in 1999 , a dutch surgeon transmitted hepatitis b virus ( hbv ) to at least eight patients and possibly to a total of 28 patients . literature shows that this form of transmission is not unique , numerous cases of hbv transmission from health care workers to patients have been reported , as reviewed by mele and gunson [ 2 , 3 ] . in 2000 , the dutch health care inspectorate established the  commissie preventie iatrogene hepatitis b ( committee for prevention of iatrogenic hepatitis b ; hereinafter referred to as the committee ) . the committee was asked ( 1 ) to review all hbv - infected health care workers in the netherlands who potentially perform exposure prone procedures ( epps ) and to advise them on how to prevent transmission ; and ( 2 ) to develop a national guideline for the prevention of transmission of hbv from health care workers to patients . the guideline on prevention of iatrogenic hepatitis b was published in june 2002 and was subsequently endorsed by the dutch health council . in 2003 since 2003 national guidelines for the management of infected health care workers have been instituted in several countries , as reviewed during a meeting of the viral hepatitis prevention board in 2005 . to prevent iatrogenic transmission of hbv , the dutch guideline states that the hbv status of all medical personnel performing epps must be known . the definition of epps was adopted from a report of the uk health advisory group . this report defines epps as follows : " exposure prone procedures ( epps ) are those where there is a risk that injury to the worker may result in exposure of the patient s open tissues to the blood of the worker . these procedures include those where the worker s gloved hands may be in contact with sharp instruments , needle tips or sharp tissues ( spicules of bone or teeth ) inside a patient s open body cavity , wound or confined anatomical space where the hands or fingertips may not be completely visible at all times . " in all but one case of reported hbv transmission to a patient , the level of hbv viremia in the health care worker was higher than 100,000 copies / ml [ 3 , 7 ] . balancing the risk of hbv transmission and the loss of medical specialists , the hbv dna threshold level above which the dutch guideline prohibits epps was chosen to be 100,000 copies / ml . in an hbv - infected person who performs epps , it has to be demonstrated twice yearly that the hbv viremia remains below this threshold . antiviral maintenance therapy using hbv polymerase inhibitors may successfully suppress the level of hbv dna below 100,000 copies / ml . in this situation the level of hbv viremia in the health care worker must be monitored every three months . to ensure proper management of hbv - infected health care workers , and to help decide whether a procedure is exposure prone or not , in the netherlands every hbv - infected health care worker potentially performing epps must be reported to the committee for evaluation and advice . to facilitate reporting , this article describes the number and nature of hbv - infected health care workers in the netherlands as submitted to the committee in the years 20002008 . the committee for prevention of iatrogenic hepatitis b considered the nature of the professional activities and reviewed the hbv - related laboratory test results of all hbv - infected health care workers that were submitted . the confidential database containing the reviews and test results of the submitted cases was accessed only by members of the committee , thus guaranteeing the privacy of the persons involved . all hbv - infected health care workers were placed into one of the following three categories : performing epps , not performing epps , or potentially performing epps in the future . although medical interns in the netherlands in general do not perform epps , medical interns were categorized as ' performing epps ' , because they unexpectedly may encounter exposure prone situations . for this report , all hbv dna test results expressed in international units were converted from iu / ml to copies / ml , assuming that 1  iu equals 5.8 copies of hbv dna . the committee for prevention of iatrogenic hepatitis b considered the nature of the professional activities and reviewed the hbv - related laboratory test results of all hbv - infected health care workers that were submitted . the confidential database containing the reviews and test results of the submitted cases was accessed only by members of the committee , thus guaranteeing the privacy of the persons involved . all hbv - infected health care workers were placed into one of the following three categories : performing epps , not performing epps , or potentially performing epps in the future . although medical interns in the netherlands in general do not perform epps , medical interns were categorized as ' performing epps ' , because they unexpectedly may encounter exposure prone situations . for this report , all hbv dna test results expressed in international units were converted from iu / ml to copies / ml , assuming that 1  iu equals 5.8 copies of hbv dna . from 20002008 , 99 cases of hbv - infected health care workers were submitted to the committee for reviewing and advice . fifty of the 99 hbv - infected health care workers performed epps ( see table  1 ) . seven of 99 were medical students who may perform epps in the future , and 42 were categorized as not performing