Hepatitis A virus vaccine

Hepatitis A virus (HAV) is transmitted via faecal-oral spread and causes an acute (rarely fulminant) hepatitis. Risk factors include travel to high-risk countries, men who have sex with men (MSM) and injecting drug use. HAV infection does not appear to be associated with worse clinical outcomes in people with HIV, but has been associated with higher and more prolonged viraemia (3).

HAV vaccine is recommended for all patients with HIV infection who have additional risk factors mentioned above. The vaccine’s immunogenicity, whilst high, is correlated with CD4+ T cell count and suppression of HIV replication on ART (4, 5).  The proportion of responders and titres of HAV antibodies were higher in recipients of three doses (at 0, 1 and 6 months) compared with two doses (6, 7). A meta-analysis of five studies of people with HIV infection concluded that pooled seroprotection from HAV infection was 92% after two years and 82% after five years (8). Vaccination can be administered from 12 months of age.

The single antigen vaccine is recommended in 2 doses 6-12 months apart in patients with CD4+ T cell counts >350/mL. In patients with CD4+ T cell counts <350/m L, three doses are recommended at 0, 1 and 6 months. Combination HAV/hepatitis B virus (HBV) vaccines are also available and should be administered in 3 doses at 0, 1 and 6 months, although the HBV component dose is lower than recommended for HIV-infected individuals (see HBV section).