A hepatitis B vaccination program in a community teaching hospital

Sexual dimorphism of humoral immunity with human vaccines

It has been contended that limited data exist on sex-difference in immune response with vaccines in humans. However, a comprehensive search of the literature retrieved 97 studies with 14 vaccines influenza (7 studies), hepatitis A (15 studies), hepatitis B (50 studies), pnuemococcal polysaccaride (4 studies), diphtheria (4 studies), rubella (3 studies), measles (2 studies), yellow fever (3 studies), meningococcal A (1 study), meningococcal C (1 study), tetanus (1 study), brucella (1 study), Venezuelan equine encephalitis (1 study) and rabies (4 studies), with sex-difference in humoral (antibody) response. These differences are associated with sex-difference in the clinical efficacy of influenza, hepatitis A, hepatitis B, pneumococcal polysaccharide and diphtheria vaccines and significant adverse reactions with rubella, measles and yellow fever vaccines. The genesis of these differences is uncertain but not entirely related to gonadal hormones (differences are seen in pre-pubertal and post-menopausal subjects not on hormone replacement therapy) or female sex (males had greater serological response for pneumococcal, diphtheria, yellow fever, Venezuelan equine encephalitis and in some studies with rabies vaccine. As sex-difference in humoral immune response was seen with most vaccines which cover the spectrum of mechanisms by which infectious agents cause disease (mucosal replication, viral viraemia, bacterial bacteraemia, toxin production and neuronal invasion), it is mandatory that vaccine trialists recruit a representative sample of females and males to be able to assess sex-differences which may have clinical implications.

Antibody response to Engerix-BR and Recombivax-HBR hepatitis B vaccination in end-stage renal disease

Recombivax-HB (REC) and Engerix-B (ENG) are FDA-approved vaccines for hepatitis B virus (HBV) in end-stage renal disease (ESRD). This study compares antibody response rates between them in routine clinical practice. Patients completing the recommended 40 mug dose of REC (3 doses) or ENG (4 doses) between January 1, 2000 to April 30, 2003 were eligible. Patients with prior positive HBV surface antigen (HBsAg) or antibody (HBsAb) test results were excluded. The conversion rate and persistence of protective titer (HBsAb titer>or=10 IU/mL) were tracked for 1 year. A supplemental analysis of a one-to-one matched patient sample was also performed. REC patients (N=885) were older, had longer dialysis vintage, and had a larger proportion of whites than ENG patients (N=13,661). Cumulative conversion response was greater in ENG (58%) than REC (40%) at 1 year (p<0.0001). The odds ratio for response to ENG compared with REC was 1.96 (95% limits: 1.56, 2.45; p<0.0001) adjusted for age, gender, race, diabetes, vintage, BSA, hemoglobin, and eKt/V. Persistent protective HBsAb after 1 year was 77% (ENG) vs. 53% (REC). HBsAg was positive in 208 ENG patients (1.5%) with all but 1 because of transient, vaccine-related antigenemia. The difference in conversion response favoring ENG persisted in a one-to-one sample matched for age, gender, race, modality, and dialysis vintage. The study found higher seroconversion response to ENG compared with REC at several time points up to 1 year. Protective HBsAb disappeared in 23-47% of patients 1 year later, validating CDC recommendations to re-test HBsAb yearly. The observed difference in response rates may be related to the extra ENG dose given at the second month (0, 1, 2, 6 regimen). The study raises a hypothesis that requires confirmation in a prospective clinical trial.

Predictors of hepatitis B vaccine acceptance in health care workers

This article examines the relative importance of occupational, epidemiologic, and attitudinal factors in hepatitis B vaccine acceptance. A stratified random sample of 1,018 health care workers at risk for occupational blood exposure at our university hospital were contacted in 1992 and 919 (90%) participated. Potential reasons for vaccine acceptance or refusal were evaluated with factor analysis. Logistic regression models were calibrated on a stratified random subsample to identify independent predictors of initiating and completing the series, then validated on the remaining subjects. Fifty-four percent (482 of 898) of previously nonimmune workers had completed the series, while 70% (626) had received one or more doses. Hepatitis B vaccine acceptance was related strongly to social influence (physicians, supervisors, role models, friends, and spouse) and knowledge of the disease and vaccine, whereas refusal was primarily related to concern about vaccine side effects and problems with vaccine access. Independent predictors of initiating the vaccine series included younger age (odds ratio [OR] 0.98 per year, 95% confidence interval [CI95] 0.96-0.997), occupation (housestaff: OR 2.9, CI95 1.1-7.9; nurses: OR 2.1, CI95 1.0-4.3 versus housekeepers), increased blood exposure frequency (OR 2.4, CI95 1.6-3.5 for 1-6 versus 0 exposures in past year), and increased frequency of recent influenza vaccination (OR 3.3, CI95 2.0-5.3 for 1 versus 0 doses in prior 3 years). Occupation (increased acceptance among housestaff, nurses, nursing assistants, laboratory technicians), increased frequency of blood exposure, and recent influenza vaccination also were predictors of series completion. Factors such as occupation, blood exposure frequency and acceptance of other preventive services may help identify health care worker groups with low vaccine acceptance most likely to benefit from targeted vaccine delivery. Hepatitis B vaccine should be offered routinely during evaluation for occupational blood exposure. Future vaccine implementation efforts should emphasize the involvement of physicians and supervisors and education about occupational disease risk, liability, and the safety of the vaccine.

