INFECTION AND IMMUNITY, Apr. 1975, p. 732-736 Copyright © 1975 American Society for Microbiology
Vol. 11, No. 4 Printed in U.S.A.
Prevalence of Antibody to Hepatitis B Surface Antigen in Various Populations G. G. FROESNER,1 D. A. PETERSON,* A. W. HOLMES, AND F. W. DEINHARDT Departments of Microbiology and Medicine, Rush-Presbyterian-St. Luke's Medical Center,* and the Department of Microbiology, University of Illinois Medical Center, Chicago, Illinois 60612
Received for publication 21 October 1974
Sera from individuals with different degrees of exposure to the agent of hepatitis B were tested for antibodies to hepatitis B surface antigen (anti-HB8) by passive hemagglutination and for hepatitis B surface antigen (HBS Ag) by radioimmunoassay and immunoelectroosmophoresis. In a plasma fractionation plant, anti-HB8 was detected in 82% of workers processing human plasma and 3.3% were healthy carriers of the antigen. Fifty-six percent of the workers having only casual contact with plasma processing exhibited anti-HB5 and 24% of workers with no contact had anti-HB8, yet HB8 Ag was not found in either of these two groups of workers. A similar correlation was shown in hospital personnel; 31% of employees with direct contact to serum specimens and only 8% without direct contact had anti-HB,. The frequency of HB8 Ag (0.8% in patients with disorders not involving the liver; 49.8% in patients tentatively diagnosed as viral hepatitis) and anti-HB8 (14.5% to 28.5%, respectively) in selected groups of hospitalized patients varied greatly. In 508 paid blood donors, anti-HB8 was present in 19.9%, whereas it was present in only 6.6% of 1,146 volunteer donors. These data demonstrate a correlation between frequency of exposure to human blood or blood products and the prevalence of anti-HB,.
Hepatitis B surface antigen (HBS Ag) (1) has clearly been associated with serum hepatitis (hepatitis B) (14), but early epidemiologic investigations were hindered by the failure to detect antibodies to hepatitis B surface antigen (anti-HB8) after primary infection (3, 4, 8). The development of more sensitive techniques (radioimmunoassay [2, 9, 22]) and passive hemagglutination (21) permitted the detection of low levels of both HB8 Ag and anti-HB8 in study populations. Walsh et al. (22) found anti-HB8 in 16% of patients admitted to a large Veterans Administration Hospital with illness not related to hepatitis. Lander et al. (9) showed that 22.6% of a blood donor population had anti-HB8. This report describes the correlation between the prevalence of HB5 Ag and anti-HB8 and the exposure to the agent of hepatitis B, present in human plasma and serum, in various populations. MATERIALS AND METHODS Sera from workers in a plasma fractionation plant. Due to a high incidence of hepatitis in workers of a plasma fractionation plant, an investigation was 'Present address: Department of Medical Virology and
Epidemiology of Virus Diseases, Hygiene-Institute of the University of Tuebingen, Tuebingen, West Germany.
conducted by the National Institute for Occupational Safety and Health (20). Serum was drawn from each worker and tested for HB. Ag and anti-HB. to determine the relationship between exposure to HB8 Ag and development of antibodies and/or the carrier state. The employees were divided in three groups according to their contact with human plasma and plasma products. A high exposure group of 91 workers was directly involved in the processing of plasma and 13 of these employees had had hepatitis between 1968 and 1971. A moderate exposure group consisted of 64 workers not directly involved in processing of plasma but having some contact with plasma fractions or products. Fifty-one workers, clerical and administrative, with no obvious exposure, served as controls. Sera from hospital personnel. Sera were obtained from 152 employees of Presbyterian-St.Luke's Hospital who had frequent contact with blood specimens or patients and from 112 employees with no direct exposure to patients or patient sera. The first group consisted of laboratory technicians, nurses, and physicians, and the second group of sera was collected from technical (without contact), administrative, and clerical personnel. Blood donor sera. Sera from 508 paid donors drawn at Presbyterian-St.Luke's Hospital in October to December 1969, which had been stored at -20 C, were retested for HB. Ag and anti-HB.. In a 42-day period, October to December 1972, 1,146 volunteer blood donors were tested for HB. Ag and anti-HB.. Of these volunteers, 658 were drawn in the blood bank of
7:32
VOL. 11, 1975
PREVALENCE OF ANTIBODY TO HBs AG
Presbyterian-St.Luke's Hospital and 488 were obtained from other transfusion services in the metropolitan area of Chicago. Sera from hospitalized patients. Sera were obtained from 508 patients with tentative diagnosis of viral hepatitis, 51 patients with various chronic liver diseases, and 51 patients of the hemodialysis unit. Three hundred and fifty-nine patients who were hospitalized for disorders other than those of the liver or kidney were selected by age and sex to match the chronic liver disease and hemodialysis patients. Testing for anti-HB, and HB. Ag. Testing for anti-HB, employed a passive hemagglutination technique, using HB. Ag-coated human erythrocytes and uncoated control cells (Virgo reagents). Sera were screened at dilutions of 1:4, 1:8, and 1:128. The 1:128 dilution was found to be necessary to eliminate occasional false negative results caused by an antibody prozone effect. Test specificity was determined by hemagglutination inhibition with known subtype HB. Ag. Antibody titers .1:4 were considered positive. Sera from the plasma fractionation plant and health-care workers and hospitalized patients were tested with both ad and ay HB. Ag-coated erythrocytes. For testing of blood donors only erythrocytes coated with the ad type were used. In our experience, testing with cells coated only with ad type HB. Ag fails to detect low titers of type ay anti-HB, in about 10% of the total number of sera giving positive results when tested with both ad and ay HB. Ag-coated cells. HB. Ag testing was done by solid-phase radioimmunoassay (Ausria-125, Abbott Laboratories). Radioimmunoassay results were calculated as suggested by the manufacturer (positive > 2.1 times the mean of seven simultaneous tests with one standardized negative control). Since nonspecific positive reactions have been reported (13, 15, 17) to occur in the radioimmunoassay test, the specificity of positive tests was confirmed by immunoelectroosmophoresis (Hapindex-60 Test, Ortho Diagnostic) and/or Ausria-125 confirmatory neutralization test (Abbott Laboratories).
