Vaccination Against Mpox in Pregnant Individuals and Children: Safety and Efficacy Review
Overview
Vaccinia-based vaccines demonstrate a generally favorable safety profile in pregnant persons and children, with second- and third-generation vaccines showing no increased risk of adverse pregnancy outcomes. Serious adverse events in children are rare and typically mild, but safety data for third-generation mpox vaccines remain limited, highlighting the need for ongoing research.
Background
Mpox, caused by the monkeypox virus, has recently caused global outbreaks with significant spread beyond endemic regions. Pregnant persons and children are at higher risk of severe disease and complications. Vaccination strategies have relied on smallpox vaccines, particularly third-generation non-replicating formulations like MVA-BN and LC16m8, due to immunological cross-protection. However, these populations were largely excluded from initial vaccine trials, necessitating continuous evaluation of vaccine safety and efficacy in these vulnerable groups.
Data Highlights
First-generation vaccinia vaccines were linked to a slight increase in congenital anomalies, whereas second- and third-generation vaccines showed no increased risk of adverse pregnancy outcomes. In children, serious adverse events are rare and usually mild and self-limiting. Observational data from the 2022–23 mpox outbreak reported minimal maternal or pediatric vaccine safety data. Ongoing studies are recruiting infants and children to assess safety and immunogenicity of third-generation vaccines like MVA-BN.
Key Findings
First-generation vaccinia vaccines had a slightly increased risk of congenital anomalies in pregnant persons.
Second- and third-generation vaccines have not been associated with increased adverse pregnancy outcomes.
Serious adverse events in vaccinated children are rare and typically mild and self-limiting.
Safety data for third-generation mpox vaccines in pregnancy and pediatric populations remain limited.
Pregnant persons and children were largely excluded from initial vaccine trials, underscoring the need for dedicated studies.
Ongoing living systematic reviews aim to continuously integrate emerging evidence to guide vaccination policies.
Clinical Implications
Clinicians should consider the favorable safety profile of second- and third-generation vaccinia-based vaccines when vaccinating pregnant persons and children, balancing the risks of mpox infection against vaccine safety. Continued pharmacovigilance and enrollment of these populations in vaccine studies are essential to inform evidence-based vaccination policies during ongoing outbreaks.
Conclusion
Vaccinia-based vaccines, particularly second- and third-generation formulations, appear safe for use in pregnant persons and children, but limited data on third-generation vaccines warrant ongoing research and surveillance to optimize vaccination strategies in these vulnerable groups.
References
WHO/CDC/2022-23 -- Mpox outbreak and vaccination guidance
