We know children are less likely than adults to become seriously ill from COVID-19. But a new study looks at how long the virus is detected in kids—even when they are asymptomatic—and what that means for transmission.

By Anna Halkidis
September 01, 2020

Children are less likely than adults to need to be hospitalized for the coronavirus or even become seriously ill from it—and that’s great news for parents. But new research from South Korea reveals many kids are not only asymptomatic, they can carry the virus for an extended period of time.

The study, published in JAMA Pediatrics on August 28, concludes the virus can be detected in the respiratory tract of children for a mean of 17.6 days overall. That includes asymptomatic kids who had detectable virus for a mean of 14.1 days after testing positive.

Girl wearing homemade protective mask and backpack
Credit: Westend61/Getty Images

Why is that concerning? The report states: "These data suggest 93 percent of the children with COVID-19 could have been missed were it not for Korea’s intensive contact tracing and aggressive diagnostic testing. Cases of children with undocumented COVID-19 are worrisome because they could facilitate the rapid spread of SARS-CoV-2 in the community.”

A closer look at the study

The study looked at 91 children younger than 19 years old in South Korea with COVID-19. These kids were tested because they either had a history of close contact with someone diagnosed with COVID-19, were linked to outbreaks, came from abroad, or had symptoms of the virus.

Twenty-two percent of the kids were asymptomatic—aka they had no symptoms for as long as they tested positive. As for the symptomatic cases? Only 8.5 percent had symptoms when diagnosed, 66.2 percent had “unrecognized symptoms before diagnosis,” and 25.4 percent developed symptoms after being diagnosed. Two of the symptomatic patients had severe cases and required oxygen via nasal prong, while 46 patients had mild symptoms and 20 had moderate.

How do kids affect transmission?

So it’s clear kids can catch the virus. But are they spreading it at the same rate as adults, especially when not showing any symptoms?

Some experts are not so sure. “The presence of the virus genetic material in swabs the respiratory tract need not equate with transmission, particularly in people who do not have important symptoms such as cough and sneeze,” Calum Semple, Ph.D., professor in child health and outbreak medicine at the University of Liverpool and a consultant respiratory pediatrician at Alder Hey Children's Hospital in Liverpool, England said in a statement.

But other experts say children shouldn’t be disregarded as spreaders no matter what. Even though most infected kids “have mild or unrecognized disease,” they may still “play important epidemiologic roles by potentiating spread of infection through communities,” Roberta L. DeBiasi, M.D., M.S. and Meghan Delaney, D.O., M.P.H. wrote in an editorial about the study. Infected kids, they later added, “may be more likely to go unnoticed either with or without symptoms and continue on with their usual activities, which may contribute to viral circulation within their community.”

That’s especially true since cases for children are on the rise. New numbers from the American Academy of Pediatrics (AAP) show kids now account for 9.5 percent of COVID-19 cases in the U.S., or more than 476,000 out of more than 5 million cases. That's a 700 percent increase since late May.

And as the AAP previously pointed out, kids play an important role in stopping the spread. “We all are in this together, and we all need to practice social distancing and that includes children, young adults, and the rest of us,” Sean T. O'Leary, M.D., M.P.H., FAAP, a member of the AAP Committee on Infectious Diseases said in a March 2019 statement. “The more we can slow the spread of this virus, the more lives we will save.”

That means a lot of hand-washing, wearing masks, and social distancing!

Anna Halkidis is the features editor at Parents.com. Keep up with her on Twitter.