Hepatitis A vaccines

Hepatitis A virus (HAV) is the most common cause of acute viral hepatitis, with approximately 1.4 million clinical cases annually ⁴⁵. The disease burden is most likely underestimated due to a high incidence asymptomatic infection. The main route of infection is faecal-oral, and infection is driven by poor access to safe water and sanitation services.  In Africa, data on HAV infection are limited but the continent is considered to be a high endemic setting ⁴⁶. In such settings, routine vaccination in childhood is not recommended due to immunity acquired  following natural infection ⁴⁶. Data from South Africa show that antibodies to HAV in Black African adults is almost 100% by the age of 20 years, while only 30-40% of White adults are positive for HAV antibodies by the age of 20 years ⁴⁶.

Men who have sex with men (MSM) are at a higher risk of acquiring HAV infection with reported outbreaks in some parts of the world ^7,47. The burden of disease in this population group is 1.5-3 times that of the general population especially in the developed world ⁴⁸.

About 13 studies have reported data on HAV vaccination of HIV-infected adults ⁴⁵. All these studies explored the immune responses to HAV vaccination and report that the vaccine is safe and without effect on the clinical progression of HIV infection among adults on ART ⁴⁵. Vaccination at higher CD4+ counts is associated with better vaccine-induced immune responses. However, given the heterogeneity of the methodology and study populations, these results should be interpreted with caution ⁴⁵.

There is no consensus on the benefits of routine vaccination of HIV-infected adults with HAV vaccines. Advisory groups such as ACIP and the WHO Strategic Advisory Group of Experts on Immunisation (SAGE) recommend vaccination in the presence of other risk factors (medical, behavioural, epidemiological or occupational risk factor). High risk groups to HAV infection typically include MSM; injection drugs users; people travelling to or working in countries with a high or intermediate endemicity to HAV; people with chronic liver disease (including hepatitis B or C); bleeding diathesis; immunosuppressed persons who have undergone transplantation; and contacts of children arriving from countries with high or intermediate HAV endemicity ⁴⁵.

We recommend that HAV vaccination should be given if there are other medical, behavioural, epidemiological or occupational conditions in addition to HIV infection. The accepted schedule is two doses separated by 6-12 months ⁴⁵.