Prevalence of Long COVID-associated symptoms in adults with and without SARS-CoV-2 infection in Germany: Results of the population-based study: Corona Monitoring Nationwide 2021/22 (RKI-SOEP-2) (preprint)

Background Controlled population-based studies on long-term health sequelae of SARS-CoV-2 can help to identify clinical signs specific to Long COVID and to evaluate this emerging public health challenge. Aim To examine prevalence differences of Long COVID-associated symptoms among adults with and without SARS-CoV-2 infection in Germany. Methods This population-based, retrospective study (11/2021-2/2022) included 7,683 working aged adults (18-65 years), a subset of the Corona Monitoring Nationwide study in Germany. Prior SARS-CoV-2 infection was defined based on self-reported PCR-confirmed infections and IgG-antibody dried blood spot testing. Participants answered a questionnaire including 19 common symptoms of Long COVID experienced in the six months preceding the survey. We estimated population-weighted prevalence of (1) individual symptoms, and (2) [≥]1 symptom, with and without impact on work ability, by infection status within strata of sex, age group, income and comorbidity. We calculated model-adjusted prevalence differences and the probability that symptoms among infected are attributable to infection. Results 12 of 19 symptoms showed a significantly higher prevalence in infected than non-infected participants, including fatigue (27.5% versus 18.3%; p<0.001), concentration problems (22.2% vs. 13.1%; p<0.001), shortness of breath (15.6% vs. 7.5%; p<0.001), and smell and taste disorder (10% vs. 1.2%; p<0.001). [≥]1 symptom with impact on work ability was more prevalent following infection (16.0% vs. 12.2%; p=0.06) with a model-adjusted prevalence difference of 3.8% (95%-CI -0.5-8.0). Conclusion We observed a rather small excess prevalence attributable to SARS-CoV-2 infection. However, the absolute number of persons places great demands on the health care system and may affect economic productivity.

Germany's low SARS-CoV-2 seroprevalence confirms effective containment in 2020: Results of the nationwide RKI-SOEP study (preprint)

Pre-vaccine SARS-CoV-2 seroprevalence data from Germany are scarce outside hotspots, and socioeconomic disparities remained largely unexplored. The nationwide RKI-SOEP study with 15,122 adult participants investigated seroprevalence and testing in a supplementary wave of the Socio-Economic-Panel conducted predominantly in October-November 2020. Self-collected oral-nasal swabs were PCR-positive in 0.4% and Euroimmun anti-SARS-CoV-2-S1-IgG ELISA from dry capillary blood in 1.3% (95% CI 0.9-1.7%, population-weighted, corrected for sensitivity=0.811, specificity=0.997). Seroprevalence was 1.7% (95% CI 1.2-2.3%) when additionally adjusting for antibody decay. Overall infection prevalence including self-reports was 2.1%. We estimate 45% (95% CI 21-60%) undetected cases and analyses suggest lower detection in socioeconomically deprived districts. Prior SARS-CoV-2 testing was reported by 18% from the lower educational group compared to 25% and 26% from the medium and high educational group (p<0.0001). Symptom-triggered test frequency was similar across educational groups. However, routine testing was more common in low-educated adults, whereas travel-related testing and testing after contact with an infected person was more common in highly educated groups. In conclusion, pre-vaccine SARS-CoV-2-seroprevalence in Germany was very low. Notified cases appear to capture more than half of infections but may underestimate infections in lower socioeconomic groups. These data confirm the successful containment strategy of Germany until winter 2020.