epps , which included general practitioners , a nuclear physician , a pulmonologist , a geriatric doctor , nurses , technicians , researchers , drivers , janitors , etc . the 50 epp performing persons included 20 medical specialists ( of which seven were still in training ) , nine dentists ( four in training ) , 11 medical interns , three midwives , two operating room assistants , two dentistry assistants , two dental hygienists , and one surgical intensive care nurse . table  1number and nature of hbv - infected health care workers as submitted to and reviewed by the dutch committee for prevention of iatrogenic hepatitis b yearpersonnelperforming eppspotentially performing epps in futurenot performing eppstotal200012015272001908172002405920037281720048241420053025200623052007300320082002total5074299hbv hepatitis b virus , epp  exposure prone procedure number and nature of hbv - infected health care workers as submitted to and reviewed by the dutch committee for prevention of iatrogenic hepatitis b hbv hepatitis b virus , epp  exposure prone procedure eleven of the 50 epp performing persons had a viral load above the dutch threshold level ( 100,000 hbv dna copies / ml ) ; hence they were no longer allowed to perform epps . twenty - five persons had a hbv dna load below the threshold value , enabling them to perform epps provided that their hbv dna load is monitored . the duration of monitoring in these persons ranged from 0 to 106  months ( median 54  months ) . monitoring of hbv dna did not take place in 14/50 persons because they stopped working , moved abroad , died , or changed profession . in the 25 persons undergoing monitoring of hbv dna , the highest level of hbv dna encountered during follow - up was as follows : below 1,000 copies / ml in 4/25 persons , between 1000 and 10,000 copies / ml in 10/25 persons , and between 10,000 and 100,000 copies / ml in 11/25 persons . table  2 shows the number of restricted persons if other hbv dna threshold levels would have been applied . table  2number of hbv - infected health care workers excluded from exposure prone procedures according to various hbv dna threshold levelshbv dna threshold level ( copies / ml)percentage of restricted personnel100,00031% ( 11/36)10,00061% ( 22/36)100089% ( 32/36)hbv hepatitis b virus number of hbv - infected health care workers excluded from exposure prone procedures according to various hbv dna threshold levels hbv hepatitis b virus according to the dutch guideline , hbv - infected persons may perform epps again if antiviral therapy forces the hbv load below 100,000 copies / ml , provided that three - monthly monitoring of hbv dna takes place . in five of the 11 restricted cases the ban could be lifted because of successful antiviral therapy . in one of the 11 restricted cases the hbv dna level initially was low . during follow - up the level of hbv dna increased , exceeding the threshold value and necessitating a ban on epps . one of the four dentistry students had a high hbv load and initially was prohibited to carry out epps , which meant that the training had to be postponed . nevertheless , the dentistry students , medical students , medical interns and medical - specialists - in - training were advised to consider a non - epp profession , because the possibility of them developing a high viral load in the future could not be excluded . from 20002008 , 99 cases of hbv - infected health care workers were submitted to the committee for reviewing and advice . fifty of the 99 hbv - infected health care workers performed epps ( see table  1 ) . seven of 99 were medical students who may perform epps in the future , and 42 were categorized as not performing epps , which included general practitioners , a nuclear physician , a pulmonologist , a geriatric doctor , nurses , technicians , researchers , drivers , janitors , etc . the 50 epp performing persons included 20 medical specialists ( of which seven were still in training ) , nine dentists ( four in training ) , 11 medical interns , three midwives , two operating room assistants , two dentistry assistants , two dental hygienists , and one surgical intensive care nurse . table  1number and nature of hbv - infected health care workers as submitted to and reviewed by the dutch committee for prevention of iatrogenic hepatitis b yearpersonnelperforming eppspotentially performing epps in futurenot performing eppstotal200012015272001908172002405920037281720048241420053025200623052007300320082002total5074299hbv hepatitis b virus , epp  exposure prone procedure number and nature of hbv - infected health care workers as submitted to and reviewed by the dutch committee for prevention of iatrogenic hepatitis b hbv hepatitis b virus , epp  exposure prone procedure eleven of the 50 epp performing persons had a viral load above the dutch threshold level ( 100,000 hbv dna copies / ml ) ; hence they were no longer allowed to perform epps . twenty - five persons had a hbv dna load below the threshold value , enabling them to perform epps provided that their hbv dna load is monitored . the duration of monitoring in these persons ranged from 0 to 106  months ( median 54  months ) . monitoring of hbv dna did not take place in 14/50 persons because they stopped working , moved abroad , died , or changed profession . in the 25 persons undergoing monitoring of hbv dna , the highest level of hbv dna encountered during follow - up was as follows : below 