Case study: breakthrough mpox infection in Aotearoa New Zealand and Australia after completed two-dose course of subcutaneous modified vaccinia Ankara (MVA-BN) vaccines.

Background: In August 2022, in response to a global mpox outbreak, the World Health Organization recommended the Vaccinia vaccination for at-risk people.

Methods: Case study.

Results: We describe a case of a HIV-negative bisexual man who developed a symptomatic mpox infection 13weeks after completing a two-dose course of subcutaneous third-generation modified vaccinia Ankara vaccines. The case likely acquired his mpox infection in the USA; was diagnosed in Aotearoa, New Zealand; and was followed-up in Australia, as he was actively travelling during his infection.

Conclusions: This case highlights the importance of maintaining clinical suspicion for mpox in people who present with consistent symptoms, even if they are fully vaccinated. Also, as he travelled around Aotearoa, New Zealand, and Australia during his infection, this case highlights how public health authorities and clinicians can cooperate across jurisdictional boundaries to support cases and minimise the risk of onward transmission.