World faces 4,000 Covid-19 variants

Race to improve vaccination as Britain explores mixed vaccine shots

LONDON: The world faces around 4,000 variants of the virus that causes Covid-19, prompting a race to improve vaccines, Britain said, as researchers began to explore mixing doses of the Pfizer and AstraZeneca shots in a world first.

Thousands of variants have been documented as the virus mutates, including the so-called British, South African and Brazilian variants which appear to spread more swiftly than others.

British Vaccine Deployment Minister Nadhim Zahawi said yesterday that it was very unlikely that the current vaccines would not work against the new variants.

“Its very unlikely that the current vaccine won’t be effective on the variants whether in Kent or other variants, especially when it comes to severe illness and hospitalisation,” Zahawi told Sky News.

“All manufacturers – Pfizer-BioNTech, Moderna, Oxford-AstraZeneca and others – are looking at how to improve their vaccine to make sure that we are ready for any variant.

There are about 4,000 variants of Covid-19 around the world now.”

While thousands of variants have arisen as the virus mutates on replication, only a small minority are likely to be important and change the virus in an appreciable way, said the British Medical Journal.

The so called British variant, known as VUI-202012/01, has mutations including a change in the spike protein that viruses use to bind to the human ACE2 receptor, meaning that it is probably easier to catch.

Britain yesterday launched a trial to assess the immune responses generated if doses of the vaccines from Pfizer and AstraZeneca are combined in a two-shot schedule.

Initial data on immune responses is expected to be generated in June.

The trial will examine the immune responses of an initial dose of Pfizer vaccine followed by a booster of AstraZeneca’s, as well as vice versa, with intervals of four and 12 weeks.

The trial will be the first of its kind to combine a mRNA shot – the one developed by Pfizer and BioNtech – and a adenovirus viral vector vaccine of the type developed by Oxford University and AstraZeneca.

AstraZeneca’s shot is separately being trialled in combination with another viral vector vaccine, Russia’s Sputnik V.

The researchers behind the trial said data on vaccinating people with the two types of vaccines could boost understanding of whether shots can be rolled out with greater flexibility and might even increase immune responses. — Reuters