2 research outputs found
German federal-state-wide seroprevalence study of 1st SARS-CoV-2 pandemic wave shows importance of long-term antibody test performance
Background Reliable data on the adult SARS-CoV-2 infection fatality rate in Germany are
still scarce. We performed a federal state-wide cross-sectional seroprevalence study named
SaarCoPS, that is representative for the adult population including elderly individuals and
nursing home residents in the Saarland.
Methods Serum was collected from 2940 adults via stationary or mobile teams during the
1st pandemic wave steady state period. We selected an antibody test system with maximal
specificity, also excluding seroreversion effects due to a high longitudinal test performance.
For the calculations of infection and fatality rates, we accounted for the delays of seroconversion and death after infection.
Results Using a highly specific total antibody test detecting anti-SARS-CoV-2 responses
over more than 180 days, we estimate an adult infection rate of 1.02% (95% CI: [0.64;
1.44]), an underreporting rate of 2.68-fold (95% CI: [1.68; 3.79]) and infection fatality rates
of 2.09% (95% CI: (1.48; 3.32]) or 0.36% (95% CI: [0.25; 0.59]) in all adults including
elderly individuals, or adults younger than 70 years, respectively.
Conclusion The study highlights the importance of study design and test performance for
seroprevalence studies, particularly when seroprevalences are low. Our results provide a
valuable baseline for evaluation of future pandemic dynamics and impact of public health
measures on virus spread and human health in comparison to neighbouring countries such as
Luxembourg or France
Pooled RT-qPCR testing for SARS-CoV-2 surveillance in schools - a cluster randomised trial
Background: The extent to which children and adolescents contribute to SARS-CoV-2 transmission remains not fully understood. Novel high-capacity testing methods may provide real-time epidemiological data in educational settings helping to establish a rational approach to prevent and minimize SARS-CoV-2 transmission. We investigated whether pooling of samples for SARS-CoV-2 detection by RT-qPCR is a sensitive and feasible high-capacity diagnostic strategy for surveillance of SARS-CoV-2 infections in schools. Methods: In this study, students and school staff of 14 educational facilities in Germany were tested sequentially between November 9 and December 23, 2020, two or three times per week for at least three consecutive weeks. Participants were randomized for evaluation of two different age adjusted swab sampling methods (oropharyngeal swabs or buccal swabs compared to saliva swabs using a ‘lolli method’). Swabs were collected and pooled for SARS-CoV-2 RT-qPCR. Individuals of positive pooled tests were retested by RT-qPCR the same or the following day. Positive individuals were quarantined while the SARS-CoV-2 negative individuals remained in class with continued pooled RT-qPCR surveillance. The study is registered with the German Clinical Trials register (registration number: DRKS00023911). Findings: 5,537 individuals were eligible and 3970 participants were enroled and included in the analysis. In students, a total of 21,978 swabs were taken and combined in 2218 pooled RT-qPCR tests. We detected 41 positive pooled tests (1·8%) leading to 36 SARS-CoV-2 cases among students which could be identified by individual re-testing. The cumulative 3-week incidence for primary schools was 564/100,000 (6/1064, additionally 1 infection detected in week 4) and 1249/100,000 (29/2322) for secondary schools. In secondary schools, there was no difference in the number of SARS-CoV-2 positive students identified from pooled oropharyngeal swabs compared to those identified from pooled saliva samples (lolli method) (14 vs. 15 cases; 1·3% vs. 1·3%; OR 1.1; 95%-CI 0·5–2·5). A single secondary school accounted for 17 of 36 cases (47%) indicating a high burden of asymptomatic prevalent SARS-CoV-2 cases in the respective school and community. Interpretation: In educational settings, SARS-CoV-2 screening by RT-qPCR-based pooled testing with easily obtainable saliva samples is a feasible method to detect incident cases and observe transmission dynamics. Funding: Federal Ministry of education and research (BMBF; Project B-FAST in “NaFoUniMedCovid19”; registration number: 01KX2021)