The interim results from Phase 3 trials of COVAXIN have been heartening, with overall interim clinical efficacy being at 78 per cent and the vaccine showing 100 per cent efficacy against severe COVID-19 disease.
Vaccine efficacy is calculated statistically, and whenever we are making such calculations, especially in the medical field, we take the confidence interval to be 95 per cent. According to the press release of Covaxin’s third phase trial, Bharat Biotech also had taken the confidence interval at 95 and found that the vaccine is effective.
To put this data in a lay man’s perspective, the vaccine’s overall efficacy is 78 per cent. Post-vaccination, it was found that in 70 per cent of cases, COVID-19 did not show any symptoms at all, and in 100 per cent of cases, there were no deaths. Hence, this vaccine will not only decrease the severe effects of the virus but also prevent deaths. In 30 per cent of cases, there may be symptoms, but those symptoms will not lead to something extreme like death or severe like hospitalisation or being put on ventilation.
The Phase 3 study of Covaxin enlisted 25,800 participants between the age of 18-98 years, including a 10 per cent population over the age of 60. The trial was conducted 14 days post the second dose of vaccination. COVAXIN was made with the seed strains received from the National Institute of Virology. The phase three clinical trial was co-funded by the Indian Council of Medical Research and Bharat Biotech.
Previously, questions have been raised about Covaxin’s efficacy rate, given that the phase three trials were still underway. Therefore, this report should work towards dissuading any efficacy fears that people might have previously had.
If you ask me which vaccine should one opt for – Covishield, Covaxin, or Sputnik V, which too will be available in India soon, I would say that it doesn’t matter which vaccine you take as long as you take a vaccine.
I will not recommend one vaccine over another because the number of vaccines available in India is scarce. Our priority at present is to get as many people vaccinated as possible. As microbiologists, we are always saying that the whole vaccination process should be completed with urgency because as we delay vaccination, the virus gets the chance to mutate. If a virus mutates so much that it resists the vaccine, then a new vaccine has to be prepared all over again, which is a mammoth task and is economically stressful and will cost many lives in the meantime.
More details about the covaxin will be available once the safety and efficacy results from the final analysis are made available in the coming months.
Prof A M Deshmukh is the President of the Microbiologists Society, India