Students wear masks during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Students write during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Students fold paper during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Students listen to a teacher during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Students listen to a teacher during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Students listen to a teacher during a lesson at Heath Mount school as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

A teacher at Heath Mount school holds a lesson outside as schools reopen in England, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Staff at Heath Mount school performs a lateral flow test, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Staff at Heath Mount school performs a lateral flow test, amid the coronavirus disease (COVID-19) pandemic, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Cakes are seen in the school canteen to welcome children back to Heath Mount school, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Cakes are seen in the school canteen to welcome children back to Heath Mount school, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Cakes are seen in the school canteen to welcome children back to Heath Mount school, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Staff at Heath Mount school performs a lateral flow test, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

A welcome back cake station is seen in a school canteen at Heath Mount school, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Staff at Heath Mount school performs a lateral flow test, in Watton at Stone, Hertfordshire, Britain March 8, 2021. REUTERS/Andrew Couldridge

Tampa Fire Rescue paramedic Natalie Allen administers the Pfizer-BioNTech COVID-19 vaccine to a woman at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A woman receives the Pfizer-BioNTech COVID-19 vaccine from a Hillsborough County Fire Rescue paramedic Neil Brown at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area wait to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Tampa Fire Rescue paramedic Natalie Allen administers the Pfizer-BioNTech COVID-19 vaccine to a man at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area wait to receive the Pfizer-BioNTech COVID-19 vaccine held at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Hillsborough County Commissioner Gwen Myers calls names from a roster of members from historic African-American churches in the Tampa Bay Area to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A man arrives to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Hillsborough County Fire Rescue Ken Forward assists a man as he arrives to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A woman receives the Pfizer-BioNTech COVID-19 vaccine from a Hillsborough County Fire Rescue paramedic Neil Brown at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A woman receives the Pfizer-BioNTech COVID-19 vaccine from a Hillsborough County Fire Rescue paramedic at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area prepare to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Tampa Fire Rescue paramedic Angela Farrulla administers the Pfizer-BioNTech COVID-19 vaccine to a man at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A man prepares a dose of a vaccine as vaccinations against the coronavirus disease (COVID-19) are held at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area wait to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A woman receives the Pfizer-BioNTech COVID-19 vaccine from a Hillsborough County Fire Rescue paramedic at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A Florida Department of Health worker prepares a dose of the Pfizer-BioNTech COVID-19 vaccine to be administered at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area wait in line to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A woman waits in line to receive the Pfizer-BioNTech COVID-19 vaccine held at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A Florida Department of Health worker prepares vials of the Pfizer-BioNTech COVID-19 vaccine to be administered at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

A bottle of the Pfizer-BioNTech COVID-19 vaccine is pictured at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Members from historic African-American churches in the Tampa Bay Area wait in line to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

One of the members of historic African-American churches in the Tampa Bay Area prepares to receive the Pfizer-BioNTech COVID-19 vaccine at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

Tampa Fire Rescue paramedic Natalie Allen prepares to administer the Pfizer-BioNTech COVID-19 vaccine to a man at the historic Greater Bethel Missionary Baptist Church in Tampa, Florida, U.S. February 14, 2021. REUTERS/Octavio Jones

People walk by Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People walk by Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People walk by Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People enjoy at Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People enjoy at Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People enjoy at Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

A man skis down Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

Seb Shower carries his snowboard as he walks up Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

People sledge down Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

Seb Shower snowboards down Parliament Hill in Hampstead Heath, during a snowfall in London, Britain, February 9, 2021. REUTERS/Hannah McKay

A sign is seen outside a coronavirus disease (COVID-19) vaccination centre, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

View of a coronavirus disease (COVID-19) vaccine dose, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

Medical staff prepare a coronavirus disease (COVID-19) vaccine dose, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

A man receives the coronavirus disease (COVID-19) vaccine, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

A member of the medical staff works at a coronavirus disease (COVID-19) vaccination centre, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

Medical staff work at a coronavirus disease (COVID-19) vaccination centre, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine

A woman receives the coronavirus disease (COVID-19) vaccine, at the Al-Abbas Islamic Centre, in Balsall Heath, Birmingham, Britain, January 21, 2021. REUTERS/Carl Recine