Covaxin Booster Dose Increases Vaccine Effectiveness Against Delta, Omicron Variants, Says ICMR Study


New Delhi, 15 June

Administration of Covaxin as a booster dose enhances the vaccine’s effectiveness against the delta variant of COVID-19 and provides protection against Omicron variants BA.1.1 and BA.2, a study by ICMR and Bharat Biotech has found.

It said the protective efficacy of Bharat Biotech’s Covaxin after two- and three-dose vaccination against Delta variants and Covaxin’s efficacy against Omicron variants was studied in the Syrian hamster model (animal model to study human-associated diseases), it said. was done in

It said antibody response, clinical observation, reduction in viral load and severity of lung disease were observed after virus challenge.

The study’s findings are published Tuesday on BioRxiv, a pre-print server, and have not been reviewed.

“In the Delta Infection Study, where we compared the protective response between the two- and three-dose regimens, we could observe a benefit of booster dose vaccination in protection. Although neutralizing antibody levels were comparable between the groups, the three doses The severity of lung disease was found to be lower after vaccination.

The study, conducted by the Indian Council of Medical Research and Bharat Biotech, said, “Virus shedding and viral organ load were significantly reduced in two-dose and three-dose vaccinated animals, indicating the effectiveness of the vaccine against the delta variant.” Shows.”

In the second study, which assessed the protective response against Omicron variants, ie, ba.1 and ba.2, after three-dose vaccination, reduced virus shedding, lung viral load and lung disease severity were compared with the immunized groups. was seen in comparison. placebo group.

“Evidence from the present study suggests that Covaxin booster vaccination broadens the protective immune response and reduces disease severity against Delta and Omicron type infections,” it adds.