Fig. 1: Analysis of anti-Spike and anti-RBD antibodies in saliva from participants receiving COVID-19 mRNA vaccines.

A–D Anti-Spike/RBD IgG and IgA were measured in the saliva of vaccinated LTCH workers after two doses of mRNA vaccine (n = 107) and compared to COVID-19 convalescent controls (n = 11) and individually run negative controls (n = 9). The positive cutoff (dotted line) was calculated as 2 standard deviations above the mean of a pool of negative control samples (n = 51) for each individual assay. E–H Anti-Spike/RBD IgG and IgA were also analyzed in the saliva of vaccinated participants that were followed at sequential timepoints before and after dose 1 and dose 2 of mRNA vaccination (MSB-1, n = 27, with n = 13 participants at 3 months post-dose 1, and n = 26 at 2 weeks post-dose 2). All data are expressed as a percentage of a pooled positive plate control of n = 11 COVID-19 convalescent saliva (see Methods). Solid black bars denote the median for each cohort. Mann–Whitney U test was used to calculate significance for (A–D). For (E–H) a Friedman pair-wise multiple comparison test was used for pair-wise comparisons for multiple timepoints, considering only data points from participants who had completed all timepoints (n = 11). *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. † = we were only able to recall n = 13 of the participants at 3 months post-dose 1.