<i>Notes from the Field:</i> Acute Hepatitis A Virus Infection Among Previously Vaccinated Persons with HIV Infection — Tennessee, 2018

Abstract

Complete immunization against hepatitis A requires 2 doses of a monovalent vaccine or 3 doses of a combined hepatitis A and hepatitis B vaccine; approximately 90% of vaccinated persons achieve protective antibody levels after a single dose of either product (1). However, persons living with human immunodeficiency virus (HIV) infection might not develop the same level of immunity after hepatitis A virus (HAV) vaccination as do immunocompetent persons (2,3). Compared with immunocompetent persons, seroconversion rates among persons with HIV infection are lower and are further affected by CD4 count and HIV viral load at the time of the first dose of vaccine (3). In addition, time to seroconversion is longer (3), and duration of protection wanes earlier (4) among persons with HIV infection. During an outbreak, evaluating predictors of a better vaccine response (CD4 count and HIV viral load at the time of first vaccination) is generally not feasible. Routine assessment of immune response after vaccination is not recommended for persons in general, nor for those with HIV infection (1); therefore, providers use a documented history of HAV vaccination to guide decisions regarding administration of HAV postexposure prophylaxis (PEP). However, compared with vaccination among the general population, a previous hepatitis A vaccination in persons with HIV infection after a high-risk exposure (e.g., household member or sexual contact) might not reliably protect against illness. The Tennessee Department of Health (TDH) sought to determine the frequency at which persons with HIV infection who were previously vaccinated for hepatitis A developed HAV infection during an HAV outbreak.