Fig. 2: Anti-S1 IgG levels over time between first vaccine dose and serosurvey by socio-demographic and clinical correlates.

Plot of predictited anti-S1 antibody levels by A age, B sex, c body mass index, D smoking history, E diabetes, and F chronic obstructive pulmonary disease. Predicted anti-S1 antibody levels generated from generalized additive model with smoothing spline since vaccination adjusted for age, sex, race/ethnicity, smoking history, education attainment, body mass index, diabetes, cardiovascular disease, asthma, chronic obstructive pulmonary disease, anti-N, COVID-19 infection history, dried blood spot batch, and vaccine type, except for those risk factors of primary interest that are stratified (A–F). Lighter color bands indicate 95% confidence intervals.