Immune correlates against SARS-CoV-2 infection – results of population and hospital-based studies in the IMMUNEBRIDGE project in Germany, 2022

Einleitung  In spring 2022, Germany lacked systematically collected population-based SARS-CoV-2 data allowing real-time assessment of protection levels against severe course of COVID-19. To fill this gap, the IMMUNEBRIDGE project, a joint collaboration of eight population- and one hospital-based studies, was launched.

Methoden  We resampled and collected data on SARS-CoV-2 in the general German population including children between June and November 2022. Built on literature synthesis, we formed four protection levels against severe COVID-19 based on the number of self-reported infections/vaccinations and nucleocapsid/spike antibody responses ("confirmed exposures"). The highest protection was based on four “confirmed exposures”, and no exposure characterised the lowest protection level.

Ergebnisse  Across a total number of 33,637 participants, 95% had S antigen (<18 years 80%) and 52% showed N antigen responses (<18 years 68% and >79 years 28%). Among persons above 79 years, 40% had not received a fourth vaccine dose in summer 2022. In addition, relevant gaps emerged particularly among people with comorbidities and in different regions of Germany (N-antigen ranged from 37% in Lüneburg to 60% in Leipzig).

Schlussfolgerung  We observed moderate to high levels of protection against severe COVID-19. We found protection gaps in the elderly persons and amongst person with comorbidities, confirming the importance for additional protective measures in these groups. These data provided essential input parameter to enable modelling.