Most children with severe inflammatory disease linked to the coronavirus had initial COVID-19 infections without symptoms or only mild, according to new US research.
The unusual post-infection condition tends to be milder in children who were sicker with COVID-19, although more than half of affected youth received intensive hospital care, according to an analysis from the Centers for Disease Control and Federal Prevention (CDC) released Tuesday in JAMA Pediatrics.
The study represents the largest analysis to date of U.S. cases of multi-system inflammatory syndrome in children and strengthens evidence that this is a delayed immune response to COVID-19. The study included nearly 1,800 cases reported to the CDC from March 2020 to mid-January. Most involved children under the age of 15, but the study included people up to the age of 20.
The increases in cases occurred two to five weeks after the COVID-19 peaks and followed the spread of initial infections from urban to rural areas, the researchers said. More recent data from the CDC indicates that there is another emerging peak in pediatric disease consistent with this trend.
The cases reported by the state up to March 29 totaled 3,185 and included 36 deaths, the CDC website says. State reports aren’t always timely, so it’s uncertain how many American children have developed the disease since the study ended.
Most children who have had COVID-19 do not develop post-infection illness. Nearly 3.5 million American children and adolescents have tested positive for COVID-19, according to data compiled by the American Academy of Pediatrics and the Children’s Hospital Association.
The condition was first reported in Europe in late winter and spring last year. Some cases, especially those that follow silent and undiagnosed COVID-19 infections, can be mistaken for Kawasaki disease, a rare condition that can cause red skin, swelling, and heart problems.
Dr Sean O’Leary, vice chair of the pediatric academy’s infectious disease committee, said inflammatory disease usually causes very rapid illness in children, but most “respond very well to treatment and the vast majority improve completely ”.
Treatments can include steroids and other drugs that can reduce inflammation.
The best way to prevent it is to prevent infections with COVID-19, “which vaccines are very good to do,” he said. Studies on the COVID-19 vaccine in children are underway.
In the CDC’s analysis, fever was among the most common symptoms. Abdominal pain, vomiting, diarrhea and a red rash have occurred in at least half of the affected children. Almost a third had heart inflammation or other heart damage. These symptoms were less common in children up to age 4, who were also less likely to require intensive care than older children.