U.S. Senators Joe Manchin (D-WV) and Maggie Hassan (D-NH) talk as they walk to the Senate floor during a vote at the U.S. Capitol in Washington, U.S., October 26, 2021. REUTERS/Elizabeth Frantz

U.S. Senators Joe Manchin (D-WV) and Maggie Hassan (D-NH) talk as they walk to the Senate floor during a vote at the U.S. Capitol in Washington, U.S., October 26, 2021. REUTERS/Elizabeth Frantz

U.S. Senators Joe Manchin (D-WV) and Maggie Hassan (D-NH) talk as they walk to the Senate floor during a vote at the U.S. Capitol in Washington, U.S., October 26, 2021. REUTERS/Elizabeth Frantz

U.S. Representative Chris Pappas (D-NH) arrives to the U.S. Capitol in Washington, U.S., October 21, 2021. REUTERS/Elizabeth Frantz

A person walks past an NHS COVID-19 vaccination health campaign advertisement, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

An NHS COVID-19 vaccination health campaign advertisement is displayed near a housing block, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

An NHS COVID-19 vaccination health campaign advertisement is displayed near a housing block, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

An NHS COVID-19 vaccination health campaign advertisement is displayed, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

An NHS COVID-19 vaccination health campaign advertisement is displayed near a housing block, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

A man walks past a NHS COVID-19 vaccination health campaign advertisement, amidst the spread of the coronavirus disease (COVID-19), in London, Britain, October 21, 2021. REUTERS/Toby Melville

Stephen Powis, NHS England National Medical Director looks on during a press conference held in Downing Street, London, Britain, October 20, 2021. REUTERS/Toby Melville/Pool

Britain's Health Secretary Sajid Javid listens as Stephen Powis, NHS England National Medical Director speaks during a press conference held in Downing Street, London, Britain, October 20, 2021. REUTERS/Toby Melville/Pool

Britain's Health Secretary Sajid Javid speaks next to Stephen Powis, NHS England National Medical Director and UK Health Security Agency Chief Executive, Dr Jenny Harries during a press conference held in Downing Street, London, Britain, October 20, 2021. REUTERS/Toby Melville/Pool

Britain's Health Secretary Sajid Javid speaks next to Stephen Powis, NHS England National Medical Director and UK Health Security Agency Chief Executive, Dr Jenny Harries during a press conference held in Downing Street, London, Britain, October 20, 2021. REUTERS/Toby Melville/Pool

Dr Mridul Kumar and Dr Saroj Datta win the joint Oldie NHS Angels of the Year award during the Oldie Of The Year Awards 2021 at The Savoy Hotel in London, Britain, October 19, 2021. Chris Jackson/Pool via REUTERS

Britain's Camilla, Duchess of Cornwall, presents Dr Saroj Datta the joint Oldie NHS Angels of the Year award at the Oldie Of The Year Awards 2021 at The Savoy Hotel in London, Britain, October 19, 2021. Chris Jackson/Pool via REUTERS

Britain's Camilla, Duchess of Cornwall, presents Dr Mridul Kumar and Dr Saroj Datta with the joint Oldie NHS Angels of the Year award during the Oldie Of The Year Awards 2021 at The Savoy Hotel in London, Britain, October 19, 2021. Chris Jackson/Pool via REUTERS

People walk past a thank you message for the National Health Service (NHS) near the venue where the annual Conservative Party Conference is taking place, in Manchester, Britain, October 5, 2021. REUTERS/Toby Melville

U.S. Senator Jeanne Shaheen (D-NH) listens during a Senate Armed Services Committee hearing on the conclusion of military operations in Afghanistan and plans for future counterterrorism operations, on Capitol Hill in Washington, U.S., September 28, 2021. Sarahbeth Maney/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon and Health Secretary Humza Yousaf visit a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon and Health Secretary Humza Yousaf visit a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon visits a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon and Health Secretary Humza Yousaf visit the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

Scottish First Minister Nicola Sturgeon looks at a mock theatre set up with innovative new medical equipment including robotic surgery devices at the NHS Golden Jubilee in Clydebank, Scotland, Britain August 25, 2021. Jeff J Mitchell/Pool via REUTERS

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

NHS workers prepare doses of the Pfizer BioNTech vaccine behind a drinks bar at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

A person receives a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

People queue to receive a dose of the Pfizer BioNTech vaccine at an NHS vaccination centre hosted at the Heaven nightclub, amid the coronavirus disease (COVID-19) pandemic, in London, Britain, August 8, 2021. REUTERS/Henry Nicholls

U.S. Vice President Kamala Harris, right, walks with Senator Tom Carper, (D-DE) following meetings at the U.S. Capitol in Washington, August 7, 2021. Harris also met Senator Jon Tester (D-MT), Sen. Maggie Hassan (D-NH), Sen. Amy Klobuchar (D-MN). REUTERS/Ken Cedeno

U.S. Rep. Ann McLane Kuster (D-NH) hugs Rep. Veronica Escobar (D-TX) after a hearing of the House Select Committee investigating the Jan. 6 attack on Capitol Hill in Washington, U.S., July 27, 2021. Chip Somodevilla/Pool via REUTERS

U.S. Rep. Ann McLane Kuster (D-NH) (C) and Rep. Veronica Escobar (D-TX) talk to Capitol Police officer Sgt. Aquilino Gonell after he testified before the House Select Committee investigating the Jan. 6 attack on Capitol Hill in Washington, U.S., July 27, 2021. Chip Somodevilla/Pool via REUTERS

A sign hangs on the door of the ''Ye Olde Fighting Cocks'' pub, after members of the staff were contacted by NHS Government Track and Trace App to isolate themselves due to the spread of the coronavirus disease (COVID-19), in St Albans, Britain, July 21, 2021. REUTERS/Paul Childs

General view shows a closed ''Ye Olde Fighting Cocks'' pub, after members of the staff were contacted by NHS Government Track and Trace App to isolate themselves due to the spread of the coronavirus disease (COVID-19), in St Albans, Britain, July 21, 2021. REUTERS/Paul Childs

Britain's Prince William speaks as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Band plays as Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William speaks as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

A band member plays the trumpet as Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William speaks as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William reacts next to Chief Executive of NHS Charities Together Ellie Orton as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William reacts as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William reacts as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William thanks band members as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool

Britain's Prince William walks with Chief Executive of NHS Charities Together Ellie Orton (L) and Chief Executive of NHS England Simon Stevens as he attends a tea party to celebrate the NHS' birthday at Buckingham Palace in London, Britain, July 5, 2021. REUTERS/Henry Nicholls/Pool