1,000 copies / ml in 4/25 persons , between 1000 and 10,000 copies / ml in 10/25 persons , and between 10,000 and 100,000 copies / ml in 11/25 persons . table  2 shows the number of restricted persons if other hbv dna threshold levels would have been applied . table  2number of hbv - infected health care workers excluded from exposure prone procedures according to various hbv dna threshold levelshbv dna threshold level ( copies / ml)percentage of restricted personnel100,00031% ( 11/36)10,00061% ( 22/36)100089% ( 32/36)hbv hepatitis b virus number of hbv - infected health care workers excluded from exposure prone procedures according to various hbv dna threshold levels hbv hepatitis b virus according to the dutch guideline , hbv - infected persons may perform epps again if antiviral therapy forces the hbv load below 100,000 copies / ml , provided that three - monthly monitoring of hbv dna takes place . in five of the 11 restricted cases the ban could be lifted because of successful antiviral therapy . in one of the 11 restricted cases the hbv dna level initially was low . during follow - up the level of hbv dna increased , exceeding the threshold value and necessitating a ban on epps . one of the four dentistry students had a high hbv load and initially was prohibited to carry out epps , which meant that the training had to be postponed . nevertheless , the dentistry students , medical students , medical interns and medical - specialists - in - training were advised to consider a non - epp profession , because the possibility of them developing a high viral load in the future could not be excluded . over a period of nine years , from 2000 to 2008 , 99 hbv - infected health care workers were reported to the committee for prevention of iatrogenic hepatitis b in the netherlands . a ban on performing epps had to be imposed in eleven cases . the committee continues to receive requests for advice on hbv - infected personnel , but the number of submitted health care workers decreased after 2004 ( see table  1 ) . this can be attributed to the fact that most ' prevalent ' hbv - infected persons have been detected and only new ' incident ' cases are to be reviewed . in addition , local officials have learned to determine which health care workers certainly do not perform epps and thus are not to be submitted for review by the committee . it is unknown how many hbv - infected , epp - performing health care workers went unreported . to investigate whether the safety of patients was sufficiently safeguarded with regard to the prevention of hepatitis b , and to enforce reporting , in 2002 and 2003 the dutch health care inspectorate sent a standardised questionnaire on the local hbv vaccination status and testing policy to all hospitals , independent treatment centres and private clinics in the netherlands . responses to the questionnaire showed that 75% of the institutions lacked an effective hbv prevention policy . subsequently , a representative of the dutch health care inspectorate ( author b - m ) visited selected hospitals , checking local vaccination and control procedures and explaining the liability if the guideline appeared not to be implemented . by march 2004 , since 2005 , all hospitals , independent treatment centres , and private clinics known to the dutch health care inspectorate adhere to the dutch guideline on prevention of iatrogenic hepatitis b. in conclusion , the exact residual risk probably is low , but remains unknown . the level of hbv viremia in the health care workers who continued to perform epps while being monitored varied considerably from person to person . if the european consensus threshold level ( 10,000 hbv dna copies / ml ) would have been applied in the netherlands , the number of restricted workers would have doubled . application of the british threshold level ( 1000 copies / ml ) would have nearly tripled the number of restrictions ( see table  2 ) . unfortunately , it remains unknown how these different threshold values affect the safety of patients , as no follow - up takes place of patients undergoing epps by hbv - infected personnel . during the last decade inhibitors of hbv polymerase gradually became available for treatment of chronic hbv infection . lamivudine and adefovir were approved by the federal drug administration in 1998 and 2002 , and received marketing authorization for the european union in 1999 and 2003 . unfortunately , these early hbv inhibitors frequently cause the emergence of drug - resistant hbv variants [ 8 , 9 ] . hence , in the first years of the committee 's existence , long - term medically maintained suppression of hbv replication did not seem a solution for highly viremic , epp performing personnel . more recent hbv inhibitors like entecavir and tenofovir display a much more favourable resistance profile [ 10 , 11 ] . buster et al . have shown that prolonged antiviral therapy for hbv - infected health care workers is a viable option instead of work restriction , provided that the level of hbv dna is monitored regularly . indeed in five cases the ban on epps could be lifted , because of successful suppression of hbv . more cases are expected to follow . nevertheless , it remains questionable whether highly viremic dentistry students and surgeons in training should rely on long - term antiviral medication . the future will tell whether a switch to a non - exposure prone profession would have been wiser .