Relationship between viral load and symptoms in children infected with SARS-CoV-2.

Background: The purpose of this study is to evaluate the association between SARS-CoV-2 viral load in respiratory secretions of infected children and signs/symptoms of COVID-19.

Methods: We reported the clinical characteristics of SARS-CoV-2-infected children during the study period. We compared viral load for several clinical variables, performed a predictive linear regression analysis to identify signs and symptoms significantly associated with viral load, and searched for discriminant viral load thresholds for symptomatic versus asymptomatic infections based on receiver-operating characteristics.

Results: A total of 570 patients were included. The median age was 4.75 years. Comparison of CT values by dichotomous variable showed higher viral loads in children with fever, respiratory symptoms, and previous exposure to SARS-CoV-2. The linear regression analysis confirmed a significant relationship between the CT value with these variables and with age, other symptoms, and asymptomaticity. In particular, infants with fever and SARS-CoV-2 exposure had higher viral loads. No viral load cut-offs were found to distinguish symptomatic from asymptomatic patients.

Conclusion: Our study shows that fever, SARS-CoV-2 exposure, and respiratory symptoms are associated with higher viral load in children, especially infants, while age, presence of nonrespiratory symptoms, or absence of any symptoms are associated with lower viral load.

Impact: Key message: the clinical variables that best predict viral load in infected children are history of previous exposure to a SARS-CoV-2-infected person and presence of fever and respiratory symptoms (higher viral load). Added value to the current literature: this is the first article to prove this point.

Impact: SARS-CoV-2 viral load should not be used as a measure of clinical severity of COVID-19 in the pediatric population; however, lower viral load appears to be associated with asymptomatic COVID-19 in older children.