Monkeypox infections reported after two JYNNEOS vaccine doses in the United States

A report from the United States describes cases of monkeypox virus infection occurring in individuals who had received two preexposure doses of the JYNNEOS vaccine. The report does not provide details on the study design, the size or characteristics of the population, the comparator group, or the length of follow-up. The main finding is that monkeypox virus infections occurred after vaccination, but the number of cases, the rate of infection, and any effect size are not reported.

No information is provided on safety, tolerability, or adverse events related to the vaccine in this context. The report does not list specific methodological limitations, but the absence of fundamental study details—such as sample size, comparator, and outcome measures—severely limits interpretability.

Given the incomplete nature of this report, its direct practice relevance is minimal. It serves only to note that breakthrough monkeypox infections after a two-dose JYNNEOS regimen have been observed. Clinicians should be aware of this possibility but cannot infer vaccine effectiveness, failure rates, or risk factors from this information alone. Further, more rigorous investigation is required.