Biotechnology company Bharat Biotech on Wednesday announced that a booster dose of its Covaxin vaccine administered six months after the last two shots generates robust antibody responses against both the Delta and Omicron variants of Covid-19.

The company said that the vaccine neutralised the virus at levels compared to those seen with mRNA vaccines (such as those developed by Pfizer and Moderna).

Bharat Biotech announced the results from an ongoing study at the Emory University in the United States. The study was based on data from a total of 13 participants. It has not been peer-reviewed or published in any medical journal.

The study has been sponsored by Ocugen, Bharat Biotech’s partner in the United States and Canada.

Bharat Biotech said that the Delta variant was neutralised in 100% of the samples tested, while the Omicron variant was neutralised in 90% of the samples.

Mehul Suthar, who led the laboratory analysis at the Emory Vaccine Center, said that the findings suggest that a booster dose of Covaxin “has the potential to reduce disease severity and hospitalisations”.

Bharat Biotech’s Managing Director Krishna Ella said that the findings validate its hypothesis that Covaxin generates both humoral (through antibodies) and cell-mediated immune responses. “Our goals of developing a global vaccine against Covid-19 have been achieved with the use of [Covaxin] as a universal vaccine for adults and children,” he said.

On January 10, India began administering precautionary third doses of the Covid-19 vaccine to healthcare workers and senior citizens with co-morbidities.

Covaxin has been used in India since the country began its immunisation drive on January 16 last year. The vaccine received the World Health Organization’s emergency use approval on November 3.

Phase 3 trial results published by Bharat Biotech in November showed that the two-dose regimen of the vaccine had an overall efficacy of 77.8% in symptomatic Covid-19 patients.

The results on booster doses of Covaxin have been announced amid a sharp increase in coronavirus cases across the country. India on Wednesday reported 1,94,720 new Covid-19 cases and 442 deaths due to the disease.