PHILADELPHIA, Pa. — The news about coronavirus and children just got a lot worse. A troubling study by researchers at the Children’s Hospital of Philadelphia reports a “high proportion” of children infected with SARS-CoV-2 show elevated levels of a biomarker tied to blood vessel damage. Making matters worse, this sign of cardiovascular damage is being seen in asymptomatic children as well as kids experiencing COVID-19 symptoms.
Additionally, many examined children testing positive for SARS-CoV-2 are being diagnosed with thrombotic microangiopathy (TMA). TMA leads to clots in small blood vessels and has been linked to severe COVID symptoms among adult patients.
“We do not yet know the clinical implications of this elevated biomarker in children with COVID-19 and no symptoms or minimal symptoms,” says co-senior author David T. Teachey, MD, Director of Clinical Research at the Center for Childhood Cancer Research at CHOP, in a media release. “We should continue testing for and monitoring children with SARS-CoV-2 so that we can better understand how the virus affects them in both the short and long term.”
The complex connection between kids and COVID
It’s fairly well established at this point that most children who contract coronavirus experience little to no symptoms. However, a small portion of young patients develop major symptoms or a post-viral inflammatory response to COVID-19 called Multisystem Inflammatory Syndrome in Children (MIS-C).
TMA in adults has a connection to more severe cases of COVID-19. Scientists believe the component of the immune system called “complement cascade” helps to mediate TMA in adults. The complement cascade is supposed to enhance and strengthen immune responses when a threat is present, but it can also backfire and lead to more inflammation. Up until now, the role of complement cascade during childhood TMA hadn’t been investigated.
To research the topic of “complement activation” in kids with SARS-CoV-2, researchers analyzed a group of 50 pediatric COVID-19 patients between April and July 2020. Among the group, 21 showed minimal to no symptoms, 11 experienced severe symptoms, and 18 developed MIS-C.
To search for complement activation and TMA among each patient, researchers used soluble C5b9 (sC5b9) as a biomarker. Scientists have used this substance for quite some time to assess the severity of TMA after stem cell procedures. In brief terms, the higher the level of sC5b9 in a transplant patient, the greater their mortality risk.
No symptoms doesn’t mean there’s no problem
Study authors discovered elevated levels of C5b9 in both patients with severe COVID-19 and MIS-C. While this didn’t surprise researchers, they did get a shock from seeing high levels of C5b9 among even asymptomatic youngsters.
Some of the lab data regarding TMA had to be obtained after the fact. This meant researchers didn’t have a complete dataset to work with for all 50 studied patients. Among 22 patients researchers did have complete data for, 86 percent (19 children) were diagnosed with TMA. Every child had elevated levels of sC5b9, even those without TMA.
“Although most children with COVID-19 do not have severe disease, our study shows that there may be other effects of SARS-CoV-2 that are worthy of investigation,” Dr. Teachey concludes. “Future studies are needed to determine if hospitalized children with SARS-CoV-2 should be screened for TMA, if TMA-directed management is helpful, and if there are any short- or long-term clinical consequences of complement activation and endothelial damage in children with COVID-19 or MIS-C. The most important takeaway from this study is we have more to learn about SARS-CoV-2. We should not make guesses about the short and long-term impact of infection.”
The study is published in Blood Advances.