Symptom progression and viral shedding dynamics in children and adolescents with asymptomatic and mild COVID-19 infections

OBJECTIVE: Limited research has examined the progression of disease symptoms and viral shedding dynamics using continuous daily cycle threshold (Ct) values in large pediatric populations infected with SARS-CoV-2. METHODS: This analysis included 7803 children and adolescents selected from a retrospective cohort of 174,371 individuals with COVID-19. Factors influencing symptom progression and viral shedding were evaluated across asymptomatic, asymptomatic-to-mild and mild symptom groups. Inverse Probability of Treatment Weighting (IPTW) was used to adjust for confounding and correct group imbalances. RESULTS: During follow-up, 86.2% of initially asymptomatic individuals progressed to mild disease. The median durations of hospital stay and viral shedding were both six days (interquartile range: 4–8 days). Older children (AOR: 1.13–1.53), females (AOR: 1.21), lower nadir N gene (AOR: 0.89) and vaccinated individuals (AOR by IPTW: 1.75–1.99) exhibited a higher likelihood of symptom progression. Older age (AHR: 1.13–1.44) and higher nadir N gene values (AHR: 1.15) were associated with an increased likelihood of viral shedding. Full vaccination demonstrated a modest association with viral shedding (AHR by IPTW: 1.08). Compared to the asymptomatic group, viral shedding was less likely in the asymptomatic-to-mild (AHR: 0.64) and mildly symptomatic (AHR: 0.60) groups. CONCLUSION: In pediatric COVID-19 patients, older age, female sex, lower nadir N gene and vaccination are associated with an increased likelihood of progression from asymptomatic to mild symptoms. Older age and higher nadir N gene correlate with a greater probability of viral shedding. Vaccination status is associated with a higher probability of symptomatic presentation and a weakly accelerated viral clearance.