FACTBOX-UK says new coronavirus variant up to 70% more transmissible

- In areas where the new variant was dominant, hospital admission rates were rising quickly and previously agreed social restrictions were no longer strong enough. - Vallance said he thought the new variant may be in other countries as well but might have started in the UK.

Following are details of a new coronavirus variant that has been identified in the United Kingdom, given at a news conference on Saturday by Prime Minister Boris Johnson, Patrick Vallance, the UK's chief scientific adviser, and Chris Whitty, the chief medical adviser.

- The new variant is thought to have first occurred in mid-September in London or Kent, in the southeast of England. - UK analysis suggests it may be up to 70% more transmissible than the old variant, which could increase the reproduction "R" rate by 0.4.

- There is no evidence to suggest it is more lethal or causes more severe illness. - There is no evidence suggesting vaccines will be any less effective against the new variant.

- The new variant contains 23 different changes, many of them associated with alterations in a protein made by the virus. Vallance said this was an unusually large number of changes. - It has variants in areas of the virus that are known to be associated with how the virus binds to cells and enters cells.

- The variant has spread quickly in London, the southeast and east of England, becoming the dominant form of the virus in these areas. - In London, 62% of cases were due to the new variant in the week of Dec. 9. That compared to 28% three weeks earlier.

- In London, the overall infection rate doubled in the last week. - In areas where the new variant was dominant, hospital admission rates were rising quickly and previously agreed social restrictions were no longer strong enough.

- Vallance said he thought the new variant may be in other countries as well but might have started in the UK. - The UK submitted its findings to the World Health Organization on Friday night.

(Additional reporting by William Schomberg Editing by Frances Kerry)