Breakthrough infections, hospital admissions, and mortality after major COVID-19 vaccination profiles: a prospective cohort study

Summary Background Several COVID-19 vaccination rollout strategies are implemented. Real-world data from the large-scale, government-mandated Central Vaccination Center (CVC), Thailand, could be used for comparing the breakthrough infection, across all available COVID-19 vaccination profiles. Methods This prospective cohort study combined the vaccine profiles from the CVC registry with three nationally validated outcome datasets to assess the breakthrough COVID-19 infection, hospitalization, and death among Thais individuals who received at least one dose of the COVID-19 vaccine. The outcomes were analyzed by comparing vaccine profiles to investigate the shot effect and homologous effect. Findings Of 2,407,315 Thais who had at least one dose of COVID-19 vaccine, 63,469 (2.75%) had breakthrough infection, 42,001 (1.79%) had been hospitalized, and 431 (0.02%) died. Per one vaccination shot added, there was an 18% risk reduction of breakthrough infection (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.80–0.82), a 25% risk reduction of hospitalization (HR 0.75, 95% CI 0.73–0.76), and a 96% risk reduction of mortality (HR 0.04, 95% CI 0.03–0.06). The heterologous two-shot vaccine profiles had a higher protective effect against infection, hospitalization, and mortality compared to the homologous counterparts. Interpretation COVID-19 breakthrough infection, hospitalization, and death differ across vaccination profiles that had a different number of shots and types of vaccines. Funding This study did not involve any funding.

วารสาร : Lancet Reg Health Southeast Asia. 2023 Jan; 8: 100106. Published online 2022 Nov 4. doi: 10.1016/j.lansea.2022.100106

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