As schools reopen in parts of the United States, a study published Thursday found that some children have high levels of virus in their airways during the first three days of infection despite having mild symptoms or none at all — suggesting their role in community spread may be larger than previously believed.
One of the study’s authors, Alessio Fasano, a physician at MassGeneral Hospital for Children, said that because children tend to exhibit few if any symptoms, they were largely ignored in the early part of the outbreak and not tested. But they may have been acting as silent spreaders all along.
“Some people thought that children might be protected,” Fasano said. “This is incorrect. They may be as susceptible as adults — but just not visible.”
The study in the Journal of Pediatrics comes on the heels of two others that offer insights about children and coronavirus transmission. On July 30, researchers reported in JAMA Pediatrics that children younger than 5 with mild or moderate illness have much higher levels of virus in the nose, compared with older children and adults. Shortly before that, investigators in South Korea published a household study that some believed implied older children could spread the virus as readily as adults, while younger children less so. But researchers later clarified that it was unclear whether the transmission came from the older children or from contacts that they shared with other family members.
All three studies were small and contradicted one another in some details, so researchers said they could not draw any definitive conclusions based on any one of them alone. But taken together, they paint a worrisome new picture of children’s role in the pandemic.
The newest study reported that the viral loads of the children were significantly higher than those of severely ill adults in the hospital. However, the children and adults were not in the same stage of illness — the children’s levels were measured on days zero to two of infection, compared to days seven or longer for the adults.
Lael Yonker, the study’s lead author and a pediatric specialist at Massachusetts General Hospital, said larger side-by-side analysis is needed to compare viral loads over time in adults versus kids.
“But the point is, when you consider the ICU … there are many many precautions in place to protect health care workers from contracting the virus,“ Yonker said. “Kids, mildly symptomatic and early in the infection, are walking around in the community, and we need to minimize the potential of these children to spread virus.”