A woman reacts as she gets vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar TPX IMAGES OF THE DAY

Jeet Lal Maharjan, 91, reacts as he gets vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

Nani Maya Maharjan, 89, reacts as she gets vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

Nani Maya Maharjan, 89, is assisted after getting vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

Nani Maya Maharjan, 89, returns as her husband Jeet Lal Maharjan, 91, sits on a bench after getting vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

Jeet Lal Maharjan, 91, sits in an ambulance as he returns home along with his wife Nani Maya Maharjan, 89, (not pictured) after getting vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

People wait to register themselves to get vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

A woman reacts as she gets vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

Men sit at a resting area after getting vaccinated against the coronavirus disease (COVID-19) as the government started a campaign to vaccinate elderly people above 65 years old, in Lalitpur, Nepal March 7, 2021. REUTERS/Navesh Chitrakar

A health worker applies the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to Rosi Moraes de Barros, an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

A health worker prepares to administer the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

A health worker administers the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to Francisca Evaristo Maciel, an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

A health worker prepares to administer the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to Antonio Andrade dos Santos, an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

Health workers leaves a home after applying the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

A health worker prepares to administer the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to Antonio Andrade dos Santos, an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

Health workers leaves a home after applying the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine on an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

A healthcare worker prepares to administer to Paulino Ramalho, an elderly citizen, the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

Health workers leave a home after applying the second dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine to an elderly citizen, at Tatuquara neighborhood in Curitiba, Brazil March 5, 2021. REUTERS/Rodolfo Buhrer

An elderly man reacts after receiving the first dose of Sinovac's CoronaVac coronavirus disease (COVID-19) vaccine for senior citizens, in Duque de Caxias, Rio de Janeiro state, Brazil March 5, 2021. REUTERS/Pilar Olivares

A man wearing a protective mask receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A healthcare worker wearing a protective mask and a face shield prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A woman wearing a protective mask reacts as she receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A man wearing a protective mask receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A healthcare worker prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A health care worker wearing a protective mask and a face shield prepares a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A person wearing a protective mask sits inside a car during a medical screening before receiving a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A man wearing a protective mask receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

A man wearing a protective mask receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

Healthcare workers serve people queuing up in their vehicles to receive a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 5, 2021. REUTERS/Willy Kurniawan

Christian Estrosi, Mayor of Nice, wearing a protective face mask, is seen during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

A medical worker performs a COVID-19 saliva test at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/Eric Gaillard

A medical worker administers a COVID-19 saliva test to a resident at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/ Eric Gaillard

A medical worker administers a COVID-19 saliva test to a resident at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/ Eric Gaillard

A medical worker administers a COVID-19 saliva test to a resident at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/ Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective face mask, is seen during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Professor Charles-Hugo Marquette adjusts his protective face mask during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Professor Charles-Hugo Marquette and Christian Estrosi, Mayor of Nice, wearing protective face masks, talk to journalists during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective suit and a face mask, talks to residents during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective face mask, talks to journalists during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective face mask, talks to journalists during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

A medical worker performs a COVID-19 saliva test at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective suit and a face mask, talks to a resident and a medical worker during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

Christian Estrosi, Mayor of Nice, wearing a protective suit and a face mask, talks to residents during a visit as part of the COVID-19 saliva testing at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, amid the coronavirus disease (COVID-19) outbreak in France, March 4, 2021. REUTERS/Eric Gaillard

A medical worker performs a COVID-19 saliva test at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/ Eric Gaillard

A medical worker administers a COVID-19 saliva test to a resident at the Valrose retirement home (Ehpad - Housing Establishment for Dependent Elderly People) in Nice, as part of the coronavirus disease (COVID-19) testing campaign in France, March 4, 2021. REUTERS/ Eric Gaillard

Doctor Carlos Herrera leaves the house of an elderly woman after administering the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) to her, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Nurse Aracelli Lara administers the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) to an elderly woman inside her room, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

An elderly woman is checked before receiving the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) at her home, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Pictutre taken March 3, 2021. REUTERS/Ivan Alvarado

An elderly woman is checked after receiving the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) at her home, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

An elderly woman receives the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) at her home, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 4, 2021. REUTERS/Ivan Alvarado

Nurse Aracelli Lara puts on her gloves as she prepares to apply the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) to an elderly woman at her home, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

A healthcare worker prepares to administer the second dose of China's SINOVAC vaccine against the coronavirus disease (COVID-19) to an elderly woman at her room, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Nurse Aracelli Lara prepares the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) inside the room of an elderly woman, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Nurse Aracelli Lara prepares the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19), as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Nurse Aracelli Lara checks her stuff as she holds an ID reading 'I get vaccined' while applying the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19), as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Doctor Carlos Herrera prepares to check an elderly woman inside her room after receiving the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19), at her home, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 3, 2021. Picture taken March 3, 2021. REUTERS/Ivan Alvarado

Doctor Carlos Herrera prepares to administer the second dose of the China's SINOVAC vaccine against the coronavirus disease (COVID-19) to an elderly woman, as Chile starts applying the second dose of the COVID-19 vaccine to its elderly citizens, in Santiago, Chile March 4, 2021. REUTERS/Ivan Alvarado

A woman wearing a protective mask and a face shield receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 4, 2021. REUTERS/Willy Kurniawan

A woman wearing a protective mask and a face shield receives a dose of China's Sinovac Biotech vaccine for the coronavirus disease (COVID-19) at a drive-thru vaccination station, during the mass vaccination program for elderly people, in Jakarta, Indonesia, March 4, 2021. REUTERS/Willy Kurniawan

Elderly residents line up during early morning to receive the Sputnik V coronavirus disease (COVID-19) vaccine in Xochimilco on the outskirts of Mexico City, Mexico March 3, 2021. REUTERS/Edgard Garrido TPX IMAGES OF THE DAY