A mural in Manchester, England. British Prime Minister Boris Johnson announced a third national lockdown to limit the spread of the new, more transmissible, strain of coronavirus on January 6. | Oli Scarff/AFP via Getty Images

The new mutations from the UK and South Africa are spreading fast around the world — and could diminish the effectiveness of the existing vaccines.

We knew it was going to be a long, dark winter. But unfortunately, it’s now looking even more grim. Just as the first coronavirus vaccines began rolling out in the US and countries around the world in December — offering hope for the end of the Covid-19 pandemic — two fast-spreading variants of the SARS-CoV-2 virus were discovered in the United Kingdom and South Africa.

Within a matter of weeks, the new mutants replaced other versions of the virus