Periodontitis is associated with altered salivary anti-SARS-CoV-2 antibody patterns in vaccinated individuals

Background Periodontitis is characterized by chronic inflammation and mucosal barrier disruption, which may influence salivary antibody dynamics after systemic vaccination. This study investigated the impact of periodontal disease severity on salivary anti-SARS-CoV-2 antibody responses in vaccinated, non-infected individuals. Methods Saliva samples were collected from 258 SARS-CoV-2-naïve individuals who had received three vaccine doses. Participants were stratified into three groups based on a standardized oral examination: periodontally healthy controls (n=109), stage I/II periodontitis (n=93), and stage III/IV periodontitis (n=56). Anti-spike IgG, IgA, and sIgA levels were quantified using a validated in-house ELISA. Results Salivary anti-spike IgG levels were significantly elevated in both stage I/II ( p = 0.0002) and stage III/IV ( p < 0.0001) periodontitis groups compared to controls, while IgA and sIgA levels did not differ between groups. IgG levels showed a strong positive correlation with periodontal bleeding scores (r=0.52, p < 0.0001). In contrast, sIgA did not correlate with bleeding (r=0.09, p = 0.12). Analysis of immunoglobulin isotype coordination revealed a strong positive correlation between IgG and IgA in controls (r=0.42, p < 0.0001) and stage I/II periodontitis (r=0.71, p < 0.0001), which was absent in stage III/IV periodontitis (r=0.25, p = 0.06). Conclusions Periodontitis was associated with higher salivary anti-spike IgG binding levels, which also showed a strong positive correlation with periodontal bleeding. In contrast, IgA and sIgA binding levels did not differ across periodontal groups. The coordinated relationship between IgG and IgA observed in healthy individuals was disrupted in severe periodontitis. These findings demonstrate distinct alterations in salivary antibody patterns associated with periodontal disease severity following SARS-CoV-2 mRNA vaccination.