The US Centres for Disease Control and Prevential now recommends boosters targeting Omicron sub-variants. Image Credit: AP

Washington: The US Centers for Disease Control and Prevention (CDC) has recommended COVID-19 booster shots from Pfizer and Moderna targeting the Omicron variant, clearing the way for the administration of the shots.

New generation

This new generation of anti-COVID vaccines targets both the original strain of coronavirus and the BA.4 and BA.5 lineages, the subvariants of Omicron that are causing the most cases in the United States.

Target age groups

The Pfizer-BioNTech shot is recommended for people 12 and older and Moderna's for those 18 years and up.

"The updated Covid-19 boosters are formulated to better protect against the most recently circulating COVID-19 variant. They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants," CDC Director Rochelle Walensky said in a statement.

"This recommendation followed a comprehensive scientific evaluation and robust scientific discussion," she added.

The new versions of the vaccines, approved by the US Food and Drug Administration on Wednesday, could potentially be available in the United States as early as next week.

The vaccines currently in circulation target the initial strain of the virus that first appeared in Wuhan, China. But they have gradually proven to be less effective against the variants that have appeared over time, due to rapid evolution of the virus.

In contrast to the Alpha and Delta variants, which eventually waned, Omicron and its subvariants have come to dominate infections worldwide in 2022.

Dodging antibodies

The two sublineages BA.4 and BA.5 of the Omicron coronavirus variant are able to dodge antibodies from earlier infection, which triggered a new COVID wave. On the upside, South African scientists found that the variants are far less able to thrive in the blood of people vaccinated against SARS-CoV2.

The scientists from multiple institutions checked Omicron’s BA.4 and BA.5 sublineages by taking blood samples from people previously infected by Omicron when it first showed up at the end of last year.

The scientists found that the vaccinated group showed about a 5-fold higher neutralisation capacity vs the unvaccinated group.