Bharat Biotech’s Covid shot is 81% effective – Expert’s opinion

Dr K K Aggarwal President CMAAO, HCFI,

With input from Dr Monica Vasudev

Interim final-phase data: Bharat Biotech’s Covid shot is 81% effective

1. Already more than a million doses of Covaxin, the country’s first indigenous vaccine have been administered to the priority group of healthcare and frontline workers.

2. Bharat Biotech said on Wednesday that its vaccine against Covid-19 had demonstrated 81 per cent interim efficacy in phase 3 clinical trials in protecting participants without prior infection after the second dose.

3. The vaccine candidate, Covaxin, developed by Bharat Biotech along with the Indian Council of Medical Research (ICMR), received regulatory approval for emergency use in “clinical trial mode” — in which beneficiaries have to sign a consent form before being vaccinated — at the beginning of January.

4. The interim trial data will be submitted to the regulator seeking emergency use authorisation similar to the one that has been granted to Covishield

5. Data will be put forward to the regulator. This is the data given by an independent data safety monitoring board.

6. The results are the first interim efficacy data of a Covid-19 vaccine being clinically tested in India. Serum is relying on efficacy data from the UK and Brazil trials for Covishield.

7. Under the clinical trial mode, those who are given Covaxin are tracked and monitored after vaccination, and in case of serious adverse events, the vaccine manufacturer is liable to pay compensation, if the event is proven to be causally related to the vaccine. Also, in case of any adverse event, the company provides the standard of care in designated health centres, as in the case of regular clinical trials.

8. The company said that the first interim analysis was based on 43 cases, of which 36 cases of Covid-19 were observed in the placebo group versus 7 cases observed in the Covaxin group, resulting in a point estimate of vaccine efficacy of 80.6 per cent.

9. Additional interim analysis was planned for 87 cases, and the final analysis was planned for 130 cases, the company said.

10. Bharat Biotech also said that an interim analysis on the safety of the vaccine had “showed that severe, serious, and medically attended adverse events occurred at low levels and were balanced between vaccine and placebo groups”.

11. Covaxin demonstrates high clinical efficacy trend against Covid-19 but also significant immunogenicity against the rapidly emerging variants

12. Earlier he expert body that recommended the approvals to the regulator had said that the permission was in the public interest, “specially in the context of infection by mutant strains”. Since the vaccine was based on inactive whole virion technology, it had the potential, theoretically, to target mutated coronavirus strains

13. The firm is currently conducting one of the largest phase 3 trials in India across 21 sites: 25,800 participants between 18-98 years of age, including 2,433 over the age of 60, and 4,500 with comorbidities have been included in the trial.