A child checks the bandage on his arm from a vaccineShare on Pinterest
Juan Monino/Getty Images
  • Multi-system inflammation syndrome (MIS-C) causes inflammation in the lungs, kidneys, and other parts of the body.
  • The disease is rare, but it has been manifesting in adults and children after they develop COVID-19.
  • Researchers say the Pfizer COVID-19 vaccine can reduce the risk of MIS-C in children with COVID-19 by as much as 91 percent.
  • In another study, researchers said most children treated MIS-C return to normal heart function within 3 months.

Children who receive two doses of a Pfizer COVID-19 vaccine have a significantly lower risk of developing multi-system inflammation syndrome (MIS-C) after contracting the novel coronavirus, new research from the Centers for Disease Control and Prevention (CDC) suggests.

MIS-C is a rare but potentially deadly inflammatory disease that attacks the body’s vital organs and can get severe enough for a person to be put on a ventilator.

Research shows that Black, Asian, and Latino children are also at a higher risk of the disease than other ethnicities.

“This is a new syndrome that has not been seen with other virus infections,” said Dr. Mark Sawyer, FAAP, an infectious disease specialist at Rady Children’s Hospital and a professor of clinical pediatrics at the University of California at San Diego.

“It is thought to relate to the enhanced immune response that SARS-CoV-2 elicits in both adults and children,” he said. “This is manifested in adults by worsening illness in some people around 1 week after the start of symptoms. In children, it is manifested as MIS-C. MIS-C is characterized by inflammation in the lungs, gastrointestinal tract, kidneys, liver, skin, muscles, and sometimes the brain.”

Notably, MIS-C can occur in children who’ve developed COVID-19 but don’t have symptoms, meaning the inflammatory reaction is the first sign they have COVID-19.

“It is not known exactly why SARS-CoV-2 elicits this brisk immune response,” Sawyer told Healthline. “Both children with MIS-C and adults with severe COVID are often treated with steroids or other medication to blunt the immune response. There is concern that this widespread inflammation can lead to chronic health problems.”

A new study does report that most children treated for MIS-C have normal heart functions again within 3 months.

Though not much is known why MIS-C presents itself following COVID-19 infection in children, Pfizer’s vaccine appears to cut the risk of developing the syndrome by as much as 91 percent, according to the CDC report, which studied instances of MIS-C in children ages 12 to 18.

“In kids, we are learning that if we can limit the inflammation, it diminishes the chances of developing long COVID, MIS-C, and other complications related to the virus,” Dr. Ilan Shapiro, FAAP, medical director of health education and wellness at AltaMed Health Services, told Healthline. “In case of becoming infected with the virus, the vaccine serves as a ‘seat belt’ to protect against the complications as a result of the virus.”

Experts say that’s just one more reason to get your child vaccinated if they’re eligible.

“The same report showed results of a study in which all children with MIS-C requiring life support were unvaccinated,” said Dr. Shanika Boyce, MPH, FAAP, an assistant professor, department of pediatrics and director of longitudinal primary care clerkship at Charles R. Drew University of Medicine and Science in Los Angeles.

So far, only the Pfizer vaccine is approved for children ages 5 and older. There is not yet an approved vaccine for those under 5 years old.

But when other vaccines are approved, it’s “very likely” that protection against MIS-C will be similar to that shown in the Pfizer vaccine, Boyce told Healthline.

The benefits of vaccination also extend beyond MIS-C protection.

“Vaccination can reduce the severity of the virus and inflammation in a child’s body, and that can make a huge difference in what we’re seeing with complications and reduction in long COVID, which can affect a child’s development and ability to concentrate,” Shapiro said. “The vaccine is not just to reduce the severity of symptoms, but also serves to protect against the side effects of the virus and any long-term lingering symptoms.”