Fig. 2: Reduction in incidence rate of COVID-19-related hospitalization compared to non-recent vaccine immunity (dashed blue line at x = 0).

Data are presented as point estimates of the percentage reduction in incidence rate (1−IRR) and 95% confidence intervals. N (person-days at risk) = 143,612,328 for boosted vaccine immunity, 9,759,128 for infection-induced immunity, 9,266,031 for enhanced infection-induced immunity and 72,914,787 for non-recent vaccine immunity (reference, dashed blue line).