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.

COVID-19 infection among vaccinated and unvaccinated: Does it make any difference?

“…Sagiraju HKR et al [12] from India conducted a similar study and reported a lower mortality rate in vaccinated patients; however, only 3% of patients in their study cohort were completely vaccinated as compared to 37.7% patients in our study. Almost 15% of the patients with breakthrough infections were asymptomatic, dyspnea was reported in 22%, and a higher proportion of unvaccinated patients were symptomatic in their study.…”

Application of Traditional Vaccine Development Strategies to SARS-CoV-2

“…However, a much lower effectiveness (22 to 29%) was estimated in a real-world setting during an analysis of cases in health care workers from April to May 2021 ( 117 ). All the same, monitoring of hospitalized COVID-19 patients between April and June 2021 indicated that the vaccines were highly effective in preventing severe illness ( 118 ).…”

Silent Hypoxia in Coronavirus disease-2019: Is it more dangerous? -A retrospective cohort study

“…In a comparative study of vaccinated and unvaccinated individuals from our cohort, we found that vaccination significantly reduced the odds of developing hypoxia and death. [ 23 ] However, the presentation of silent hypoxia was not significantly different in the groups receiving the vaccination against COVID-19 and non-vaccinated groups. Further research on the pathogenesis of post-vaccination breakthrough infections is needed.…”