733
tact) staff (Table 2). The dialysis unit (34.6%) and other medical staff (30.2%) were significantly different (P < 0.001) from the hospital administration staff (8%) but not from each other. In addition, three persons of the exposed group were healthy carriers of the antigen. Anti-HB5 and HBR Ag in paid donors. One hundred and one (19.9%) of these donors had detectable anti-HB. (Table 2). Thirteen (2.6) sera were positive for HB. Ag. Anti-HB. and HB5 Ag in volunteer blood donors. The above groups with high prevalence of anti-HB. were compared with 1,146 volunteer blood donors who were expected to have a normal exposure to the agent of 1hepatitis B. Only 76 (6.6%) anti-HB. positive sera were detected (Table 2). However, a significant (P < 0.0001) difference existed in the prevalence of TABLE 1. Hepatitis B surface antibody and hepatitis B surface antigen in plasma fractionation workers Group Group
Workers with direct contact Workers with indirect contact Workers with no con-
%
No.
%
No.
91
3
3
75 82
64
0
0
36
56
51
0
0
12
24
tactII
I
Solid-phase radioimmunoassay for HB. Ag. b Passive hemagglutination test for anti-HB5.
a
TABLE 2. Hepatitis B surface antibody and hepatitis B surface antigen in hospital personnel and blood donors
RESULTS
Prevalence of anti-HB. and HB. Ag in plasma fractionation workers. Of 91 workers who had been directly involved in the processing of plasma, three (3.3%) were carriers of the antigen and 75 (82%) exhibited anti-HB5. (Table 1). In the second lower exposure group, 56% showed anti-HB5, and in the group which had no obvious exposure to plasma, 24% exhibited anti-HB.. In the last two groups no HB, Ag was detected. The three groups exhibit significant differences (P < 0.001) among each other. Prevalence of anti-HBR and HBR Ag in hospital personnel. Sera from medical technicians, nurses, and physicians who have repeated contact with patients and/or to serum specimens were compared with sera from administrative, clerical, and technical (without con-
HB. Ag Anti-HB. positivea positive"
tedNo. ~~tested
Group
No.
tested
HB, Ag positivea No.
Dialysis unit staff Other medical staffc Hospital administration staff" Paid blood donors Volunteer blood do-
26 126 112 508
2,680
%
0 0 3 2.4 0 0
Anti-HB. positive'
No.
%
9 34.6 38 30.2 9 8.0
13 2.6 101 19.9 16 0.6 76 6.6
norse
Solid-phase radioimmunoassay for HB. Ag. 'Passive hemagglutination test for anti-HB,. c Other medical staff with patient or serum-plasma contact. d Hospital staff with no patient or serum-plasma a
contact.
e Only 1,146 of these donors were tested for antiHB8.
734
INFECT. IMMUN.
FROESNER ET AL.
anti-HB. between volunteer and paid donors.
Sixteen sera (0.6%) were positive for HB8 Ag. In 658 volunteer donors from the blood bank at Presbyterian-St.Luke's Hospital there was no significant difference in the percentage of antiHB.-positive donors living in the city of Chicago as compared to donors living in the suburbs (Table 3). There was a slightly higher percentage of anti-HB.-positive female donors compared to male donors which was, however, not significant. This difference may be due to the higher percentage of females working in occupations which expose them more frequently to the hazard of hepatitis. The volunteer donor histories revealed that 9% of the female donors, but only 1% of the male donors, were working in the medical fields. Of 13 anti-HB,-positive females, three worked as medical technicians and one as a nurse, whereas none of the 26 anti-HB8-positive males worked in professions with high prevalence of exposure to hepatitis. Examining the different age groups, the percentage of anti-HB.-positive donors increased from 2.7% in donors 18 to 25 years of age to 7.4% in donors 46 to 55 years of age (Table 3). Anti-HB8 and HB8 Ag in hospitalized patients. Of 508 hospitalized patients who were tentatively diagnosed as having viral hepatitis, 49.8% had detectable HB8 Ag and 28.5% had anti-HB8 (Table 4). Although the frequency of anti-HB8 in chronic liver disease patients (21.6%) and hemodialysis patients (23.5%) was essentially the same, the chronic liver disease patients had significantly (P < 0.001) more HB8 Ag-positive individuals (23.5% versus 1.9%). The "other disorders" patient group had signifi-
TABLE 4. Hepatitis B surface antibody and hepatitis B surface antigen in hospitalized patients Group
No. tested
HB. Ag
Anti-HB.
positivea
- positiveb __ No. %
No.
