ABSTRACT
SARS-CoV-2 serology may be helpful to retrospectively understand infection dynamics in specific settings including kindergartens. We assessed SARS-CoV-2 seroprevalence in individuals connected to kindergartens in Berlin, Germany in September 2021. Children, staff, and household members from 12 randomly selected kindergartens were interviewed on COVID-19 history and sociodemographic parameters. Blood samples were collected on filter paper. SARS-CoV-2 anti-S and anti-N antibodies were assessed using Roche Elecsys. We assessed seroprevalence and the proportion of so far unrecognized SARS-CoV-2 infections. We included 277 participants, comprising 48 (17.3%) kindergarten children, 37 (13.4%) staff, and 192 (69.3%) household members. SARS-CoV-2 antibodies were present in 65.0%, and 52.7% of all participants were vaccinated. Evidence of previous infection was observed in 16.7% of kindergarten children, 16.2% of staff, and 10.4% of household members. Undiagnosed infections were observed in 12.5%, 5.4%, and 3.6%, respectively. Preceding infections were associated with facemask neglect. In conclusion, two-thirds of our cohort were SARS-CoV-2 seroreactive in September 2021, largely as a result of vaccination in adults. Kindergarten children showed the highest proportion of non-vaccine-induced seropositivity and an increased proportion of previously unrecognized SARS-CoV-2 infection. Silent infections in pre-school children need to be considered when interpreting SARS-CoV-2 infections in the kindergarten context.
ABSTRACT
Within 5 weeks in 2021, B.1.1.7 became the dominant severe acute respiratory syndrome coronavirus 2 lineage at an outpatient testing site in Berlin, Germany. Compared with outpatients with wild-type virus infection, patients with B.1.1.7 had similar cycle threshold values, more frequent sore throat and travel history, and less frequent anosmia/ageusia.
Subject(s)
COVID-19 , SARS-CoV-2 , Berlin , Germany/epidemiology , Humans , OutpatientsABSTRACT
BACKGROUND: Considering the possibility of nasal self-sampling and the ease of use in performing SARS-CoV-2 antigen-detecting rapid diagnostic tests (Ag-RDTs), self-testing is a feasible option. OBJECTIVE: The goal of this study was a head-to-head comparison of diagnostic accuracy of patient self-testing with professional testing using a SARS-CoV-2 Ag-RDT. STUDY DESIGN: We performed a manufacturer-independent, prospective diagnostic accuracy study of nasal mid-turbinate self-sampling and self-testing with symptomatic adults using a WHO-listed SARS-CoV-2 Ag-RDT. Procedures were observed without intervention. For comparison, Ag-RDTs with nasopharyngeal sampling were professionally performed. Estimates of agreement, sensitivity, and specificity relative to RT-PCR on a combined oro-/nasopharyngeal sample were calculated. Feasibility was evaluated by observer and participant questionnaires. RESULTS: Among 146 symptomatic adults, 40 (27.4%) were RT-PCR-positive for SARS-CoV-2. Sensitivity with self-testing was 82.5% (33/40; 95% CI 68.1-91.3), and 85.0% (34/40; 95% CI 70.9-92.9) with professional testing. At high viral load (≥7.0 log10 SARS-CoV-2 RNA copies/ml), sensitivity was 96.6% (28/29; 95% CI 82.8-99.8) for both self- and professional testing. Deviations in sampling and testing were observed in 25 out of the 40 PCR-positives. Most participants (80.9%) considered the Ag-RDT as easy to perform. CONCLUSION: Laypersons suspected for SARS-CoV-2 infection were able to reliably perform the Ag-RDT and test themselves. Procedural errors might be reduced by refinement of the instructions for use or the product design/procedures. Self-testing allows more wide-spread and frequent testing. Paired with the appropriate information of the public about the benefits and risks, self-testing may have significant impact on the pandemic.
