A non-randomized, single-blinded (laboratory) study was conducted among the healthy general population across four sites (Bangalore & Pune) between June 2021 and Jan 2022.

No sample size was determined.

Recruited participants were grouped into two groups based on serostatus [positivity/negativity] at baseline.

The clinical sites integrated unbiased enrollment with pre-screening for anti-spike antibodies to ensure equitable recruitment within each serostatus.

Seroconversion rates due to Covaxin after the first and second vaccination doses were 36.6% and 74.4%, respectively.

Whereas Covishield resulted in 93.2% and 98.3% seroconversion in the baseline seronegative population.

Hence Covishield was proved superior to Covaxin, as interpreted from both: