(ABC4) – Multisystem inflammatory syndrome in children (MIS-C) is a severe inflammatory condition that sets in anywhere from two to six weeks after a typically mild or asymptomatic infection of Covid-19. According to the Centers for Disease Control and Prevention (CDC), the Pfizer vaccine demonstrates a high rate of effectiveness against severe Covid-19, but is also associated with lower MIS-C incidents among adolescents.

The CDC states that criteria for the diagnosis of MIS-C involves any of the following (for a current or recent Covid-19 infection): a temperature of over 100.4°F (38°C) for more than 24 hours or subjective fever, evidence of inflammation (demonstrated by elevated levels of inflammatory markers), or involvement of two or more organ systems, and no plausible alternative diagnosis.

According to a study done by the CDC, among 102 MIS-C patients and 181 hospitalized controls, 2 doses of the Pfizer vaccine against MIS-C showed a rate 91% effectiveness.

On the other end of the spectrum, all 38 MIS-C patients requiring life support were unvaccinated. MIS-C is typically severe enough to require hospitalization.

This figure highlights the importance of vaccination, even among those aged 12-18 years (given that children aged 5–11 years were not recommended to receive the Pfizer vaccine until Nov. 2 2021, this analysis focuses on ages 12-18).

In an evaluation of vaccine effectiveness, 24 U.S. pediatric hospitals found that 2 doses of the Pfizer vaccine was associated with a high level of protection against MIS-C among patients who received their second vaccine dose more than 28 days before hospitalization.

In fact, no fully vaccinated patients with MIS-C required respiratory or cardiovascular life support, as opposed to 39% of unvaccinated MIS-C patients who did.

These findings contribute to the growing body of evidence that vaccination is likely effective in preventing severe COVID-19–related complications in children.