Suspected viral
508
%
253 49.8 145 28.5
hepatitis Chronic liver disease Hemodialysis patients Other disordersc
51
12 23.5
11 21.6
51
1
1.9
12 23.5
359
3
0.8
52 14.5
Solid-phase radioimmunoassay for HB. Ag. bPassive hemagglutination test for anti-HB8. c Patients who were hospitalized for disorders other than those of the liver were selected by age and sex to match the chronic liver disease and hemodialysis patients. a
cantly less HB, Ag (P < 0.001)- and anti-HB8 (P < 0.01 and P < 0.001)-positive individuals than the other three groups of patients.
DISCUSSION Plasma fractionation workers have a unique exposure to the agents of hepatitis in human plasma. An expression of this exposure is the high prevalence of anti-HB8 found in these employees. Eighty-two percent of the workers actually pooling plasma and 56% of these individuals who had contact with plasma fractions or products exhibited anti-HB8, whereas only 24% of the workers with no direct contact to plasma or plasma products had detectable antibody. A similar high antibody prevalence of 83% has been shown only in multiple transfused TABLE 3. Prevalence of hepatitis B surface antibody patients by Lander et al. (9), by using a in 658 volunteer blood donors by residential area, sex, radioimmunoprecipitation test. It is of particuand age lar interest that although 82% of workers who had direct contact with plasma processing had Anti-HB. anti-HB5, only 14 (15.4%) had had hepatitis and Group No. tested one of these did not have detectable anti-HB,. No. % From this group of 91 workers with direct contact, three (3.3%) were found to be carriers City residence of HB. Ag, but only one had had clinical Male 237 16 6.7 hepatitis. Female 83 7 8.5 The occupational hazard of hepatitis among Suburban residence Male medical, nursing, and laboratory staff is well 239 10 4.2 Female 99 6 6.3 recognized (7, 11, 16, 23) and the risk seems to be Age group (years) especially great among laboratory workers hand18-25 185 5 2.7 ling human serum and plasma specimens (7). 26-35 187 11 5.9 Patients with viral hepatitis and chronic liver 36-45 144 10 6.9 diseases, and hemodialysis patients, are poten46-55 94 7 7.4 tial sources of infection as indicated by the high >56 48 3 6.3 frequency of HB8 Ag and anti-HB8 found here Passive hemagglutination test for anti-HB,. and by others (3, 5, 19). In the health-care positive
a
VOL. ll, 1975
PREVALENCE OF ANTIBODY TO HBs AG
workers studied here, 31% of those with patient, plasma, or serum contact had anti-HB5 as compared to only 8% of the administrative staff. Six (3.9%) of the former had had clinical hepatitis, and two individuals with no history of hepatitis were found to be carriers of HB8 Ag, yet 31% of these workers had detectable antiHB.. Lewis et al. (11) in an extensive study, primarily on National Institutes of Health personnel, found no significant difference in the frequency of HB, Ag and a twofold difference in anti-HB8 between health-care workers and other professions. The low-exposure health-care worker exhibited an antibody prevalence (8%) similar to the volunteer blood donors (6.6%) but significantly different (P < 0.001) from the paid blood donors, whereas the low-risk plasma fractionation workers and the paid donors were similar (24% and 19.9%, respectively). Since blood donors are a selected population of healthy subjects, with negative history of previous hepatitis, the anti-HB8 prevalence of a normal population can be assumed to lay between the above values. In a normal population in Washington D.C., 20% had anti-HB8 (10), whereas in the New York metropolitan area 20% of paid donors but only 6.7% of volunteer donors had detectable anti-HB8 (18). These results are very similar to those found in our blood donors. Szmuness et al. (18) found HB8 Ag two times more frequently in donors in New York City than in those residing in the suburban communities. A high incidence of HB. Ag among male donors has been described in different countries (6, 18) but this was not reflected in the antibody pattern of the relatively small number of volunteer donors tested here, nor was there a significant difference between donors living in the city and donors living in suburbs, or between males and females. These data show a correlation between exposure to the agent of hepatitis B and the prevalence of anti-HB8 in various populations. Six of seven individuals of the high risk groups with anti-HB8 had no history of overt hepatitis, which indicates a substantial level (85%) of inapparent infections. The prevalence of anti-HB8 in health-care workers is similar to that reported by others (7, 11, 16, 19, 23) but the frequency of anti-HB8 in the plasma processing plant workers is strikingly higher. ACKNOWLEDGMENTS This investigation was supported by the U.S. Army Medical Research and Development Command grant DADA-17-73-C-3136, by Public Health Service grant RR-05477 from the General Research Support Branch, Division of
