Fig. 2: Study population.
From: Protection against Omicron BA.1/BA.2 severe disease 0–7 months after BNT162b2 booster
The participants in the study included persons who were 60 years of age or older, who received 2nd dose at least 4 months before the end of the study, who were not infected by SARS-CoV-2 before the study period, had available data regarding sex and demographic sector, had not stayed abroad during the whole study period, and had not been vaccinated with a vaccine different from BNT162b2 before the study period.
