(CNN) – Children can carry the coronavirus in their noses and throats for weeks, even if they show no symptoms, which could explain how the virus can spread silently, South Korean researchers said Friday.
“In this case, a serial study, inconspicuous infections in children may be associated with silent transmission of COVID-19 to the community,” the researchers wrote in a new study.
“Interestingly, this study is consistent with data for adults, in whom up to 40% of adults may remain asymptomatic to the infection,” Dr. Roberta DeBassi and Dr. Megan Delaney, both of the Children’s National Hospital in Washington, DC, writes in an accompanying version. Neither was involved in the study.
“In this study, the authors estimated that 85 infected children (93%) would be missed using a testing strategy focused only on testing symptomatic patients,”
The study comes at a time when the US Centers for Disease Control and Prevention has been criticized for changing its guidelines for asymptomatic testing, which the American Academy of Pediatrics called a “dangerous step back” on Friday.
In the updated CDC guidelines, some asymptomatic people may not need testing, even if they have been in close contact with someone who is known to have the virus.
This recent study adds further evidence as to why throwing a wide network when it comes to contact tracking is a key strategy to mitigate the spread of the virus.
“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 individuals who are not yet able to show symptoms of COVID-19 is crucial for contact tracking, which helps identify and support other people who are at risk of infection, “the president said in a statement. of AAP Dr. Sally Goza.
It is difficult to diagnose
The study, published in the journal JAMA Pediatrics on Friday, included data on 91 asymptomatic, presymptomatic and symptomatic children diagnosed with Covid-19 between February 18 and March 31 at 22 centers in South Korea.
Among these patients, 20 of them – or 22% – showed no obvious symptoms and remained asymptomatic throughout the study.
Another 18 children – or 20% – were presymptomatic, meaning they didn’t look or feel sick at the time, but eventually had symptoms later.
In total, more than half of the children – 71 children or 78% – showed symptoms, among which other symptoms included fever, cough, diarrhea, abdominal pain and loss of smell or taste. The duration of symptoms seems to vary, ranging from one to 36 days.
“This suggests that even mild and moderately affected children remain symptomatic for long periods of time,” DeBiasi and Delaney wrote in the editorial.
The data show that only 8.5% of these patients with symptoms were diagnosed with Covid-19 at the time their symptoms began. Most – 66.2% – of patients with symptoms had symptoms that were not recognized before diagnosis, and 25.4% developed symptoms after they were diagnosed.
“This underscores the concept that infected children may go unnoticed with or without symptoms and continue with their normal activities, which can contribute to viral circulation in their community,” DeBiasi and Delaney wrote.
The virus remains in the airways
The study found that the genetic material from the virus was found in children for an average of 17.6 days. Even in children who have no symptoms, the virus is detected in an average of 14 days. It is also possible for the virus to stay in children even longer, the study said, as the date of the initial infection has not been identified.
However, this does not necessarily mean that children are spreading the virus, experts say.
The presence of viral genetic material in tampons “should not be equated with transmission, especially in people who do not have important symptoms such as coughing and sneezing,” Calum Sample, a professor of pediatrics and epidemics at the University of Liverpool, who was not involved in the study. , said in a written statement on Friday.
In addition, “sensitive molecular detection methods can detect a viable, infected virus, but also non-viable or non-transmissible RNA fragments,” writes DeBiasi and Delaney.
More research is needed to determine whether such findings will occur among a larger group of children from other parts of the world.
However, the new study provides information that can be used by public health officials when considering the spread of the virus in schools, according to DeBiasi and Delaney.
“A surveillance strategy that tests only symptomatic children will not identify children who silently spread the virus as they move around 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 media can serve as an important reservoir that can facilitate silent distribution in the community.”
Friday’s statement by Goza from AAP reinforced the need for systematic, wide-ranging follow-up.
“Without data and transparency, science and medicine professionals are struggling – and families are harmed because we lack information to help us understand how easily this virus can be passed on to others and how to stop it,” he said. she.
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