Biomarkers May indicate Severity of COVID in Children

Tara Haelle

October 15, 2021

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Two biomarkers could potentially indicate which children with SARS-CoV-2 infection will develop severe disease, according to research presented at the American Academy of Pediatrics 2021 National Conference.

"Most children with COVID-19 present with common symptoms, such as fever, vomiting, and abdominal pain, which are very similar to other common viruses," said senior researcher Usha Sethuraman, MD, professor of pediatric emergency medicine at Central Michigan University College of Medicine in Detroit.

"It is impossible, in many instances, to predict which child, even after identification of SARS-CoV-2 infection, is going to develop severe consequences, such as multisystem inflammatory syndrome [MIS-C] or severe pneumonia," she told Medscape Medical News.

"In fact, many of these kids have been sent home the first time around as they appeared clinically well, only to return a couple of days later in cardiogenic shock and requiring invasive interventions," she added. "It would be invaluable to have the ability to know which child is likely to develop severe infection so appropriate disposition can be made and treatment initiated."

In their prospective observational cohort study, Sethuraman and her colleagues collected saliva samples from children and adolescents when they were diagnosed with SARS-CoV-2 infection. They assessed the saliva for micro (mi)RNAs, which are small noncoding RNAs that help regulate gene expression and are "thought to play a role in the regulation of inflammation following an infection," the researchers write in their poster.

Of the 129 young people assessed, 32 (25%) developed severe infection and 97 (75%) did not. The researchers defined severe infection as an MIS-C diagnosis, death in the 30 days after diagnosis, or the need for at least 2 L of oxygen, inotropes, mechanical ventilation, or extracorporeal membrane oxygenation.

The expression of 63 miRNAs was significantly different between young people who developed severe infection and those who did not (P < .05). In cases of severe disease, expression was downregulated for 38 of the 63 miRNAs (60%).

"A model of six miRNAs was able to discriminate between severe and nonsevere infections with high sensitivity and accuracy in a preliminary analysis," Sethuraman reported. "While salivary miRNA has been shown in other studies to help differentiate persistent concussion in children, we did not expect them to be downregulated in children with severe COVID-19."

The significant differences in miRNA expression in those with and without severe disease is "striking," despite this being an interim analysis in a fairly small sample size, said Sindhu Mohandas, MD, a pediatric infectious disease specialist at Children's Hospital Los Angeles.

"It will be interesting to see if these findings persist when larger numbers are analyzed," she told Medscape Medical News. "Biomarkers that can predict potential severity can be very useful in making risk and management determinations. A child who has the biomarkers that indicate increased severity can be monitored more closely and complications can be preempted and prevented."

The largest difference between severe and nonsevere cases was in the expression of miRNA 4495. In addition, miRNA 6125 appears to have prognostic potential, the researchers conclude. And three cytokines from saliva samples were elevated in cases of severe infection, but cytokine levels could not distinguish between severe and nonsevere infections, Sethuraman said.

If further research confirms these findings and determines that these miRNAs truly can provide insight into the likely course of an infection, it "would be a game changer, clinically," she added, particularly because saliva samples are less invasive and less painful than blood draws.

The potential applications of these biomarkers could extend beyond children admitted to the hospital, Mohandas noted.

"For example, it would be a noninvasive and easy method to predict potential severity in a child seen in the emergency room and could help with deciding between observation, admission to the general floor, or admission to the ICU," she told Medscape Medical News. "However, this test is not easily or routinely available at present, and cost and accessibility will be the main factors that will have to be overcome before it can be used for this purpose."

These findings are preliminary, from a small sample, and require confirmation and validation, Sethuraman cautioned. And the team only analyzed saliva collected at diagnosis, so have no data on potential changes in cytokines or miRNAs that occur as the disease progresses.

The next step is to "better characterize what happens with time to these profiles," she explained. "The role of age, race, and gender differences in saliva biomarker profiles needs additional investigation as well."

It would also be interesting to see whether varied expression of miRNAs "can help differentiate the various complications after COVID-19, like acute respiratory failure, MIS-C, and long COVID," said Mohandas. "That would mean it could be used not only to potentially predict severity, but also to predict longer-term outcomes."

This study was supported by a grant from the Eunice Kennedy Shriver National Institute of Child Health and Human Development through the National Institutes of Health’s Rapid Acceleration of Diagnostics (RADx) program. Coauthor Steven D. Hicks, MD, PhD, reports being a paid consultant for Quadrant Biosciences.

American Academy of Pediatrics (AAP) 2021 National Conference. Presented October 11, 2021.

Tara Haelle is a Dallas-based science and medical journalist.

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