Fig. 3: Percent change on IgA and IgG antibody responses to RBD at T10 and T11 in first-vaccinated group minus first-infected group*.

*Estimates from linear mixed models estimating the %MFI increase in those first-vaccinated compared to the first-infected group (reference). The models accounted for repeated measurements in the same individual with a random intercept per individual. The models were adjusted as follows: M0, crude; M1, M0 + age (restricted cubic spline with 3 df) and sex; M2, M1 + number of chronic comorbidities and tobacco smoking status; M3, M2 + number of non-Omicron and Omicron symptomatic infections (as factors), and number of non-Omicron and Omicron asymptomatic infections (as factors); M4, M3 + number of non-bivalent and bivalent vaccines (as factors); and finally, M5 (main model), M4 + days from last infection (restricted cubic spline with 3 df) and days from last vaccine (restricted cubic spline with 3 df). MS1, M5 but expanding the number of chronic comorbidities as three binary factors (cardio-metabolic, immunosuppressed and previous allergy); MS2, running M5 in those individuals without any history of asymptomatic infections; MS3, M5 but instead of non-bivalent/valent, using number of mRNA and adenovirus-based vaccines; MS4, MS3 but instead of number of non-Omicron/Omicron, using number of previous infections by each variant of concern. For each model, there were 337 samples from T10 and 309 samples from T11, totaling 646 samples from 357 individuals. The central circles represent the point estimates, and the vertical bars indicate the 95% confidence intervals. Source data are provided in the source data. df: degrees of freedom. MFI: Median fluorescence intensity. RBD: Receptor binding domain. T: timepoint. M: model.