Speaker
Description
Background: Real-world evidence on the clinical presentation and severity of mpox infections following vaccination with the MVA-BN vaccine remains limited.
Methods: We conducted a scoping review and meta-analysis of 45 studies published between 2022 and 2025 to epidemiologically characterise mpox breakthrough infections following MVA-BN vaccination.
Results: 17 studies provided suitably stratified data for an odds ratio estimation of progression to more severe forms of disease, conditional on first being recognised as a case. Vaccinated cases had significantly lower odds of developing systemic symptoms and becoming hospitalised compared to unvaccinated cases.
Interpretation: Although many breakthrough infections after MVA-BN vaccination have been documented, the vaccine effectiveness ($\operatorname{VE}$) in reducing the rate of infection is unknown. We did not estimate total $\operatorname{VE} = 1-(1-\operatorname{VE}_S)(1-\operatorname{VE}_P)$, with $\operatorname{VE}_S$ the $\operatorname{VE}$ in reducing the risk of becoming a case and $\operatorname{VE}_P$ the $\operatorname{VE}$ in reducing the risk of progression to severe outcomes once already diagnosed. The 17 studies contributed to an estimate of $VE_P$ but not to an estimate of $\operatorname{VE}_S$, which could be the primary benefit of the vaccine in protecting against severe mpox disease. Future studies are needed to address this.
