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Hepatitis B in health workers in Italy
Public Health (1994), 108, 433-437
(~) The Society of Public Health, 1994
Hepatitis B in Health Workers in Italy T. Stroffolini, 1 F. P a l u m b o , 2 C. Galanti, 3 A. M o i r a g h i , 4 F. Novaco, s R. Corona, 1-6 A. Marzolini 1 and A. M e l e 1
llstituto Superiore di SanitY, Roma, Italy; 20ssorvatorio Epidemiologico, Regione Campania, Roma, Italy; 3Assessorato alia SanitY, Regione Toscana, Firenze, Italy; 41stituto di Igiene, Universita di Torino, Italy," 5Assessorato alia Sanit& Regione Emilia Romagna, Bologna, Italy and 61stituto Dermopatico dell'lmmacolata, Roma, Italy
In Italy, a vaccination campaign against hepatitis B was launched in 1985. It was strongly recommended for health care workers. Over the period 1986-91 the incidence rate of acute B hepatitis in the general population declined from 12/100,000 in 1986 to 5/100,000 in 1991. The corresponding figures among hospital workers were 42.5/100,000 (RR 3.5; 95% CI 2.55-4.92) in 1986 and 14.5/100,000 (RR 2.9; 95% CI 2.03-4.14) in 1991, respectively. The proportion of HBV cases with jaundice was about the same in the general population (77.6%) and ha the health care staff (74.2%). Nearly 6% of hospital workers cases had completed the schedule of HBV vaccine. Despite the fact that vaccination against HBV has been strongly recommended for hospital workers, the incidence of infection in this job category has continued to be higher than that in the general population, probably as a consequence of poor vaccine coverage. These findings reiterate the need for aggressive vaccination programmes in hospital workers. Introduetion Health workers h a v e an increased risk of hepatitis B virus infection. 1-5 In Italy, a vaccination campaign against hepatitis B was started in 1985. It was strongly r e c o m m e n d e d for at-risk groups, particularly hospital workers. Since 1985 a voluntary specific surveillance system for viral hepatitis ( S E I E V A ) has b e e n operating in Italy, coordinated by the Istituto Superiore di Sanit~ in collaboration with health districts. 6 The n u m b e r of health districts collaborating increased greatly during the period 1985-91. This surveillance system offered us a good o p p o r t u n i t y to evaluate the incidence of hepatitis B in health care workers following the introduction of vaccination against hepatitis B. Methods In Italy there are 650 health d e p a r t m e n t s (USL). O v e r the p e r i o d 1986-91 the number of U S L s participating in the surveillance system increased gradually f r o m 85 in 1986 to 213 in 1991. In 1991 the population of U S L s reporting to S E I E V A was close to 32.6% of the total Italian population. S E I E V A participants are scattered all over the country and they are representative of Italy as a whole° Following ascertainment of l a b o r a t o r y results, each notified case of viral hepatitis, hospitalized or not, was interviewed by either a public health inspector or a physician. Correspondence to: Dr Tommaso Stroffotini, Istituto Superiore di Sanita, Laboratorio di Epidemiologia e Biostatistica, V. ie Regina Elena 299, 00161 Roma, Italy.
