German pharmaceutical company BioNTech is confident that its coronavirus vaccine works against the new UK variant, but further studies are needed to be completely sure, its chief executive said on Tuesday.

Ugur Sahin, the co-founder of BioNTech, said that it was “highly likely” that its vaccine against the coronavirus works against the mutated strain detected in Britain, but it could also adapt the vaccine if necessary in six weeks.

“Scientifically, it is highly likely that the immune response by this vaccine also can deal with the new virus variant,” said Ugur Sahin.

But if needed, “in principle the beauty of the messenger technology is that we can directly start to engineer a vaccine which completely mimics this new mutation — we could be able to provide a new vaccine technically within six weeks.”

On the other hand, Pfizer and Moderna are also testing their coronavirus vaccines to see if they work against the new mutated version of the virus that’s recently been found in the United Kingdom and other countries.

Sahin said that the proteins on the UK variant are 99% the same as on the prevailing strains, and therefore BioNTech has “scientific confidence” that its vaccine will be effective.

“But we will know it only if the experiment is done and we will need about two weeks from now to get the data,” he said. “The likelihood that our vaccine works is relatively high.” Should the vaccine need to be adjusted for the new variant the company could do so in about 6 weeks, said Ugur, though regulators might have to approve the changes before the shots can be used.

BioNTech’s vaccine, developed together with U.S. pharmaceutical company Pfizer, is authorized for use in more than 45 countries including Britain, the United States and the EU.

The variant, detected mainly in London and the southeast of England in recent weeks, has sparked concern worldwide because of signs that it may spread more easily. While there is no indication it causes more serious illness, numerous countries in Europe and beyond have restricted travel from the UK as a result.