Bharat Biotech put out its safety and efficacy data of phase 3 clinical trials of Covaxin in the early hours of July 3, and was found to have an efficacy of 77.8% against symptomatic COVID-19. This comes weeks after many have been demanding that the details be released amidst controversies surrounding the vaccine. Bharat Biotech put out the final findings for Phase 3, and the same is yet to be peer reviewed. A total of 25,798 participants were recruited.
Covaxin was developed by Bharat Biotech along with the Indian Council for Medical Research and the National Institute of Virology, Pune, and has been formulated for shipping and long-term storage at 2-8ºC.
Bharat Biotech said that was evaluated through 130 confirmed cases reported two weeks after the second dose — 24 being observed in the vaccine group versus 106 in the placebo group. It said that Covaxin has 93.4% efficacy against severe symptomatic COVID-19, 63.6% protection against asymptomatic COVID-19, and 65.2% protection against the SARS-CoV-2, B.1.617.2 Delta variant.
“Safety analysis demonstrates adverse events reported were similar to placebo, with 12% of subjects experiencing commonly known side effects and less than 0.5% of subjects feeling serious adverse events,” Bharat Biotech said in its statement.
Outlining its method, Bharat Biotech said it did a double-blind, randomised, multicentre, phase 3 clinical trial in 25 Indian hospitals who received two intramuscular doses four weeks apart.
In terms of side effects, the abstract for the preprint said that Covaxin was “well tolerated with no clinically or statistically significant differences in the distributions of solicited, unsolicited, or serious adverse events between vaccine and placebo groups”. It added that no cases of anaphylaxis or vaccine-related deaths were reported.
“Vaccination was well tolerated with an overall incidence of adverse events observed over a median of 146 days that was lower than that observed with other COVID-19 vaccines,” it said.
“The primary outcome was laboratory confirmed symptomatic COVID 19, occurring at least 14 days after the second dose. Secondary outcomes were efficacy in subgroups for age (18 to < 60 years and >=60 years) and in participants with pre-existing stable medical conditions,” it added
In terms of vaccine side effects, Covaxin said that the most frequently solicited adverse effect was headache, followed by pyrexia (fever), fatigue and myalgia. However, it said incidences for this were below 1% in both groups.
Local and systemic adverse effects reported in the BBV152 group as mild (11·2%), moderate, (0·8%), or sever (0·3%) were comparable to the placebo group (mild [10·8%], moderate [1·1%], and severe [0·4%]).
In its statement to the press, Bharat Biotech said no vaccine so far has reported efficacy against asymptomatic infection in a randomised controlled trial.
No licensed SARS-CoV-2 vaccine has reported efficacy against asymptomatic infection in a randomised controlled trial, based on qPCR testing.
Bharat Biotech MD Dr Krishna Ella said, “The successful safety and efficacy readouts of Covaxin as a result of conducting the largest ever COVID Vaccines trials in India establishes the ability of India and developing world countries to focus towards innovation and novel product development.”
“Covaxin will not only benefit the Indian citizens but would also immensely contribute to protect the global community against the deadly SARS-CoV-2 virus. I am also pleased to see that Covaxin works well against all variant strains of SARS-CoV-2. The successful development of Covaxin has consolidated the position of Indian academia and Industry in the global arena,” said ICMR Director (Dr) Balram Bhargava.
Additional clinical trials are currently underway to study safety and efficacy of the vaccine for children between 2 and 18 years of age.
“A clinical trial to determine the safety and immunogenicity of a booster dose is also in process. Several research activities are being carried out to study variants of concern and to assess their suitability for follow up booster doses,” Bharat Biotech said.