist plot. Many researchers still do not consider the charge transport processes at the spacer layers (nine in the case of monolithic design), ZrOct and Rs, as realized by EIS analysis. The recombination process is also significantly suppressed. Besides, it has been found that the charge transfer resistance in the HF region increases with the spacer layer thickness. Therefore, it is crucial to optimize the spacer layer to obtain the high efficiency of HTM-free PSCs. In addition, it has been recognized  that mixed anion perovskites such as MAPbI(3−x)Brx provide better performance by suppressing recombination rate and hence enhancing the Voc of the device. This is attributed to their wider bandgap, which makes them capable of acting as electron blocking materials at the perovskite/counter electrode interface, and hence this avoids the requirement of an HTM layer.It has been realized by EIS analysis that the key to optimizing the performance of HTM-free PSCs is by choosing an ETL with the following properties: provides high contact area to minimize trapping sites for recombination and well-matched energy alignment with perovskite. The combination of these properties results in reduced RThe EIS study of the HTM-free PSCs has also proven that the hole collecting layer (counter electrode) indeed has a significant effect on HTM-free PSCs performance. The hole collecting layer is highly responsible for the HF region of the Nyquist plot. Moreover, it also affects the LF region of EIS spectra (in the case of monolithic architecture) because it provides a pathway to perovskite infiltration. Therefore, the better the porous morphology (absorbency) of CE is, the more uniform the perovskite infiltration will be in the monolithic design. Moreover, EIS analysis has also shown that manipulating the work function of the counter electrode to improve the energy alignment and enhance the conduction properties by doping is an effective technique in obtaining high-performance HTM-free PSCs.We believe that the use of the EIS tool in the field of PSCs is essential, and utilizing this tool to its maximum potential will pave the way for substantial improvements in our understanding. EIS tool has been used consistently in previous works for the analysis of HTM-free PSCs, yet the scope for further studies is significant. The studies that are highlighted in this review can help researchers gain an intimate understanding of the interpretation of EIS data, and the different ways in which the EIS tool can be utilized to analyze HTM-free PSCs.


A higher percentage of Veterans in rural areas are older, have multiple chronic conditions and select the VA for healthcare. To address the needs of rural older Veterans with complex needs, GRECC Connect hubs use case finding approaches combined with regular outreach and education to VA community-based outpatient clinic (CBOC) providers serving rural Veterans and caregivers. Alignment of GRECC Connect services with needs of providers and patients promotes establishment of therapeutic alliances in caring for medically complex older Veterans. After identifying high risk, high need patients, hubs use the following strategies to increase access to geriatric specialty care through telehealth modalities: 1) Co-management of patients through e-consultation and telehuddles ; 2) Clinical video telehealth to CBOCs and Video on Demand to Veteran homes (to reduce travel burden); and, 3) Tele-group visits .