From left, Chief Medical Officer for England Chris Witty, Britain's Prime Minister Boris Johnson and Chief Scientific Adviser Patrick Vallance speak during a press conference about coronavirus in 10 Downing Street in London, Monday, March 9, 2020.

From left, Chief Medical Officer for England Chris Witty, Britain's Prime Minister Boris Johnson and Chief Scientific Adviser Patrick Vallance speak during a press conference about coronavirus in 10 Downing Street in London, Monday, March 9, 2020.

© 2020 AP Photo/Alberto Pezzali