735
Research Facilities and Resources, and by the Liver Research Fund, Rush-Presbyterian-St. Luke's Medical Center. G. Froesner is the recipient of a grant from the Deutsche Forschungsgemeinschaft. We thank Peter Knoblauch for technical assistance. LITERATURE CITED 1. Blumberg, B. S., H. J. Alter, and S. Visnich. 1965. A "new" antigen in leukemia sera. J. Am. Med. Assoc. 191:101-106. 2. Coller, J. A., J. Millman, T. C. Halbherr, and B. S. Blumberg. 1971. Radioimmunoprecipitation assay for Australia antigen, antibody and antigen-antibody complexes. Proc. Soc. Exp. Biol. Med. 138:249-257. 3. Gavrila, J., C. Pasravia, I. Onescive, M. Feticu, and M. Crisan. 1972. Hepatitis-associated antigen and specific antibodies in sera of convalescent patients with viral hepatitis. J. Infect. Dis. 126:200-202. 4. Greenberg, H. B., and D. J. Grocke. 1971. An analysis of antibody response to Australia antigen in man. J. Infect. Dis. 123:356-3645. Hacker, E. J., and R. D. Aach. 1973. Detection of hepatitis-associated antigen and antibody: comparison of radioimmunoassay and counterimmunoelectrophoresis. J. Am. Med. Assoc. 223:414-417. 6. Kliman, A., N. R. Reid, C. Lilly, and J. Morrison. 1971. Hepatitis-associated antigen (Australia antigen) in Massachusetts blood donors. N. Engl. J. Med. 285:783-785. 7. Koff, R. S., and K. J. Isselbacher. 1968. Changing concepts in the epidemiology of viral hepatitis. N. Engl. J. Med. 278:1371-1380. 8. Krugman, S., and J. P. Giles. 1970. Viral hepatitis. New light on an old disease. J. Am. Med. Assoc. 212:10191029. 9. Lander, J. J., H. J. Alter, and R. H. Purcell. 1971. Frequence of antibody to hepatitis-associated antigen as measured by a new radioimmunoassay technique. J. Immunol. 106:1166-1171. 10. Lander, J. J., P. V. Holland, H. J. Alter, R. M. Chanock, and R. H. Prince. 1972. Antibody to hepatitisassociated antigen; frequency and pattern of response as detected by radioimmunoprecipitation. J. Am. Med. Assoc. 220:1079-1082. 11. Lewis, T. L., H. J. Alter, T. C. Chalmers, P. V. Holland, R. H. Purcell, D. W. Alling, D. Young, L. D. Frankel, S. L. Lee, and M. E. Jamson. 1973. A comparison of the frequency of hepatitis-B antigen and antibody in hospital and nonhospital personnel. N. Engl. J. Med. 289:647-651. 12. Okochi, K., M. Mayumi, Y. Haguino, and N. Saito. 1970. Evaluation of frequency of Australia antigen in blood donors of Tokyo by means of immune adherence hemagglutination technique. Vox Sang. 19:332-337. 13. Peterson, D. A., G. G. Froesner, and F. W. Deinhardt. 1973. Evaluation of passive hemagglutination, solid phase radioimmunoassay and immunoelectroosmophoresis for the detection of hepatitis B antigen. Appl. Microbiol. 26:376-380. 14. Prince, A. M. 1968. An antigen detected in the blood during the incubation period of serum hepatitis. Proc. Natl. Acad. Sci. U.S.A. 60:814-821. 15. Prince, A. M., D. Jass, B. Brotman, and H. Ikram. 1973. Specificity of the direct solid-phase radioimmunoassay for the detection of hepatitis B antigen. Lancet 1:1346-1350. 16. Rosenberg, J. L., D. P. Jones, L. R. Lipitz, and J. B. Kirisner. 1973. Viral hepatitis: an occupational hazard to surgeons. J. Am. Med. Assoc. 223:395-400. 17. Sagouris, J. T. 1973. Limitations of the radioimmunoassay for hepatitis B antigen. N. Engl. J. Med.
736
FROESNER ET AL.
288:160-161. 18. Szmuness, W., A. M. Prince, B. Brotman, and R. L. Hirsel. 1973. Hepatitis B antigen and antibody in blood donors: an epidemiologic study. J. Infect. Dis. 127:17-25. 19. Szmuness, W., A. M. Prince, G. F. Grady, M. K. Mann, R. W. Levine, E. A. Friedman, M. J. Jacobs, A. Josephson, S. Ribot, F. L. Shapiro, K. H. Stenzel, W. N. Suki, and G. Vyas. 1974. Hepatitis B infection a point-prevalence study of 15 U.S. hemodialysis centers. J. Am. Med. Assoc. 277:901-916. 20. Taylor, J. S., E. Shmunes, and A. W. Holmes. 1974. Hepatitis B in plasma fractionation workers. J. Am.
INFECT. IMMUN.
