School closers reduced cases of mysterious disease

By Mark Waghorn via SWNS

School closures due to COVID-19 lockdowns slashed rates of a mysterious fever that causes heart disease in kids, according to new research.

Cases of Kawasaki disease fell by 28 percent in 2020 - and remained low during the peak pandemic period.

Masking mandates, less air pollution and reduced circulation of respiratory viruses were also behind the phenomenon.

Incidence went back up in the spring of 2021 - when restrictions were lifted and schools reopened.

It sheds fresh light on the causes of the most common acquired heart disease in children.

Kawasaki disease (KD) affects almost 6,000 children in the US a year. It continues to puzzle pediatricians. Its triggers and mode of entry into the body have yet to be identified.

Senior author Dr. Jane Burns, director of the Kawasaki Disease Research Centre at the University of California, San Diego (UCSD), said: "The pandemic provided an incredible natural experiment that we were poised to take advantage of."

When untreated, a quarter of patients develop coronary artery aneurysms that can lead to heart attacks, congestive heart failure or sudden death.

KD symptoms include fever, rash, bloodshot eyes and redness of the mouth, throat, hands and feet.

Unlike COVID-19, it is not contagious. But the discovery of precautions against coronavirus were an effective tool suggests it is inhaled into the upper respiratory tract.

The findings in JAMA Network Open Pediatrics could have a major impact on research and prevention.

When the pandemic began, UCSD was leading a multi-site clinical trial monitoring national KD cases between 2018 and 2020.

Dr. Burns and colleagues combined this effort with additional data from San Diego to track KD incidence as the crisis progressed.

First author Professor Jennifer Burney, also from UCSD, said: "It is a really interesting story.

"We saw a huge decline in numbers, but unlike other respiratory illnesses during the shelter-in-place period, it didn't disappear entirely, and the dynamics were not the same for all subsets of patients."

Rates of KD are typically higher in male and Asian children, and these groups saw especially large drops in cases during the pandemic.

Another group that saw a disproportionate decrease was children ages one through five.

This was notable when compared to infants, who saw no significant change in KD rates during this time period.

The reason is likely because infants' behavior was not as significantly impacted by the pandemic.

Typical activities and exposures for older children changed more dramatically in 2020, explained Dr. Burns.

The patterns suggest social behavior affects exposure to the agents that trigger KD, and are consistent with a respiratory portal of entry.

Dr. Burns said: "Kawasaki disease may be caused by a virus, a pollutant, a microbial aerosol or all of the above.

"The fact 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."

KD causes inflammation in the walls of the blood vessels and affects mostly children under five years old. It can weaken arteries that supply the heart with blood.

This can lead to aneurysms and heart attacks. It is fatal in three percent of cases that go untreated.