This case-control study compares the effectiveness of Pfizer-BioNTech (BNT162b2) and Covishield (ChAdOx1 nCoV-19) Vaccines against the Alpha and Delta variants.
Both the vaccines showed a rise in its effectiveness after administration of Dose 2.
BNT162b2 has 93.7% and 88%, while ChAdOx1 nCoV-19 shows 74.5% and 67% effectiveness against Alpha and Delta variants, respectively.
This study was conducted on 21977 individuals, 18 years and above at 25 centres in Russia. The participants were randomly assigned to placebo and vaccines by 1:3 ratio. The vaccine vector components for dose 1 and dose 2 are rAd26-S and rAd5-S, respectively. The study reported 87.6% and 91.6% efficacy at 14- and 21-days post-dose 1. The efficacy of the vaccine after dos 2 was found to be 91.1%.