Interim results report 80% efficacy for India’s COVAXIN vaccine

Simon Collins, HIV i-Base

Against a background of rapid and dramatic increases in COVID-19 cases and mortality in India, the country’s vaccine programme includes the COVAXIN vaccine developed by Bharat Biotech in collaboration with the Indian Council of Medical Research.

COVAXIN is an adjuvanted whole inactivated SARS-COV-2 vaccine (BBV152) that is given as two doses four weeks apart.

Results from randomised double-blind phase 2 study and earlier immunogenicity and safety data are both published in Lancet Infectious Diseases. [1, 2]

Clinical results from an interim analysis of a phase 3 study have so far only reported in a company press release. The study enrolled >25,000 participants, approximately 10% > 60 years old.  Top line results include 80% efficacy at reducing PCR-confirmed symptomatic COVID-19 (7 vs 36 cases). The study will continue until reaching planned 130 endpoints.  [3]


  1. Ella R et al. Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine, BBV152: interim results from a double-blind, randomised, multicentre, phase 2 trial, and 3-month follow-up of a double-blind, randomised phase 1 trial. DOI: 10.1016/S1473-3099(21)00070-0. (8 March 2021).
  2. Ella R et al. Evaluation of safety and immunogenicity of an adjuvanted, TH-1 skewed, whole virion inactivated SARS-CoV-2 vaccine – BBV152. Lancet Inf Dis. DOI: 10.1016/S1473-3099(20)30942-7 (21 January 2021).
  3. Bharat Biotech press release. Bharat Biotech announces phase 3 results of COVAXIN: India’s first COVID-19 vaccine demonstrates interim clinical efficacy of 81%. (3 March 2021). (PDF)

This report was first published on 23 April 2021.

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