Vaccine maker Bharat Biotech on Wednesday, 3 March, said that results of its Phase 3 clinical trials had shown that the interim clinical efficacy of ‘Covaxin’ is 81 percent.
The vaccine demonstrated 81 percent interim efficacy “in preventing COVID-19 in those without prior infection after the second dose," the company said.
What Did Bharat Biotech Say?
“The trials involved 25,800 subjects, the largest ever conducted in India, in partnership with ICMR,” the statement from Bharat Biotech said.
The participants in the phase 3 trials were between 18-98 years of age, including 2,433 over the age of 60 and 4,500 with comorbidities, the company further said.
The company said that the interim analysis included a preliminary review of the safety database, which showed that severe, serious, and medically attended adverse events occurred at low levels, and were balanced between vaccine and placebo groups.
"Clinical trial to continue through to final analysis at 130 confirmed cases in order to gather further data and to evaluate the efficacy of Covaxin in additional secondary study endpoints," the company further said in its statement.
“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 participant,” Dr. Krishna Ella, Chairman & Managing Director, Bharat Biotech said about the announcement.
He added that the vaccine showed high clinical efficacy trend not just against COVID-19 but also “significant immunogenicity against the rapidly emerging variants.”
How ICMR Responded
Meanwhile, Indian Council of Medical Research (ICMR), which backed the vaccine and jointly conducted the trials, said that the results had been evaluated by an independent data safety and monitoring board. It showed that the vaccine is “well-tolerated and efficacious against SARS-CoV-2 across a wide range of age groups and variants in the country.”
Dr. Balram Bhargava, Director General, ICMR, hailed Wednesday’s announcement as a testament to India’s standing in the global health community.
“The bench-to-bedside journey of completely indigenous COVID-19 vaccine in less than 8 months time showcases the immense strength of Atmanirbhar Bharat 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,” Dr. Bhargava said.
“The development and deployment of Covaxin ensures that India has a powerful weapon in its arsenal in a continually evolving pandemic situation, and will go a long way in helping us win the war against COVID-19,” said Dr. Samiran Panda, Head, Epidemiology and Communicable Disease, ICMR and Director, National AIDS Research Institute.
He added that it was essential at this time that people in India continue to receive the vaccine and break the chain of virus transmission.
What Did Experts Say?
“The efficacy sounds to be good as a point estimate. The numbers are small but its good news for the vaccine. We need to wait for subsequence results as they have indicated. The point estimate currently is very much in favour of the vaccine. It puts covaxin in the league of other vaccines around the world,” ex-Head Scientist of Epidemiology and Communicable Diseases at ICMR, Dr Gangakhedkar told FIT.
When asked if the prelim data was based on a very small number, he added, "Pfizer and Moderna also released prelim data based on small numbers. In a pandemic like situation, it is important to study initial data set. You can then proceed to add more data to the findings."
“These are encouraging findings,” added Dr Gangakhedkar.
Dr Swapneil Parikh, Internal medicine specialist in Mumbai said, “It’s wonderful news that interim analysis from the COVAXIN phase 3 trial suggests the vaccine is efficacious. We need to wait for the pre-print to see the confidence in this data but this is great news for our country!”
Controversy Around Covaxin
Covaxin is one of the two vaccines against COVID-19, which had been greenlighted by the government for emergency use. However, the approval to the vaccine while it was still in clinical trials, having completed two of the required three rounds, had caused much controversy.
Covaxin was given approval for "restricted use in emergency situation in public interest” even while there was a lack of its efficacy data available in public.
However, Dr. Ella had said that granting emergency use authorisation after completion of phase two trials is a common medical practice.
In a virtual press conference in January, an indignant Dr. Ella had said that his firm is a “global company and not one without any vaccine experience,” after questions were raised by experts over the approval given to Covaxin.
“We have manufactured 16 vaccines. We function globally, not just in India,” Krishna Ella told reporters.
According to him, Covaxin’s criticism was on account of Bharat Biotech being an Indian company. “I don't know why Indian companies are targetted by everyone in the world,” he had said in a virtual press meet in January.