Two doses of SARS-CoV-2 vaccine show protective effect against MIS-C in children

A systematic review of observational studies examined the association between SARS-CoV-2 vaccination and the incidence of multisystem inflammatory syndrome in children (MIS-C) following infection. The analysis compared children who received one or two vaccine doses with unvaccinated or partially vaccinated peers. The primary focus was on the protective effect of vaccination against MIS-C development.

The review included six studies from an initial pool of 944 identified records. This limited number of included studies reflects the current evidence base. The main finding was a significant protective effect for children who received two doses of a SARS-CoV-2 vaccine, with a reported effect size of d=0.71 and a 95% confidence interval of 0.07 to 1.35 (p=0.03). For one dose, a protective trend was observed, but it was not statistically significant.

The evidence supports a protective effect of two vaccine doses, but certainty is limited by the small number of included studies and potential bias. The review did not report on vaccine safety outcomes. It is important to note that this analysis reports an association, not causation, as it is based on observational data.

Clinicians can use this evidence to advocate for continued vaccination of children against SARS-CoV-2. The findings are specific to the studied populations and should not be extrapolated to other groups. The review underscores the importance of vaccination in preventing severe outcomes like MIS-C.