As schools and colleges reopen across the country, scientists say social distancing remains a critical public-health response to COVID-19. New research released Thursday sheds more light on children who test positive for COVID-19, and the contagiousness of coronavirus. Children often remain asymptomatic or display very few symptoms, and the research also offers insights into the course of the disease at an important time for families and communities.
A study published in the latest edition of the Journal of Pediatrics finds that the virus and antibodies can coexist in young patients. “With most viruses, when you start to detect antibodies, you won’t detect the virus anymore. But with COVID-19, we’re seeing both,” says Burak Bahar, lead author of the study and director of Laboratory Informatics at Children’s National Hospital in Washington, D.C. “This means children still have the potential to transmit the virus even if antibodies are detected.”
“ ‘Children still have the potential to transmit the virus even if antibodies are detected.’ ”
The researchers reviewed an analysis of 6,369 children tested for SARS-CoV-2, the virus that causes COVID-19, and 215 patients who underwent antibody testing at Children’s National between March 2020 and June 2020. Out of these 215 young patients, 33 tested positive for both the virus and antibodies during the course of the disease. Nine of those 33 also showed presence of antibodies in their blood while also later testing positive for the virus.
What’s more, researchers found that patients aged 6 years through 15 years old took a longer time (a median time of 32 days) to clear the virus, meaning that it had left their systems, versus patients aged 16 years through 22 years old (a median of 18 days). Females in the 6 to 15 age group also took longer to clear the virus than males: A median of 44 days for females versus 25.5 days for males. “We can’t let our guard down just because a child has antibodies or is no longer showing symptoms,” Bahar said.
The study also found that 25 days was the median time from viral positivity to negativity — the moment when the virus can no longer be detected; it took 18 days to go from viral positivity to seropositivity — or the presence of antibodies in the blood — and it took 36 days to reach adequate levels of neutralizing antibodies. These “neutralizing antibodies” are important in potentially protecting a person from reinfection of the same virus, the researchers wrote.
Four important caveats: Firstly, the study looked at a relatively small number of children. Secondly, the next phase of research will be to test whether coronavirus that is present along with the antibodies for the disease can be transmitted to other people. Thirdly, scientists need to explore whether antibodies correlate with immunity and, fourthly, they need to establish how long antibodies and potential protection from reinfection actually lasts. As such, Bahar reiterates the need for social distancing.
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A separate study published this week in JAMA Pediatrics suggests that children can spread SARS-CoV-2, even if they never develop symptoms or even long after symptoms have cleared. It found a significant variation in how long children continued to “shed” the virus through their respiratory tract and, therefore, could potentially remain infectious. The researchers also found that the duration of COVID-19 symptoms also varied widely, from three days to nearly three weeks.
A recent systematic review estimated that 16% of children with a SARS-CoV-2 infection are asymptomatic, but evidence suggests that as many as 45% of pediatric infections are asymptomatic, according to the U. S. Centers for Disease Control and Prevention. The signs and symptoms of COVID-19 in children are similar to other infections and noninfectious processes, including influenza, according to the CDC.
“ A separate study in JAMA Pediatrics said children may spread SARS-CoV-2, even if they never develop symptoms or even long after symptoms have cleared. ”
Under pressure from the teachers union to delay the start of the school year, New York City Mayor Bill de Blasio announced Tuesday that in-person classes will be pushed back until Sept. 21, 11 days later than planned. Remote learning, also originally slated to start on Sept. 10, will now commence on Sept. 16. Other countries have not fared so well with school reopenings. Israel, which also reopened schools this week, experienced outbreaks when it reopened schools on May 17.
Bahar also advised teachers and students to wear masks. To reduce the risk of spreading COVID-19, it may be preferable to use high-quality cloth or surgical masks that are of a plain design instead of face shields and masks equipped with exhale valves, according to an experiment published Wednesday by Physics of Fluids, a monthly peer-reviewed scientific journal covering fluid dynamics that was first established by the American Institute of Physics in 1958.
COVID-19 has now killed at least 889,542 people worldwide, and 188,954 in the U.S., Johns Hopkins University says. As of Labor Day, the U.S. still has the world’s highest number of COVID-19 cases (6,280,400). Worldwide, there have been at least 27,152,445 confirmed cases, which mostly does not account for asymptomatic cases.
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