Serosusceptibility and hesitancy for booster HBV vaccination among health care workers in Italy: A cross-sectional study

Background: Health care workers (HCWs) are at increased risk of exposure to hepatitis B virus (HBV). The most effective prevention measure is vaccination, with a serum hepatitis B surface antibody (HBsAb) titre > 10 mIU/ml considered protective. To date, the sociodemographic and occupational characteristics related to HBV serosusceptibility and factors associated with booster hesitancy remain unclear. Therefore, this study aimed to identify factors associated with maintaining a protective HBsAb titre in a large sample of HCWs and to evaluate factors potentially associated with hesitancy towards vaccine boosters.

Methods: A cross-sectional study was conducted among HCWs who underwent a health surveillance visit between 2017 and 2022. If the serum HBsAb titre was < 10 MIU/ml, a vaccine booster dose was offered. Based on their willingness to be vaccinated, employees were classified into three groups: acceptance, hesitation, and refusal. Uni- and multivariable analyses were performed to assess the association of demographic and occupational characteristics with serosusceptibility and attitudes towards vaccination.

Results: A total of 1632 (27%) employees were shown to be nonimmune. A lower median age and being a physician were significantly associated with a protective HBsAb titre. A total of 706 nonimmune employees (43.3%) accepted the vaccination, 865 (53%) hesitated, and 61 (3.7%) refused. The median age of those who refused vaccination was significantly higher than that of those who hesitated and those who were vaccinated. Acceptance of vaccination was significantly higher among nurses, while nurse aides hesitated more; among nonmedical graduate staff both hesitation and refusal were higher than expected. In the multivariable analysis, higher age, female sex, and employment as an allied health care professional were shown to be significantly associated with hesitation/refusal, while being born abroad turned out to be protective.

Conclusions: Our study showed that approximately a quarter of HCWs were not immune to HBV infection, and of these, more than half were hesitant towards or refused the booster dose. The risk of hesitation/refusal was higher with age in women and among allied health care staff. Based on these findings, further studies are needed to prospectively evaluate HBV seroprevalence, vaccination adherence, factors associated with hesitancy, and the effectiveness of health surveillance strategies in a high-risk population susceptible to infection.