WHO Interim Recommendation for Use of the Bharat Biotech COVAXIN vaccine against COVID-19


The Bharat Biotech vaccine (BBV152) is a whole virion inactivated SARS-CoV-2 virus vaccine, adsorbed to alum and formulated with a toll-like receptor (TLR) 7/8 agonist (Imidazoquinoline gallamide [IMDG]), and the preservative 2-phenoxyethanol. The vaccine is given in two doses, separated by four weeks.  

Inactivated vaccines have been used for diseases such as seasonal influenza, polio, and hepatitis A. Inactivated vaccines cannot replicate and therefore cannot infect individuals. IMDG and alum are adjuvants added to enhance immunogenicity. IMDG is a novel adjuvant that has not been used in any previous vaccine. Studies generally demonstrate that TLR 7/8 agonists enhance Th1 responses and inhibit Th2 responses, which is considered beneficial for COVID-19 vaccines. In addition, CD8 T-cell responses may be increased when using TLR 7/8 agonists as adjuvants.

For the phase 3 trial of the BBV152 vaccine, participants aged ≥18 years of age were recruited; An interim analysis was conducted including data to 17 May 2021, when the median follow-up period (14 or more days post dose 2) was 99 days. During the follow-up period, the Delta variant was the predominantly circulating virus.  

Vaccine efficacy (VE) against COVID-19 vaccine of any severity, 14 or more days post dose 2, was 78% (95% CI: 65–86).

  • In adults aged <60 years, VE was 79% (95% CI: 66–88); and
  • in those aged ≥60 years it was 68% (95% CI: 8–91).

There was one case of severe COVID-19 in the vaccinated group versus 15 in the placebo group (VE 93% [95% CI: 57–99]). VE against symptomatic SARS-CoV-2 infection was 64% (95% CI: 29–82).

BBV152 vaccine demonstrated an acceptable safety and reactogenicity profile in adults aged ≥18 years, including those aged ≥60 years  (and those with comorbidities associated with an increased risk of progressing to severe/critical COVID-19). In line with other inactivated vaccines, hypersensitivity reactions following immunization with BBV152 were rare and usually non-serious. Severe allergic (anaphylactic) reactions have not been reported in BBV152 clinical studies to date.

The data reviewed by WHO support the conclusion that the known benefits of BBV152 vaccine outweigh the risks that are known or considered possible. Therefore, WHO recommended the use of BBV152 in those aged ≥18 years.

Source: WHO. Interim recommendation for use of the Bharat Biotech BBV152 COVAXIN vaccine against COVID-19. Available at: https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE-recommendation-bbv152covaxin.

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