Effect of COVID-19 booster vaccination on reducing mortality of patients hospitalized for COVID-19 at Sisaket Hospital

Abstract

Background: Coronavirus disease 2019 (COVID-19) vaccines have the potential to decrease hospitalizations and mortality, regardless of the vaccine type. Toward the end of 2021, with the COVID-19 pandemic still ongoing, guidelines suggest the administration of booster shots once the primary vaccination series is completed.

Objective:This study aimed to investigate the efficacy of COVID-19 booster vaccinations and the timing between booster shots in terms of preventing mortality among patients with COVID-19 hospitalized at Sisaket Hospital.

Methods: A retrospective cohort study was conducted on individuals aged 18 years who were hospitalized with COVID-19 at Sisaket Hospital between January 1, 2022, and December 31, 2022. Data analysis was performed using descriptive statistics and multiple regression analysis techniques.

Results: The study included a total of 1,853 patients (women = 1,050, (56.7%)). The average age was 53.8 ± 20.4 years. Among them, 330 (17.8%) patients expired. According to vaccination history, the survival rates for those who did not receive any vaccination, received an incomplete primary vaccination series, and completed the primary series were 68.5%, 75.9%, and 85.6%, respectively. The survival rates of the groups that received one and two booster shots were 88.6% and 96.2%, respectively. Regarding the time interval between receiving booster shots, statistically significant differences were found among those vaccinated within 3, 3-6, and > 6 months.

Conclusion: COVID-19 booster vaccination has proven its efficacy in preventing fatalities among patients hospitalized for COVID-19, even after a single booster shot. In addition, a booster shot received > 6 months can still reduce the mortality rates compared with booster shots administered within 3 months, without significant difference.