Med. Assoc. 230:850-853. 21. Vyas, G. H., and N. R. Shulman. 1970. Hemagglutination assay for antigen and antibody associated with viral hepatitis. Science 170:332-33. 22. Walsh, J. H., R. Yalow, and S. A. Berson. 1970. Determination of Australia antigen and antibody by means of radioimmunoassay technique. J. Infect. Dis. 121:550-554. 23. Watson, D., D. J. Langley, I. L. Charystie, M. N. Islam, J. Bertrand, and J. E. Banatvala. 1973. Hepatitis B antigen and safety in pathology laboratories. Lancet 1:985-988.
Vol. 11, No. 4 Printed in U.S.A.
Prevalence of Antibody to Hepatitis B Surface Antigen in Various Populations G. G. FROESNER,1 D. A. PETERSON,* A. W. HOLMES, AND F. W. DEINHARDT Departments of Microbiology and Medicine, Rush-Presbyterian-St. Luke's Medical Center,* and the Department of Microbiology, University of Illinois Medical Center, Chicago, Illinois 60612
Received for publication 21 October 1974
Sera from individuals with different degrees of exposure to the agent of hepatitis B were tested for antibodies to hepatitis B surface antigen (anti-HB8) by passive hemagglutination and for hepatitis B surface antigen (HBS Ag) by radioimmunoassay and immunoelectroosmophoresis. In a plasma fractionation plant, anti-HB8 was detected in 82% of workers processing human plasma and 3.3% were healthy carriers of the antigen. Fifty-six percent of the workers having only casual contact with plasma processing exhibited anti-HB5 and 24% of workers with no contact had anti-HB8, yet HB8 Ag was not found in either of these two groups of workers. A similar correlation was shown in hospital personnel; 31% of employees with direct contact to serum specimens and only 8% without direct contact had anti-HB,. The frequency of HB8 Ag (0.8% in patients with disorders not involving the liver; 49.8% in patients tentatively diagnosed as viral hepatitis) and anti-HB8 (14.5% to 28.5%, respectively) in selected groups of hospitalized patients varied greatly. In 508 paid blood donors, anti-HB8 was present in 19.9%, whereas it was present in only 6.6% of 1,146 volunteer donors. These data demonstrate a correlation between frequency of exposure to human blood or blood products and the prevalence of anti-HB,.
Hepatitis B surface antigen (HBS Ag) (1) has clearly been associated with serum hepatitis (hepatitis B) (14), but early epidemiologic investigations were hindered by the failure to detect antibodies to hepatitis B surface antigen (anti-HB8) after primary infection (3, 4, 8). The development of more sensitive techniques (radioimmunoassay [2, 9, 22]) and passive hemagglutination (21) permitted the detection of low levels of both HB8 Ag and anti-HB8 in study populations. Walsh et al. (22) found anti-HB8 in 16% of patients admitted to a large Veterans Administration Hospital with illness not related to hepatitis. Lander et al. (9) showed that 22.6% of a blood donor population had anti-HB8. This report describes the correlation between the prevalence of HB5 Ag and anti-HB8 and the exposure to the agent of hepatitis B, present in human plasma and serum, in various populations. MATERIALS AND METHODS Sera from workers in a plasma fractionation plant. Due to a high incidence of hepatitis in workers of a plasma fractionation plant, an investigation was 'Present address: Department of Medical Virology and
Epidemiology of Virus Diseases, Hygiene-Institute of the University of Tuebingen, Tuebingen, West Germany.
conducted by the National Institute for Occupational Safety and Health (20). Serum was drawn from each worker and tested for HB. Ag and anti-HB. to determine the relationship between exposure to HB8 Ag and development of antibodies and/or the carrier state. The employees were divided in three groups according to their contact with human plasma and plasma products. A high exposure group of 91 workers was directly involved in the processing of plasma and 13 of these employees had had hepatitis between 1968 and 1971. A moderate exposure group consisted of 64 workers not directly involved in processing of plasma but having some contact with plasma fractions or products. Fifty-one workers, clerical and administrative, with no obvious exposure, served as controls. Sera from hospital personnel. Sera were obtained from 152 employees of Presbyterian-St.Luke's Hospital who had frequent contact with blood specimens or patients and from 112 employees with no direct exposure to patients or patient sera. The first group consisted of laboratory technicians, nurses, and physicians, and the second group of sera was collected from technical (without contact), administrative, and clerical personnel. Blood donor sera. Sera from 508 paid donors drawn at Presbyterian-St.Luke's Hospital in October to December 1969, which had been stored at -20 C, were retested for HB. Ag and anti-HB.. In a 42-day period, October to December 1972, 1,146 volunteer blood donors were tested for HB. Ag and anti-HB.. Of these volunteers, 658 were drawn in the blood bank of
7:32
VOL. 11, 1975
PREVALENCE OF ANTIBODY TO HBs AG
Presbyterian-St.Luke's Hospital and 488 were obtained from other transfusion services in the metropolitan area of Chicago. Sera from hospitalized patients. Sera were obtained from 508 patients with tentative diagnosis of viral hepatitis, 51 patients with various chronic liver diseases, and 51 patients of the hemodialysis unit. Three hundred and fifty-nine patients who were hospitalized for disorders other than those of the liver or kidney were selected by age and sex to match the chronic liver disease and hemodialysis patients. Testing for anti-HB, and HB. Ag. Testing for anti-HB, employed a passive hemagglutination technique, using HB. Ag-coated human erythrocytes and uncoated control cells (Virgo reagents). Sera were screened at dilutions of 1:4, 1:8, and 1:128. The 1:128 dilution was found to be necessary to eliminate occasional false negative results caused by an antibody prozone effect. Test specificity was determined by hemagglutination inhibition with known subtype HB. Ag. Antibody titers .1:4 were considered positive. Sera from the plasma fractionation plant and health-care workers and hospitalized patients were tested with both ad and ay HB. Ag-coated erythrocytes. For testing of blood donors only erythrocytes coated with the ad type were used. In our experience, testing with cells coated only with ad type HB. Ag fails to detect low titers of type ay anti-HB, in about 10% of the total number of sera giving positive results when tested with both ad and ay HB. Ag-coated cells. HB. Ag testing was done by solid-phase radioimmunoassay (Ausria-125, Abbott Laboratories). Radioimmunoassay results were calculated as suggested by the manufacturer (positive > 2.1 times the mean of seven simultaneous tests with one standardized negative control). Since nonspecific positive reactions have been reported (13, 15, 17) to occur in the radioimmunoassay test, the specificity of positive tests was confirmed by immunoelectroosmophoresis (Hapindex-60 Test, Ortho Diagnostic) and/or Ausria-125 confirmatory neutralization test (Abbott Laboratories).
