Seattle’s first case of rare childhood disease linked to Covid-19

Seattle has had its first confirmed case of a rare inflammatory disease closely linked to Covid-19, which affects children. It was identified and treated at Seattle Children’s Hospital.

King County Public Health said the patient was a resident of Snohomish County. There have been no other confirmed cases in the area. The hospital would not provide any other details about the patient due to privacy concerns.

It’s being called "pediatric multisystem inflammatory syndrome." It involves a “hyper response” of the child’s immune system to the virus, according to Dr. Michael Portman, who directs pediatric cardiovascular research at Children’s.

It can lead to inflammation of the blood vessels, and affect the heart’s arteries, leading to coronary aneurysms. In similar diseases, that can lead to lifelong heart issues, Portman said.

The disease is being linked to Covid-19, Portman said, because almost all of the patients have had confirmed cases of the virus, positive antibody tests, or known exposure.

“It can't be a coincidence that during this pandemic that we're seeing this syndrome that we've not really seen before,” he said.

Portman said this new disease is very similar – and at times appears almost identical to – a disease called “Kawasaki disease,” which was first identified in Japan in the 1960s. According to Portman, Kawasaki disease is “10 times” higher in Japan than here in the United States, but it’s also fairly common at Seattle Children's.

At Children’s hospital, around 30% patients with Kawasaki disease are of Asian descent, Portman said. But the disease “seems to affect Hispanic and black children more severely" due to a "more robust inflammatory response."

And at the same time that the new disease has emerged, Portman also reported a spike in Kawasaki disease at Children's, with a number of cases occurring over the past month. But Portman said it’s too soon to tell if Kawasaki disease is actually on the rise as well.

This new syndrome is extremely rare, with just dozens of cases around the country. Only a handful have been fatal. Most have been in the New York area.

So Dr. Portman’s advice to parents is “not to freak out.”

But if your child has a “persistent fever” – a possible symptom – he strongly recommended getting that checked out.