Study: Children With COVID-19 Suffer Above-Normal Kidney Damage

Public schools are reopening in New York City, even as COVID-19 continues to spread, with new cases peaking at around 3,500 a day across the city, and more contagious variants starting to take hold.

Children are much less likely to catch the virus, but some of those who do can face serious consequences in the form of multisystem inflammatory syndrome in children, or MIS-C. It is a condition in which different organs in the body can become inflamed, including the heart, lungs, brain, and skin.

Now, a study from Northwell Health, the state’s largest healthcare system, identifies a worrying result for COVID-positive children and their kidneys. Researchers examined the medical records of 152 pediatric patients with COVID-19, admitted from March to August at four New York-area hospitals. About one in 10 children with COVID-19 had acute kidney damage. The proportion doubled for those who also developed MIS-C. Severe renal dysfunction in children is usually very rare – on the order of one to two dozen cases per 100,000 children in developed countries.

Dr. Christine Sethna is Associate Professor at the Feinstein Institutes of Medical Research in Northwell and one of the study’s co-authors. She spoke with David Furst of WNYC about their findings, how parents can detect MIS-C, and when children may be eligible for COVID-19 vaccines. The interview has been edited slightly for clarity.

Can you briefly describe how MIS-C works? How long does it take to appear after a child catches COVID? And how does it affect the body?

We don’t know the exact reason or mechanism, exactly how this happens. But we do know it’s a post-viral syndrome, which means we think it’s associated with a previous COVID infection. It usually presents six to eight weeks after this infection.

What did your study find in terms of MIS-C and kidney damage? How often do you see this?

We therefore studied the incidence of acute kidney injury, defined as the abrupt cessation of kidney function. And we looked at 152 children admitted to our four hospitals in the Northwell Health System, with both acute COVID-19 infection and MIS-C. And we found in the total cohort that we had that 11.2% had this acute kidney injury. Specifically, of the 55 children with MIS-C, the incidence was slightly higher; it was about 18.2%.

Overall, children hospitalized for COVID and MIS-C are very rare, and besides, kidney damage is still rare. But we want to let the public and the medical profession know that this is a complication of COVID.

Fortunately, the majority of children who had acute kidney injury have resolved. We had a couple who needed dialysis to help the kidney remove waste from the body. But the majority have resolved. Only two children left the hospital with still residual kidney problems.

CDC says New York City and New York State have reported between 150 to 250 cases from MIS-C in childrenn. How worried should parents be?

So overall, COVID-19 infection occurs at much lower rates in children compared to adults. And from the proportion of COVID infection, the rate of MIS-C is even much rarer. So nationally there are over 2,000 cases. So it’s extremely rare, but parents should still be aware.

What should parents watch out for?

About six to eight weeks after a known COVID infection, if they show signs of vomiting, diarrhea, high fever, skin symptoms, or lethargy, they should see a doctor.

What is the latest news on COVID-19 vaccine trials in children? How long before they can get vaccinated and before they are vaccinated in large numbers?

Law. So, the Pfizer vaccine is already approved for those 16 and over, but they are not yet available from the state to get the vaccine unless you have a health condition right now. But when that opens, the Pfizer vaccine will be eligible for 16 years and over.

Pfizer and Moderna have both completed their enrollment in clinical trials for children ages 12 to 15 and up to 18 for Moderna. And so we expect these results probably in late spring, early summer.

At best, I would say summer for 12-15 year olds is late for them. The next step is for children under 12. They have not yet started to enroll in this group. So it will be much later, probably at the end of the year or even at the beginning of 2022.