The new, more infectious variants of coronavirus that could render vaccines less effective have spread quickly across dozens of countries, the World Health Organization (WHO) said on Wednesday.

Axar.az reports that in its latest epidemiological update, the U.N. health agency said the more contagious COVID-19 variant first spotted in Britain had by Jan. 25 spread to 70 countries across all regions of the world.

That variant, which is known as VOC 202012/01 and has proven to transmit more easily than previous variants of the virus, had thus spread to 10 more countries over the past week, it said.

British Prime Minister Boris Johnson last week also warned that fresh studies had indicated the strain could be deadlier, but the WHO stressed Wednesday that those "results are preliminary, and more analyses are required to further corroborate these findings."

The WHO also said the variant of the virus first found in South Africa had now spread to 31 countries, eight more than a week ago.