People with COVID-19 symptoms wait to be assisted outside a hospital that is at full capacity in Ribeirao Preto, Sao Paulo state, Brazil, Friday, May 28, 2021. The city imposed strict shutdown measures this week to stop the spread of the virus, halting public transportation for the first time and closing supermarkets. (AP Photo/Andre Penner)

Medical workers with private clinics wait to get their first dose of the Sinovac COVID-19 vaccine in Caracas, Venezuela, Friday, May 28, 2021. (AP Photo/Matias Delacroix)

A man wearing a protective face mask to help curb the spread of the coronavirus, walks past a painted wall of Ministry of Public Health, which guides social distancing in Kabul, Afghanistan, Saturday, May 29, 2021. (AP Photo/Rahmat Gul)

FILE - In this Jan. 23, 2021 file photo, a woman wearing face mask looks at her phone in Hanoi, Vietnam. Vietnam says it has discovered a new coronavirus variant that’s a hybrid of strains first found in India and the U.K. The Vietnamese health minister made the announcement Saturday, May 29. (AP Photo/Hau Dinh, File)

A health worker takes a swab sample of a woman to test for COVID-19 in Kusehta village north of Prayagraj, India, Saturday, May 29, 2021. (AP Photo/Rajesh Kumar Singh)

FILE - In this May 14, 2021, file photo, passengers from Hanover wait to pick their luggage at Nikos Kazantzakis International Airport in Heraklion, on the island of Crete, Greece. Coronavirus infections, hospitalizations and deaths are plummeting across much of Europe. Vaccination rates are accelerating, and with them, the promise of summer vacations. (AP Photo/Harry Nakos, File)

Body of a COVID-19 victim is prepared for burial at a Christian cemetery in New Delhi, India, Saturday, May 29, 2021. India's death toll is the third-highest reported in the world after the U.S. and Brazil. (AP Photo/Ishant Chauhan)

A vendor wearing a protective mask sells dairy products at the town square during a lockdown imposed to curb the spread of the coronavirus in Dharmsala, India, Saturday, May 29, 2021. (AP Photo/Ashwini Bhatia)

FILE - This Friday April 23, 2021 file photo shows people during a rest and observation period, after receiving COVID-19 vaccinations at the American Museum of Natural History in New York. The latest federal data shows two-thirds of adults in New York have received at least one dose of a COVID-19 vaccine. That's above the national average of 40%. (AP Photo/Richard Drew, File)

A resident gets tested for coronavirus in the Liwan District in Guangzhou in southern China's Guangdong province on Wednesday May 26, 2021. The southern Chinese city of Guangzhou shut down a neighborhood and ordered its residents to stay home Saturday, May 29, for door-to-door coronavirus testing following an upsurge in infections that has rattled authorities.(AP Photo)

A health worker in protective suit takes a nasal swab sample of a man to test for COVID-19 in Kusehta village north of Prayagraj, India, Saturday, May 29, 2021. (AP Photo/Rajesh Kumar Singh)