One of the few silver coatings of the new coronavirus is that it saves mainly children.
Or so we think.
Children can become infected with the virus that causes COVID-19, but children under 18 usually experience less and less severe symptoms than adults, and many do not, at all. Centers for Disease Control and Prevention.
Less than 2% of confirmed cases were diagnosed in children and a report this week in the Journal of the American Medical Assn. suggests that they may be less susceptible than adults because the cells in their nasal cavities produce less receptors than the coronavirus needs to start your attack.
However, in recent weeks, doctors in the U.S. and Europe have found that, in a small percentage of children, coronavirus can trigger a rare but severe inflammatory response, up to three weeks after the initial viral infection ends. Health officials are calling multisystem inflammatory syndrome in childrenor MIS-C.
Children who develop MIS-C have a range of symptoms that can include high fever that persists for four or five days, rash, red eyes, red lips or tongue, red or swollen hands or feet, low blood pressure, unusual abdominal pain and persistent diarrhea.
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If your child has any of these symptoms, call a doctor immediately.
"What we are learning is that some of these children are getting very sick very quickly," he said Dr. Jackie Szmuszkovicz, pediatric cardiologist at Children's Hospital Los Angeles. "I want to encourage parents to, if they are concerned about their child, contact the pediatrician and do not postpone the service."
Although MIS-C is a serious disease that usually requires care in the ICU, treatments have been successful.
And to reiterate: MIS-C is a very uncommon complication of COVID-19.
"Not everyone who receives COVID does," he said. Dr. Karin Nielsen, specialist in pediatric infectious diseases at UCLA. "Even in New York, which had a very large share of the population infected with coronavirus, MIS-C was not overwhelming."
Children with MIS-C may have the same symptoms as those who suffer from Kawasaki disease, a rare inflammatory disease that affects about 5,500 children in the United States each year. The researchers now believe that some children diagnosed with Kawasaki disease between January and May may actually have MIS-C.
There is no diagnostic test for Kawasaki disease, but its symptoms also include high fever, rash and swelling of the hands and feet. It can also cause inflammation of the artery walls, which can result in an enlarged coronary artery or aneurysms.
In a way, the late inflammatory response seen in children with MIS-C mirrors what happens in adults who become seriously ill with COVID-19.
"Adults generally don't get seriously ill in the first week of illness – they usually get a little better and then they get really sick in the third week," said Nielsen.
She noted that, in adults, this severe inflammation appears mainly in the lungs, while in children it appears to be more comprehensive throughout the system.
"It is not exactly the same, but both seem to be related to the unregulated immune response," she said.
MIS-C is a new disease and doctors are learning more about it every day. Szmuszkovicz and Nielsen talked to the Los Angeles Times about what researchers know so far, why medical professionals have only heard about it recently and what they hope to learn about in the coming weeks and months.
How was MIS-C first discovered?
Nielsen: It was first seen in the UK, about a month after the big increase in COVID's disease there. Doctors noticed a greater number of cases similar to Kawasaki disease in children, as well as children with symptoms of toxic shock syndrome.
As the epidemic progressed, there were another large number of cases of children in New York City who also had these symptoms. As people began to analyze this more closely, it became apparent that it was not a typical Kawasaki disease. That was when this condition became recognized as a separate entity called multisystemic inflammatory syndrome in children.
Szmuszkovicz: At LA Children's Hospital we had an unusual increase in the number of cases of a syndrome that looked very similar to Kawasaki's disease in April. We had nine patients in April, and we usually won't have any or maybe two.
Then we heard about patients in the UK and New York – some seemed to have Kawasaki and others were more on the shock spectrum, or even toxic shock syndrome. There appeared to be an ongoing inflammatory process that could potentially be associated with COVID-19.
What is the difference between MIS-C and Kawasaki?
Szmuszkovicz: What we are seeing is a real range of symptoms of MIS-C disease. In some patients, the inflammation looks more like Kawasaki's disease; across the spectrum, he looks more like a patient in shock.
We are also learning that some children in MIS-C are getting very sick very quickly, which is very unusual in Kawasaki disease.
Nielsen: Kawasaki's disease is an inflammatory disease of the blood vessels, usually seen in children under 5 years old and aged between 3 and 6 months. But after 10 or 11, it is very rare. MIS-C can occur in adolescents, but the average age is about 8 years.
Why did medical professionals take so long to realize MIS-C?
Szmuszkovicz: It is not uncommon to have more cases of Kawasaki disease in the winter months, so nothing looked different, until March. But April was unusual, and that's when we started to say that something is different.
We tested our patients for acute COVID-19 disease, and none of them had. I think it was only recently that we realized that the virus could be a trigger for the inflammatory response, which is why we were seeing an increase in cases. Now, we are re-testing all patients with Kawasaki disease starting January 1, looking for antibodies to the coronavirus.
Nielsen: We have not seen any publications from China on this syndrome; was first described in the UK. In addition, there is a month delay in relation to the peak of COVID infections and the development of these cases in these children. That's what we're seeing in New York – MIS-C cases started to increase four weeks after the big increase in COVID cases there.
In addition, this condition is rare. It is not like every child who has COVID has this condition. But as you have a very large number of cases, the denominator is so large that you will see more rare cases.
How do you deal with it?
Nielsen: The treatment for this has been supportive care in the ICU. Most centers are treating her as they would with Kawasaki disease. Children receive a high dose of intravenous immunoglobulin that controls the unregulated immune response. If they do not improve, some centers are giving a second dose. They also receive aspirin as an anti-inflammatory agent. Some centers also treat with steroids and cytokine blockers.
Szmuszkovicz: Our treatment is focused on anti-inflammatory therapy and clot prevention.
It includes intravenous immunoglobulin and we also use anticoagulant and antiplatelet agents to prevent clotting problems. In some patients we are using steroids, in others we are using immune system modulators.
Were the treatments effective?
Szmuszkovicz: Three of the four antibody positive patients we saw are all at home and doing well. The fourth patient was our only patient at the shock end of the spectrum and was quite ill. Fortunately, I can inform you that she is no longer in the intensive care unit and has managed to move to the normal floor. She is doing much better than expected.
Nielsen: If children go to the ICU, the vast majority of them will survive. I just heard a presentation from the CDC about it and, in a center in New York, all the children treated for it survived and recovered.
There have been two or three reported cases of death related to this. It is a serious condition, but children survive mainly if they receive the proper care they need.
Are some children at greater risk of getting MIS-C than others?
Nielsen: Not that we know. Kawasaki's disease is more common in patients of Asian heritage, however, this does not seem to be the case with MIS-C.
Szmuszkovicz: That's the big question. We don't know the cause of Kawasaki's disease. We think there is an antigenic trigger that affects genetically susceptible people. In the past few decades, there has been extensive research testing different infections that can be this trigger.
It now appears that SARS-CoV-2 [the virus that causes COVID-19] may be one of several triggers for symptoms that look like Kawasaki in a genetically susceptible host. We are working with centers around the world to collect data about these children and share them to find out if there is a predisposition in certain ethnic groups and what the age group will be.
What do you hope to learn about MIS-C going forward?
Nielsen: I think everyone who studies this is trying to examine closely what is triggering this inflammatory response.
We also need to use experimental models to better understand the basics of how this disease process occurs, so that we can prevent and treat it properly.
Szmuszkovicz: We've been working closely with the L.A. County Department of Public Health since the first day we realized something looked different at the hospital. Now they are conducting a survey of all Los Angeles hospitals to get an idea of the number of MIS-C cases in Los Angeles.
We are also working with a …