Study Published In Lancet Says Covaxin Safe To Use; But Needs Phase 3 Results To Assess Efficacy

The study published in the medical journal Lancet was only to test the safety of the vaccine, not its efficacy

New Delhi: A study published in the Lancet states that India made vaccine Covaxin by Hyderabad based Bharat Biotech is safe to use. In the study published in the medical journal on Tuesday, said Covaxin is “safe, immunogenic with no serious side effects”. The study was a "double-blind, randomised, multicentre phase 2 clinical trial to evaluate the immunogenicity and safety."

However, the study was only to test the safety of the vaccine, not its efficacy for which Phase 3 results was needed.

“In Phase 2 trial, BBV152 showed better reactogenicity and safety outcomes, and enhanced humoral and cell-mediated immune responses compared with Phase 1 trial. The 6g with Algel-IMDG formulation has been selected for the Phase 3 efficacy trial,” as per the report.

“The evaluation of safety outcomes requires extensive phase 3 clinical trials. We were unable to assess other immune responses (ie, binding antibody and cell-mediated responses) in convalescent serum samples due to the low quantity. Furthermore, no additional data on the age of the participant or the severity of disease from symptomatic individuals were obtained. Comparisons between phase 1 and 2 trials were not done in a randomised set of participants, and no adjustments on baseline parameters were made. Conclusions are to be considered as post-hoc analyses,” the report said.

The Lancet study mentioned that the study population lacked ethnic, racial, and gender diversity, further underscoring the importance of evaluating BBV152 in other populations. "This study enrolled a small number of participants aged 12-18 years and 55-65 years. Follow-on studies are required to establish immunogenicity in children and in those aged 65 years and older" 

Last week, Bharat Biotech released the efficacy data of its Coronavirus vaccine, Covaxin, revealing that Phase 3 of human trials has demonstrated an interim vaccine efficacy of 81 per cent in the clinical trials. In an official statement, the Hyderabad-based firm said that Phase 3 trials involved 25,800 subjects, the largest ever conducted in India, in partnership with the Indian Council of Medical Research (ICMR). 

"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," Bharat Biotech Chairman and Managing Director Krishna Ella said.

Covaxin was given approval for emergency use by the Drug Controller General of India (DCGI) before its final stage testing in early January which had raised concerns about the safety and effectiveness of the vaccine.