July 30 (UPI) -- Young children with mild or moderate COVID-19 may have the same or higher amounts of virus in their upper respiratory tracts as older children and adults, a study published Thursday by JAMA Pediatrics found.
This could indicate that children age 5 and younger can "spread the virus as efficiently as adults," study co-author Dr. Taylor Heald-Sargent told UPI.
"Together, with studies in other viruses that have linked high amounts of virus to increased transmission and the behaviors of young children, it is reasonable to hypothesize [based on our findings] that children could spread the virus as efficiently as adults," said Heald-Sargent, a pediatrician and infectious disease specialist at Ann and Robert H. Lurie Children's Hospital of Chicago.
Larger studies of COVID-19 in children are needed, however, to confirm whether these significant viral loads are a factor in disease transmission, she said.
Research to date has suggested children play a limited role in spreading the new coronavirus.
For example, a study published last month in the Journal of the Pediatric Infectious Diseases Society found limited evidence of child-to-child or child-to-adult transmission. But that study involved only 34 households with multiple coronavirus infections, and 73% of transmission in those households was from adult to child.
For this study, Heald-Sargent and her colleagues assessed 145 patients with mild to moderate illness within one week of showing symptoms. They used a standard screening approach for COVID-19.
The researchers sorted study participants into three groups: 46 young children age 5 and below, 51 children age 5 to 17 and 48 adults age 18 to 65.
Testing revealed that "young children have equivalent or more viral nucleic acid in their upper respiratory tract compared with older children and adults," the researchers wrote.
The upper respiratory tract includes the nose and nasal passages, sinuses, pharynx and the portion of the larynx above the vocal cords.
"Although our study does not address transmission, other work on [COVID-19] has shown that levels of viral nucleic acid similar to what we found in [young children] reflects levels of infectious virus," Heald-Sargent said.