434
T. Stroffolini et al.
A standard two-page questionnaire which collected information on the principal hepatitis risk factors was used to interview patients and subsequently a copy was forwarded to the study centre at the National Institute of Health (Istituto Superiore di Sanit/~). A hepatitis B case was defined as a subject reported with acute illness, with hepatitis B surface antigen (HBsAg) and with IgM anti-hepatitis B core antigen (anti-HBc), without anti-hepatitis A virus IgM (anti-HAV) or whose anti-HAV was unknown. Inclusion of cases was not limited by age or sex and the notification system was unchanged throughout the period considered. In Italy the number of hospital workers is 670,000. 7-8 According to the population covered by SEIEVA we have estimated that the percentage of hospital workers surveyed by SEIEVA was 13% in 1986, 22.3% in 1987, 23.4% in 1988, 25% in 1989, 25% in 1990 and 32.6% in 1991, respectively (Table I). Results
Over the period 1986-91 a total of 191 acute hepatitis B cases was reported among hospital workers: 37 in 1986, 35 in 1987, 31 in 1988, 21 in 1989, 36 in 1990 and 31 in 1991, respectively (Table I). The incidence rate of acute B hepatitis in the general population declined from 12/100,000 in 1986 to 5/100,000 in 1991. The corresponding figures among hospital workers were 42.5/100,000 (RR 3.5; 95% CI = 2.55-4.92) in 1986 and 14.5/100,000 (RR 2.9; 95% CI 2.03-4.14) in 1991, respectively (Table II). The proportion of subjects with jaundice was about the same in the general population (77.6%) and in health care staff (74.2%) (Table III). In Table IV are shown the frequencies of risk factors reported during the six months before the onset of disease. We have separated out unusual isolated risk factors (such as dental treatment or needlestick injury but no other risk factors) from those where the reported exposure is confounded by a stronger risk factor (such as dental treatment or needlestick injury in an IV drug user or in a household of an HBsAg+ carrier). The most common reported risk factors were: dental treatment alone (21.1%) and needlestick injury alone (12.6%). Nearly 6% of cases had completed the schedule of HBV vaccine (Table IV). Discussion
First, it is important to exclude any potential bias in order to assure validity of the observed figures. SEIEVA participants are scattered all over the country and they are Number of cases of acute hepatitis B among hospital workers and number of estimated hospital workers surveyed by SEIEVA Table I
Year
No. of acute HBVcases
No. of hospital workers surveyed*
1986 1987 1988 1989 1990 1991
37 35 31 21 36 31
87,000 147,000 154,000 167,000 167,000 214,000
Note: *Mean estimated number of workers within USLs participating in the surveillancesystem.
Hepatitis B in Health Workers in Italy
435
Table II Incidence rate (cases x 100,000) of acute hepatitis B among hospital workers and among the general population in Italy 1986-91 and estimated relative risk Year
Hospital workers
General population
Relative risk
95% CI
1986 1987 1988 1989 1990 1991
42.5 25.2 20.1 12.6 21.5 14.5
12 10 7 6 5 5
3.5 2.5 2.9 2,1 4.3 2.9
2.55-4.92 1,81-3.49 2.01-4.11 1.36-3.25 3.09-6.01 2.03-4.14
Table III
Proportion of HBV cases with jaundice among health care staff and among the general population in Italy, by year
Year
Health care staff
(%)
General population
(%)
1986 1987 1988 1989 1990 1991
28/37 23/35 22/27 13/21 28/36 24/30
(75.7) (65.7) (81.5) (61.9) (77.8) (80.0)
754/1,026 1,117/1,420 811/1,075 710/885 763/973 687/862
(73.5) (78.7) (75.4) (80.2) (78.4) (79.7)
Total
138/186"
(74.2)
4,842/6,241
(77.6)
Note: *This information was missing in five subjects. Table IV Frequencies (%) of risk factors reported during the six months before the onset of symptoms among hospital workers with acute HBV in Italy, 1986-91 Risk factors
%
Household of HBsAg positive carrier (even with other risk factors) IV drug user (even with other risk factors) Sexual contact of IV drug user (even with other risk factors) Blood transfusion (even with other risk factors) Surgical intervention (without blood transfusion and drug abuse) Needlestick injury (without any of the above risk factors) Dental treatment (without any of the above risk factors)
9.2 4.3 8.7 3.7 6.5 12.6 21.1
Note: Previous vaccination against HBV was reported by 5.9% of cases.
