Background & Aim: WHO listed vaccine hesitancy among the top 10 global threats to health and there are very few reports highlighting vaccine benefits against COVID-19. The aim of this study was to study the impact of vaccination on reducing the average length of stay (ALOS), intensive care unit (ICU) requirement, mortality and cost of the treatment among COVID-19 patients. Methods: In this retrospective cohort study all the patients above 45 years who underwent treatment for COVID-19 were included. The data of patients treated pan India during the period March & April 2021 with the diagnosis of COVID-19, under health insurance cover, were extracted to study parameters like the ALOS, mortality, ICU requirement, total hospital expenses and the vaccination status. Results: Among 3820 patients with COVID-19, 3301 (86.4%) were unvaccinated while 519 (13.6%) were vaccinated. Among the unvaccinated the mean (s.d) ALOS was 7 days. Fourteen days after second dose of vaccination this was significantly less (p=0.01) at 4.9. The mean total hospital expense among the unvaccinated was Rs. 277850. Fourteen days after second dose of vaccination this was further less (p=0.001) at Rs. 217850. Among the unvaccinated population 291/3301 (8.8%) required ICU and this was significantly less (p=0.03) at 31/519 (6%) among the vaccinated. Among those who received two doses of vaccination it was further less at 1/33 (3%). The mortality among unvaccinated patients was 16/3301 (0.5%) while there was no mortality among the vaccinated. Among those who received two doses of vaccination there was a 66% relative risk reduction in ICU stay and 81% relative risk reduction in mortality. Conclusions: There was a significant reduction in ALOS, ICU requirement, mortality & treatment cost in patients who had completed two doses of vaccination. These findings may be used in motivating public and promoting vaccination drive.

Keywords: COVID-19; Vaccination; Public Health; Mortality; Morbidity.