Covaxin booster dose may grant long-term protection against COVID: Study

ICMR and Bharat Biotech study touts efficacy of third Covaxin dose

covaxin rep salil bera Representational image | Salil Bera

A third booster shot of Bharat Biotech’s Covaxin COVID-19 vaccine can induce a detectable neutralising response in 90 per cent of recipients, and may offer long-term protection against severe COVID-19.

“90% of recipients had a detectable neutralizing antibody response against the wild-type strain (6 months after the second dose),” Bharat Biotech said on Saturday, citing the results of a study it conducted with the Indian Council of Medical Research (ICMR).

“Six months after a two-dose BBV152 vaccination series cell-mediated immunity and neutralising antibodies to both homologous (D614G) and heterologous strains (Alpha, Beta, Delta, and Delta plus) persisted above baseline, although the magnitude of the responses had declined,” the company said.

Neutralising antibodies against homologous and heterologous SARS-CoV-2 variants increased 19- to 265- fold after a third vaccination, it said. “Booster BBV152 vaccination is safe and may be necessary to ensure persistent immunity to prevent breakthrough infections."

Chairman and Managing Director of Bharat Biotech, Dr Krishna Ella said, “These trial results provide a strong foundation towards our goal to provide Covaxin as a booster dose. Our goals of developing global vaccine against COVID-19 have been achieved with Covaxin indicated for adults, children, 2 dose primary and booster doses. This enables the use of Covaxin as a universal vaccine.”

“COVAXIN is safe and immunogenic as a booster dose,” the company said, adding that it was the first vaccine in India to report safety and immunogenicity results from a booster clinical trial.

The Serum Institute of India had said in December that its Covishield vaccine would be effective against the Omicron variant, citing an Oxford University lab study on the efficacy of a three-dose course of the AstraZeneca vaccine.

The Centre had recently moved to administer “precautionary doses” to healthcare workers, front line workers and those aged above 60 with co-morbid conditions. Recipients have to complete nine months since their second dose.

Covaxin has been approved as a vaccine for the 15-18 age cohort, which has so far been unvaccinated.