Children younger than 5 years have 10 to 100 times more coronavirus re-genetic material in their nose compared to older children and adults, according to a small study published Thursday in the journal JAMA Pediatrics.
While the study did not measure transmissibility, it raises questions – as schools begin to reopen – about how easily the new coronavirus can spread from the under-5 set.
“We just noticed that some of the children we were testing for SARS CoV-2 were positive, the younger children appeared to have a high amount of viral nucleic acid – a high viral load in their nose – when compared to some of our older children and adults, ”lead author Dr. Taylor Heald-Sargent, a pediatric infectious disease specialist at Chicago’s Lurie Children’s Hospital, told CNN. “And so when … actually managed the numbers, checked for a few things, we found that there was actually a statistically significantly higher amount of genes that are encoded by SARS, which generally correlates with more viruses, in the nose of children under five, compared to older children and adults. “
Heald-Sargent and her team analyzed 145 swab samples collected from patients with mild to moderate Covid-19 within one week of the onset of symptoms; 46 of them were from children under 5, 51 were from 5 to 17 years old, and 48 were from adults between 18 and 65. Samples were collected between the end of March and the end of April from several hospital. , an emergency department and drive-through testing sites at a pediatric tertiary medical center in Chicago.
They found that those under 5 had a statistically significant greater amount of nasal virus particles that correlated to “an amount greater than 10 times to 100 times greater of the coronavirus in the upper respiratory system …” ir the researchers wrote in their paper.
Heald-Sargent says more studies need to look at the transmissibility of SARS-CoV-2 in children. “So far this transmission is not seen primarily by children,” Heald-Sargent said.
But her team noted in the paper that due to the stay-at-home measures implemented in mid-March, many young children had fewer opportunities to transmit.
“The question was still there: Can it be transmitted possibly by children?” she said, noting that the lack of evidence is not evidence of absence.
If other respiratory viruses are any indication, she said, the answer may indeed be yes.
“Any teacher or pediatrician at the school who tells you, [young children] they are a fairly effective vectors of virus transmission, because we get very sick in the winter from these children, “she said.” I think looking at other viruses that are similar … it seems more likely that children will transmit. “
Other experts say that while you’re not surprised by the findings, it’s good to have the study.
“Data in pediatrics has not been as robust as adults with Covid-19 so it’s nice to have additional virological data in pediatric patients,” said Seattle Children’s Dr. Alpana Waghmare.
“The authors did a great job comparing such a robust sample of subjects at different age ranges and using a fairly simple research design to look at the differences in viral load between these age groups,” said Waghmare, who is an assistant professor of pediatrics. in the division of pediatric infectious diseases at the University of Washington.
Waghmare said the findings are consistent with other published studies looking at viral loads across a spectrum of respiratory viruses in pediatric populations. “It’s not surprising to find higher viral loads in children. I think the question of what exactly it means for transmission is still unclear,” she said.
Dr. Michael Smit, a pediatric infectious disease physician at Los Angeles Children’s Hospital agrees – and after some.
“We have known for a while that for certain respiratory viruses, young children are the breeding ground and are part of the population that spreads to the rest of the community,” said Smit, who is also the epidemiologist. of the hospital. and the medical director for the prevention and control of infections.
Smit said it was previously shown with respiratory syncytial virus (RSV) and research by his own group, published as a research letter in the JAMA Open Network in mid-May, showed the same thing with seasonal coronavirus. “So, it’s a well-known phenomenon in pediatrics that younger children can be the main drivers of the spread of disease and communities.”
There are still questions about the new coronavirus. A recent study in South Korea found that 10- to 19-year-olds transmitted Covid-19 into their homes as much as adults, but children 9 and younger transmitted the virus at much lower rates. .
The question remains, what can you do about it?
“Once you discover a kind of dynamics of how many viruses there are and in what age groups it tends to be bigger and smaller in, then that can help us form strategies for surveillance, for testing, for isolation, he said.
Heald-Sargent said the “behavioral habits” of very young children – for example, lack of awareness of personal space and personal hygiene, fidgeting, hands-on games, and eye and nose wipes – make it difficult to control any potential spills, but it’s important to try.
“It’s a struggle to get them to wear their masks and wash their hands and not to put everything in their mouths and noses,” she said.
“After adults model good behavior, make them encourage their children to wash their hands and wear their mask as much as possible, clean high-touch areas, be careful with diapers” are all good practices, she said, and added that young children generally want to please their parents.
At the societal level, she said it will also be important to implement infection control practices such as contact tracing, and to take steps in school, such as keeping children in the same small groups, to limit the spread.