Booster doses of index virus vaccines are still effective against all variants of COVID-19: WHO

The World Health Organization has said that booster doses of virus-based index vaccines provide protection against all variants of SARS-CoV-2, including contemporary Omicron descendant lines. Image for representation purposes only. | Photo credit: RAMAKRISHNA G.

The World Health Organization’s Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) said that booster doses of index virus vaccines continue to confer high levels of protection against serious illness and death caused by all variants of SARS-CoV-2, including contemporary Omicron descendant lines.

The recent statement comes at a time when India sees surge in new COVID-19 cases and is at a six-month high with more than 10,000 daily new cases over the past week.

WHO said several vaccine makers have developed COVID-19 vaccines with updated antigenic composition; this includes several mRNA-based bivalent vaccines containing earlier progeny lines of Omicron, in addition to the index virus (i.e., index virus + BA.1 or BA.4/5), which have been authorized for emergency use by regulatory authorities.

India is currently ramping up its vaccine production following a rapid increase in cases caused by the Strain XBB.1.16, a sub-variant of Omicron.

The Serum Institute of India (SII) has restarted manufacturing of COVID-19 vaccines, its chief executive Adar Poonawalla said recently. Bharat Biotech, which manufactures Covaxin produced in India, said it would wait for demand to increase before resuming production. It was the second most administered vaccine in the country and the company stopped production of Covaxin in early 2022 due to lack of demand.

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Meanwhile, the WHO at its recent meeting reviewed the evidence for the performance of updated COVID-19 vaccines that incorporate progeny lines of Omicron as a booster dose and also reviewed timelines for recommendations. composition of the COVID-19 vaccine in 2023.

Based on the review of the data, TAG-CO-VAC concluded that booster doses of index virus vaccines continue to confer high levels of protection against serious illness and death caused by all variants of the virus. SARS-CoV-2, including contemporary descendant lines of Omicron.

“Protection against severe disease and symptomatic infections induced by virus-based index vaccines and bivalent mRNA vaccines containing BA.1 or BA.4/5 decreases over time.

“However, protection against severe disease is maintained longer than protection against symptomatic infections. Compared to virus-based index vaccines, booster doses of bivalent mRNA vaccines containing BA.1 or BA.4/5 may slightly increase vaccine efficacy against symptomatic disease, while the small number of studies evaluating the serious results show similar estimates of vaccine effectiveness,” TAG-CO-VAC said in its release.

He added that bivalent mRNA vaccines containing BA.1 and BA.4/5 enhance the magnitude and elicit greater magnitude of cross-reactive immune responses to SARS-CoV-2 variants when used as a dose. booster, compared to indexing virus-based vaccines.