U.K. Prime Minister Boris Johnson instituted new lockdowns of London and a large part of the country amid a spike in coronavirus cases that have been attributed to a new, seemingly more contagious strain of COVID-19. “Given the early evidence we have on this new variant of the virus and the potential risk it poses, it is with a heavy heart that we cannot continue with Christmas as planned,” Johnson said in an address on Saturday. According to The New York Times, while it is common for viruses to mutate, medical experts have expressed concern about this variant of COVID-19, saying it appears to be more contagious, and was driving a new spike of cases in the U.K. Thankfully, public health officials said there is no evidence that the new variant is more deadly or vaccine-resistant than other strains.