A mutation of the Covid-19 virus has been seen in the UK. Scientists are watching to see what clinical relevance this mutation will have. mRNA vaccines are known to mutate with each replication, so this is not unexpected. The mutation is on the spike protein, thankfully the vaccine covers a wide area of the spike protein. The mutation would have to involve several areas or a large portion of the spike protein to render the vaccine ineffective. There does not seem to be an indication that this is the case. If the mutation affects the efficacy of the vaccine, it would need to be adjusted, much like the annual influenza vaccine. One benefit of the mRNA vaccines is the ability to rapidly make adjustments.