White House Press Secretary Jen Psaki answers a question from a journalist during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Secretary of Veterans Affairs Denis McDonough delivers remarks during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Secretary of Veterans Affairs Denis McDonough delivers remarks during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

White House Press Secretary Jen Psaki and Secretary of Veterans Affairs Denis McDonough hold a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Secretary of Veterans Affairs Denis McDonough delivers remarks during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Secretary of Veterans Affairs Denis McDonough delivers remarks during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Secretary of Veterans Affairs Denis McDonough delivers remarks during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

White House Press Secretary Jen Psaki and Secretary of Veterans Affairs Denis McDonough walk towards the podium ahead of a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

White House Press Secretary Jen Psaki takes her mask off during a press briefing at the White House in Washington, U.S., March 4, 2021. REUTERS/Tom Brenner

Katy McAvoy watches her dog Molly run around in the backyard as she takes a brief break from working on her food blog in Grand Rapids, Michigan, U.S., March 2, 2021. Picture taken March 2, 2021. REUTERS/Emily Elconin

White House principal deputy press secretary Karine Jean-Pierre listens during a press briefing at the White House in Washington, U.S., March 3, 2021. REUTERS/Kevin Lamarque     

White House press secretary Jen Psaki speaks during a briefing at the White House in Washington, U.S., March 3, 2021. REUTERS/Kevin Lamarque     

Seiko Hashimoto, president of Tokyo 2020, and Toshiro Muto, CEO of Tokyo 2020, attend a media briefing following the five-party meeting at the Tokyo 2020 headquarters in Tokyo, Japan March 3, 2021. Du Xiaoyi/Pool via REUTERS

Seiko Hashimoto, president of Tokyo 2020, and Toshiro Muto, CEO of Tokyo 2020, attend a media briefing following the five-party meeting at the Tokyo 2020 headquarters in Tokyo, Japan March 3, 2021. Du Xiaoyi/Pool via REUTERS

Seiko Hashimoto, president of Tokyo 2020, speaks during a media briefing following the five-party meeting at the Tokyo 2020 headquarters in Tokyo, Japan March 3, 2021. Du Xiaoyi/Pool via REUTERS

Toshiro Muto, CEO of Tokyo 2020, speaks during a media briefing following the five-party meeting at the Tokyo 2020 headquarters in Tokyo, Japan March 3, 2021. Du Xiaoyi/Pool via REUTERS

Seiko Hashimoto, president of Tokyo 2020, and Toshiro Muto, CEO of Tokyo 2020, attend a media briefing following the five-party meeting at the Tokyo 2020 headquarters in Tokyo, Japan March 3, 2021. Du Xiaoyi/Pool via REUTERS

Seiko Hashimoto, President of the Tokyo 2020 Organising Committee, attends a media briefing with Toshiro Muto, CEO of Tokyo 2020, after a council meeting in Tokyo, Japan March 3, 2021. Kimimasa Mayama/Pool via REUTERS

Seiko Hashimoto, President of the Tokyo 2020 Organising Committee, attends a media briefing after a council meeting in Tokyo, Japan March 3, 2021. Kimimasa Mayama/Pool via REUTERS

Seiko Hashimoto, President of the Tokyo 2020 Organising Committee, attends a media briefing after a council meeting in Tokyo, Japan March 3, 2021. Kimimasa Mayama/Pool via REUTERS

Seiko Hashimoto, President of the Tokyo 2020 Organising Committee, speaks during a media briefing after a council meeting in Tokyo, Japan March 3, 2021. Kimimasa Mayama/Pool via REUTERS

White House press secretary Jen Psaki speaks during a briefing at the White House in Washington, U.S., March 2, 2021. REUTERS/Kevin Lamarque     

White House press secretary Jen Psaki fields a question during a briefing at the White House in Washington, U.S., March 2, 2021. REUTERS/Kevin Lamarque     

White House press secretary Jen Psaki speaks to reporters during a briefing at the White House in Washington, U.S., March 2, 2021. REUTERS/Kevin Lamarque     

Scotland's First Minister Nicola Sturgeon, reacts during a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, speaks during a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, writes during a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, reads during a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, attends a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, attends a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Scotland's First Minister Nicola Sturgeon, attends a COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Deputy First Minister John Swinney, arrives ahead of Topical Questions and the COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland, Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Deputy First Minister John Swinney, arrives ahead of Topical Questions and the COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland, Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

Deputy First Minister John Swinney, arrives ahead of Topical Questions and the COVID-19 briefing at the Scottish Parliament in Holyrood, Edinburgh, Scotland, Britain March 2, 2021. Jane Barlow/PA Wire/Pool via REUTERS

U.S. State Department Spokesman Ned Price takes questions during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price faces reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price addresses reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

U.S. State Department Spokesman Ned Price speaks to reporters during a news briefing at the State Department in Washington, U.S., March 1, 2021. REUTERS/Tom Brenner/Pool

Britain's Deputy Chief Medical Officer for England Jonathan Van-Tam speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Public Health England's Dr. Susan Hopkins speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock reacts during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock reacts during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock gestures as he speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock speaks during the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS

Britain's Health Secretary Matt Hancock holds the daily news briefing on the current COVID-19 situation, from Downing Street in London, Britain March 1, 2021. Ian Vogler/Pool via REUTERS