(CN) — A study of pediatric patients with Covid-19 shows that infected children are much more contagious than adults — and they often don’t have any symptoms at all.
The most comprehensive study of Covid-19 pediatric patients to date, researchers with Massachusetts General Hospital (MGH) and Massachusetts General Hospital for Children (MGHfC) studied 192 young people ranging in age from infant to age 22. They found 49 children tested positive for SARS-CoV-2, the novel coronavirus which causes Covid-19, and an additional 18 children had late-onset Covid-19-related illness. The infected children were shown to have a significantly higher level of virus in their airways than adults hospitalized in ICUs for Covid-19 treatment.
A higher viral load increases the risk of contagion. And the study, published in the Journal of Pediatrics, found that even when children exhibit known Covid-19 symptoms such as fever, runny nose and cough, they often overlap with common childhood illnesses like influenza or the common cold. This makes it harder to reach an accurate diagnosis of Covid-19 in children.
There is a widespread belief that children are less susceptible to Covid-19 infection, or even immune to it. However, the U.S. Centers for Disease Control website points out that while children comprise 22% of the U.S. population — but only 7.3% of Covid-19 cases reported to the CDC involved children — the number and rate of cases in children in the United States have been steadily increasing.
The CDC also notes that “the true incidence of SARS-CoV-2 infection in children is not known due to lack of widespread testing and the prioritization of testing for adults and those with severe illness.”
Because children are more likely to be asymptomatic carriers or carriers with few symptoms, they may go on attending school or day care. In this way, children can spread infection and bring the virus into their homes. This is a particular concern for low-income households and multigenerational families with vulnerable older adults in the same household. In the MGHfC study, 51% of children with acute Covid-19 infection came from low-income communities compared to 2% from high-income communities.
The findings have serious implications for the reopening of schools, day care centers and other locations with a high density of children and close interaction with teachers and staff members.
“Kids are not immune from this infection, and their symptoms don’t correlate with exposure and infection,” said Alessio Fasano, director of the Mucosal Immunology and Biology Research Center at MGH and senior author of the study. “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.”
The researchers believe the most critical question to the prevention of Covid-19 transmission by children returning to schools and day cares is what steps the schools will implement “to keep the kids, teachers, and personnel safe.”
The study authors recommend not relying on body temperature or symptom monitoring to identify Covid-19 infection in the school setting, routine and continued screening of all students for Covid-19 infection with timely reporting of the results an imperative part of a safe return-to-school policy, and control measures such as social distancing, universal mask use, effective hand-washing, and a combination of remote and in-person learning.
“This study provides much-needed facts for policymakers to make the best decisions possible for schools, day care centers and other institutions that serve children,” Fasano said. “Kids are a possible source of spreading this virus, and this should be taken into account in the planning stages for reopening schools.”
The authors of the study warn that “If schools were to reopen fully without necessary precautions, it is likely that children will play a larger role in this pandemic.”
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