733
tact) staff (Table 2). The dialysis unit (34.6%) and other medical staff (30.2%) were significantly different (P < 0.001) from the hospital administration staff (8%) but not from each other. In addition, three persons of the exposed group were healthy carriers of the antigen. Anti-HB5 and HBR Ag in paid donors. One hundred and one (19.9%) of these donors had detectable anti-HB. (Table 2). Thirteen (2.6) sera were positive for HB. Ag. Anti-HB. and HB5 Ag in volunteer blood donors. The above groups with high prevalence of anti-HB. were compared with 1,146 volunteer blood donors who were expected to have a normal exposure to the agent of 1hepatitis B. Only 76 (6.6%) anti-HB. positive sera were detected (Table 2). However, a significant (P < 0.0001) difference existed in the prevalence of TABLE 1. Hepatitis B surface antibody and hepatitis B surface antigen in plasma fractionation workers Group Group
Workers with direct contact Workers with indirect contact Workers with no con-
%
No.
%
No.
91
3
3
75 82
64
0
0
36
56
51
0
0
12
24
tactII
I
Solid-phase radioimmunoassay for HB. Ag. b Passive hemagglutination test for anti-HB5.
a
TABLE 2. Hepatitis B surface antibody and hepatitis B surface antigen in hospital personnel and blood donors
RESULTS
Prevalence of anti-HB. and HB. Ag in plasma fractionation workers. Of 91 workers who had been directly involved in the processing of plasma, three (3.3%) were carriers of the antigen and 75 (82%) exhibited anti-HB5. (Table 1). In the second lower exposure group, 56% showed anti-HB5, and in the group which had no obvious exposure to plasma, 24% exhibited anti-HB.. In the last two groups no HB, Ag was detected. The three groups exhibit significant differences (P < 0.001) among each other. Prevalence of anti-HBR and HBR Ag in hospital personnel. Sera from medical technicians, nurses, and physicians who have repeated contact with patients and/or to serum specimens were compared with sera from administrative, clerical, and technical (without con-
HB. Ag Anti-HB. positivea positive"
tedNo. ~~tested
Group
No.
tested
HB, Ag positivea No.
Dialysis unit staff Other medical staffc Hospital administration staff" Paid blood donors Volunteer blood do-
26 126 112 508
2,680
%
0 0 3 2.4 0 0
Anti-HB. positive'
No.
%
9 34.6 38 30.2 9 8.0
13 2.6 101 19.9 16 0.6 76 6.6
norse
Solid-phase radioimmunoassay for HB. Ag. 'Passive hemagglutination test for anti-HB,. c Other medical staff with patient or serum-plasma contact. d Hospital staff with no patient or serum-plasma a
contact.
e Only 1,146 of these donors were tested for antiHB8.
734
INFECT. IMMUN.
FROESNER ET AL.
anti-HB. between volunteer and paid donors.
Sixteen sera (0.6%) were positive for HB8 Ag. In 658 volunteer donors from the blood bank at Presbyterian-St.Luke's Hospital there was no significant difference in the percentage of antiHB.-positive donors living in the city of Chicago as compared to donors living in the suburbs (Table 3). There was a slightly higher percentage of anti-HB.-positive female donors compared to male donors which was, however, not significant. This difference may be due to the higher percentage of females working in occupations which expose them more frequently to the hazard of hepatitis. The volunteer donor histories revealed that 9% of the female donors, but only 1% of the male donors, were working in the medical fields. Of 13 anti-HB,-positive females, three worked as medical technicians and one as a nurse, whereas none of the 26 anti-HB8-positive males worked in professions with high prevalence of exposure to hepatitis. Examining the different age groups, the percentage of anti-HB.-positive donors increased from 2.7% in donors 18 to 25 years of age to 7.4% in donors 46 to 55 years of age (Table 3). Anti-HB8 and HB8 Ag in hospitalized patients. Of 508 hospitalized patients who were tentatively diagnosed as having viral hepatitis, 49.8% had detectable HB8 Ag and 28.5% had anti-HB8 (Table 4). Although the frequency of anti-HB8 in chronic liver disease patients (21.6%) and hemodialysis patients (23.5%) was essentially the same, the chronic liver disease patients had significantly (P < 0.001) more HB8 Ag-positive individuals (23.5% versus 1.9%). The "other disorders" patient group had signifi-
TABLE 4. Hepatitis B surface antibody and hepatitis B surface antigen in hospitalized patients Group
No. tested
HB. Ag
Anti-HB.
