A new study has found that coronavirus-infected children can carry COVID-19 for weeks without showing symptoms, highlighting the idea that kids can transmit the virus while remaining undiagnosed.
The South Korean study, conducted by researchers at Seoul National University and published Friday, analyzed 91 children with the coronavirus at 20 hospitals and two non-hospital isolation facilities across the country from Feb. 18 to March 31.
The researchers found that the viral respiratory infection was detectable among the kids 17.6 days on average after they tested positive for the virus, even if their symptoms were no longer present. Three asymptomatic children featured in the study shed the virus more than 21 days after testing positive.
“In conclusion, the findings of this study suggest that suspecting and diagnosing COVID-19 in children based on their symptoms without epidemiologic information and virus testing is very challenging,” the researchers wrote. “Most of the children with COVID-19 have silent disease, but SARS-CoV-2 RNA can still be detected in the respiratory tract for a prolonged period.”
The average age of the children included in the study was 11, and they were identified primarily through contact tracing from laboratory-proven cases.
Among the kids who were studied, 22%, 20 children, were asymptomatic. Of the 71 individuals who showed symptoms, 66% had unrecognized symptoms before being diagnosed. Another 25% developed symptoms after their diagnoses, and only 9% were diagnosed immediately when they started showing symptoms.
The symptomatic children had mild to moderate upper and lower respiratory tract infections, but their symptoms ranged from fevers and coughing to diarrhea and abdominal pain, according to the study.
Most of the kids who showed symptoms experienced them an average of three days prior to being diagnosed, despite being under closer scrutiny due to the fact they were identified through contact tracing. Pre-symptomatic children remained symptom-free for an average of 2.5 days before showing any symptoms.
The study’s results further emphasize the concept that infected children, either with or without symptoms, may be more likely to go unnoticed and continue with their regular activities, potentially contributing to the increased spread of COVID-19 within their communities, Dr. Roberta DeBiasi and Dr. Meghan Delaney, who work at Children’s National Hospital in Washington, D.C., wrote in an editorial that accompanied the study.
“The first important take-home point from this study is that not all infected children have symptoms, and even those with symptoms are not necessarily recognized in a timely fashion,” the doctors said in their editorial. Dr. Roberta DeBiasi and Dr. Meghan Delaney, who work at Children’s National Hospital in Washington, D.C., wrote in an editorial that accompanied the study.
The findings of the study come as more than 6 million Americans have been infected with COVID-19 and nearly 183,000 have died from it as of Sunday evening, according to a database created by the New York Times.
In Massachusetts, public health officials on Sunday reported 174 new cases of the coronavirus and 13 more fatalities linked to it. There have been a total of 18,483 cases of COVID-19 and 8,816 deaths in the commonwealth since the pandemic began.
While the majority of individuals who died from the coronavirus in Massachusetts and the U.S. more generally were above the age of 60, COVID-19 still poses some risks to children.
According to DeBiasi and Delaney, data has showed that kids are “clearly susceptible” to becoming infected and can develop severe complications, including multisystem inflammatory syndrome in children, a rare but severe condition that is reported two to four weeks on average after the onset of COVID-19 in patients.
“However, the vast majority of infected children have mild or unrecognized disease, and this population may play important epidemiologic roles by potentiating spread of infection through communities and/or boosting herd immunity.” the doctors wrote.