According to the first real-world evaluation of Covaxin, published in The Lancet Infectious Diseases, two doses of the vaccine appeared to be 50% effective against symptomatic disease.

Results of an interim study published recently in The Lancet had shown that two doses of the vaccine were 77.8% effective against symptomatic disease and there were no serious safety concerns. The latest study evaluated 2,714 hospital workers at the All India Institute of Medical Sciences (AIIMS) in Delhi, between April 15 and May 15, who were symptomatic and underwent RT-PCR test. Delta variant dominated in India during the study period.

The institute had exclusively offered Covaxin to all of its 23,000 employees. Among the 2,714 hospital workers included in the study, 1,617 tested positive for COVID-19.

The authors agree that the vaccine effectiveness noted in this study is lower than that reported in the recently published phase 3 trial, and stated that multiple factors may be accountable for the lower vaccine effectiveness seen in the latest study… (NDTV – PTI, November 24, 2021)