Immune Response to MVA-BN and Prior Smallpox Vaccination in People with HIV or at Risk for HIV Acquisition

Little is known about the serologic response elicited by MVA-BN vaccination (JYNNEOS) against mpox in elderly individuals with or without HIV. In this study, we measured levels of antibody against orthopoxvirus in selected participants (n=114) with HIV or at risk for HIV acquisition, from the Multicenter AIDS Cohort Study/Women's Interagency HIV Study Combined Cohort Study, who had no prior reported history of mpox. Participants reported MVA-BN vaccination history via questionnaires. Median age was 64 years, 24.6% were female, and 46% were HIV-seropositive. Twenty out of 114 participants received at least one dose of MVA-BN. We found that MVA-BN induced sustained IgG levels regardless of HIV status even up to one year. Birth before 1973 was correlated with higher IgG. MVA-BN unvaccinated individuals with HIV had lower IgG than those without HIV. Although limited by small sample size, our study is among the first to assess anti-orthopoxvirus antibodies specifically in a vulnerable, older population and stratified by HIV status.