Hepatitis A in Vaccinated People With HIV: Tennessee, 2018

What was found

During a hepatitis A outbreak, the Tennessee Department of Health reviewed the 249 confirmed cases reported from December 1, 2017, to September 20, 2018, looking for people who also had HIV. 11 (4%) did, and six of them — all men — had received some or all of their hepatitis A vaccine before they were infected. So about half of the patients with both infections had been vaccinated.

Why it matters

• Full protection takes 2 doses of a single-disease (monovalent) hepatitis A vaccine or 3 doses of a combined hepatitis A and hepatitis B vaccine. About 90% of vaccinated people reach protective antibody levels after one dose of either.
• People with HIV may not respond as well. Fewer develop antibodies, and how many do depends on their CD4 count and HIV viral load at the first dose. They also take longer to respond, and their protection fades sooner.
• Checking antibodies after vaccination isn't recommended routinely, for anyone, and in an outbreak it's usually not practical to check what predicts a good response. So doctors rely on a documented vaccine history when deciding whether an exposed person needs postexposure prophylaxis (PEP). For people with HIV, that history may not be enough after a high-risk exposure, such as to a household member or sexual partner.

The six patients

• Patient A finished the series 3 years before being diagnosed with HIV and 7 years before getting hepatitis A.
• Patient B had both doses 5 years before falling ill.
• Patient C had one dose 44 days before being named as a sexual contact of someone with hepatitis A. PEP followed — a vaccine dose at 7 days and immune globulin (IG) at 14 days after the last possible exposure — yet the illness began 6 days after PEP was finished.
• Patients D, E and F had only part of the three-dose combined series.
• Five of the six began vaccination after their HIV diagnosis, though all six had a reason for routine hepatitis A vaccination before it, such as being a man who has sex with men or using recreational drugs.

What doctors should consider

The Advisory Committee on Immunization Practices doesn't currently address PEP for people with HIV who are fully vaccinated against hepatitis A. CDC recommends IG plus a vaccine dose as PEP for unvaccinated people who are immunocompromised, including people with HIV.

These findings support doctors considering IG as PEP for everyone with HIV after a high-risk exposure to someone with hepatitis A — whatever their vaccine history or immune status.

Sources

Based on Julia Brennan, Kelly Moore, Lindsey Sizemore, Samantha A. Mathieson, Carolyn Wester, John R. Dunn, William Schaffner and Timothy F. Jones, "Notes from the Field: Acute Hepatitis A Virus Infection Among Previously Vaccinated Persons with HIV Infection — Tennessee, 2018," MMWR, Centers for Disease Control and Prevention; a work of the United States government in the public domain.