# Comparison of hepatitis B and SARS-CoV2 vaccination rates in people who attended Drugs and Addiction Centres

## TL;DR

People attending drug addiction centers are poorly vaccinated against hepatitis B despite high SARS-CoV-2 vaccination rates, suggesting a need for improved health policies.

## Contribution

The study compares hepatitis B and SARS-CoV-2 vaccination rates in drug addiction center attendees over two years, revealing significant disparities.

## Key findings

- Only 7.2% of eligible individuals received at least one dose of the hepatitis B vaccine during follow-up.
- 83% of individuals received at least one dose of the SARS-CoV-2 vaccine during the same period.
- The difference in vaccination rates between the two diseases was statistically significant.

## Abstract

Persons with substance use disorder are at increased risk for hepatitis B virus (HBV) infection. Although most of them are attached to social health centers, the vaccination rate in this group is low. In this context, we designed a study to evaluate the prevalence of users of drug addiction centers (DAC) not immunized against hepatitis B and to compare the rate of vaccination against hepatitis B with the rate of immunization against SARS-Cov-2 in 2 years of follow-up.

Retrospective study that included individuals attended at DAC. Patients were screened at baseline (June 2020–January 2021) for HBV immunization. Individuals with HBsAb < 10 IU/mL were recommended to receive hepatitis B vaccine, during follow-up (January 2021–October 2022). At the end of follow-up, the HBV vaccination rate among candidates was determined and compared with the vaccination rate against SARS-Cov-2 in this population in the same period.

A total of 325 subjects were surveyed and tested. At baseline, the 65% (211/325) of were candidates to initiate vaccination and were advisor to HBV vaccination. During the follow-up 15 individuals received at least one dose of HBV vaccine, supposing a vaccination rate of 7.2%. In the same period, 186 individuals received at least one dose against SARS-Cov-2, representing a vaccination rate of 83%. The comparison between vaccination rates reached statistically significant (p < 0.001).

Our study manifests a low rate of immunization against HBV in DAC users, despite a high level of immunization for SARS-Cov-2 during the same period in the same population. Consequently, the lack of immunization against HVB in this population might be related with health policy issue more than to individuals linked to care and awareness. A similar approach for vaccination intended for SARS-CoV2 should be applied in high-risk population to warrant the success of immunization program against other preventable diseases such as HBV.