LONDON (BLOOMBERG) - The UK is considering tightening controls at its borders to prevent the import of new strains of coronavirus, which it fears may undermine the success of its vaccination programme.

"The conversation has changed about the borders," Britain's health secretary Matt Hancock said on Sky News on Sunday (Jan 24).

"These new variants can really set us back and we need to protect ourselves against them coming in."

Options under consideration include quarantining arrivals in hotels and banning certain foreign-passport holders, the Sunday Times reported, without saying how it got the information. 10 Downing Street, the Department for Transport and the Home Office declined to comment.

Toughening up the UK border is an increasing priority for Prime Minister Boris Johnson as he seeks to preserve the gains from Britain's vaccination programme, which is the most successful in Europe and has seen 6.35 million people receive their first dose.

Mr Hancock said it's unclear whether new variants of the virus - such as those found in South Africa and Brazil - may be more resistant to the vaccine.

"We don't know the degree of that," Mr Hancock said. "In the meantime, we've got to have a precautionary principle that says let's not bring these new variants back to the UK."

Britain has already stopped all flights from South America and South Africa, and travellers need a negative virus test within 72 hours of entering the UK. They then need to self-isolate for 10 days.

Mr Johnson's government will make a decision about new measures at a meeting on Tuesday, the Sunday Times reported.

In a sign of the outcome Britain is trying to avoid, Mr Hancock said on the BBC's "The Andrew Marr Show" that there are 77 known cases of the South African variant in the UK, and at least nine cases of the Brazilian variant.

Mr Hancock said there is a "long, long, long way" to go before social restrictions can be lifted.

More than three-quarters of over 80s in Britain have been vaccinated, Mr Hancock said. He was not able to say if schools will be back by Easter.