Children with COVID-19 may shed the virus for up to three weeks, even when asymptomatic, according to a study from South Korea.
Among 91 children with confirmed COVID-19 infection, SARS-CoV-2 RNA was detected in nasopharyngeal and oropharyngeal swabs for a mean 17.6 days after an initial positive test, reported Jong-Hyun Kim, MD, PhD, of The Catholic University of Korea, in Seoul.
About half of children with symptoms continued to shed the virus for three weeks, including 49% of children with upper respiratory tract infections and 55% of children with lower respiratory tract infections, they wrote in JAMA Pediatrics.
Of 20 asymptomatic children in the cohort, SARS-CoV-2 RNA was detected for a mean 14.1 days after the initial positive test, and 4 (20%) were still shedding the virus at 3 weeks.
Notably, this study involved PCR tests, and the detection of SARS-CoV-2 using this method may not equate to infectivity, the authors noted.
“The major hurdle implicated in this study in diagnosing and treating children with COVID-19 is that a considerable number of children are asymptomatic, and even if symptoms are present, they are unrecognized and overlooked before COVID-19 is diagnosed,” Kim and co-authors wrote.
Although most COVID-19 cases tend to be less severe in children than adults, the role children play in transmission is not yet clear. With many school districts resuming in-person schooling next month, a renewed attention has been placed on how children spread the virus. In adults, an estimated 20%-45% of infections are asymptomatic.
Younger children with COVID-19 have been shown to carry greater amounts of SARS-CoV-2 in their upper respiratory tract than adults, indicating they could be important drivers of viral spread.
However, it’s unclear whether a high viral load correlates with disease severity or longer periods of shedding in children, commented Roberta L. DeBiasi, MD, MS, and Meghan Delaney, DO, MPH, both of Children’s National Hospital in Washington, D.C., in an accompanying editorial.
Regardless, it has been suspected that the low number of cases originally reported in children was not because they weren’t getting infected, but because they were asymptomatic or had mild cases and were not getting tested, commented Thomas A. Russo, MD, of the University of Buffalo, who was not involved in this research.
“With kids going back to school, if they do get infected and bring it back to the house, it is going to increase cases,” Russo told MedPage Today. “Just because kids come back from school feeling great, doesn’t mean they aren’t going to spread the virus.”
Kim and colleagues estimated that 93% of infections in children would have been missed if only symptomatic cases were tested. Symptomatic children experienced symptoms a median of 3 days prior to being diagnosed, but this varied widely (1 to 28 days), and only 7% of children tested positive concurrently with the onset of symptoms, Kim and co-authors reported.
“A surveillance strategy that tests only symptomatic children will fail to identify children who are silently shedding virus while moving about their community and schools,” DeBiasi and Delaney wrote.
Earlier this week, the CDC changed its COVID-19 testing guidelines to now state that non-vulnerable, asymptomatic close contacts of infected individuals “do not necessarily need a test” unless a provider or local health authorities recommend it.
In contrast, the public health response in South Korea allows for expansive testing, contact tracing, and isolation; children who come into contact with a confirmed or suspected COVID case are quarantined in healthcare facilities.
The current study involved a cohort of children who tested positive while under observation, and were tested at median 3-day intervals. The cohort — median age 11, 58% boys — were most commonly infected through a household contact (63%), followed by infections imported from travel (17%), cluster-associated transmission (12%), by another contact outside their social circle (4%), or an unknown route (4%). Three children had asthma and three had epilepsy, but no other comorbid conditions or immunodeficiencies were reported.
The most common symptoms experienced by children were fever (69%), respiratory symptoms (60%), gastrointestinal symptoms (18%), and loss of smell or taste (16%). Just 12 children received treatment, most commonly with lopinavir-ritonavir (Kaletra) or hydroxychloroquine, and none required mechanical ventilation.
Median duration of symptoms was 13 days, but this also varied widely, with some kids having symptoms for 5 weeks. Among kids who were presymptomatic at the time of diagnosis, symptom duration was a median 3.5 days, while those who had just developed symptoms at diagnosis experienced symptoms for a median 6.5 days; symptoms lasted a median 13 days in children who were symptomatic before diagnosis.
There was no significant difference in duration of symptoms between children with upper respiratory tract infections and those with mild or moderate lower respiratory tract infections.
The latter finding “suggests that even mild and moderately affected children remain symptomatic for long periods of time,” DeBiasi and Delaney wrote.
The study had all of the limitations of available testing. Some patients may test negative on one platform and positive on the next, and sampling at different locations within the respiratory tract or even by different staff can influence whether a test comes back positive, DeBiasi and Delaney noted.
SARS-CoV-2 has also been detected in other bodily fluids, including stool, for prolonged periods, which were not measured in this study.
Disclosures
Neither the authors nor the editorialists reported any ties with industry.
Primary Source
JAMA Pediatrics
Secondary Source
JAMA Pediatrics
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