RESUMO
ObjectiveTo investigate SARS-COV-2 viral clearance and viral load kinetics in the course of infection in children aged 1-6 years in comparison with adults. MethodsProspective cohort study of infected daycare children and staff and their close contacts in households from 11/2020-06/2021, comprising serial (self) sampling of upper respiratory tract specimen and testing for SARS-CoV-2 via PCR. Data on symptoms and exposure were used to determine the date of probable infection for each participant. We determined (a) viral clearance, and (b) viral load dynamics over time. Samples were taken from day 4-6 to day 16-18 after diagnosis of the index case in the respective daycare group (5 samples per participant). ResultsWe included 40 children (1-6 years) and 67 adults (18-77 years) with SARS-CoV-2 infection. Samples were available at a mean of 4.3 points of time per participant. Among the participants, the 12-day study period fell in different periods within the individual course of infection, ranging from day 5-17 to day 15-26 after assumed infection. Children reached viral clearance at a median of 20 days after assumed infection (95% CI 17-21 days, Kaplan Meier Analysis), adults at 23 days (95% CI 20-25 days, difference not significant). In both children and adults, viral load decreased over time with trajectories of the mean viral load not being statistically different between groups. Only small proportions of those tested positive had a viral load of >1 million copies/ml, which is considered the threshold for infectivity. Kaplan-Meier calculations show that from day 15 (95% CI 13-15), 50% of all participants that had a viral load no longer infectious or were negative. ConclusionChildren aged 1-6 and adults infected with SARS-CoV-2 (wild type and Alpha variant) did not differ significantly in terms of viral load kinetics and time needed to clear the virus. Therefore, containment measures are important also in the daycare settings as long as the pandemic continues.
RESUMO
BackgroundWhereas the majority of children under 6 years of age attend daycare centers in Germany, evidence on the role of daycare centers in the transmission of SARS-CoV-2 is scarce. AimsThis study aims to investigate the transmission risk in daycare centers among children and staff and the spread of infections to associated households. Methods30 daycare groups with at least one recent laboratory-confirmed SARS-CoV-2 case (child or staff) were enrolled in the study (10/2020-06/2021). Close contacts within the daycare group and households were examined over a 12-day period (repeated SARS-CoV-2 PCR tests, genetic sequencing of viruses, documentation of symptoms). Households, local health authorities and daycare staff were interviewed to gain comprehensive information on each outbreak. We determined primary cases for all daycare groups. ResultsThe number of secondary cases varied considerably between daycare groups. The pooled secondary attack rate (SAR) across all 30 daycare centers was 9.6%. The SAR tended to be higher in daycare centers in which the Alpha variant of the virus was detected (15.9% vs. 5.1% with evidence of wild type). The SAR in households was 53.3%. Exposed children were less likely to get infected with SARS-CoV-2 in daycare centers, compared to adults (7.7% vs. 15.5%). ConclusionContainment measures in daycare programs are critical and become increasingly important with highly transmissible new variants to reduce SARS-CoV-2 transmission, especially to avoid spread to associated households. Virus variants may modify transmission dynamics in daycare programs.