What we know about the new coronavirus strain

The new COVID-19 strain, B117, has been linked to a rise in cases in the UK. It contains 23 mutations and is reportedly 70% more transmissible. The strain has spread rapidly in London and the southeast of England, and has been detected in several other countries. Despite its increased transmissibility, there is no evidence it causes more severe illness. Key symptoms remain unchanged. Two mutations in the spike protein, N501Y and H69V70, enhance the virus's ability to spread and evade antibodies. Over 30 countries have imposed travel restrictions from the UK to curb the spread.

What mutations have been identified in the virus's spike protein?

As of December 21st, how many countries have restricted travel from the UK due to the new strain?