Third dose of Covishield significantly boosts antibodies against Omicron: Study

Express News Service

NEW DELHI: A three-dose course of AstraZeneca’s Covid-19 vaccine, available in India under the brand name of Covishield, is effective against the newest Covid virus variant Omicron, the pharmaceutical major said on Thursday, citing data from an Oxford University lab study.

Covishield, produced by Serum Institute of India, is India’s highest used Covid vaccine and over 124 crore doses of this vaccine have been administered in the country so far.

Significantly, the evidence emerges ahead of an all-important meeting by India’s top advisory panel on immunization to deliberate on the need for booster or additional doses in the local context, especially in the wake of the Omicron scare.

Findings from the study, yet to be published in a peer-reviewed medical journal, match those from rival vaccines such as Pfizer-BioNTech and Moderna which had also found that the third dose of their shots raises the vaccine efficacy significantly.

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The study on AstraZeneca’s vaccine, Vaxzevria — earlier called simply its Covid vaccine — demonstrated that after a three-dose course of the vaccine, neutralizing levels against Omicron were broadly similar to those against the virus’s Delta variant after two doses.


The firm said that researchers at Oxford University who carried out the study were independent of those who worked on the vaccine with AstraZeneca.

“As we better understand Omicron, we believe we will find that T-cell response provides durable protection against severe disease and hospitalisations,” Mene Pangalos, the head of AstraZeneca’s biopharmaceuticals R&D said in a statement.

Antibody levels against Omicron after the booster shot were higher than antibodies in people who had been infected with and recovered naturally from Covid-19, the company also said.

The results are based on analysis of blood samples from those infected with Covid-19, those vaccinated with two doses of the vaccine and a booster, and those previously infected with other variants of concern. It also included samples from 41 people given three doses of this vaccine.

Earlier this week, however, AstraZeneca had announced that it was working with its partner Oxford University to produce a vaccine tailored specifically for Omicron, joining similar efforts from other vaccine-makers.