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Will new ‘bivalent booster’ head off a winter Covid wave?

  • August 16, 2022

A new Covid vaccine designed to target both the original virus and the newer Omicron variant is set to be rolled out in the UK after being approved by the country’s medicines regulator in a world first.  

Made by Moderna, the bivalent vaccine is known as “Spikevax bivalent Original/Omicron” and combines the original form of the Covid vaccine with a version tailored for Omicron variant BA.1, “the strain that fuelled a wave of Covid in the UK last winter”, said The Guardian’s science correspondent Nicola Davis.

But while the UK is leading the way in approving the new jab for adult booster doses, some experts have suggested the vaccine “may not offer huge gains in the fight” to prevent another wave of winter infections, Davis reported.

How does the bivalent booster work?

In each dose, “half of the vaccine (25 micrograms) targets the original virus strain from 2020 and the other half (25 micrograms) targets Omicron”, said the Medicines and Healthcare products Regulatory Agency (MHRA). 

Coronavirus is “continually evolving in order to evade the immunity provided by vaccines”, said Professor Munir Pirmohamed, chair of the Commission on Human Medicines. “This novel bivalent vaccine represents the next step in the development of vaccines to combat the virus, with its ability to lead to a broader immune response than the original vaccine.”

Who will get the new booster and when?

Britain’s autumn Covid vaccination campaign is due to begin in September, with 26m people to be invited to get a fresh dose, including “the over-50s, healthcare workers and the vulnerable”, The Telegraph’s science correspondent Joe Pinkstone reported.

The Joint Committee for Vaccinations and Immunisations (JCVI) “has said that Moderna’s Omicron vaccine will be the default option” throughout the boost campaign, Pinkstone added. But “should there be supply issues then older versions will be used, with the most vulnerable prioritised for the new jab”. 

Will it head off a winter wave of Covid?

The decision to approve the new jab is based on a clinical trial that “showed that a booster with the  bivalent Moderna vaccine triggers a strong immune response against both Omicron (BA.1) and the original 2020 strain”, said the Medicines and Healthcare products Regulatory Agency. “In an exploratory analysis the bivalent vaccine was also found to generate a good immune response against the Omicron sub-variants BA.4 and BA.5.”

According to US pharma giant Moderna, trial participants who were given the booster had antibody levels against these sub-variants that were 1.69 times higher than those given the original booster.

BA.4 and BA.5 “fuelled the most recent Covid wave in the UK, and have caused infections, breakthrough reinfections, deaths and disruption around the world”, said The Guardian’s Davis.

But some experts fear that the new vaccine may offer only marginal gains in the push to prevent further suffering.

“This is a really difficult juncture for all policymakers in terms of vaccine booster procurement and booster programmes,” Danny Altmann, a professor of immunology at Imperial College London, told the paper.

“We lack the certainties we had in early 2020 of which way to go with the vaccines, not least, how to keep up with evolution of the variants. BA.5 is highly immune evasive so that even boosted people have highly impaired protection. Even exposure to the original Omicron sequence – as used in this, new, bivalent vaccine booster – only gives a rather marginal advantage to the antibody response.”

But “any booster programme is better than nothing, and this bivalent booster almost certainly an improvement over the first-generation vaccines”, Altmann added.

“My view is that this approach offers a marginal improvement in our battle against BA.5, but actually, we still need to think harder about this and look more broadly at the diverse vaccine candidates. In the meantime, get boosted.”

Article source: https://www.theweek.co.uk/covid-19/957661/will-new-bivalent-booster-head-off-a-winter-covid-wave

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