Children under 5 can carry as much of the coronavirus in their nose as older children and adults, researchers at Chicago’s Lurie Children’s Hospital reported Thursday.
The study, published in the journal JAMA Pediatrics, raises the possibility that young children may be able to spread COVID-19 as easily as adults, even if they are not sick.
Full coverage of the coronavirus outbreak
Dr. Taylor Heald-Sargent, a pediatric infectious disease specialist at Laurie Children, and colleagues analyzed data from diagnostic tests of 145 COVID-19 patients who had mild to moderate cases of the disease. Tests look for pieces of virus RNA, or genetic code, to make a diagnosis.
The 145 patients were divided into three groups: those under 5, those aged 5 to 17 years, and adults aged 18 to 65 years.
“Children had equal – if not more – viral RNA in their noses compared to older children and adults,” Heald-Sargent said.
Compared to adults, young children had anywhere from 10 to 100 times the amount of viral RNA in their upper respiratory tract, the study authors wrote.
“This supports the idea that children are able to infect and replicate the virus and therefore spread and transmit the virus as much as older children and adults,” she said, noting that more research is needed to confirm this.
Really, “you may have someone who has a high nasal viral load, but that doesn’t necessarily mean they will spread more than someone who has a little less,” said Dr. Rick Malley, a senior pediatrician in the division of infectious diseases at Boston Children’s Hospital.
“We don’t know for sure,” said Malley, who was not involved in the new study.
Still, the findings add another layer to the complex question of whether schools should reopen their doors for the fall semester, and if so, how to do so safely.
Download the NBC News app for full outbrea coronavirus coveragek
“We don’t have evidence that children will play the same role with this virus as they do, say, with the flu virus, where it’s pretty clear that children with the flu are a major driver. of the spread, ”Malley said.
However, he added, COVID-19 is “behaving unpredictably.”
Some young people have developed a potentially fatal condition called multisystem inflammatory syndrome in children, or MIS-C, which is thought to be linked to COVID-19.
The condition is relatively rare; the Centers for Disease Control and Prevention reported that as of July 15, 342 cases of MIS-C had been diagnosed in the country. Six children died.
However, in general, children have been relieved of the most severe consequences of COVID-19.
In the Heald-Sargent study, the ages of patients ranged from less than a month to 65 years. Those in need of breathing aid were excluded from the study. All were diagnosed in March and April.
Lurie Children was asked by all hospital patients to have a COVID-19 test, and some cases were detected, even though the children had minimal symptoms.
“Children who came in with a broken arm system who happened to test positive are being caught,” Heald-Sargent said.
It is not yet clear how prevalent COVID-19 is among children, in part because testing is limited, especially for asymptomatic ones. And schools have been largely closed since spring, making it difficult to verify how much children can spread the virus.
There are some theories as to why children may not spread the coronavirus as easily as adults: Their lung capacity is smaller, so they may not be able to cough or sneeze with the same force as adults. Also, any emitting respiratory drops can fall to the ground because their bodies are simply closer to the ground.
Heald-Sargent, who has her own young children, rejected this idea. “We have to remember that COVID-19 can throw in the stool, it can be in the mouth and nose. The children touch it. They are small germ factories.”
Follow NBC HEALTH on Twitter and Facebook.