Study: Children Found to be “Silent Spreaders” of SARS-CoV-2

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Children infected with coronavirus disease 2019 (COVID-19) were shown to have a significantly higher level of the virus in their airways than hospitalized adults, according to the most comprehensive study of COVID-19 pediatric patients to date published in The Journal of Pediatrics.

“I was surprised by the high levels of virus we found in children of all ages, especially in the first two days of infection,” said lead study author Lael Yonker, MD, director, Massachusetts General Hospital (MGH) Cystic Fibrosis Center, in a press release. “I was not expecting the viral load to be so high. You think of a hospital, and of all of the precautions taken to treat severely ill adults, but the viral loads of these hospitalized patients are significantly lower than a ‘healthy child’ who is walking around with a high SARS-CoV-2 viral load.”

As schools across the US plan for reopening, researchers from MGH and Mass General Hospital for Children examined 192 children aged 0-22 years who were seen at urgent care clinics for suspected COVID-19 to understand the potential role they play in the COVID-19 pandemic.

Overall, 49 children tested positive for SARS-CoV-2 (26%) and an additional 18 children met criteria for Multisystem Inflammatory Syndrome in Children, a multi-organ, systemic infection that can develop in children with COVID-19 several weeks after infection.

Also, 25 (51%) of children with acute SARS-CoV-2 infection presented with fever; symptoms of SARS-CoV-2 infection, if present, were non-specific. Participants provided nose and throat swabs and blood samples.

The results showed nasopharyngeal viral load was highest in children in the first 2 days of symptoms, significantly higher than adults in the intensive care unit for COVID-19 treatment (P=.002).

“Kids are not immune from this infection, and their symptoms don’t correlate with exposure and infection,” said senior author Alessio Fasano, MD, director, Mucosal Immunology and Biology Research Center, MGH. “During this COVID-19 pandemic, we have mainly screened symptomatic subjects, so we have reached the erroneous conclusion that the vast majority of people infected are adults. However, our results show that kids are not protected against this virus. We should not discount children as potential spreaders for this virus.”

In another “breakthrough” finding, the researchers challenged the current hypothesis that because children have lower numbers of immune receptors for SARS-CoV-2, they are less likely to become infected or seriously ill with the novel disease.

Results showed that although younger children have lower numbers of the virus receptor vs older children and adults, “this does not correlate with a decreased viral load,” noted the press release. According to study authors, this finding means children can carry a high viral load, regardless of their susceptibility to developing COVID-19.

“This study provides much-needed facts for policymakers to make the best decisions possible for schools, daycare centers and other institutions that serve children,” said Fasano in the press release. “Kids are a possible source of spreading this virus, and this should be taken into account in the planning stages for reopening schools.”