NEW DELHI: Covaxin, India's homegrown potential Covid-19 vaccine by Bharat Biotech, has shown dual immune response, raising hopes for immunity against coronavirus lasting up to one year, according to the results of phase 1 and 2 clinical trials made public on Wednesday.
The company, which has developed the vaccine in collaboration with ICMR, has already sought emergency use approval from the Drug Controller General of India based on the data but has been asked to submit additional data on safety and immunogenicity.
The vaccine, as of now, is under phase 3 trial and the company has planned to test it in 26,000 individuals aged 12-65 years across several states in the country.
As per the scientific paper released on BioRxiv, a preprint server of medical studies, in a double-blind, randomised, multi-centre, phase 2 clinical trial, a total of 380 healthy children and adults were randomised to receive two vaccine formulations and two intramuscular doses of vaccines were administered four weeks apart.
In a follow-up of the phase 1 trial, Covaxin produced high levels of neutralising antibodies that remained elevated in all participants three months after the second vaccination.
Based on these results, researchers associated with the trial have said that the vaccine can generate antibodies that may persist for 6-12 months.
In what seems like encouraging news, immunologist Seyed Hasnain when approached by The New Indian Express for his comments on the study, pointed out the vaccine candidate generated both antibodies and T-cell response.
"The study design is very good and results are extremely encouraging," he said. "I particularly liked the fact that it has already been tested in children. But phase 3 study will give a clearer picture."
As per the research paper, higher neutralising titres of up to two-fold was observed in the phase 2 study as compared to phase 1 study.
Also, after two doses, local and systemic adverse reactions observed in both vaccine groups were minimal, and the majority of them resolved within 24 hours of onset and no serious adverse events were reported in this study.
"The results from the phase 2 study show that both humoral and cell-mediated responses were observed," the company said in a statement. "No neutralising antibody differences were observed between sexes and across age groups. BBV152 (Covaxin) was well tolerated in both dose groups with no serious adverse events."
The scientific paper which is under peer-review has been released a day after the company said that it has recruited more than 13,000 of the targeted 26,000 volunteers on whom the vaccine will be tested as part of the late-stage trial.