Bharat Biotech said on March 3 that its Covaxin vaccine was 81 percent effective in preventing COVID-19 after a third round of clinicals trials.
Covaxin demonstrated 81 percent interim efficacy in preventing COVID-19 in those without prior infection after the second dose, the company said in a statement.
“Data from 25,800 participants received a vaccine or placebo in a 1:1 ratio showed that the vaccine candidate was well tolerated,” the company said in a statement.
The first interim analysis is 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 percent.
The AstraZeneca-Oxford University vaccine has efficacy of 62 percent, Pfizer-BioNTech - 95 percent, Moderna's vaccine has 94 percent efficacy while Sputnik V has 92 percent efficacy. J&J claims its vaccine has 66 percent efficacy.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
The vaccine has been approved for restricted emergency use under clinical trial mode. The vaccine will have to be taken in two doses with 28 days apart.
“Today is an important milestone in vaccine discovery, for science and our fight against coronavirus. With today’s results from our Phase 3 clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2, and 3 trials involving around 27,000 participants," said Krishna Ella, Chairman and Managing Director of Bharat Biotech.
"Covaxin demonstrates high clinical efficacy trend against COVID-19 but also significant immunogenicity against the rapidly emerging variants,” Ella added.Covaxin or BBV152 contains a whole virion inactivated SARS-CoV-2 vaccine, which is produced in Vero cells. It is stable at 2 to 8°C (refrigerated) and is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels.