A decline in cases of a rare heart disease in children during the COVID pandemic may provide clues about its cause and how to prevent it, researchers say.
Kawasaki disease (KD) affects fewer than 6,000 kids in the United States each year, but is the most common acquired heart disease in children. Symptoms include fever, rash, bloodshot eyes and redness of the mouth, throat, hands and feet.
Untreated children are at increased risk for heart attack, heart failure or sudden death.
"Kawasaki disease may be caused by a virus, a pollutant, a microbial aerosol or all of the above," said study senior author Dr. Jane Burns, director of the Kawasaki Disease Research Center at University of California, San Diego. "The fact that the pandemic affected each age group differently supports the idea that there are multiple triggers of KD, and different children develop the disease after exposure to different ones."
In a new study, Burns and her colleagues found that KD cases in the United States fell by 28% in 2020 and remained low during the pandemic's peak period. The drop in KD cases corresponded with school closures, mask mandates, lower air pollution levels and reduced spread of respiratory viruses.
Cases rebounded in the spring of 2021 as mask mandates were lifted and in-person schooling resumed, according to the report published online June 17 in JAMA Network Open.
Exactly how kids get Kawasaki disease - which is not contagious - is unclear. The fact that KD cases fell when COVID-19 prevention measures were in place suggests that whatever causes KD enters the body through the upper respiratory tract, the researchers said.
If confirmed, the finding could have a significant impact on KD research and prevention, they added.
"The pandemic provided an incredible natural experiment that we were poised to take advantage of," Burns said in a university news release.
The researchers found that male and Asian children have higher rates of KD, and these two groups had especially large drops in cases when COVID-19 prevention measures were in place.
Children aged 1 to 5 had a significant decrease in KD cases, the study found. There was no change in rates among infants - probably because they were not affected by COVID-19 prevention measures such as mask wearing.
There's more on Kawasaki disease at the American Academy of Pediatrics.
SOURCE: University of California, San Diego, news release, June 17, 2022