Fig. 3.

Associations between vaccine inoculations, anti S1/S2 IgG test results and COVID-19 infection. a COVID-19 infection-free survival from epidemic onset according to vaccination status as a time-varying covariate (see “Methods”), split by study group. *, p < 0.05 for 2 vs. 0–1 inoculations. b Risk of COVID-19 infection by inoculation status and age group (< 58 year old vs. ≥ 58 year old). The model also included a patient identifier and was stratified by study group. c COVID-19 events presented as Kaplan Meier curves according to IgG serology status. d Histograms showing the distribution of serology results (logarithmic scale) according to whether or not the participant became infected after the test was performed, but prior to the subsequent test. A putative protective cutoff is observed at ~ 60 AU/ml. e Determinants of COVID-19 risk in a model including log IgG level as a time-varying covariate. The older vs. younger break is the median age, 58 years. In a and c the green star marks the beginning of the vaccination period