In a study by the National Institutes of Health, health workers vaccinated against hepatitis B virus in adulthood lower the titer of antibodies to the hepatitis virus surface antigen B (anti-HBs antibody) over time. These data were presented at the poster session of the 63rd Annual Liver Meeting 2012 of the American Association for the Study of Liver Diseases (AASLD). It has been found that the absence of anti-HBsAg antibodies is more common in health workers who have been vaccinated at an older age.

Widespread vaccination against hepatitis B dramatically reduces the incidence of hepatitis B and hepatocellular carcinoma worldwide. Studies in endemic areas of viral hepatitis have shown that many children vaccinated at birth against viral hepatitis B subsequently experience a drop in the protective titer of anti-HBs antibodies. In this study, we studied the duration of the immune response to vaccination in adults vaccinated in adulthood, living in regions not endemic for hepatitis.

A prospective study included medical workers aged 18 to 60 at the time of the primary hepatitis vaccination. Since the time of vaccination, 10 to 14 years have passed in group 1 (n = 50), in groups 2, 15 to 19 years (n = 50) and 20 years or more have passed since l introduction of the vaccine in group 3 patients (n = 59). All study participants determined (1) the presence of hepatitis B virus surface antigen (HBsAg), (2) antibodies to the nuclear antigen (anti-HBc), and (3) the titer of anti-Hbs antibodies. Health workers with an anti-HBs antibody titer of less than 12 ppm / ml (i.e. they were considered to be HIV negative) received a booster dose of the hepatitis B vaccine after whereby the antibody titers were determined on day 1, day 7 and after 3 weeks after the introduction of the booster dose.

The average age of participants at the time of the primary vaccination was 31 years in group 1, 32 years in group 2 and 34 years in group 3. Most participants were women (74%). The baseline characteristics of the group 3 study participants were comparable to those of group 1 and group 2, except for a higher history of damage from needle injections from a group 3 syringe (47% vs 20% in groups 1 and 26% in group 2) and smoking (32% vs 16% and 12%, respectively, p is lower 0.05 for both groups).

Of the 159 medical workers, 23% of the anti-Hbs antibody titers were not determined, i.e. they were anti-HBs negative (16%, 26% and 25% in groups 1, 2 and 3, respectively). None of the study participants were positive for HbAg, which indicates current viral hepatitis B.

36 medical personnel without detectable anti-HBs antibodies were, on average, more than 123 study participants whose anti-HBs antibodies were at a protective level (51 ± 10 years vs 47 ± 10 years , respectively, p = 0.04) and were vaccinated at an older age (36 ± 9 years vs 32 ± 9 years, p = 0.02). In the group with protective anti-HBs titers, there were more smokers (24%) than in the group with negative titers (8%, p = 0.04).

The mean antibody titers decreased as a function of the time elapsed since the initial vaccination, with the highest antibody titers in group 1, the mean in group 2 and the minimum in group 3 (p = 0, 02).

As the study shows, the only predictor of the reduction and complete disappearance of protective antibodies over time is age at the time of vaccination (p less than 0.001). Thus, the older the primary vaccination against hepatitis B, the more likely it was to be HIV negative thereafter.

The booster dose of hepatitis B vaccine was 94% effective in the group of HIV negative providers. Of the 34 participants with negative levels of anti-HBs antibodies who received a booster dose of the vaccine, an increase in titers was observed in 32 people - in 1 participant on day 1 after the booster administration, in 18 people - after 7 days and in 32 - after 21 days.

The study authors recommend determining the titer of anti-HBs antibodies in health workers vaccinated at an older age, and a single revaccination if seronegative exam results.

The Advisory Committee on Immunization Practices (ACIP) and the United States Centers for Disease Control and Prevention (CDC) evaluated the efficacy and cost-effectiveness data and discussed these aspects to formulate recommendations, in particular focusing on health care providers and their protection against viral hepatitis B.

Universal vaccination against viral hepatitis B has been practiced in the United States since 1991. It is important that the first dose of the vaccine is given at birth. The 3 recommended doses are administered during the first 6 months of life, they have a fairly rapid decrease in antibody titers by 20 years. Therefore, in children vaccinated at 1 year of life, the protective titer of antibodies is maintained for about 15 years, which is shorter than children vaccinated at an advanced age or in adults, in most of whom the titer antibody persists up to 30 years.