The effectiveness of COVID–19 vaccination against all–cause mortality in patients with type 2 diabetes mellitus: The observation during the initial period of the cancellation of the “Dynamic Zero Policy” in mainland China

AIMS: This study aims to assess the effectiveness of COVID–19 vaccination against all–cause death in patients with type 2 diabetes mellitus (T2DM). METHODS: Subjects were patients with T2DM who were administered by general practitioner (GP). Use electronic exchange platform to obtain the information on COVID–19 vaccination, all–cause deaths and risk factors. Logistic regression models were used to calculate the odd ratio (OR) and 95% CI for the association between COVID–19 vaccination and mortality. The vaccine effectiveness (VE) was calculated as (1- adjusted OR) × 100%. RESULTS: A total of 26,916 subjects had 53.81%, 17.65%, and 23.43% coverage for the booster, full, and partial COVID-19 vaccination, reported 328 deaths and a mortality of 1.2%. The adjusted OR (95%CI) was 0.85(0.60–1.21) for those received partial vaccination, 0.31(0.22–0.43) for those received full vaccination, and 0.12(0.08–0.18) for those received booster vaccination, compared to the unvaccinated individuals. The VE (95%CI) was 88.00%(82.30–91.80) of booster vaccination, 69.30%(56.60–78.30) of full vaccination, and 17.60%(-17.10–42.00) of partial vaccination. CONCLUSION: COVID–19 vaccination could effectively prevent the all–cause death in patients with T2DM during the omicron variant outbreak period, after the cancellation of the “Dynamic Zero Policy” in mainland China.