Iain Chapple, University of Birmingham, England, presented the oral session "Longitudinal Serological and Vaccination Responses to SARS-COV-2 in Dental Professionals" at the virtual 99th General Session & Exhibition of the International Association for Dental Research (IADR), held in conjunction with the 50th Annual Meeting of the American Association for Dental Research (AADR) and the 45th Annual Meeting of the Canadian Association for Dental Research (CADR), on July 21-24, 2021.

The COVID-19 pandemic significantly impacted dental professionals, who are thought to be at high occupational risk of infection. The aim of this study was to determine the magnitude, persistence and neutralizing capacity of serum antibody responses to the SARS-COV-2 spike glycoprotein at baseline (3-months following first wave), 3- and 6-months in an observational cohort of United Kingdom dental professionals, and the IgG threshold for protection from re-infection.

Participants provided baseline venous blood samples and the total antibody response (combined IgG, A and M), and individual isotype response against the SARS-CoV-2 spike glycoprotein were measured. The neutralizing ability of antibodies was determined using a plaque reduction micro-neutralization assay.

Baseline seroprevalence was 16.3%. Seropositivity was retained in 73% of participants who returned 3-months post-baseline and 72% of participants who returned at 6-months, prior to their vaccination. Seropositivity arising following natural infection during the first wave, conferred a 74% risk reduction for re-infection during follow-up (9.6% seronegative, vs. 2.8% seropositive). The results show that natural infection with SARS-COV-2 leads to persistent, neutralizing and protective serological responses in over 70% of DPs 9-months post-infection (6-months post-baseline).