PHARMACEUTICAL firms producing Covid-19 vaccines are working to adapt them to work against a new concerning strain of the virus that has sparked travel bans.

The strain, named Omicron and designated a “variant of concern” by the World Health Organisation (WHO), has reached Belgium after being discovered in South Africa.

The WHO warned that preliminary evidence suggests the variant has an increased risk of reinfection and may spread more rapidly than other strains.

A number of pharmaceutical firms have said they are working to adapt their vaccines in light of the emergence of Omicron.

The UK has banned flights from South Africa, Botswana, Lesotho, Eswatini, Zimbabwe and Namibia to limit the spread of the new variant.

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The six African countries were added to the UK’s travel red list on Thursday evening and passengers arriving in the UK from these countries from 4am on Sunday will be required to book and pay for a Government-approved hotel quarantine for 10 days.

There are concerns the variant may be more transmissible, make existing vaccines less effective, and it may hinder one of the UK’s Covid treatments, Ronapreve.

The EU, US and Canada have also imposed travel restrictions on visitors from southern Africa ahead of the WHO adding the strain, also known as B.1.1.529, to its highest category for concerning variants.

Experts at the WHO said there is early evidence to suggest Omicron has an “increased risk of reinfection” and its rapid spread in South Africa suggests it has a “growth advantage”.

Novavax said it has “already initiated development of a new recombinant spike protein based on the known genetic sequence of B.1.1.529 and will have it ready to begin testing and manufacturing within the next few weeks”.

Moderna said: “Since early 2021, Moderna has advanced a comprehensive strategy to anticipate new variants of concern.

“This strategy includes three levels of response should the currently authorized 50 µg (microgram) booster dose of mRNA-1273 prove insufficient to boost waning immunity against the Omicron variant.”

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Pfizer and BioNTech said that in the event of a variant which could escape the effects of the vaccines, the firm expects “to be able to develop and produce a tailor-made vaccine against that variant in approximately 100 days, subject to regulatory approval”.

AstraZeneca said it has “developed, in close collaboration with Oxford University, a vaccine platform that enables us to respond quickly to new variants that may emerge” and is “already conducting research in locations where the variant has been identified”.

The firm is also testing its antibody combination drug against the new variant and is “hopeful” it “will retain efficacy since it comprises two potent antibodies with different and complementary activities against the virus”.