The effectiveness of SARS-CoV-2 vaccination in preventing severe illness and death- real-world data from a cohort of patients hospitalized with COVID-19.

Abstract

Background: Due to the unprecedented speed of SARS-CoV-2 vaccine development, their efficacy trials and issuance of emergency use approvals and marketing authorizations, additional scientific questions remain that need to be answered regarding vaccine effectiveness, vaccination regimens and the need for booster doses. While long-term studies on the correlates of protection, vaccine effectiveness, and enhanced surveillance are awaited, studies on breakthrough infections help us understand the nature and course of this illness among vaccinated individuals and guide in public health preparedness. Methods: This observational cohort study aimed at comparing the differences in clinical, biochemical parameters and the hospitalization outcomes of 53 fully vaccinated individuals with those of unvaccinated (1,464) and partially vaccinated (231) individuals, among a cohort of 2,080 individuals hospitalized with SARS-CoV-2 infection. Results: Completing the course of vaccination protected individuals from developing severe COVID-19 as evidence by lower proportions of those with hypoxia, abnormal levels of inflammatory markers, requiring ventilatory support and death compared to unvaccinated and partially vaccinated individuals. There were no differences in these outcomes among patients who received either vaccine type approved in India. Conclusion: With a current rate of only 9.5% of the Indian population being fully vaccinated, efforts should be made to improve the vaccination rates as a timely measure to prepare for the upcoming waves of this highly transmissible pandemic. Vaccination rates of the communities may also guide in the planning of the health needs and appropriate use of medical resources.