positivea
- positiveb __ No. %
No.
Suspected viral
508
%
253 49.8 145 28.5
hepatitis Chronic liver disease Hemodialysis patients Other disordersc
51
12 23.5
11 21.6
51
1
1.9
12 23.5
359
3
0.8
52 14.5
Solid-phase radioimmunoassay for HB. Ag. bPassive hemagglutination test for anti-HB8. c Patients who were hospitalized for disorders other than those of the liver were selected by age and sex to match the chronic liver disease and hemodialysis patients. a
cantly less HB, Ag (P < 0.001)- and anti-HB8 (P < 0.01 and P < 0.001)-positive individuals than the other three groups of patients.
DISCUSSION Plasma fractionation workers have a unique exposure to the agents of hepatitis in human plasma. An expression of this exposure is the high prevalence of anti-HB8 found in these employees. Eighty-two percent of the workers actually pooling plasma and 56% of these individuals who had contact with plasma fractions or products exhibited anti-HB8, whereas only 24% of the workers with no direct contact to plasma or plasma products had detectable antibody. A similar high antibody prevalence of 83% has been shown only in multiple transfused TABLE 3. Prevalence of hepatitis B surface antibody patients by Lander et al. (9), by using a in 658 volunteer blood donors by residential area, sex, radioimmunoprecipitation test. It is of particuand age lar interest that although 82% of workers who had direct contact with plasma processing had Anti-HB. anti-HB5, only 14 (15.4%) had had hepatitis and Group No. tested one of these did not have detectable anti-HB,. No. % From this group of 91 workers with direct contact, three (3.3%) were found to be carriers City residence of HB. Ag, but only one had had clinical Male 237 16 6.7 hepatitis. Female 83 7 8.5 The occupational hazard of hepatitis among Suburban residence Male medical, nursing, and laboratory staff is well 239 10 4.2 Female 99 6 6.3 recognized (7, 11, 16, 23) and the risk seems to be Age group (years) especially great among laboratory workers hand18-25 185 5 2.7 ling human serum and plasma specimens (7). 26-35 187 11 5.9 Patients with viral hepatitis and chronic liver 36-45 144 10 6.9 diseases, and hemodialysis patients, are poten46-55 94 7 7.4 tial sources of infection as indicated by the high >56 48 3 6.3 frequency of HB8 Ag and anti-HB8 found here Passive hemagglutination test for anti-HB,. and by others (3, 5, 19). In the health-care positive
a
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PREVALENCE OF ANTIBODY TO HBs AG
workers studied here, 31% of those with patient, plasma, or serum contact had anti-HB5 as compared to only 8% of the administrative staff. Six (3.9%) of the former had had clinical hepatitis, and two individuals with no history of hepatitis were found to be carriers of HB8 Ag, yet 31% of these workers had detectable antiHB.. Lewis et al. (11) in an extensive study, primarily on National Institutes of Health personnel, found no significant difference in the frequency of HB, Ag and a twofold difference in anti-HB8 between health-care workers and other professions. The low-exposure health-care worker exhibited an antibody prevalence (8%) similar to the volunteer blood donors (6.6%) but significantly different (P < 0.001) from the paid blood donors, whereas the low-risk plasma fractionation workers and the paid donors were similar (24% and 19.9%, respectively). Since blood donors are a selected population of healthy subjects, with negative history of previous hepatitis, the anti-HB8 prevalence of a normal population can be assumed to lay between the above values. In a normal population in Washington D.C., 20% had anti-HB8 (10), whereas in the New York metropolitan area 20% of paid donors but only 6.7% of volunteer donors had detectable anti-HB8 (18). These results are very similar to those found in our blood donors. Szmuness et al. (18) found HB8 Ag two times more frequently in donors in New York City than in those residing in the suburban communities. A high incidence of HB. Ag among male donors has been described in different countries (6, 18) but this was not reflected in the antibody pattern of the relatively small number of volunteer donors tested here, nor was there a significant difference between donors living in the city and donors living in suburbs, or between males and females. These data show a correlation between exposure to the agent of hepatitis B and the prevalence of anti-HB8 in various populations. Six of seven individuals of the high risk groups with anti-HB8 had no history of overt hepatitis, which indicates a substantial level (85%) of inapparent infections. The prevalence of anti-HB8 in health-care workers is similar to that reported by others (7, 11, 16, 19, 23) but the frequency of anti-HB8 in the plasma processing plant workers is strikingly higher. ACKNOWLEDGMENTS This investigation was supported by the U.S. Army Medical Research and Development Command grant DADA-17-73-C-3136, by Public Health Service grant RR-05477 from the General Research Support Branch, Division of
