Covid-19, a nightmare for many children 1:23
(CNN) -
Children can carry the coronavirus in their noses and throats for weeks, even if they don't show any symptoms, which could explain how the virus can spread silently, South Korean researchers reported Friday.
"In this case series study, inapparent infections in children may have been associated with silent transmission of COVID-19 in the community," the researchers wrote in a new study.
"Interestingly, this study aligns with data from adults in which up to 40% of adults may remain asymptomatic to infection," wrote Dr. Roberta DeBiasi and Dr. Meghan Delaney, both of Children's National Hospital in Washington , in an editorial accompanying the investigation.
Neither of them participated in the investigation.
"In this study, the authors estimate that 85 infected children (93%) would have been missed using a testing strategy focused on evaluating only symptomatic patients," they wrote.
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The study comes to light at a time when the U.S. Centers for Disease Control and Prevention (CDC) has come under fire for changing its guidelines on testing in asymptomatic people, which the American Academy of Pediatrics (AAP) called it "a dangerous step backward," in a statement Friday.
In the updated CDC guidelines, some people without symptoms may not need to be tested, even if they have been in close contact with someone who is known to have the virus.
This recently published research adds further evidence as to why launching a wide web, when it comes to contact tracing, is a key strategy for mitigating the spread of the novel coronavirus.
“We know that children often show little or no symptoms of Covid-19.
We also know that they are not immune to this virus and can get very sick.
Testing exposed individuals who do not yet show symptoms of COVID-19 is critical to locating contacts, which helps identify and support others who are at risk of infection, "said AAP President Dr. Sally Goza , in the statement.
Difficult to diagnose
New study shows high viral load in young children 0:41
The study, published in the journal JAMA Pediatrics on Friday, included data from 91 asymptomatic, presymptomatic and symptomatic children diagnosed with Covid-19 between February 18 and March 31, at 22 centers in South Korea.
Among those patients, 20 of them, or 22%, did not show any obvious symptoms and remained asymptomatic throughout the study.
Another 18 children, or 20%, were presymptomatic, meaning they did not look or feel sick at the time, but eventually developed symptoms later.
In total, more than half of the children - 71 children or 78% - did show symptoms, including fever, cough, diarrhea, abdominal pain, and loss of smell or taste, among other symptoms.
The duration of symptoms appeared to vary, from one to 36 days.
"This suggests that even mildly and moderately affected children remain symptomatic for long periods of time," DeBiasi and Delaney wrote in the editorial.
The data showed that only 8.5% of patients with symptoms were diagnosed with Covid-19 at the time their symptoms began.
The majority (66.2%) of the patients with symptoms had symptoms that were not recognized before being diagnosed, and 25.4% developed symptoms after being diagnosed.
"This highlights the concept that infected children are more likely to go unnoticed with or without symptoms and to continue their usual activities, which can contribute to viral circulation within their community," DeBiasi and Delaney wrote.
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The virus remained in the respiratory tract
The study found detectable virus genetic material in children for an average of 17.6 days overall.
Even in children who did not have symptoms, the new coronavirus was detectable for 14 days, on average.
It is also possible that the virus stayed in children longer, according to the study, because the date of initial infection was not identified.
However, this does not necessarily mean that the children were spreading the virus, experts say.
The presence of the virus' genetic material in swabs "does not have to be equated with transmission, especially in people who do not have significant symptoms such as coughing and sneezing," said Calum Semple, Professor of Children's Health and Outbreak Medicine at the University of Liverpool. , who was not participating in the study, in a written statement.
Furthermore, "sensitive molecular detection methods can detect viable, but also non-viable infectious viruses or non-transmissible RNA fragments," DeBiasi and Delaney wrote.
More research is also needed to determine whether similar findings would emerge among a larger group of children from other parts of the world.
Still, the new study provides information that public health officials can use when considering the spread of the virus in schools, according to DeBiasi and Delaney.
"A surveillance strategy that tests only symptomatic children will not be able to identify children who are quietly spreading viruses as they move through their community and schools," they wrote.
"In regions where the use of face masks is not widely accepted or used by the general public, asymptomatic carriers can serve as an important reservoir that can facilitate silent spread throughout a community."
The AAP's Goza statement on Friday reinforced the need for systematic and comprehensive monitoring.
"Without data and transparency, science and medical professionals are hampered, and families are harmed, as we lack information to help us understand how easily this virus can be transmitted to other people and how to stop it," he said. .
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