A variant of the coronavirus identified in South Africa is more problematic than the strain found in the U.K., Britain's health minister has said, as both strains continue to spread rapidly.

Speaking to the BBC Monday, Health Secretary Matt Hancock said the variant found in South Africa was especially concerning.

"I'm incredibly worried about the South African variant, and that's why we took the action that we did to restrict all flights from South Africa," he told the BBC's Today program.

"This is a very, very significant problem ... and it's even more of a problem than the U.K. new variant."

Both the U.K. and South Africa are struggling with a surge in COVID-19 infections, which have been attributed in large part to new mutations in the virus that make it more transmissible.

The U.K.'s new variant was first identified in Kent, southeast England, in December. The U.K. authorities alerted the World Health Organization to its emergence.

Experts note that while the new variant makes the virus spread more easily, it does not appear to make it more deadly. Nonetheless, the U.K.'s hospitals are under pressure from a dramatic rise in infections and admissions.

Vaccine effectiveness

Questions have been raised over how the coronavirus vaccines will work against the new variants.

A number of experts have said they expect vaccines — such as those from Pfizer and BioNTech, and the Oxford University/AstraZeneca — to protect against the new strains.

Earlier in December, the WHO's Chief Scientist Soumya Swaminathan tried to allay fears over the variants, telling the BBC that it was "very unlikely" that the latest mutations would cause the current vaccines not to work. The WHO has said further investigations are required "to understand the impact of specific mutations on viral properties and the effectiveness of diagnostics, therapeutics and vaccines."

Regius Professor of Medicine at Oxford University John Bell said on Sunday that the variant identified in South Africa was worrying in this regard, however.

"They both have multiple, different mutations in them, so they're not a single mutation," he told Times Radio. "And the mutations associated with the South African form are really pretty substantial changes in the structure of the (virus' spike) protein."

He said there were questions as to whether the Pfizer/BioNTech and Oxford University/AstraZeneca vaccines would be "disabled" in the presence of such mutations.

The team behind the Oxford University jab was investigating the effect of the variants on its vaccine, he said, adding that his gut feeling was that it would still be effective against the strain identified in the U.K., but he was more uncertain about the one identified in South Africa.

However, he told the radio station that if the vaccine did not work on this variant then it was likely the vaccines could be adapted and that would not take as long as a year.

More lockdowns

Coronavirus vaccines are the only bright spot in a pandemic that continues to rage in the West. On Monday, the U.K. began its rollout of the Oxford-AstraZeneca vaccine after starting to deploy the Pfizer/BioNTech shot in December.

In the meantime, restrictions on public life continue and the U.K.'s Prime Minister Boris Johnson has hinted that more restrictions could be introduced in England. Many parts of the country are already effectively under lockdown, with all but essential shops closed and people told to stay at home as much as possible. Still, further restrictions could be introduced in parts of the country with more relaxed measures.

The U.K. has now recorded over 2.6 million cases of the virus, and over 75,000 deaths to date, according to a tally from Johns Hopkins University, and the new variant of the virus has prompted a surge in infections in London and the South East and is starting to appear in other parts of the country.

In South Africa, over 1.1 million cases have been recorded, and almost 30,000 deaths and the new strain has become dominant in the Western Cape, Eastern Cape and KwaZulu-Natal.

The variant originally identified in the U.K. has also been discovered in some European countries and the U.S., prompting many nations to ban flights from the U.K. For its part, the U.K. has banned visitors from South Africa.