Longitudinal testing for SARS-CoV-2 RNA in day care centers in Hesse, Germany, during increased local incidence and with VOC Alpha as dominant variant: Results of the SAFE KiDS 2 and SAFE KiDS 3 study

In the summer of 2020, we investigated the rate of inapparent shedding of SARS-CoV-2 in a representative sample of day care centers from Hesse, Germany, and found a low positivity rate during a period of low local community spread. To investigate the influence of a high local incidence setting, we conducted the SAFE KiDS 2 study. 577 children and 334 staff members of 47 day care centers were tested for respiratory and gastrointestinal shedding of SARS-CoV-2, and three infections with SARS-CoV-2 in the infectious period were detected. We conclude that viral shedding occurred infrequently while the original "wild-type" variant was dominant. The more transmissible SARS-CoV-2 variant Alpha (B.1.1.7) became the dominant strain after SAFE KiDS 2 was concluded. The SAFE KiDS 3 study investigated the impact of the Alpha variant of SARS-CoV-2 on inapparent viral shedding in the day care setting. In this study, 756 children and 226 staff members from 46 day care centers provided self-collected saliva swabs, the so-called "Lollipop" swabs, which were tested by RT-PCR. In the four-week study period, none of the participants tested positive for SARS-CoV-2 RNA, demonstrating that inapparent shedding of SARS-CoV-2 in the day care setting was also rare during the dominance of the Alpha variant. The influence of the variant of concern Delta on day care centers has yet to be studied.

Longitudinal testing for respiratory and gastrointestinal shedding of SARS-CoV-2 in day care centres in Hesse, Germany. Results of the SAFE KiDS Study

BackgroundWith the pandemic of SARS-CoV-2 ongoing in Europe in July of 2020, day care centres were reopened in the state of Hesse, Germany, after the lockdown. The role young children play in the dynamics of the transmission was unknown. MethodsWe conducted a longitudinal study over a period of 12 weeks (18th of June 2020 to 10th of September, 2020) to screen attendees and staff from day care centres in the state of Hesse, Germany, for both respiratory and gastrointestinal shedding of SARS-CoV-2. 825 children (age range 3 months to 8 years) and 372 staff members from 50 day care centres, which were chosen representatively from throughout the state, participated in the study. Parents were asked to perform both a buccal mucosa and an anal swab on their children once a week. Staff were asked to self-administer the swabs. RT-PCRs for SARS-CoV-2 were performed in a multiple-swab pooling protocol. Findings7,366 buccal mucosa swabs and 5,907 anal swabs were analysed. No respiratory or gastrointestinal shedding of SARS-CoV-2 was detected in any of the children. Shedding of SARS-CoV-2 could be detected in two staff members from distinct day care centres. One was asymptomatic at the time of testing, and one was symptomatic. InterpretationRespiratory or gastrointestinal shedding of SARS-CoV-2 in children or staff members in day care centres was very rare in the context of low community activity. The data indicate day care centres do not pose a reservoir for SARS-CoV-2 in a low prevalence setting, no inapparent transmissions were observed. FundingThe study was commissioned by the Hessian Ministry of Social Affairs and Integration and was supported by Roche Diagnostics, Basel, Switzerland.