Risk factors for hepatitis C virus infection among health care personnel in a community hospital

OBJECTIVE

To determine the prevalence of and risk factors for antibody to the hepatitis C virus in hospital employees.

METHODS

Retrospective testing of serum samples obtained from 1677 hospital employees during a prehepatitis B vaccination program in a private teaching community hospital.

RESULTS

Twenty-three employees (1.4%) were found to have antibody to hepatitis C virus. The prevalence of antibody to hepatitis C virus was higher in blacks (3.4%) than in whites (1.1%, p = 0.03) and Hispanics (2.6%, p = 0.88). In a logistic regression model, factors significantly associated with antibody to hepatitis C virus seropositivity included antibody to hepatitis B core antigen (p = 0.002), a history of blood transfusion (p = 0.03), and needlestick injuries (p = 0.04).

CONCLUSION

Although the prevalence of antibody to hepatitis C virus in health care workers was not high, needlestick injuries were associated with an increased risk for acquiring hepatitis C virus infection.

Response to hepatitis B vaccine of persons positive for antibody to hepatitis B core antigen

The significance of antibody to hepatitis B core antigen (anti-HBc) present in a person's serum without hepatitis B surface antigen (HBsAg) or its antibody (anti-HBs) is unknown. Serum specimens from 281 persons initially positive only for anti-HBc by enzyme immunoassay (EIA) were retested by radioimmunoassay (RIA), and of these, 177 (63%) remained positive for anti-HBc by both assays. Of these 177 persons, 3 were positive for HBsAg, and 72 possessed low levels of anti-HBs [less than 10 sample ratio units; (SRU's)]. When persons positive for anti-HBc by EIA and RIA were given one 20-micrograms dose of plasma-derived hepatitis B vaccine and tested for anti-HBs 1 month later, a booster response was observed in 14 of 41 (34%) persons with low level anti-HBs and 3 of 50 (6%) persons negative for anti-HBs. Of those positive only for anti-HBc by EIA but negative by RIA, only 3 of 37 (8.1%) showed a booster response. Of those who completed the three-dose immunization series and did not show a booster response, 63 of 80 (78.8%) developed anti-HBs levels greater than 10 standard ratio unit. The majority of persons with isolated anti-HBc will have a primary rather than a booster response to hepatitis B vaccine.

Prevalence of hepatitis B surface antigen and antibody among health care employees in Negri Sembilan, Malaysia, 1989

This study was based on a hepatitis B screening program conducted in one of the states in Malaysia in 1989. The majority (84.6%) of the 2986 health employees were screened. One quarter (25%) was found to have serological markers for the Hepatitis B Virus (HBV); 2.1% had Hepatitis B surface Antigen (HBsAg) and 22.8% had antibody to the Hepatitis B surface Antigen (anti-HBs). The occurrence of HBsAg was higher in ethnic Chinese (6.3%) compared to Malays (1.8%) and Indians (0.9%), even when analyzed by sex, but not with age, type of institution and geographical locality. The distribution of anti-HBs was higher with ethnic Chinese (41.6%), male sex (27.2%) and age. There was a wide variation of the prevalence of serological markers among occupations and increased relative risks of HBsAg were found among medical assistants (RR3.7; 95% CI 1.4-9.1) and laboratory staff (RR 3.2; 95% CI 1-8.8), and that of anti-HBs among medical assistants (RR 2.8; 95% CI 1.8-3.7). The variations of HBsAg among occupations by type of institutions was marginal while that of anti-HBs was higher among attendants and midwives in hospitals, medical assistants in health departments, and assistant nurses and dentists in dental centers. The patterns of distribution of serological markers of HBV among health staff reflect the situation in the community with high endemicity and resemble specific occupational factors noted in previous studies in the West.

