Noubar Afeyan’s Moderna said on Monday it believes its COVID-19 vaccine protects against new variants found in Britain and South Africa.

The company said in a press release that it found no reduction in the antibody response against the variant found in Britain. Against the variant found in South Africa, it found a reduced response but still believed its two-dose regimen would provide protection.

The emergence of new variants in Britain, South Africa and Brazil has created some concern that mutations in the virus may make vaccines less effective.