Bharat Biotech’s Covaxin was found to be 77.8% effective against symptomatic COVID-19 and 93.4% effective against severe symptomatic COVID-19, according to the safety and efficacy analysis data from Phase 3 trial results.
The efficacy data also demonstrated 63.6% protection against asymptomatic COVID-19 and 65.2% protection against the SARS-CoV-2, B.1.617.2 Delta variant. Covaxin is the first to report promising efficacy against asymptomatic infections based on qPCR testing that will help in reducing disease transmission, said the company.
Phase 3 clinical trials of Covaxin was an event-driven analysis of 130 symptomatic COVID-19 cases, reported at least two weeks after the 2nd dose, conducted at 25 sites across India.
The vaccine which was developed by the company in partnership with ICMR and NIV Pune is a whole virion inactivated shot against SARS-CoV2. Covaxin is formulated with a novel Algel+IMDG adjuvant. IMDG is a TLR7/8 agonist known to induce memory T cell responses along with strong neutralising antibodies.
The activation of cell mediated immune responses is especially valuable in a multi epitope vaccine such as Covaxin, where immune protection can be achieved from S, RBD and N proteins alike. IMDG was developed under partnership between Virovax and NIAID, National Institutes of Health USA.
The vaccine was well tolerated and the Data Safety Monitoring Board (DSMB) has not reported any safety concerns related to the vaccine, said the company. Safety analysis demonstrated 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
Additional clinical trials to establish the safety and efficacy of Covaxin in children between 2-18 years of age is well underway. 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.
Covaxin has been formulated to enable shipping and long-term storage at 2-8ºC. It is also formulated to adhere to a multi-dose vial policy, thereby reducing open vial wastage thus making it more economical. The vaccine has now received emergency use authorisations in 16 countries including, Brazil, India, Philippines, Iran and Mexico. The company is in discussions with WHO to obtain emergency use listing for Covaxin.