Background In response to an outbreak of hepatitis A in men who have sex with men (MSM) in Victoria, Australia in 2017; the Victorian government funded a free hepatitis A vaccination program for all Victorian MSM in 2018. This study aimed to determine hepatitis A vaccine uptake among MSM in a sexual health clinic in Melbourne during the program, and assess the factors associated with vaccine uptake.

Methods All MSM attending the Melbourne Sexual Health Centre (MSHC) in 2018 were included in the analysis. Chart review was performed to determine why men did not receive the vaccine and the proportion of men vaccinated for hepatitis A was calculated. Multivariable logistic regression was then performed to examine the factors associated with vaccine uptake.

Results There were 9,582 MSM who attended MSHC in 2018, of whom 61.3% (n=5,869, 95%CI:60.3–62.2%) reported already being immune to hepatitis A, either from previous vaccination or infection. Of the 3,713 remaining eligible men, 62.7% (n=2,327, 95%CI:61.1–64.2%) received the hepatitis A vaccine. Compared with HIV-negative MSM not taking PrEP, MSM taking PrEP (aOR=1.28; 95%CI:1.01–1.62) were more likely to receive the vaccine. In addition, vaccine uptake was associated with being aged 16–25 years (aOR=2.49; 95%CI:2.06–3.02) and 26–35 years (aOR=2.10; 95%CI:1.76–2.50) compared to being aged ≥35 years. 1,386 men did not receive the vaccine. Of these men, the majority (55.4%; n=768) were not offered the vaccine by their treating clinician, and 21.6% (n=300) were identified as non-immune after serological testing but did not return for vaccination. By the end of 2018, a total of 85.5% of MSM (8,196/9,582) were immune to hepatitis A.

Conclusion The critical vaccination threshold for hepatitis A has been estimated at ≥70%. Continuation of the targeted hepatitis A vaccination program will improve immunity amongst the MSM population to prevent ongoing transmission and the likelihood of future outbreaks.

Disclosure No significant relationships.