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Updated June 15th, 2022 at 13:39 IST

COVID-19: Covaxin booster improves efficacy against Delta & Omicron variants, finds study

A new study has found that the booster dose of the anti-coronavirus vaccine, Covaxin, improves efficacy against the Delta & Omicron variants of the coronavirus.

Reported by: Aparna Shandilya
COVID-19
Image: PTI | Image:self
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A booster dose of the anti-coronavirus vaccine, Covaxin, will improve its efficacy against the Delta variant of the SARS-CoV-2 virus, commonly known as COVID-19, as well as the Omicron variants BA.1.1 and BA.2, according to a new study. The study on hamsters was carried out by the National Institute of Virology, the apex virology laboratory of the Indian Council of Medical Research (ICMR).

The anti-COVID vaccine Covaxin is one of two anti-COVID vaccinations used in the national coronavirus immunisation programme, which began in January 2021. Hyderabad-based Bharat Biotech and the ICMR collaborated on the inactivated whole-virion coronavirus vaccine.

In a Syrian hamster model, the researchers examined the efficacy of Covaxin after the second and third doses against the Delta variant that reached India during the second wave, as well as its efficacy against the Omicron variant. Researchers looked at antibody response, clinical observations, viral load reduction, and lung disease severity, according to the study published on June 14.

Protective response observed in second and third doses of Covaxin

The research paper stated, "Protective response in terms of the reduction in lung viral load and lung lesions were observed in both the second as well as third dose of Covaxin immunised group when compared to placebo group following the Delta variant challenge. In spite of the comparable neutralising antibody response against the homologous vaccine strain in both the Dose 2 and Dose 3, considerable reduction in the lung disease severity was observed in the third dose immunised group post Delta variant challenge, indicating the involvement of cell mediated immune response also in protection."

In a vaccine efficacy study against the Omicron variants BA.1 and BA.2, the immunised groups showed lower virus shedding, lung viral load, and lung disease severity than the placebo groups, according to the paper. Bharat Biotech has previously released the results of Phase 2 double-blind, randomised controlled Covaxin studies, which showed long-term safety and no significant side events six months after the second shot. The findings also revealed a positive cell-mediated response.

(Image: PTI)

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Published June 15th, 2022 at 13:38 IST

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