Researchers from the University of California San Diego School of Medicine, Scripps Institution of Oceanography and Rady Children’s Hospital-San Diego worked with partners in the United States to assess the frequency of Kawasaki disease (KD) before and during the COVID-19 outbreak. follow the pandemic.
The study, published on June 17, 2022 in JAMA Network Open Pediatrics, found that KD cases dropped 28 percent in 2020 and remained low during the peak period of the pandemic. The decline was related to school closures, masking mandates, reduced air pollution and reduced circulation of respiratory viruses. KD cases recovered in the spring of 2021, coinciding with the lifting of masking mandates and the return of personal schooling.
KD is the most common acquired heart disease in children. When left untreated, a quarter of patients develop coronary aneurysms that can lead to heart attacks, congestive heart failure, or sudden death. Symptoms in children include fever, rash, bloodshot eyes, and redness of the mouth, throat, hands, and feet. Although KD affects fewer than 6,000 children in the US each year, the incidence has been rising in San Diego County.
The disease continues to confuse pediatricians as the exact trigger(s) and mode of entry into the body have yet to be identified. Unlike COVID-19, KD is not contagious. However, the discovery that coronavirus precautions were effective in reducing KD suggests that the trigger(s) are similarly inhaled into the upper respiratory tract. The authors said that once verified, this finding could have a major impact on KD research and prevention.
“The pandemic created an incredible natural experiment that we were poised to take advantage of,” said senior author Jane C. Burns, MD, director of the Kawasaki Disease Research Center at UC San Diego School of Medicine and pediatrician at Rady Children’s Hospital- San Diego.
When the pandemic began, UC San Diego conducted a multi-site clinical trial that monitored KD cases nationwide between 2018 and 2020. Burns’s team combined this effort with additional data from San Diego to track the incidence of KD as the pandemic progressed.
“It’s a really interesting story,” said first author Jennifer A. Burney, PhD, associate professor of environmental sciences at the UC San Diego School of Global Policy and Strategy. “We saw a huge drop in numbers, but unlike other respiratory diseases during the shelter period, it didn’t disappear completely and the dynamics were not the same for all subgroups of patients.”
Rates of KD tend to be higher in male and Asian children, and these groups especially saw large declines in cases during the pandemic.
Another group that saw a disproportionate decrease were children ages one to five. This was remarkable compared to infants, who saw no significant change in KD rates during this period. According to Burns, the reason is likely because infant behavior was not as significantly affected by the pandemic, while typical activities and exposures for older children changed more drastically in 2020.
The patterns suggest that social behavior influences exposure to the agent(s) that cause KD, and are consistent with a respiratory portal of entry.
“Kawasaki disease can be caused by a virus, a pollutant, a microbial aerosol, or all of the above,” Burns said. “The fact that the pandemic has affected each age group differently supports the idea that there are multiple triggers of KD and that different children develop the disease after being exposed to different ones.”
Co-authors include: Jennifer A. Burney, Laurel L. DeHaan, Samantha C. Roberts, Chisato Shimizu, Emelia V. Bainto, Adriana Tremoulet, and Daniel R. Cayan at UC San Diego; Jane W. Newburger at Harvard University; Samuel Dominguez and Pei-Ni Jone at the University of Colorado; Preeti Jaggi at Emory University; Jacqueline R. Szmuszkovicz at the University of Southern California; Anne H. Rowley at Northwestern University; Nichole Samuy and Paul Scalici at the University of Alabama at Birmingham; and the KIDCARE Study Researchers.
The study was funded by the Gordon and Marilyn Macklin Foundation and the Patient-Centered Outcomes Research Institute.
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Samuel Dominguez received grants from Biofire Diagnostics and Pfizer and advised for Karius, Biofire Diagnostics and DiaSorin Molecular outside of this work. Anne H. Rowley received grants from the National Institutes of Health outside of this work and has a patent pending for Kawasaki disease antigens and antibodies.
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