436
T. Stroffolini et al.
representative of Italy as a whole. Moreover, the notification system was unchanged~ throughout the period considered. More importantly, the ascertainment of hepatitis has not been different (better) ini health care workers than in members of the general population, as H B V cases in~ both groups are identified through the same surveillance system and are therefor~ exposed to similar selective factors, if any. Furthermore, the proportion of subjects~ with jaundice (who are more easily ascertained) is similar in the general population~ (77.6%) and in the health care staff (74.2%). ~ Thus any potential ascertainment bias is unlikely. This makes valid the observed/! differences between health care staff and the general population. ~: It has been shown recently in the U S A 9 that a programme of hepatitis B: immunization for health care workers was associated with a significant decline in~ clinical H B V infection despite continued exposure to patients positive for HBsAg. In Italy, despite vaccination against H B V having been strongly recommended for! hospital workers, the incidence of the infection in this job category has continued t o be higher than that in the general population, probably as a consequence of poor~ vaccine coverage. ,~ Unfortunately, nation-wide figures for vaccination coverage against H B V in health workers in Italy are not available. Therefore, we cannot comment on whether t h e decreasing incidence observed even in hospital workers from 1986 to 1991 may b e attributable to increasing vaccine coverage over time and/or reflect the decreasing spread of H B V infection in the Italian general population. We suspect, however, that the reduction of incidence observed in 1989 may be attributable to a higher coverage following the introduction in that year of the recombinant H B V vaccine instead of the plasma-derived vaccine. Nearly 6% of subjects have completed the vaccination schedule against HBV. However, we do not know how many days before the onset of symptoms the subjects had completed the vaccination schedule. Therefore, we cannot rule out the possibility that some subjects might have been exposed to the virus before the vaccine schedule was completed. Health-care workers often do not realize that they are at risk of H B V infection, either because they are sometimes unaware that they have been exposed to blood and/or other body fluids or because HBsAg positive source patients are frequently not known to have H B V infection. 9 Moreover, the risk of infection is higher during the early years of health care work. In fact, a recent study has shown that recalled needlestick injury rate, which is a very frequent hazard, was 32% in subjects with less than five years of employment, but 28% ( P < 0.01) in those with more than 20 years' service, I° as an effect of increasing experience and skills with advancing seniority. These observations, combined with the increased risk observed in this survey for occupationally acquired hepatitis B infection in health workers, reiterate tile need for aggressive vaccination programmes in these subjects, especially during the first years of employment.
Acknowledgements This study was partially supported by Regione Campania, Assessorato alia SanitY. References 1. Dienstag, 3. L. & Ryan, D. M. (1982). Occupation exposure to hepatitis B virus in hospital personnel: infection or immunization? American Journal of Epidemiology, llS, 26-39.
Hepatitis B in Health Workers in Italy
437
2. Snydman, D. R., Munoz, A., Werner, B. G. et al. (1984). A multivariate analysis of risk factors for hepatitis B virus infection among hospital employees screened for vaccination. American Journal of Epidemiology , 120, 684-693. 3. Hadler, S. C., Dato, I. L., Maynard, J. E. et al. (1985). Occupational risk of hepatitis B infection in hospital workers. Infection Control, 6, 24-31. 4. Osterholm, M. T. & Garayalde, S. M. (1985). Clinical viral hepatitis B among Minnesota hospital personnel: results of a ten year statewide survey. Journal of the American Medical Association, 254, 3207-3212. 5. Gibas, A., Blewett, D. R., Schoenfeld, D. A. & Dienstag, J. L. (1992). Prevalence and incidence of viral hepatitis in health workers in the prehepatitis B vaccination era. American Journal of Epidemiology, 136, 603-610. 6. Mele, A., Rosmini, F. & Zampieri, A. (1986). Integrated epidemiological system for acute viral hepatitis in Italy (SEIEVA): description and preliminary results. European Journal of Epidemiology, 2,300-304. 7. Istat: Annuario Statistico Italiauo 1991. 8. Mele, A., Catapano, R., Ferrigno, L. et al. (1991). SEIEVA, Rapporto Annuale 1991. Istisan, 16, 1-40. 9. Lanphear, B. P., Linneman, C. C., Cannon, G. C. & De Ronde, M. M. (1993). Decline of clinical hepatitis B in workers at a general hospital: relation to increasing vaccine-induced immunity. Clinical Infectious Diseases, 16, 10-14. 10. Albertoni, F., Ippolito, G., Petrosillo, N. et al. (1992). Needlestick injury in hospital personnel: a multicenter survey from central Italy. Infection Control and Hospital Epidemiology , 13,540-544.
