Fig. 4

Association between potential risk factors and SARS-CoV-2 sero-positivity taking into account time between baseline and Follow-up 4; events are thus right-censored. Results are based on multiple imputation. The main individual level risk factors were country of birth outside Germany and being employed in a job more in contact with the epidemic. Living in an apartment with a living area of 30–40 square meters per inhabitant revealed a slightly higher risk, while for 40–55 square meters per inhabitant the hazard ratio decreased