Work

Renewed Absence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infections in the Day Care Context in Berlin, January 2021

Year: 2021

Type: letter

Abstract: To the Editor—Hoehl et al [1] report the absence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among 859 children attending day care in Hesse, Germany, who were screened weekly over a 12-week period in summer 2020 by parentally conducted buccal mucosal and anal swabs. Two day care staff members tested positive. In that period, the regional community transmission was low (weekly incidence, 0–66/100 000). We would like to complement these findings with data from kindergarten children, staff, and household members obtained during higher community transmission in January 2021 in metropolitan Berlin. Germany experienced a strong second coronavirus disease 2019 wave, which in Berlin started in early October 2020, and peaked between mid-November and mid-December 2020. Between 17 and 23 January 2021, health authorities reported a weekly incidence of 110 per 100.000 [2]. In this week, we conducted the second round of a longitudinal study in 12 randomly selected kindergartens across Berlin including 156 kindergarten children, 80 staff, and 488 household members of children and staff. The first round had taken place in September 2020 [3]. Because of entry restrictions to these facilities in January 2021 and only partial attendance, we sent and recollected self-swabbing kits with illustrated instructions (CoronaOne, Germany) to all study participants. Swabs (Nerbe Plus, Germany) were self-collected from oropharynx and both nostrils, and parents swabbed their children accordingly. SARS-CoV-2 infection was determined by reverse-transcription polymerase chain reaction including human RNase P gene coamplification (GFE-Blut, Frankfurt, Germany). History data were obtained by electronic questionnaires. At the January assessment, 57.9% (70/121) of children and 98.5% (65/66) of staff had visited their kindergarten at least once during the preceding 2 weeks (median, 8 days [range, 0–11], and 10 days [range, 1–14], respectively). One hundred forty-nine children (median age, 5 years [range, 2–8]), 74 staff members (45 years [range, 19–79]), and 472 household members (36 years [range, 1–91]) provided a swab. Mainly cold-like symptoms were reported for 11.6% (17/147), 55.4% (41/74), and 24.9% (112/449) of children, staff, and household members on the day of sample collection. All tested negative for SARS-CoV-2. At 2 time points, our entire cohort tested negative for SARS-CoV-2, in September 2020 [3] and in January 2021. As a limitation, our participants might not be representative for the children and adults connected to the >2600 kindergartens in Berlin. Nevertheless, repeated absence of SARS-CoV-2 infection 4 months apart, at weekly community incidences of 38 and 110/100 000, together with the findings of Hoehl et al [1], support our initial interpretation that kindergartens are not silent transmission reservoirs. Likewise, colleagues in Munich did not identify any kindergarten infections by weekly screening in summer and autumn 2020 [4]. This does not exclude the occurrence of outbreaks in such facilities, as reported elsewhere [5–7] and as seen in 1 of our studied kindergartens in November 2020. So far, health authorities were capable to detect and control these within a reasonable time frame. This may possibly change with the emergence of more transmissible viral mutants. In the current situation, the manageable risk of SARS-CoV-2 infection associated with kindergarten attendance must be weighed very carefully against the manifold health and social risks posed by closed facilities [8, 9]. Acknowledgments. The authors thank the children, daycare staff, and families for participation, and Charité–Universitätsmedizin Berlin and the Senate of Berlin for support. Financial support. This work was supported by the Senate of Berlin. Author contributions. F. H., S. T., T. K., J. S., and F. P. M. designed the study. C. v. K. supervised logistics. M. S. did laboratory examinations. W. v. L. was responsible for analysis. W. v. L. and F. P. M. wrote the manuscript. All authors participated in drafting the article or revising it critically for intellectual content, and approved the final version. Potential conflicts of interest. T. K. has received personal fees from Eli Lilly and Company, Newsenselab, Total, and the BMJ, outside the submitted work. M. S. has a patent pending on detection of SARS-CoV-2 in a plurality of biological samples (number 1649P102EP). All other authors report no potential conflict of interests. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Source: Clinical Infectious Diseases

DOI: 10.1093/cid/ciab199