Australian study identifies major mpox immunity gap, signals need to strengthen outbreak prevention measures

A new Australian study has estimated that mpox vaccination coverage among gay, bisexual and other men who have sex with men (GBMSM) is far lower than previously reported, potentially leaving at-risk populations vulnerable to future outbreaks.

Published in eClinicalMedicine, the study is the first to use national, population-level Australian data to comprehensively describe mpox epidemiology, vaccine uptake and vaccination coverage among GBMSM – the population most affected during the global outbreak and a key target for vaccination programs.
 

A unique pattern of outbreaks in Australia

Researchers identified 2 distinct outbreaks between 2022 and 2024: a relatively small outbreak in 2022, followed by a much larger outbreak in 2024. This pattern differs from comparable countries such as the United States, United Kingdom and Canada, which experienced their largest outbreaks in 2022.
 

A major immunity gap 

Despite the rollout of a publicly funded mpox vaccination program in August 2022, the study estimated that 2-dose vaccination coverage among GBMSM was between 9.6% and 15%. These are substantially lower than estimates from community surveys, which show coverage of around 40% to more than 70% and may over-represent people with strong links to GBQ+ community networks and sexual health services.

‘These findings suggest a major immunity gap within the broader at-risk population in Australia,’ said Associate Professor Frank Beard, Associate Director at NCIRS and senior author of the study.

Previous Australian research has shown that people who receive mpox vaccination are more likely to have strong social and community connections within GBQ+ networks, while MSM who do not identify as GBQ+ may be less engaged with sexual health services. This may reduce their exposure to mpox risk messaging and awareness of free vaccination opportunities.
 

Now is the window to prevent future outbreaks

With mpox transmission currently remaining relatively low in Australia, the authors emphasise that now is the optimal time to strengthen vaccination coverage and disease prevention efforts to safeguard communities against future outbreaks, including the integration of mpox vaccination into routine sexual health care. 

‘Mpox vaccination should be offered opportunistically to all sexually active gay and bisexual men and other men who have sex with men wherever they receive care – including general practice and sexual health clinics,’ noted Scientia Professor Andrew Grulich from the Kirby Institute at UNSW Sydney, and co-author of the study.

The study also highlights the importance of clear, consistent messaging, delivered through trusted community channels, to increase awareness that mpox vaccination is recommended and freely available in Australia. 

‘Continued national monitoring of mpox epidemiology, vaccine uptake and vaccination coverage among higher-risk groups, including gay and bisexual men and other men who have sex with men, will be essential to inform policy, optimise programs, improve access through targeted communication and prevent future outbreaks,’ Associate Professor Beard concluded.

Access the study