Fariba Zomorrodi Zare, Fatemeh Khosravi Shadmani, Roya Safari Faramani, Fatemeh Torkamanasadi, Yazdan Rezaei, Farid Najafi,
Volume 20, Issue 1 (Vol.20, No.1, Spring 2024)
Abstract
Background and Objectives: During the COVID-19 pandemic, vaccination was crucial in preventing the spread of SARS-CoV-2 and saving numerous lives. Countries implementing COVID-19 vaccination programs have reported significant reductions in cases, ICU admissions, and COVID-19-related deaths. This study aimed to evaluate the effectiveness of vaccines used in Hamadan province, explicitly focusing on their impact on hospitalization and death caused by COVID-19.
Methods: A test-negative case-control design (TND) was conducted involving patients aged 12 and above who were admitted to hospitals in Hamadan province, Iran, and had symptoms of acute respiratory diseases. Data were extracted from hospital and health system databases. Multiple logistic regression analysis was performed to estimate vaccine effectiveness for the first, second, and reminder doses in prevention of hospitalization, and severe outcomes (ICU admission or death).
Results: The study was conducted on 3,702 patients, and the maximum effectiveness of vaccines against hospitalization was 50% for patients who received a booster dose. The effectiveness of the first dose of vaccine on severe outcomes (admission to ICU or death) was estimated as 42%, but the effectiveness of the vaccines in the second and booster doses were not significant.
Conclusion: Despite the predominant use of inactivated virus vaccines and delayed initiation of vaccination in Iran, this study shows the effect of vaccination on reducing hospitalization and improving the outcomes of COVID-19. The use of more effective vaccines at a more appropriate time plays an important role in reducing the burden on health services and preventing further transmission in future epidemics.