(~) The Society of Public Health, 1994
Hepatitis B in Health Workers in Italy T. Stroffolini, 1 F. P a l u m b o , 2 C. Galanti, 3 A. M o i r a g h i , 4 F. Novaco, s R. Corona, 1-6 A. Marzolini 1 and A. M e l e 1
llstituto Superiore di SanitY, Roma, Italy; 20ssorvatorio Epidemiologico, Regione Campania, Roma, Italy; 3Assessorato alia SanitY, Regione Toscana, Firenze, Italy; 41stituto di Igiene, Universita di Torino, Italy," 5Assessorato alia Sanit& Regione Emilia Romagna, Bologna, Italy and 61stituto Dermopatico dell'lmmacolata, Roma, Italy
In Italy, a vaccination campaign against hepatitis B was launched in 1985. It was strongly recommended for health care workers. Over the period 1986-91 the incidence rate of acute B hepatitis in the general population declined from 12/100,000 in 1986 to 5/100,000 in 1991. The corresponding figures among hospital workers were 42.5/100,000 (RR 3.5; 95% CI 2.55-4.92) in 1986 and 14.5/100,000 (RR 2.9; 95% CI 2.03-4.14) in 1991, respectively. The proportion of HBV cases with jaundice was about the same in the general population (77.6%) and ha the health care staff (74.2%). Nearly 6% of hospital workers cases had completed the schedule of HBV vaccine. Despite the fact that vaccination against HBV has been strongly recommended for hospital workers, the incidence of infection in this job category has continued to be higher than that in the general population, probably as a consequence of poor vaccine coverage. These findings reiterate the need for aggressive vaccination programmes in hospital workers. Introduetion Health workers h a v e an increased risk of hepatitis B virus infection. 1-5 In Italy, a vaccination campaign against hepatitis B was started in 1985. It was strongly r e c o m m e n d e d for at-risk groups, particularly hospital workers. Since 1985 a voluntary specific surveillance system for viral hepatitis ( S E I E V A ) has b e e n operating in Italy, coordinated by the Istituto Superiore di Sanit~ in collaboration with health districts. 6 The n u m b e r of health districts collaborating increased greatly during the period 1985-91. This surveillance system offered us a good o p p o r t u n i t y to evaluate the incidence of hepatitis B in health care workers following the introduction of vaccination against hepatitis B. Methods In Italy there are 650 health d e p a r t m e n t s (USL). O v e r the p e r i o d 1986-91 the number of U S L s participating in the surveillance system increased gradually f r o m 85 in 1986 to 213 in 1991. In 1991 the population of U S L s reporting to S E I E V A was close to 32.6% of the total Italian population. S E I E V A participants are scattered all over the country and they are representative of Italy as a whole° Following ascertainment of l a b o r a t o r y results, each notified case of viral hepatitis, hospitalized or not, was interviewed by either a public health inspector or a physician. Correspondence to: Dr Tommaso Stroffotini, Istituto Superiore di Sanita, Laboratorio di Epidemiologia e Biostatistica, V. ie Regina Elena 299, 00161 Roma, Italy.
