'COVAXIN' is safe, shows no serious adverse effects and generates immune response which can be well tolerated in all dose groups, according to the preprint paper titled ‘A Phase 1: Safety and Immunogenicity Trial of an Inactivated SARS-CoV-2 Vaccine- BBV152’. 

For the first phase clinical trials of  COVAXIN, around 375 participants were enrolled out of which only one had shown side effects, that too it was not related to the vaccine. The trial was conducted on volunteers from diverse geographic locations and socio-economic conditions to ensure generality.

Out of 375 participants, 300 were given the vaccine doses while 75 volunteers received the placebo. The interim findings from the phase-1 placebo-controlled randomised double-blind trial on the safety and immunogenicity of three different formulations of BBV152 reported the results of the clinical trial on all the 375 volunteers.

Covaxin is being developed in partnership between the Indian Council of Medical Research (ICMR) and Bharat Biotech (Hyderabad-based company). The preprint paper on MedRxiv, noted: “Reactogenicity was absent in the majority of participants, with mild events. The majority of adverse events were mild and were resolved. One serious adverse event was reported, which was found to be unrelated to vaccination. All three vaccine formulations resulted in robust immune responses comparable to a panel of convalescent serum.”

Researchers from Bharat Biotech, ICMR, All India Institute of Medical Sciences (AIIMS) New Delhi and Patna, and several other institutes, participated in the analysis.

“We conducted a double-blind randomized controlled phase 1 clinical trial to evaluate the safety and immunogenicity of BBV152. A total of 375 participants were randomized equally to receive three vaccine formulations. Vaccines were administered on a two-dose intramuscular accelerated schedule on day 0 (baseline) and day 14. The primary outcomes were reactogenicity and safety,” said the study.

The secondary outcomes were immunogenicity based on the anti-IgG S1 response which was detected with an enzyme-linked immunosorbent assay or ELISA and wild-type virus neutralisation or microneutralisation and plaque reduction neutralisation assays. In addition to this cell-mediated responses were also evaluated.

One adverse event was reported where the volunteer vaccinated on July 30 was found to be positive for SARS-CoV-2 after five days of vaccination. However, the symptoms were mild but the patient was admitted to hospital on August 15. The participant was discharged on August 22 after a negative nucleic acid result. The event was not associated with the vaccine, the findings showed.

With 25,800 volunteers from age group 18 to 55, Bharat Biotech is currently conducting the phase-3 trials of its vaccine and has applied to the Drugs Controller General of India for an emergency use authorization.