Phase 3 clinical trial results for Bharat Biotech’s coronavirus vaccine – Covaxin – were released Wednesday afternoon, with the drug demonstrating “81 per cent interim efficacy in preventing COVID-19 in those without prior infection after the second dose”, the company said.
“The first interim analysis is based on 43 cases, of which 36 cases of COVID-19 were observed in the placebo group versus seven cases observed in the BBV152 (COVAXIN) group, resulting in a point estimate of vaccine efficacy of 80.6%,” the company said in its statement.
The trial, which began in November last year, involved 25,800 participants across 25 sites, who were randomly divided into two groups. One group was given the vaccine and the other got a placebo. 43 people (seven from the group that got the vaccine) were found to have coronavirus.
Interim analysis also showed that severe, serious, and medically attended adverse events occurred at low levels and were balanced between vaccine and placebo groups, Bharat Biotech said.
The company also said that “analysis from the National Institute of Virology indicates that vaccine-induced antibodies can neutralise the UK variant strains and other heterologous strains”.
This data, though, has yet to be peer-reviewed.
Trials will continue to final analysis of 130 confirmed cases in order to gather more data and evaluate the efficacy of the vaccine, the company added.
“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,” Dr Krishna Ella, the Bharat Biotech Chairman and Managing Director, said.
Data from the third stage of trials – which measures the vaccine’s success in protecting against the coronavirus – has been widely anticipated amid concerns over Covaxin’s safety and efficacy.
Covaxin is one of two Covid vaccines to have been cleared for emergency use approval by the government – the other is Covishield, which was developed by AstraZeneca and Oxford University and is produced by Pune-based Serum Institute.
Covishield has an efficacy rate of 70 per cent after the second dose.
Both vaccines were cleared by the Drug Controller General of India (DCGI) in early January, at a time when late-stage trial data for Covaxin was not available; it was cleared on the basis of Phase I and II data that confirmed its “safety and immunogenicity”.
Covaxin was given “restricted use in emergency situation in public interest”, meaning all those who were administered the drug as part of the vaccination drive were enrolled as part of the study.
The criticism prompted an emotional pushback from Dr Ella, who said: “… don’t accuse us of inexperience. We are a global company… have manufactured 16 vaccines…”
As the government launched the national vaccination drive on January 16, many expressed reservations about being given Covaxin, particularly since a choice of vaccines was not offered. Doctors from Delhi and Karnataka were among those wrote to centre and state governments, asking to be given a choice in the vaccination process.
On Monday, as the second phase of the vaccination drive began, Prime Minister Narendra Modi rolled up his sleeve and got a shot of Covaxin at Delhi’s AIIMS to dispel any fears.
This morning the centre reported nearly 15,000 new Covid cases in the past 24 hours, with the active caseload increasing by around 1,700.
As of March 1, of these the number of UK strain cases are 187.