434
T. Stroffolini et al.
A standard two-page questionnaire which collected information on the principal hepatitis risk factors was used to interview patients and subsequently a copy was forwarded to the study centre at the National Institute of Health (Istituto Superiore di Sanit/~). A hepatitis B case was defined as a subject reported with acute illness, with hepatitis B surface antigen (HBsAg) and with IgM anti-hepatitis B core antigen (anti-HBc), without anti-hepatitis A virus IgM (anti-HAV) or whose anti-HAV was unknown. Inclusion of cases was not limited by age or sex and the notification system was unchanged throughout the period considered. In Italy the number of hospital workers is 670,000. 7-8 According to the population covered by SEIEVA we have estimated that the percentage of hospital workers surveyed by SEIEVA was 13% in 1986, 22.3% in 1987, 23.4% in 1988, 25% in 1989, 25% in 1990 and 32.6% in 1991, respectively (Table I). Results
Over the period 1986-91 a total of 191 acute hepatitis B cases was reported among hospital workers: 37 in 1986, 35 in 1987, 31 in 1988, 21 in 1989, 36 in 1990 and 31 in 1991, respectively (Table I). The incidence rate of acute B hepatitis in the general population declined from 12/100,000 in 1986 to 5/100,000 in 1991. The corresponding figures among hospital workers were 42.5/100,000 (RR 3.5; 95% CI = 2.55-4.92) in 1986 and 14.5/100,000 (RR 2.9; 95% CI 2.03-4.14) in 1991, respectively (Table II). The proportion of subjects with jaundice was about the same in the general population (77.6%) and in health care staff (74.2%) (Table III). In Table IV are shown the frequencies of risk factors reported during the six months before the onset of disease. We have separated out unusual isolated risk factors (such as dental treatment or needlestick injury but no other risk factors) from those where the reported exposure is confounded by a stronger risk factor (such as dental treatment or needlestick injury in an IV drug user or in a household of an HBsAg+ carrier). The most common reported risk factors were: dental treatment alone (21.1%) and needlestick injury alone (12.6%). Nearly 6% of cases had completed the schedule of HBV vaccine (Table IV). Discussion
First, it is important to exclude any potential bias in order to assure validity of the observed figures. SEIEVA participants are scattered all over the country and they are Number of cases of acute hepatitis B among hospital workers and number of estimated hospital workers surveyed by SEIEVA Table I
Year
No. of acute HBVcases
No. of hospital workers surveyed*
1986 1987 1988 1989 1990 1991
37 35 31 21 36 31
87,000 147,000 154,000 167,000 167,000 214,000
Note: *Mean estimated number of workers within USLs participating in the surveillancesystem.
Hepatitis B in Health Workers in Italy
435
Table II Incidence rate (cases x 100,000) of acute hepatitis B among hospital workers and among the general population in Italy 1986-91 and estimated relative risk Year
Hospital workers
General population
Relative risk
95% CI
1986 1987 1988 1989 1990 1991
42.5 25.2 20.1 12.6 21.5 14.5
12 10 7 6 5 5
3.5 2.5 2.9 2,1 4.3 2.9
2.55-4.92 1,81-3.49 2.01-4.11 1.36-3.25 3.09-6.01 2.03-4.14
Table III
Proportion of HBV cases with jaundice among health care staff and among the general population in Italy, by year
Year
Health care staff
(%)
General population
(%)
1986 1987 1988 1989 1990 1991
28/37 23/35 22/27 13/21 28/36 24/30
(75.7) (65.7) (81.5) (61.9) (77.8) (80.0)
754/1,026 1,117/1,420 811/1,075 710/885 763/973 687/862
(73.5) (78.7) (75.4) (80.2) (78.4) (79.7)
Total
138/186"
(74.2)
4,842/6,241
(77.6)
Note: *This information was missing in five subjects. Table IV Frequencies (%) of risk factors reported during the six months before the onset of symptoms among hospital workers with acute HBV in Italy, 1986-91 Risk factors
%
Household of HBsAg positive carrier (even with other risk factors) IV drug user (even with other risk factors) Sexual contact of IV drug user (even with other risk factors) Blood transfusion (even with other risk factors) Surgical intervention (without blood transfusion and drug abuse) Needlestick injury (without any of the above risk factors) Dental treatment (without any of the above risk factors)
9.2 4.3 8.7 3.7 6.5 12.6 21.1
Note: Previous vaccination against HBV was reported by 5.9% of cases.
436
T. Stroffolini et al.
representative of Italy as a whole. Moreover, the notification system was unchanged~ throughout the period considered. More importantly, the ascertainment of hepatitis has not been different (better) ini health care workers than in members of the general population, as H B V cases in~ both groups are identified through the same surveillance system and are therefor~ exposed to similar selective factors, if any. Furthermore, the proportion of subjects~ with jaundice (who are more easily ascertained) is similar in the general population~ (77.6%) and in the health care staff (74.2%). ~ Thus any potential ascertainment bias is unlikely. This makes valid the observed/! differences between health care staff and the general population. ~: It has been shown recently in the U S A 9 that a programme of hepatitis B: immunization for health care workers was associated with a significant decline in~ clinical H B V infection despite continued exposure to patients positive for HBsAg. In Italy, despite vaccination against H B V having been strongly recommended for! hospital workers, the incidence of the infection in this job category has continued t o be higher than that in the general population, probably as a consequence of poor~ vaccine coverage. ,~ Unfortunately, nation-wide figures for vaccination coverage against H B V in health workers in Italy are not available. Therefore, we cannot comment on whether t h e decreasing incidence observed even in hospital workers from 1986 to 1991 may b e attributable to increasing vaccine coverage over time and/or reflect the decreasing spread of H B V infection in the Italian general population. We suspect, however, that the reduction of incidence observed in 1989 may be attributable to a higher coverage following the introduction in that year of the recombinant H B V vaccine instead of the plasma-derived vaccine. Nearly 6% of subjects have completed the vaccination schedule against HBV. However, we do not know how many days before the onset of symptoms the subjects had completed the vaccination schedule. Therefore, we cannot rule out the possibility that some subjects might have been exposed to the virus before the vaccine schedule was completed. Health-care workers often do not realize that they are at risk of H B V infection, either because they are sometimes unaware that they have been exposed to blood and/or other body fluids or because HBsAg positive source patients are frequently not known to have H B V infection. 9 Moreover, the risk of infection is higher during the early years of health care work. In fact, a recent study has shown that recalled needlestick injury rate, which is a very frequent hazard, was 32% in subjects with less than five years of employment, but 28% ( P < 0.01) in those with more than 20 years' service, I° as an effect of increasing experience and skills with advancing seniority. These observations, combined with the increased risk observed in this survey for occupationally acquired hepatitis B infection in health workers, reiterate tile need for aggressive vaccination programmes in these subjects, especially during the first years of employment.
Acknowledgements This study was partially supported by Regione Campania, Assessorato alia SanitY. References 1. Dienstag, 3. L. & Ryan, D. M. (1982). Occupation exposure to hepatitis B virus in hospital personnel: infection or immunization? American Journal of Epidemiology, llS, 26-39.
Hepatitis B in Health Workers in Italy
437
2. Snydman, D. R., Munoz, A., Werner, B. G. et al. (1984). A multivariate analysis of risk factors for hepatitis B virus infection among hospital employees screened for vaccination. American Journal of Epidemiology , 120, 684-693. 3. Hadler, S. C., Dato, I. L., Maynard, J. E. et al. (1985). Occupational risk of hepatitis B infection in hospital workers. Infection Control, 6, 24-31. 4. Osterholm, M. T. & Garayalde, S. M. (1985). Clinical viral hepatitis B among Minnesota hospital personnel: results of a ten year statewide survey. Journal of the American Medical Association, 254, 3207-3212. 5. Gibas, A., Blewett, D. R., Schoenfeld, D. A. & Dienstag, J. L. (1992). Prevalence and incidence of viral hepatitis in health workers in the prehepatitis B vaccination era. American Journal of Epidemiology, 136, 603-610. 6. Mele, A., Rosmini, F. & Zampieri, A. (1986). Integrated epidemiological system for acute viral hepatitis in Italy (SEIEVA): description and preliminary results. European Journal of Epidemiology, 2,300-304. 7. Istat: Annuario Statistico Italiauo 1991. 8. Mele, A., Catapano, R., Ferrigno, L. et al. (1991). SEIEVA, Rapporto Annuale 1991. Istisan, 16, 1-40. 9. Lanphear, B. P., Linneman, C. C., Cannon, G. C. & De Ronde, M. M. (1993). Decline of clinical hepatitis B in workers at a general hospital: relation to increasing vaccine-induced immunity. Clinical Infectious Diseases, 16, 10-14. 10. Albertoni, F., Ippolito, G., Petrosillo, N. et al. (1992). Needlestick injury in hospital personnel: a multicenter survey from central Italy. Infection Control and Hospital Epidemiology , 13,540-544.