RNS: Covaxin, a coronavirus vaccine, developed by Bharat Biotech a Hyderabad-based company in India, has been found to be “safe with no serious side effects.” This is based on the interim result of its phase 2 trial results, published on Tuesday in the international medical journal— The Lancet.
“In the phase 1 trial, BBV152 induced high neutralising antibody responses that remained elevated in all participants at 3 months after the second vaccination,” it said in the study published.
“In the phase 2 trial, BBV152 showed better reactogenicity and safety outcomes and enhanced humoral and cell-mediated immune responses compared with the phase 1 trial. The 6µg with Algel-IMDG formulation has been selected for the phase 3 efficacy trial,” The Lancet said about the vaccine being currently inoculated along with Covishield of the Pune-based Serum Institute of India.
The phase 3 results of Covaxin, developed by the Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV), Pune in partnership with Hyderabad-based Bharat Biotech International Limited (BBIL), had shown an interim vaccine efficacy of 81 per cent in preventing Covid-19. The phase 3 efficacy rate is yet to be published in a scientific journal.
The vaccine has been granted emergency use authorisation in clinical trial mode by the government late last year. The phase 3 trial, jointly initiated by ICMR and BBIL in mid-November 2020, was conducted on a total of 25,800 individuals across 21 sites.
Covaxin had initially raised concerns among experts over its emergency approval by India’s drug regulator.
The latest study comes a week after Bharat Biotech announced that the vaccine has shown 81 per cent efficacy in the third phase of clinical trials, the results of which are yet to be published.
The phase 2 trial to evaluate the immunogenicity and safety of BBV152 vaccine was conducted in healthy adults and adolescents aged 12-65 years at nine hospitals across nine states in India. Two intramuscular doses of vaccine were administered on day 0 and day 28.
The primary outcome was assessed in all participants who had received both doses of the vaccine. Safety was assessed in participants who received at least one dose of the vaccine.
Between September 5 and 12, last year, 921 potential participants were screened, 380 of whom were enrolled. “We report interim findings of the phase 2 trials on the immunogenicity and safety of BBV152, with the first dose administered on day 0 and the second dose on day 28,” the authors of the study said.
Covaxin is an inactivated vaccine developed by chemically treating novel coronavirus samples to make them incapable of reproduction.
“The results reported in this study do not permit efficacy assessments. The evaluation of safety outcomes requires extensive phase 3 clinical trials,” the authors of the Lancet study said.
“We were unable to assess other immune responses in convalescent serum samples due to the low quantity,” they said.
Even though direct comparisons between the phase 1 and 2 trials cannot be made, the reactogenicity assessments reported in this study was substantially better in the phase 2 trial than the phase 1 trial and other trials with a placebo group, according to the authors.
Also, the proportion of participants reporting adverse events in the phase 2 trial was lower than in the phase 1 trial, they noted.
