Multisystem inflammatory syndrome in children, MIS-C, after Covid-19 is still rare, but according to a study published last week in JAMA Network Open, it is more common and severe than previously reported, and there are significant racial disparities in the noted cases.

MIS-C primarily emerged after a Covid-19 infection in children, and causes inflammation in different parts of the body. It can affect major organs and can be very serious--even deadly.

A quarter of the kids who are hospitalized for Covid or MIS-C have symptoms for months, and the United States Centers for Disease Control and Prevention (CDC) has logged about 9,000 cases and 74 deaths from MIS-C. Out of the millions of Covid-19 cases, this may make the statistic seem rare, but after a formal diagnosis code was established in 2021, new research suggests that for every 100 children hospitalized with COVID-19 in 2021, about 17 MIS-C hospitalizations occurred.

The research found that the more organs affected by the MIS-C, the worse the outcomes were, and the length of stay in the hospital doubled, with mortality increasing as well.

The data showed that over 60% of children hospitalized with MIS-C had more than two organ systems affected and about 8% had at least six organ systems affected.

More, there were significant and well-established racial disparities in Covid-19 outcomes, with the new research finding even more contrast in the MIS-C outcomes.

MIS-C hospitalizations were twice as likely among Black children as compared to white children. Black children represented nearly a quarter of all MIS-C cases and they represented almost a third of the most severe cases that affected at least six organ systems.

The team found that socioeconomic factors likely exacerbated MIS-C severity for black children, as those living in socially vulnerable communities spent more time in the hospital. This was not consistently connected to Covid-19 hospitalizations, though.

While the findings increase the knowledge of MIS-C and Covid-19 outcomes and disparities, which brings awareness about risks and impacts on organ systems, there are more questions that come up about how to decrease adverse outcomes, but particularly where vast racial disparities occur.