Hepatitis A seroprevalence among special populations in the Rio de Janeiro Metropolitan Area, Brazil

The objectives were to estimate hepatitis A virus seroprevalence in subjects attending to a travel medicine and immunization clinic in Rio de Janeiro, Brazil, and to develop a prediction model for hepatitis A virus seroprevalence. This retrospective research included individuals sequentially from April 2011 to June 2019 at a travel medicine and special population immunization clinic with an anti-hepatitis A virus IgG chemiluminescence result. Participants' data were verified via electronic medical records. Data were split into devel-opment and validation set taking 2018 as the date break. A cross-validated elastic generalized linear model with binomial distribution was performed. In total, 2,944 subjects were analyzed. Hepatitis A virus overall seroprevalence was 67.8%. Health professionals, travelers, and those who had contact with immunocompromised subjects had lower seroprevalence (40%-55%), whereas subjects with chronic conditions (heart, lung, and liver) ranged from 89% to 94%. The retained predictors in the final model were sex, age, year of birth, travelers, HIV/AIDS, spleen dysfunction, transplant candidates, household communicators, cancer-related immunosuppression, health care professionals. Area under the curve was 0.836 and maximum error was 0.051. Users can make predictions with the following calculator: https://pedrobrasil.shinyapps. io/INDWELL/. The groups with lower seroprevalence should be evaluated more carefully regarding need for hepatitis A virus vaccination even when they seek immunization clinics for other purposes.