Children aged younger than 5 years may carry 10-fold to 100-fold greater amount of SARS-CoV-2 in the upper respiratory tract compared to those aged 5 to 17 years and adults (18 to 65), finds a recent study published in JAMA Pediatrics .
The study sheds light on an important public health implication that may arise especially while considering the safety of reopening schools and daycare centres.
“Our study is limited to detection of viral nucleic acid, rather than the infectious virus, although SARS-CoV-2 paediatric studies reported a correlation between higher nucleic acid levels and the ability to culture infectious virus,” Taylor Heald-Sargent, MD, Ph D, paediatric infectious disease specialist at Lurie Children’s Hospital of Chicago, and colleagues wrote.
“Thus, young children can potentially be important drivers of SARS-CoV-2 spread in the general population, as has been demonstrated with the respiratory syncytial virus, where children with high viral loads are more likely to transmit.” noted the authors.
The researchers tested nasopharyngeal swabs collected from 145 patients — 46 younger than 5 years, 51 aged 5 to 17 years, and 48 aged between 18 and 65 years. The researchers reported similar median cycle threshold (CT) values in youths aged 5 to 17 years (11.1 [6.3-15.7]) and adults (11 [6.9-17.5]), The CT is defined as the number of cycles required for the fluorescent signal to cross the threshold which gives a relative measure of the concentration of target in the PCR reaction.
The children aged younger than 5 years had significantly lower CT values (6.5[4.8-12]) which indicated that young children have equivalent or more viral nucleic acid in their upper respiratory tract compared with older children and adults.