Hyderabad-based 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.
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.
Since January 16, when India’s vaccination programme was rolled out, more than a million doses of Covaxin, the country’s first indigenous vaccine against the novel coronavirus, have been administered to the priority group of healthcare and frontline workers.
ICMR Director-General Dr Balram Bhargava told The Indian Express that the interim trial data will be submitted to the regulator seeking emergency use authorisation similar to the one that has been granted to Covishield, a variant of the Oxford-AstraZeneca vaccine that is being manufactured under licence by Pune-based Serum Institute of India.
“Data will be put forward to the regulator. This is the data given by an independent data safety monitoring board. The regulator will look into it and decide (on administering the shots in clinical trial mode),” Dr Bhargava said.
First such data from Indian trial
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.
Both Covishield and Covaxin are being given to beneficiaries including, from March 1, members of the public older than 60 years, and those between ages 45 and 60 with associated comorbidities. 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.
On Wednesday night, the government’s Co-Win dashboard showed 1,25,36,582 doses of the Covid-19 vaccine had been administered, only 10.42 per cent of which were Covaxin. The Co-Win data lag actual vaccination data by a few days – total vaccinations had crossed 1.63 crore on Wednesday – but the proportion of Covaxin to Covishield has been around 1:10 throughout the vaccination drive. The larger share of Covishield is due to the significantly higher manufacturing capacity of Serum Institute.
Some states like Chhattisgarh had asked the Centre for only Covishield, given that Covaxin was approved without efficacy data and in clinical trial mode. Following Wednesday’s interim results, and with Covaxin expected to receive emergency use authorisation similar to Covishield, the administration of Bharat Biotech’s vaccine is likely to see a ramping-up across the country.
The company said on Wednesday 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.
Additional interim analysis was planned for 87 cases, and the final analysis was planned for 130 cases, the company said. “All data from the second interim and final analyses will be shared via pre-publication servers as well as submitted to a peer-reviewed journal for publication,” it said.
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”.
The Centre had procured 55 lakh doses of Covaxin ahead of the inoculation drive; Bharat Biotech had offered 16.5 lakh doses for free as a special gesture.
“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. Covaxin demonstrates high clinical efficacy trend against Covid-19 but also significant immunogenicity against the rapidly emerging variants,” Dr Krishna Ella, Bharat Biotech chairman & managing director, said on Wednesday.
Dr Bhargava said: “The bench-to-bedside journey of completely indigenous Covid-19 vaccine in less than eight months’ time showcases the immense strength of self-reliant India to fight the odds and stand tall in the global public health community. It is also a testament to India’s emergence as a global vaccine superpower.”
On January 3, the Drug Controller General of India granted emergency approval to Covaxin based on only immunogenicity – the ability to trigger an immune response – and safety data generated in phase 1 and phase 2 clinical trials. While experts raised concerns over introducing Covaxin for commercial use without efficacy data, the 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, it had said.
“COVAXIN approval is ‘Monitored Approval’ with strict follow-up & rolling review. This approval ensures India has an additional vaccine shield in its arsenal esp[ecially] against potential mutant strains in a dynamic pandemic situation – A strategic decision for our vaccine security,” Union Health Minister Dr Harsh Vardhan had posted on Twitter.
During the first phase of the vaccination drive, the country’s top doctors including AIIMS Director Dr Randeep Guleria and the chairman of the Covid-19 task force, Dr V K Paul, were administered Covaxin. On Monday, as the country rolled out the second phase of vaccinating priority groups in the general population, Prime Minister Narendra Modi was also administered Covaxin.
The announcement of the interim data is significant as 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.
Bharat Biotech had earlier published that the vaccine was found to be well tolerated, with no vaccine-related serious adverse events, and that it had triggered a robust immune response in early phase 1 trial.
The vaccine had triggered both humoral and cell-mediated immune responses, and was well-tolerated with no serious adverse events in phase 2 trials, it had said.