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Mysterious Syndrome Kills Children Diagnosed with Covid-19

Rare condition looks like a known disease that’s carried on high-altitude winds

Robert Roy Britt
May 10 · 5 min read

A mysterious syndrome linked to Covid-19 in recent weeks has taken the lives of three children in New York, in a development that has vexed doctors there and elsewhere around the world.

Dozens of children diagnosed with Covid-19, including toddlers and at least one infant, have also developed a syndrome characterized by persistent fever and inflammation of body tissues that affects the function of one or more organs. That suggests the two conditions might be related. But it’s not clear if “pediatric multi-system inflammatory syndrome,” as it’s being called, is a symptom of Covid-19 or a separate disease occurring simultaneously.

The symptoms of the mystery syndrome resemble Kawasaki disease, an acute childhood illness that in a small percentage of cases causes a severe drop in blood pressure and organ failure. Scientists don’t yet know if the two diseases are occurring together, but it’s probable, one doctor tells me, that the cases involve an immune-system overreaction to Covid-19 that ends up looking like Kawasaki disease. Still, no conclusions have been reached.

Kawasaki disease, also called Kawasaki syndrome, is rare, affecting fewer than 6,000 U.S. children each year, but it is the leading cause of heart disease in children in North America, typically afflicting kids 5 years old and younger. Scientists do not know what causes it, but they’re pretty sure it involves a toxin that rides the prevailing winds, high above the planet, from one country to another (more on that below).

California, New York, Canada, England, Italy

Most of the apparent double-disease cases have not been studied to determine if the symptoms of “pediatric multi-system inflammatory syndrome” are in fact Kawasaki disease, or if the two just present similarly. In one new case, however, a 6-month-old girl in California was diagnosed with Kawasaki disease and Covid-19, according to the preprint of a paper that has been peer-reviewed and accepted for publication in the journal Hospital Pediatrics.

Meanwhile, more than 70 children in New York have been reported to have the toxic shock syndrome, and three had died, Gov. Andrew M. Cuomo said over the weekend. Two of the deaths were among children of elementary school age, the other an adolescent.

A week ago, doctors in Canada were already looking into at least a dozen cases of the syndrome there. “We’ve been seeing this this last few weeks, it struck us as unusual to have so many at the same time,” Fatima Kakkar, a doctor at Sainte-Justine Hospital in Montreal, told CTV News. “We’re not quite sure what to make of it yet.”

By late April, at least a dozen children had been admitted to intensive care units in England because of the syndrome, but the diagnoses have been unclear. “The cases have in common overlapping features of toxic shock syndrome and atypical Kawasaki disease with blood parameters consistent with severe COVID-19 in children,” according to a warning issued by the National Health Service in England April 27. “Abdominal pain and gastrointestinal symptoms have been a common feature as has cardiac inflammation.”

[See also: Data and new research reveal all age groups are at risk of severe Covid-19 symptoms, from children to middle-age and beyond.]

Kawasaki disease symptoms

Kawasaki disease can cause the following symptoms, though not necessarily all of them, according to a set of joint statements issued recently by a group of Kawasaki health organizations around the world led by Kawasaki Disease Canada:

  • High fever persistent beyond 4 days (despite antibiotics)
  • Redness of the eyes without thick discharge
  • Red, dry, cracked lips and a red, swollen tongue
  • Skin rash
  • Swollen, red skin on the palms of the hands and the soles of the feet
  • Swollen lymph nodes in the neck

“The single defining characteristic is a distinctively persistent high fever,” the group notes. “Other symptoms can include a rash, cracked lips and sore mouth, bloodshot eyes, and swollen glands in the neck — often just on one side.”

Kawasaki syndrome remains rare, and Covid-19 has also been rare in children, so parents should not be alarmed in general, health officials say. But if your child is sick, here’s some advice from the group:

“If symptoms develop your child should be assessed as soon as possible (do not wait it out because you are afraid to seek medical attention, hospitals are taking extreme precautions right now and are safe), since early diagnosis and treatment of Kawasaki disease is important to prevent heart complications.”

Riding the wind

Kawasaki disease was first described in 1967 in Japan by Tomisaku Kawasaki. Its causes remain enigmatic. Several studies suggest large-scale climate patterns, including prevailing winds above 20,000 feet, as well as local weather, are involved.

A 2011 study found Kawasaki syndrome cases “are often linked to large-scale wind currents originating in central Asia and traversing the North Pacific,” researchers said. “Results suggest that the environmental trigger for [the disease] could be wind-borne.”

“Prevailing wind patterns associated with [Kawasaki disease] cases in Japan track back to northeastern China, which is the country’s main cereal grain-growing region,” an international team of researchers, including Jane Burns, MD, a pediatrician at Rady Children’s Hospital and director of the Kawasaki Disease Research Center at UC San Diego School of Medicine, concluded in 2014.

Burns and colleagues extended that work to the United States in a 2018 study published in the journal Scientific Reports. They found clusters of cases in San Diego related to changes in atmospheric pressure, temperature, precipitation and wind patterns.

“We are seeing firsthand evidence of these weather patterns in San Diego, where eight children have recently been diagnosed with Kawasaki disease,” she said at the time.

There must be something in the air, Burns and other experts say. But they don’t yet know what it is.

Kawasaki disease appears to have a short incubation time, less than 24 hours between exposure and the start of fever, “suggesting the cause is not a traditional infectious organism, but more likely a toxin, perhaps fungal in origin,” Burns says.

No proven link

Meantime, any actual connection between Covid-19 in children and Kawasaki disease remains unknown.

“Kawasaki disease is a puzzling illness, and there is currently no known cause; we believe that a virus or bacteria triggers inflammation and an immune system overreaction,” says Michael Portman, MD, a pediatric cardiologist and director of the Kawasaki Disease Clinic at Seattle Children’s Hospital. “We do not know yet if the coronavirus produces a similar immune response in children. Adults with the coronavirus often show a massive immune response, which is in some ways is similar to that occurring in children with Kawasaki disease.”

Robert Salata, MD, a professor of medicine in epidemiology and international health at Case Western Reserve University, thinks these cases are probably a severe immune system reaction to Covid-19 that just looks like Kawasaki disease. “We don’t know for sure,” Salata tells me, “but that’s what it really looks like.”

UPDATE: On May 14, the CDC issued a report on the syndrome, here.


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Robert Roy Britt

Written by

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.



Health and wellness news and information about the human body and mind, the world around us, and our place in it.

Robert Roy Britt

Written by

Explainer of things, independent health and science journalist, author, former editor-in-chief of LiveScience and Space dot com.



Health and wellness news and information about the human body and mind, the world around us, and our place in it.

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