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Research Facilities and Resources, and by the Liver Research Fund, Rush-Presbyterian-St. Luke's Medical Center. G. Froesner is the recipient of a grant from the Deutsche Forschungsgemeinschaft. We thank Peter Knoblauch for technical assistance. LITERATURE CITED 1. Blumberg, B. S., H. J. Alter, and S. Visnich. 1965. A "new" antigen in leukemia sera. J. Am. Med. Assoc. 191:101-106. 2. Coller, J. A., J. Millman, T. C. Halbherr, and B. S. Blumberg. 1971. Radioimmunoprecipitation assay for Australia antigen, antibody and antigen-antibody complexes. Proc. Soc. Exp. Biol. Med. 138:249-257. 3. Gavrila, J., C. Pasravia, I. Onescive, M. Feticu, and M. Crisan. 1972. Hepatitis-associated antigen and specific antibodies in sera of convalescent patients with viral hepatitis. J. Infect. Dis. 126:200-202. 4. Greenberg, H. B., and D. J. Grocke. 1971. An analysis of antibody response to Australia antigen in man. J. Infect. Dis. 123:356-3645. Hacker, E. J., and R. D. Aach. 1973. Detection of hepatitis-associated antigen and antibody: comparison of radioimmunoassay and counterimmunoelectrophoresis. J. Am. Med. Assoc. 223:414-417. 6. Kliman, A., N. R. Reid, C. Lilly, and J. Morrison. 1971. Hepatitis-associated antigen (Australia antigen) in Massachusetts blood donors. N. Engl. J. Med. 285:783-785. 7. Koff, R. S., and K. J. Isselbacher. 1968. Changing concepts in the epidemiology of viral hepatitis. N. Engl. J. Med. 278:1371-1380. 8. Krugman, S., and J. P. Giles. 1970. Viral hepatitis. New light on an old disease. J. Am. Med. Assoc. 212:10191029. 9. Lander, J. J., H. J. Alter, and R. H. Purcell. 1971. Frequence of antibody to hepatitis-associated antigen as measured by a new radioimmunoassay technique. J. Immunol. 106:1166-1171. 10. Lander, J. J., P. V. Holland, H. J. Alter, R. M. Chanock, and R. H. Prince. 1972. Antibody to hepatitisassociated antigen; frequency and pattern of response as detected by radioimmunoprecipitation. J. Am. Med. Assoc. 220:1079-1082. 11. Lewis, T. L., H. J. Alter, T. C. Chalmers, P. V. Holland, R. H. Purcell, D. W. Alling, D. Young, L. D. Frankel, S. L. Lee, and M. E. Jamson. 1973. A comparison of the frequency of hepatitis-B antigen and antibody in hospital and nonhospital personnel. N. Engl. J. Med. 289:647-651. 12. Okochi, K., M. Mayumi, Y. Haguino, and N. Saito. 1970. Evaluation of frequency of Australia antigen in blood donors of Tokyo by means of immune adherence hemagglutination technique. Vox Sang. 19:332-337. 13. Peterson, D. A., G. G. Froesner, and F. W. Deinhardt. 1973. Evaluation of passive hemagglutination, solid phase radioimmunoassay and immunoelectroosmophoresis for the detection of hepatitis B antigen. Appl. Microbiol. 26:376-380. 14. Prince, A. M. 1968. An antigen detected in the blood during the incubation period of serum hepatitis. Proc. Natl. Acad. Sci. U.S.A. 60:814-821. 15. Prince, A. M., D. Jass, B. Brotman, and H. Ikram. 1973. Specificity of the direct solid-phase radioimmunoassay for the detection of hepatitis B antigen. Lancet 1:1346-1350. 16. Rosenberg, J. L., D. P. Jones, L. R. Lipitz, and J. B. Kirisner. 1973. Viral hepatitis: an occupational hazard to surgeons. J. Am. Med. Assoc. 223:395-400. 17. Sagouris, J. T. 1973. Limitations of the radioimmunoassay for hepatitis B antigen. N. Engl. J. Med.
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288:160-161. 18. Szmuness, W., A. M. Prince, B. Brotman, and R. L. Hirsel. 1973. Hepatitis B antigen and antibody in blood donors: an epidemiologic study. J. Infect. Dis. 127:17-25. 19. Szmuness, W., A. M. Prince, G. F. Grady, M. K. Mann, R. W. Levine, E. A. Friedman, M. J. Jacobs, A. Josephson, S. Ribot, F. L. Shapiro, K. H. Stenzel, W. N. Suki, and G. Vyas. 1974. Hepatitis B infection a point-prevalence study of 15 U.S. hemodialysis centers. J. Am. Med. Assoc. 277:901-916. 20. Taylor, J. S., E. Shmunes, and A. W. Holmes. 1974. Hepatitis B in plasma fractionation workers. J. Am.
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