A novel oral adjuvant for hepatitis B virus (HBV) vaccines

A plasma-derived HBV vaccine was administered to 86 healthy men ranging in age from 40-56 years. A relatively high rate of nonresponders was found among the men who received the HBV vaccine alone. There was a significantly higher HBs antibody response rate among the vaccinees who received an oral adjuvant (taurine) compared to those not receiving the adjuvant. In the vaccinees who received the oral adjuvant, an in vitro polyclonal antibody response to taurine was detected in 17 (58.6%) of the 29 HBs responders, but in none of the HBs nonresponders. The development of oral adjuvants other than aluminum may be a valuable approach to the study of HBV vaccination.

Immunization against hepatitis B--what can we expect? Results of a survey of antibody response to immunization in persons 'at risk' of occupational exposure to hepatitis B

One thousand three hundred and twenty adults at risk of occupational exposure to hepatitis B were immunized using genetically engineered surface antigen and their antibody response (anti-HBs IU/l) assessed. Sex was known for all subjects and age for 1120 (range from 17-71 years). Seven hundred and sixty-four subjects were immunized in the local Department of Occupational Health, the remainder mainly by general practitioners. Analysis of 'good responders' (anti-HBs greater than 100 IU/l) according to age and sex showed that increasing age and male sex had independent adverse effects on the likelihood of developing a satisfactory level of antibody to HBsAg. Furthermore even those most likely to respond well (young women), had a 1/5 to 1/6 failure rate to achieve greater than 100 IU/l anti-HBs. Of 63 persons who received a fourth dose of vaccine, 26 developed anti-HBs titres greater than 100 IU/l when tested after 6 months. Subjects who had a low level of anti-HBs following primary immunization were more likely to develop greater than 100 IU/l anti-HBs following a booster dose than were non-responders (less than 10 IU/l).

Hepatitis B vaccine: persistence of antibody following immunization

We examined the persistence of hepatitis B surface antibody following hepatitis B vaccination in a group of health care workers. Of the 187 vaccine recipients screened, 39 were found to be antibody negative. Life table analysis showed the proportion retaining antibody at one, two, three, and four years from the first dose of vaccine was 92%, 84%, 73%, and 55% respectively. The likelihood of retaining antibody was significantly decreased as the age of the vaccine recipient increased. These results indicate that a large proportion of vaccine recipients no longer had detectable antibody four years after receipt of the vaccine. It remains to be shown if such individuals who have lost antibody are susceptible to the development of clinical hepatitis.

Acceptance of hepatitis B vaccine by medical and surgical residents

To assess factors influencing acceptance of hepatitis B vaccine, 547 medical residents and 230 surgical residents were surveyed. The vaccination rate among 315 (58%) medical residents who responded was 46%; for 124 (54%) surgical residents who responded it was 76%. Most medical (93%) and surgical (94%) residents who were vaccinated believed they were at risk of hepatitis B virus infection. Among unvaccinated medical residents, 71% indicated concern about vaccine-related side effects, including potential but unknown reactions (58%) and possible transmission of AIDS (37%) and hepatitis (16%). Unvaccinated surgical residents were also concerned about side effects (64%). Stepwise discriminant function analysis revealed that medical residents were vaccinated if they were concerned about risk of exposure to hepatitis B virus and the chronic complications of infection and if they had received hepatitis B immune globulin and influenza vaccine. Surgical residents were vaccinated if they believed hepatitis B vaccine was efficacious, but were not vaccinated if they believed hepatitis B virus infection was not serious.

A cost comparison analysis for screening and vaccination of hospital personnel with high- and low-prevalence hepatitis B virus antibodies in California

We compared the cost of antibody screening and the projected cost for hepatitis B vaccination of antibody-negative individuals at hospitals with "high prevalence" and "low prevalence" rates for hepatitis B virus antibodies among their employees. The use of hepatitis B core antibody for screening and subsequent hepatitis B vaccination of antibody-negative personnel was most cost-effective for hospitals considered to have high prevalence for hepatitis B virus antibodies among its staff, although use of hepatitis B surface antibody in this setting only increased costs by 1.4%. In a hospital with low prevalence for hepatitis B virus antibodies among its staff, use of hepatitis B surface antibody and subsequent vaccination of antibody-negative individuals was the most cost-effective approach, while use of hepatitis B core antibody for the above purposes would have increased costs by 3.4%. The use of both hepatitis B surface antibody and core antibody in either setting followed by immunization was least economical, as costs were increased by 13% and 13.5% respectively. We concluded that hepatitis B core antibody should be used for screening in hospitals with high prevalence for hepatitis B virus antibodies among employees while hepatitis B surface antibody be used for screening in hospitals with low prevalence for hepatitis B virus antibodies among employees. A prediction of high and low prevalence for hepatitis B virus antibodies in hospital personnel may be made by knowledge of the distribution in ethnicity of staff.