Covaxin safe in Phase 2, need Phase 3 results to corroborate: Lancet report  

Bharat Biotech’s Covaxin, India’s indigenous COVID-19 vaccine, has been declared “safe” and “immunogenic” by Lancet which published its Phase 2 results.

The Lancet report said that while the Phase 2 results have found the vaccine “safe, immunogenic with no serious side effects,” however, stressed that this is not the complete evaluation of the vaccine, which still awaits phase 3 results.

“The evaluation of safety outcomes requires extensive Phase 3 clinical trials. We were unable to assess other immune responses (i.e., binding antibody and cell-mediated responses) in convalescent serum samples due to the low quantity,” the Lancet report said.

Related news: What’s behind the rise in COVID-19 cases?

“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,” it added.

While fewer participants reported ‘adverse events’ in the Phase 2 trials when compared to Phase 1, the response to the vaccine was comparatively better in Phase 2 even though direct comparisons between both the first phases could not be made.

The study was done with the help of volunteers aged between 12 and 18 and 55 and 65 years.

However, more research needs to be done to test the immunogenicity of the vaccine in adults above 65 and children, the report said.

The report said that the study didn’t have data on the vaccine’s efficacy on other populations, and lacked ethnic, racial and gender diversity. It recommended a longitudinal follow-up on the additional post-vaccination visits to understand the durability of immune responses in inoculated people.

A venture of Indian company Bharat Biotech and ICMR, Covaxin was approved by the drug regulator for emergency use in January this year, just in time for the government’s mass vaccination drive on January 16.

The vaccine’s release, however, raked up a storm, mostly because it had not cleared the Phase 3 trials and discouraged many to opt for it.

A slight change in mindset was seen after Prime Minister Narendra Modi was administered Covaxin on March 1, the day the second round of the vaccination drive, for those above 60 and above 45 with co-morbidities, was flagged off.

Soon after, Bharat Biotech claimed that the vaccine was found to be 81 per cent effective during interim analysis of the Phase 3 trials, even though the results need to be peer reviewed.

Related news: Continue to test, track and treat: Centre tells 8 states, UTs