Effectiveness of COVID-۱۹ Vaccines in Mahabad, Iran: A Cohort Study

The COVID-۱۹ pandemic has shown that infectious diseases can become serious crises, emphasizing the importance of vaccination as the best way to prevent such outbreaks. The aim of study was to examine how well COVID-۱۹ vaccines work in the northwestern region of Iran, city of Mahabad.This retrospective cohort study compared ۱۰۷۷ vaccinated employees of the Mahabad city health department (exposed group) with ۱۳۳۸ unvaccinated employees from other departments (unexposed group). Demographic details, vaccination dates, types, and outcomes were extracted from the local health system. Data on cases came from the disease unit, while hospitalization was retrieved from the Medical Care Monitoring Center (MCMC). Attributable fractions for the exposed group and relative risks with ۹۵% confidence intervals were calculated for each vaccine dose, stratified by sex, age group, and exposure level. Data analysis was conducted using STATA۱۶, with a p-value < ۰.۰۵ considered statistically significant.The overall efficacy of COVID-۱۹ vaccines in preventing the disease is ۵۱%, with a ۲۶% effectiveness in averting hospitalization. Stratifying by vaccine type, AstraZeneca exhibits an ۸۱% efficacy (۹۵% CI: ۰.۶۱–۰.۹۱) in preventing infection, followed by Sputnik at ۴۱% (۹۵% CI: ۰.۰۸۶–۰.۶۲) and Sinopharm-Baharat at ۱۰% (۹۵% CI: ۰.۵۰–۰.۴۶). Similarly, in preventing hospitalization, AstraZeneca demonstrates a ۷۹% efficacy (۹۵% CI: ۰.۰۸۳–۰.۹۵), Sputnik at ۲۹% (۹۵% CI: ۰.۷۷–۰.۷۱), and Sinopharm–Bharat at ۴۴% (۹۵% CI: ۰.۶۳–۰.۸۱). Notably, effectiveness in preventing both disease and hospitalization is higher in men than women. AstraZeneca vaccine emerges as the most effective in preventing both disease and hospitalization, followed by Sputnik with optimal efficacy. Analyzing vaccine effectiveness across age groups reveals the lowest efficacy in individuals below ۳۰ years old, while the highest efficacy is observed in the age group above ۵۱ years. Despite challenges in vaccine selection and timely administration in Iran, our findings demonstrate that three doses of COVID-۱۹ vaccines achieve an effectiveness exceeding ۷۵% for preventing hospitalization and death, underscoring the vital role of vaccination as a primary preventive measure against infectious disease outbreaks. This reinforces the importance of proactive preparation and investment in robust vaccination programs for optimal epidemic control.

کلیدواژه ها:

COVID-۱۹ Vaccines ، Vaccine Efficacy ، Risk Assessment ، Risk Ratio ، Iran