Kids can get the coronavirus too, but what parents may not know is that children are more contagious despite having mild or no symptoms, according to a recent study by Massachusetts General Hospital.

For the investigation, researchers looked at 192 children between ages 0 and 22. Of these individuals, 49 tested positive for the coronavirus, and an additional 18 experienced late-onset, COVID-19–related illness. Youngsters with the virus were found to have a much higher viral load than adults hospitalized in intensive care units for COVID-19 treatment.

The findings contradict previous research that suggested children were less likely to become infected or seriously ill because they had lower numbers of the receptors for the coronavirus. These reduced numbers among younger kids didn’t mean a decreased viral load, however. In fact, scientists noted that children could carry higher levels of the coronavirus in their airways, rendering them more contagious regardless of their susceptibility to developing COVID-19 infection.

This means that even if children don’t become seriously ill, they can bring the virus home and spread infection while exhibiting few or no symptoms. Researchers said this possibility would be of special concern to families in certain socioeconomic groups, who have been significantly affected by COVID-19. (The study showed that 51% of children with the virus hailed from low-income communities compared with 2% from high-income communities.)

Researchers explained that youngsters may exhibit COVID-19 symptoms such as fever, runny nose and cough. But these symptoms overlap with common childhood illnesses, such as the flu and the common cold, which makes accurately diagnosing COVID-19 difficult.

“The study provides much-needed facts for policymakers to make the best decisions possible for schools, day care centers and other institutions that serve children,” said Alessio Fasano, MD, director of the Mucosal Immunology and Biology Research Center at Massachusetts General and the study’s senior author. “Kids are a possible source of spreading this virus, and this should be taken into account in the planning stages for reopening schools.”

If schools open without instituting necessary precautions, such as social distancing, universal mask use, effective handwashing protocols and a combination of remote and in-person learning, children may end up playing a much larger role in the spread of COVID-19, researchers concluded.

For related coverage, read “Prioritizing Children in the COVID-19 Response” and “Study Tracks Coronavirus Spread in Pediatric Dialysis Unit.”