Doctors Ines Veselinovic and Suzana Stojanovic stand at the intensive care unit of the Clinical Hospital Center, where they treat patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Doctors Ines Veselinovic and Suzana Stojanovic stand at the intensive care unit of the Clinical Hospital Center, where they treat patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

A medical worker looks a a tablet at the intensive care unit of the Clinical Hospital Center, where she treats patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers place a placard reading "The clinic of smiling people" at the intensive care unit of the Clinical Hospital Center, where they treat patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Patients suffering from the coronavirus disease (COVID-19) are seen at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers treat a patient suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers treat patients suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

A medical worker treats a patient suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

A patient suffering from the coronavirus disease (COVID-19) is seen at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

A medical worker treats a patient suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers treat patients suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

A medical worker treats a patient suffering from the coronavirus disease (COVID-19) at the intensive care unit of the Clinical Hospital Center in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers stand at the intensive care unit of the Clinical Hospital Center, where they treat patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Medical workers stand at the intensive care unit of the Clinical Hospital Center, where they treat patients suffering from the coronavirus disease (COVID-19), in Nis, Serbia, March 3, 2021. REUTERS/Marko Djurica

Intensivist Kostis Pontikis and medical workers move a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 1, 2021. Picture taken March 1, 2021. REUTERS/Giorgos Moutafis

Intensivist Iliana Ioannidou is reflected on a monitor at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, February 28, 2021. Picture taken February 28, 2021. REUTERS/Giorgos Moutafis

Intensivists Kostis Pontikis and Iliana Ioannidou at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 1, 2021. Picture taken March 1, 2021. REUTERS/Giorgos Moutafis

A pulse oximeter is placed on the hand of a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the COVID-19 pandemic, in Athens, Greece, March 1, 2021. Picture taken March 1, 2021. REUTERS/Giorgos Moutafis

Speech specialist Vasia Kostakou removes her medical scrubs as she exits the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

Anesthesiologist-intensivist Vasso Hantziara and her colleagues perform a tracheostomy on a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

Anesthesiologist-intensivist Vasso Hantziara and her colleagues perform a tracheostomy on a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

Anesthesiologist-intensivist Vasso Hantziara and her colleagues perform a tracheostomy on a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

A nurse prepares for the transport of a patient who died from the coronavirus disease (COVID-19) at the intensive care unit (ICU) of the Sotiria hospital, amid the COVID-19 pandemic, in Athens, Greece, March 1, 2021. Picture taken March 1, 2021. REUTERS/Giorgos Moutafis

Anesthesiologist-intensivist Vasso Hantziara looks at a colleague during a tracheostomy on a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

A member of the medical staff treats a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, March 3, 2021. REUTERS/Giorgos Moutafis

A statue of "The Lorax" from a book by Theodor Seuss Geisel (Dr. Seuss) stands in the Dr. Seuss National Memorial Sculpture Garden, after the company set up to preserve the deceased author's legacy announced that six of his children's books will no longer be published because they contain racist and insensitive imagery, in his birthplace of Springfield, Massachusetts, U.S., March 2, 2021. The sign with the sculpture carries the quote "Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not." REUTERS/Brian Snyder

A health care worker prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19), during mass vaccination for elderly people at Indonesia's health ministry in Jakarta, Indonesia, March 2, 2021. REUTERS/Ajeng Dinar Ulfiana

A health care worker prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19), during mass vaccination for elderly people at Indonesia's health ministry in Jakarta, Indonesia, March 2, 2021. REUTERS/Ajeng Dinar Ulfiana

Students get playtime at a primary school, as schools reopen amid the coronavirus disease (COVID-19) outbreak, in Santiago, Chile, March 1, 2021. The sign reads 'Back to school. We all take care'. REUTERS/Ivan Alvarado

Health care worker prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19), during a mass vaccination program for vendors and workers at a shopping mall in Tangerang, on the outskirts of Jakarta, Indonesia, March 1, 2021. REUTERS/Ajeng Dinar Ulfiana

Rosamund Pike, winner of Best Actress - Motion Picture - Musical/Comedy award for "I Care a Lot," smiles via video, in this handout screen grab from the 78th Annual Golden Globe Awards in Beverly Hills, California, U.S., February 28, 2021. NBC Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. NO RESALES. NO ARCHIVES.

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a healthcare centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker has the temperature checked by a medical staff before receiving the AstraZeneca COVID-19 vaccine at a health care centre, as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A nursing home worker receives the AstraZeneca COVID-19 vaccine at a health care centre as South Korea starts a vaccination campaign against the coronavirus disease (COVID-19), in Seoul, South Korea February 26, 2021. REUTERS/Heo Ran

A medical staff (R) checks a nursing home worker after receiving the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

Nursing home workers take a seat after receiving the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

Nursing home workers (R) wait to receive the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

Nursing home workers wait to receive the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nurse fills a syringe with the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nurse fills a syringe with the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nurse fills a syringe with the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nursing home worker (L) receives the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nursing home worker (L) receives the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nursing home worker (L) receives the first dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nurse prepares to administer a dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

A nurse prepares to administer a dose of the AstraZeneca Covid-19 vaccine at a health care centre in Seoul on February 26, 2021, as South Korea starts coronavirus vaccination campaign. Jung Yeon-je/Pool via REUTERS

French Health Minister Olivier Veran and French Junior Minister of Autonomy Brigitte Bourguignon visit the coronavirus disease (COVID-19) emergency and intensive care units of the Hospital Centre in Dunkirk, February 24, 2021. Denis Charlet/Pool via REUTERS

French Health Minister Olivier Veran and French Junior Minister of Autonomy Brigitte Bourguignon visit the coronavirus disease (COVID-19) emergency and intensive care units of the Hospital Centre in Dunkirk, February 24, 2021. Denis Charlet/Pool via REUTERS

French Health Minister Olivier Veran and French Junior Minister of Autonomy Brigitte Bourguignon visit the coronavirus disease (COVID-19) emergency and intensive care units of the Hospital Centre in Dunkirk, February 24, 2021. Denis Charlet/Pool via REUTERS

French Health Minister Olivier Veran and French Junior Minister of Autonomy Brigitte Bourguignon visit the coronavirus disease (COVID-19) emergency and intensive care units of the Hospital Centre in Dunkirk, February 24, 2021. Denis Charlet/Pool via REUTERS

Members of the medical staff move a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, February 24, 2021. REUTERS/Giorgos Moutafis

French Health Minister Olivier Veran and French Junior Minister of Autonomy Brigitte Bourguignon visit the coronavirus disease (COVID-19) emergency and intensive care units of the Hospital Centre in Dunkirk, February 24, 2021. Denis Charlet/Pool via REUTERS

Medical staff work at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, February 24, 2021. REUTERS/Giorgos Moutafis

A nurse treats a patient at the intensive care unit (ICU) of the Sotiria hospital, amid the coronavirus disease (COVID-19) pandemic, in Athens, Greece, February 24, 2021. REUTERS/Giorgos Moutafis