Summary: U.K. models have shown the new variant to have an increased transmission rate of 70% compared to other strains in the U.K. This strain was first found in southeastern England in September, but by November, the new variant was responsible for 25% of the cases in London. A month later, it was responsible for 60% of cases in the city. Lockdown measures were mandated in London and large areas of southern England, while a number of nations banned travel from the U.K

Colorado confirms first known US case of new COVID-19 strain believed to be more contagious, USA Today. Grace Hauck (December 29, 2020).