Fig. 2From: Gam-COVID-Vac, EpiVacCorona, and CoviVac effectiveness against lung injury during Delta and Omicron variant surges in St. Petersburg, Russia: a test-negative case–control studyPatients dynamics and proportion of patients with any lung injury through the study period October 2021–April 2022 (dashed vertical line marks the start of the Omicron surge)Back to article page