Hepatitis A in central Argentina: anti-HAV prevalence in adults living in a region of low endemicity after 17 years of the official introduction of the vaccine.

Hepatitis A virus (HAV) has a low endemic circulation pattern in Argentina. Notifications of clinical cases occur especially in susceptible young adults in whom outbreaks have recently been reported. The aim of this study was to provide updated information on HAV immune status of the adult population from central Argentina. A retrospective analysis was carried out recording the results of IgG-anti HAV in 4235 samples of people without prior vaccination from Córdoba, Argentina (2019 and 2022). Epidemiological data was recorded: sex, age, HIV status, income-status. The overall prevalence of anti-HAV was 70.1%. It increased with age, was associated with the low-income population and was significantly higher in female patients (p<0.0001). Individuals under 35 years old exhibited anti-HAV IgG rates <54%. Considering the high proportion of young adult individuals susceptible to HAV infection found, together with evidence of HAV circulation in the region, which can be easily introduced by unvaccinated immigrants or travelers from medium/high endemic countries and the existence of a safe, efficient vaccine, we strongly recommend to increase the study of HAV immunity in individuals >18 years old in our region. In case they are negative, it is recommended vaccination.