Viral Dynamics of the SARS-CoV-2 Omicron Variant in Pediatric Patients: A Prospective Cohort Study

Background There are limited data on the viral dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children. Understanding viral load changes over the course of illness and duration of viral shedding may provide insight into transmission dynamics to inform public health and infection-control decisions.Methods We conducted a prospective cohort study of children aged 18 years and younger with polymerase chain reaction-confirmed SARS-CoV-2 between 1 February 2022 and 14 March 2022. SARS-CoV-2 testing occurred on daily samples for 10 days; a subset of participants completed daily rapid antigen tests (RATs). Viral RNA trajectories were described in relation to symptom onset and resolution. The associations between both time since symptom onset/resolution and non-infectious viral load were evaluated using a Cox proportional hazards model.Results Among 101 children aged 2 to 17 years, the median time to study-defined non-infectious viral load was 5 days post-symptom onset, with 75% meeting this threshold by 7 days and 90% by 10 days. On the day of and day after symptom resolution, 43 (49%) and 52 (60%) of 87 had met the non-infectious thresholds, respectively. Of the 50 participants completing a RAT, positivity at symptom onset and on the day after symptom onset was 67% (16/24) and 75% (14/20). On the first day where the non-infectious threshold was met, 61% (n = 27/44) of participant RAT results were positive.Conclusions Children often met the study-defined non-infectiousness threshold on the day after symptom resolution. The RATs were often negative early in the course of illness and should not be relied on to exclude infection. Clinical Trials Registration. clinicaltrials.org; NCT05240183.Conclusions Children often met the study-defined non-infectiousness threshold on the day after symptom resolution. The RATs were often negative early in the course of illness and should not be relied on to exclude infection. Clinical Trials Registration. clinicaltrials.org; NCT05240183. We evaluated the SARS-CoV-2 viral load changes over the course of illness in children. The median time to presumably non-infectious viral load was 5 days after symptom onset, with 60-90% of children meeting the threshold of non-infectiousness on the day after symptom resolution.