High efficacy of Indian Covaxin vaccine against COVID confirmed

Covaxin, a vaccine developed by India’s medical research agency and Bharat Biotech International Ltd., was 77.8% effective in preventing symptomatic COVID-19 in an interim analysis of a long-awaited study.

The researchers concluded that Covaxin, which uses traditional inactivated virus technology, induced a robust antibody response two weeks after the second dose was administered. There were no vaccine-related serious adverse events or deaths during the randomized trial of 24,419 adults. The research, conducted between November 2020 and May 2021 in India, was published in the scientific journal The Lancet.

The interim analysis, based on 130 laboratory-confirmed infections, is in line with the company’s previous efficacy and safety announcements and may help end the controversy surrounding the advance authorization of the vaccine in January in India. The study was funded by Bharat Biotech and the Indian Council for Medical Research (ICMR), and involved researchers from both organizations.

At the time of India’s approval, the vaccine had not yet passed the final phase of trials, prompting widespread reluctance in the first weeks of the country’s immunization campaign. Since then, more than 120 million doses of Covaxin have been distributed throughout India. Last week, the World Health Organization (WHO) added the inoculation to its list of COVID vaccines authorized for emergency use.

The endorsement did not come quickly. Over the course of its months-long analysis, the WHO’s independent technical body that evaluates the vaccine repeatedly asked the company for more information, delaying its addition to the agency’s list of prequalified vaccines and frustrating the Prime Minister’s government. Narendra Modi, who had championed the locally developed vaccine as a nationalist cause.

Bharat Biotech president Krishna Ella previously lashed out at those questioning Covaxin and this week told a conference that the WHO approval took so long due to criticism of the vaccine that it damaged his image.

The publication in one of the most important medical journals in the world “shows the immense strength of ‘Atmanirbhar Bharat’ ”, with Indian industry and academics“ fighting through thick and thin“Said Balram Bhargava, director of the ICMR, in a statement referring to the government’s self-reliance campaign.

Long term safety

The researchers will follow the participants for a year to obtain long-term safety data. Additional information is also needed on its effectiveness over time, as well as on protection against serious illness, hospitalization, and death.

In the study, 106 people who received placebo and 24 who received the vaccine contracted the virus. The researchers found that 15 of the participants who received placebo developed a severe COVID infection, compared to one who received the vaccine. The vaccine appeared to be 65% effective against the most infectious delta variant, although more work is needed to confirm the results, they said.