Estimates and determinants of SARS-CoV-2 seroprevalence and infection fatality ratio using latent class analysis: the population-based Tirschenreuth study in the hardest-hit German county in spring 2020

SARS-CoV-2 infection fatality ratios (IFR) remain controversially discussed with implications for political measures, but the number of registered infections depends on testing strategies and deduced case fatality ratios (CFR) are poor proxies for IFR. The German county of Tirschenreuth suffered a severe SARS-CoV-2 outbreak in spring 2020 with particularly high CFR. To estimate seroprevalence, dark figure, and IFR for the Tirschenreuth population aged [≥]14 years in June/July 2020 with misclassification error control, we conducted a population-based study, including home visits for elderly, and analyzed 4203 participants for SARS-CoV-2 antibodies via three antibody tests (64% of our random sample). Latent class analysis yielded 8.6% standardized county-wide seroprevalence, dark figure factor 5.0, and 2.5% overall IFR. Seroprevalence was two-fold higher among medical workers and one third among current smokers with similar proportions of registered infections. While seroprevalence did not show an age-trend, the dark figure was 12.2 in the young versus 1.7 for [≥]85-year-old. Age-specific IFRs were <0.5% below 60 years of age, 1.0% for age 60-69, 13.2% for age 70+, confirming a previously reported age-model for IFR. Senior care homes accounted for 45% of COVID-19-related deaths, reflected by an IFR of 7.5% among individuals aged 70+ and an overall IFR of 1.4% when excluding senior care home residents from our computation. Our data underscore senior care home infections as key determinant of IFR additionally to age, insufficient targeted testing in the young, and the need for further investigations on behavioral or molecular causes of the fewer infections among current smokers.

Performance evaluation of the Roche Elecsys Anti-SARS-CoV-2 S immunoassay

BackgroundThe Elecsys(R) Anti-SARS-CoV-2 S immunoassay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) has been developed for the in vitro quantitative detection of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein. We evaluated the performance of this assay using samples from seven sites in Germany, Austria, and Switzerland. MethodsAnonymized frozen, residual serum, or plasma samples from blood donation centers or routine diagnostic testing were used for this study. For specificity and sensitivity analyses, presumed negative samples collected before October 2019 and SARS-CoV-2 PCR-confirmed single or sequential samples were tested, respectively. The performance of the Elecsys Anti-SARS-CoV-2 S immunoassay was also compared with other commercial immunoassays. ResultsThe overall specificity (n=7880 pre-pandemic samples) and sensitivity (n=240 PCR-positive samples [[≥]14 days post-PCR]) for the Elecsys Anti-SARS-CoV-2 S immunoassay were 99.95% (95% confidence interval [CI]: 99.87-99.99) and 97.92% (95% CI: 95.21- 99.32), respectively. Compared with seven other immunoassays, the Elecsys Anti-SARS-CoV-2 S assay had comparable or greater specificity and sensitivity. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher specificity compared with the LIAISON(R) SARS-CoV-2 S1/S2 IgG, ADVIA Centaur(R) SARS-CoV-2 Total, ARCHITECT SARS-CoV-2 IgG, iFlash-SARS-CoV-2 IgM, and EUROIMMUN Anti-SARS-CoV-2 IgG and IgA assays, and significantly higher sensitivity ([≥]14 days post-PCR) compared with the ARCHITECT SARS-CoV-2 IgG, iFlash-SARS-CoV-2 IgG and IgM, and EUROIMMUN Anti-SARS-CoV-2 IgG assays. ConclusionThe Elecsys Anti-SARS-CoV-2 S assay demonstrated a robust and favorable performance across samples from multiple European sites, with a very high specificity and sensitivity for the detection of anti-S antibodies.

The impact of the COVID-19 pandemic on families in Germany

ObjectiveTo assess the impact of the COVID-19 pandemic on families with young children in two population-based childhood cohorts with a low and moderate COVID-19 prevalence, respectively. MethodsA cross-sectional study using online questionnaires in families from LIFE Child (n=306, Leipzig) and KUNO Kids (n=612, Regensburg) was performed at the end of the German lock-down period. Outcomes were parent-reported impact of the COVID-19 pandemic on family life, concerns and trust in political measures. ResultsMost families were concerned about the COVID-19 pandemic and lock-down measures, with major concerns directed towards the economic situation (>70%), the health of close-ones (37%), but less towards their own health (<10%). Many concerns, seeking information and approval of federal measures were more pronounced in the more affected region. Approval of lockdown measures and concerns about economic recession were related to regional differences and not significantly dependent on educational status or being personally affected by the disease. ConclusionRegional differences in approval of lockdown measures were observed and thus, measures to specifically support families according to the regional impact of the COVID-19 pandemic are needed.