A Chinese national flag flutters among Sinopharm's and China National Biotec Group (CNBG) flags, during a government-organised visit to the production line of COVID-19 vaccine by Beijing Institute of Biological Products of Sinopharm's CNBG, in Beijing, China February 26, 2021. REUTERS/Tingshu Wang

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is transported on the tarmac after being unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A LATAM Airlines plane carrying a shipment of the Sinovac coronavirus disease (COVID-19) vaccine arrives at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is transported on the tarmac after being unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is transported on the tarmac after being unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif REFILE - QUALITY REPEAT

A shipment of the Sinovac coronavirus disease (COVID-19) vaccine, bearing the Uruguay flag, is unloaded from a LATAM Airlines plane after its arrival at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif REFILE - QUALITY REPEAT

A LATAM Airlines plane carrying a shipment of the Sinovac coronavirus disease (COVID-19) vaccine arrives at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A LATAM Airlines plane carrying a shipment of the Sinovac coronavirus disease (COVID-19) vaccine arrives at Carrasco Airport in Montevideo, Uruguay February 25, 2021. REUTERS/Mariana Greif

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an Aerolineas Argentinas plane after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

Aircrew walk on the tarmac as they disembark from an Aerolineas Argentinas plane arriving with a shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arrives from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

Argentina's Health Minister Carla Vizzotti (R) and Chief of cabinet Santiago Cafiero (L) witness a shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

Argentina's Health Minister Carla Vizzotti watches as a shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arrives from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine is unloaded from an aircraft after arriving from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

Argentina's Health Minister Carla Vizzotti (C), Chief of cabinet Santiago Cafiero (R), and China's Ambassador to Argentina Zou Xiaoli (L) watch as a shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arrives from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

Argentina's Health Minister Carla Vizzotti (C), Chief of cabinet Santiago Cafiero (R), and China's Ambassador to Argentina Zou Xiaoli (L) watch as a shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arrives from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian

A shipment of 900,000 doses of Sinovac coronavirus disease (COVID-19) vaccine arrives from China at Ezeiza International Airport, in Buenos Aires, Argentina, February 25, 2021. REUTERS/Agustin Marcarian REFILE - QUALITY REPEAT

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

State Council Information Office spokesman Chen Wenjun, Chinese Commerce Minister Wang Wentao, Vice Commerce Minister Wang Shouwen and Vice Commerce Minister Qian Keming attend a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao and Vice Commerce Minister Wang Shouwen attend a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

State Council Information Office spokesman Chen Wenjun, Chinese Commerce Minister Wang Wentao, Vice Commerce Minister Wang Shouwen and Vice Commerce Minister Qian Keming attend a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao attends a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

Chinese Commerce Minister Wang Wentao speaks during a State Council Information Office news conference in Beijing, China February 24, 2021. REUTERS/Carlos Garcia Rawlins

A sign is pictured in a Chinese restaurant amid the outbreak of the coronavirus disease (COVID-19), in Buckingham, Britain, February 23, 2021. REUTERS/Andrew Boyers

Chinese State Councilor and Foreign Minister Wang Yi delivers a speech at the Lanting Forum in Beijing, China February 22, 2021. REUTERS/Shubing Wang

Chinese State Councilor and Foreign Minister Wang Yi delivers a speech at the Lanting Forum on China-U.S. relations in Beijing, China February 22, 2021. REUTERS/Gabriel Crossley

Chinese State Councilor and Foreign Minister Wang Yi delivers a speech at the Lanting Forum in Beijing, China February 22, 2021. REUTERS/Shubing Wang

Chinese State Councilor and Foreign Minister Wang Yi delivers a speech at the Lanting Forum in Beijing, China February 22, 2021. REUTERS/Shubing Wang

Chinese State Councilor and Foreign Minister Wang Yi delivers a speech at the Lanting Forum in Beijing, China February 22, 2021. REUTERS/Shubing Wang

Residential buildings can be seen in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A woman wearing a protective mask to prevent the spread of the coronavirus disease (COVID-19) waits for customers at a market in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A metro is seen above highways in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A construction site is seen at sunset hours in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A construction site in seen during sunset in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A woman wearing a protective mask to prevent the spread of the coronavirus disease (COVID-19) walks in the streets in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A woman wearing a protective mask to prevent the spread of the coronavirus disease (COVID-19) shops at a market in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A man works at a construction site of residential buildings in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

Three women wearing protective masks to prevent the spread of the coronavirus disease (COVID-19) make dumplings in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

A man works at a construction site of residential buildings in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang

General view of a construction site in Taipei, Taiwan, February 19, 2021. REUTERS/Ann Wang