From first to second wave: follow-up of the prospective Covid-19 cohort (KoCo19) in Munich (Germany)

Abstract

Background: In the 2nd year of the Covid-19 pandemic, knowledge about the dynamics of the infection in the general population is still limited. Such information is essential for health planners, as many of those infected show no or only mild symptoms and thus, escape the surveillance system. We therefore aimed to describe the course of the pandemic in the Munich general population living in private households from April 2020 to January 2021. Methods: The KoCo19 baseline study took place from April to June 2020 including 5313 participants (age 14 years and above). From November 2020 to January 2021, we could again measure SARS-CoV-2 antibody status in 4,433 of the baseline participants (response 83%). Participants were offered a self-sampling kit to take a capillary blood sample (dry blood spot; DBS). Blood was analysed using the Elecsys(R) Anti-SARS-CoV-2 assay (Roche). Questionnaire information on socio-demographics and potential risk factors assessed at baseline was available for all participants. In addition, follow-up information on health-risk taking behaviour and number of personal contacts outside the household (N=2768) as well as leisure time activities (N=1263) were collected in summer 2020. Results: Weighted and adjusted (for specificity and sensitivity) SARS-CoV-2 sero-prevalence at follow-up was 3.6% (95% CI 2.9-4.3%) as compared to 1.8% (95% CI 1.3-3.4%) at baseline. 91% of those tested positive at baseline were also antibody-positive at follow-up. While sero-prevalence increased from early November 2021 to January 2021, no indication of geospatial clustering across the city of Munich was found, although cases clustered within households. Taking baseline result and time to follow-up into account, men and participants in the age group 20-34 years were at the highest risk of sero-positivity. In the sensitivity analyses, differences in health-risk taking behaviour, number of personal contacts and leisure time activities partly explained these differences. Conclusion: The number of citizens in Munich with SARS-CoV-2 antibodies was still below 5% during the 2nd wave of the pandemic. Antibodies remained present in the majority of baseline participants. Besides age and sex, potentially confounded by differences in behaviour, no major risk factors could be identified. Non-pharmaceutical public health measures are thus still important.

Severe acute respiratory syndrome coronavirus 2 antibody prevalence in adult patients with short bowel syndrome—A German multicenter cross‐sectional study

“…Despite previous studies showing an association with the rate of community‐acquired COVID‐19 and frequency of contact with nursing staff in patients with intestinal failure in the United Kingdom, our seroprevalence was within the German national average, which was 4.1%–11.6% measured in antibodies against the spike (S) antigen for the first half of 2021 14,15 . More recent data from July 2021 to October 2021 suggest a seroprevalence of up to 7.9% (KoCo19 Study) 16,17 …”

“…14,15 More recent data from July 2021 to October 2021 suggest a seroprevalence of up to 7.9% (KoCo19 Study). 16,17 All the infections in our SBS cohort had mild clinical courses, with two patients having no symptoms at all. This would be unexpected in a group of high-risk patients.…”

“… 14 , 15 More recent data from July 2021 to October 2021 suggest a seroprevalence of up to 7.9% (KoCo19 Study). 16 , 17 …”

Early nucleocapsid-specific T cell responses associate with control of SARS-CoV-2 in the upper airways and reduced systemic inflammation before seroconversion

“…SARS-CoV-2-specific antibodies were assayed in EDTA plasma as described previously 50,51 using the following kits: Anti-SARS-CoV-2-ELISA Anti-S1 IgA (EI-S1-IgA, Euroimmun), Anti-SARS-CoV-2-ELISA Anti-S1 IgG (EI-S1-IgG, Euroimmun), and Elecsys Anti-SARS-CoV-2 Anti-N (Ro-N-Ig, Roche).…”

Integrative modelling of reported case numbers and seroprevalence reveals time-dependent test efficiency and infectious contacts

“…Clearly, the number of performed tests and the selection criteria have changed over time (e.g., due to the introduction of antigen tests). As an alternative to the officially reported case numbers, the officially reported death numbers, which are generally considered as more reliable (Radon, Bakuli, et al 2021; Pritsch et al 2021), can be used. However, there the effects of NPIs are smoothed over time and only visible after a substantial delay.…”