Persistence of Immunity for Hepatitis B Virus among Heathcare Workers and Italian Medical Students 20 Years after Vaccination

Abstract

Background: Immunization of healthcare workers (HCWs) and medical students for the hepatitis B virus (HBV) is a crucial part of the hospital infection control programs. The aim of our study was to evaluate the persistence of anti-HBV specific antibodies in HCWs vaccinated during infancy or adolescence. Methods: Medical records of 734 consecutive subjects born after 1980 (481 females, 65.5% and 253 males, 34.5%) who underwent serological testing for anti-hepatitis B surface antibodies (anti-HBs) were evaluated. Results: A non-protective titer (<10 mUI) was found in 88/734 (12.0%) subjects; 84 (47.8%) of them received a booster dose of anti-hepatitis B vaccine and the anti-HBs titer of 58 subjects was measured 1 month after administration. A protective titer (anti-HBs >10 mIU/mL) was observed in almost 90% of subjects receiving the booster dose. Conclusions: A substantial percentage of HCWs had a non-protective anti-HBs titer at the time of the first employment, especially those vaccinated at birth age. However, the response to the booster dose showed that in these subjects, an anti-HBs titer <10 mIU/mL was due to the physiological decline of antibodies over the years. Therefore, primary immunization in childhood is highly effective and provides lasting immunity against HBV infection.

Kinetics of Anti-Hepatitis B Surface Antigen Titers in Nurse Students after a Two-Year Follow-Up

“…Furthermore, in our study, the percentage of students with titers <10 mIU/mL was relatively higher than that found in other studies that evaluated medical students in Italy (40.8%, 29.3%, 12%, 15.8%) and lower with respect to that in other countries (72.4% in Malaysia, 59% in Israel) [22][23][24][25][26].…”

“…For this reason and consistent with the Centers for Disease Control and Prevention (CDC) recommendations, anti-HBs testing was performed for all students upon admission to medical school if a recent protective titer was not available. All students with anti-HBs titers <10 mIU/mL were thus administered a booster dose, and the large majority responded to the vaccination with a considerable increase in the anti-HBs titer after 1 month, as reported in nearly all other studies [24,36,37].…”

Hepatitis B surface antibodies seroprevalence among people born before and after implementation of universal HBV vaccination

“…The decrease in anti-HBs antibodies over time below the seroprotection threshold is a controversial issue. Several studies have shown that individuals with aHBs levels between 1 and 9.99 mIU/mL quickly recover seroprotective aHBs levels after receiving a booster [19][20][21][22], due to immune memory [23,24]. In this context, the available bibliography widely reports that individuals with aHBs levels between 1 and 9.99 mIU/mL mostly generate an adequate anamnestic response and, therefore, are considered protected against HBV infection [25][26][27].…”

Long-term persistency of hepatitis B immunity: an observational cross-sectional study on medical students and resident doctors

“…Occupational Physicians should consider with particular attention the evaluation of the persistence of anti-HBV specific antibodies in medical students (in most cases vaccinated at birth age) and HCWs specifically at the time of the first employment in order to identify subjects with non-protective anti-HBs titer [32, 33]. Occupational Physicians’ contribution to reduce vaccine delays or refusals and vaccine hesitancy that are also affecting HCWs is crucial [34].…”