SARS-CoV-2 Viral RNA Load Dynamics in the Nasopharynx of Infected Children

ABSTRACT

It is important to understand the temporal trend of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load to estimate the transmission potential of children in schools and communities. We determined differences in SARS-CoV-2 viral load dynamics between nasopharyngeal samples of infected asymptomatic and symptomatic children. The daily cycle threshold values of SARS-CoV-2 in the nasopharynx of a cohort of infected children were collected for analysis. Among 17 infected children, 10 (58.8%) were symptomatic. Symptomatic children, when compared to asymptomatic children, had higher viral load (mean cycle threshold on day 7 of illness 28.6 versus 36.7, p = 0.02). Peak SARS-CoV-2 viral loads occured around days 2-3 of illness/days of diagnosis in infected children. After adjusting for the estimated date of infection, the higher SARS-CoV-2 viral loads in symptomatic children remained. We postulate that symptomatic SARS-CoV-2-infected children may have higher transmissibility than asymptomatic children. As peak viral load in infected children occurred in the early stage of illness, viral shedding and transmission in the pre-symptomatic phase probable. Our study highlights the importance of screening for SARS-CoV-2 in children with epidemiological risk factors, even when they are asymptomatic in order to improve containment of the virus in the community, including educational settings. Key pointsO_LISymptomatic children had higher SARS-CoV-2 viral loads in the nasopharynx than asymptomatic children, which may indicate that symptomatic children have higher transmissibility. C_LIO_LIPeak SARS-CoV-2 viral loads occurred early around 2-3 days post symptom onset iin children and therefore, pre-symptomatic transmission of the virus is probable. C_LIO_LISymptom based screening for SARS-CoV-2 may not be effective in diagnosing coronavirus disease 2019 (COVID-19) in children as a proportion of children may be asymptomatic or pauci-symptomatic. C_LIO_LIChildren with high epidemiological risk factors should be screened or isolated as they may be carriers of the virus and contribute to transmission. C_LI