On December 16th, 2020 England’s health secretary, Matt Hancock, announced that a new variant of SARS-CoV-2 had been detected in the UK. Amid worries that the new variant may be more transmissible, PM Boris Johnson announced new lockdowns in London and England's southeast, including a ban on Christmas gatherings. The new variant is said to account for 60% of the infections in London.

The spread of a new variant has prompted concerns that a mutation in SARS-CoV-2 could lead to the currently approved vaccines and treatments becoming less effective. The British Medical Journal has the following to say about this possibility:

The new variant has mutations to the spike protein that the three leading vaccines are targeting. However, vaccines produce antibodies against many regions in the spike protein, so it’s unlikely that a single change would make the vaccine less effective.

Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.

Peacock said, “With this variant there is no evidence that it will evade the vaccination or a human immune response. But if there is an instance of vaccine failure or reinfection then that case should be treated as high priority for genetic sequencing.”

If there is a mutation and the SARS-CoV-2 vaccine must be updated, it is possible the United States CDC will start recommending revaccination with an updated vaccine. This question asks how likely that scenario is.