Serologic Immunity and Vaccination for Hepatitis A Among Incarcerated Adults in California State Prisons, 2024.

BACKGROUND: Hepatitis A is a vaccine-preventable infection which may lead to serious consequences, and which may spread among people experiencing homelessness or substance use disorder. Because these factors are highly prevalent in incarcerated populations, identifying susceptible groups and establishing high levels of immunity are crucial to reducing disease transmission and morbidity. AIM: To describe hepatitis A immunity and vaccination status in the California prison population and to identify predictors of susceptibility. METHODS: This cross-sectional study used secondary data and employed descriptive, bivariate, and multivariable logistic regression analyses. RESULTS: Among the 86,387 incarcerated adults in June 2024, 41.7% had received at least two doses of hepatitis A vaccine, 49.3% had an identified risk factor for HAV, and 47.2% had been tested by serology. The majority (83.1%) had evidence of immunity either by vaccination or seropositivity. Among those who underwent serological testing, 29.7% were seronegative. Independent predictors in an adjusted model of susceptibility included older age, being non-Hispanic, and being U.S.-born. Individuals with certain medical conditions were less likely to be susceptible. CONCLUSION: Although HAV immunity was high among the California prison population, the substantial prevalence of risk factors supports correctional facilities as an important venue for routine HAV vaccination.