Graph shows how far COVID-19 cases have soared in the UK since the more contagious variant was discovered

• Coronavirus cases have been soaring in the UK, with the country's total number of positive tests rising by 70% just since the new, more infectious variant was announced on December 14.
• The sharp increase came even after the UK tightened restrictions in December.
• The variant is called B.1.1.7. Scientists worldwide are urgently investigating how its mutations affect its behavior.
• The variant has been discovered in several US states and countries around the world.

The total number of people who have ever tested positive for the novel coronavirus in the UK has risen by 70% in roughly four weeks, according to government stats.

UK Health Secretary Matt Hancock announced the discovery of the new variant called B.1.1.7, or VUI 20212/01 - Variant Under Investigation, year 2020, month 12, variant 01 - on December 14.

From that date to this week, the country's number of daily positive tests roughly doubled, per the UK government, as the total number of positive tests increased to 3,164,051 from 1,869,666.

The new variant, which includes several mutations, is thought to be 30% to 50% more contagious than other forms of the virus, according to estimates from Public Health England. Precisely what makes B.1.1.7 more contagious is not yet known.

The variant has been found in multiple US states, including New York, Florida, and California. Experts believe it has been circulating in the US for several weeks.

The figures reported in the graph include people testing positive from nasal swabs that go to the lab as well as from the quicker lateral-flow tests. It is not clear from the data set how people who tested positive more than once were counted.