A nurse draws up the vaccine of the manufacturer Moderna against the coronavirus with a syringe in a posed situation a the vaccination centre in Bielefeld, Germany, Friday, April 16, 2021. (Friso Gentsch/dpa via AP)

Entertainment workers gather in Piazza del Popolo Square to protest against the Italian government's economic policies to combat the spread of COVID-19 and to demand to reopen their business, in Rome, Saturday, April 17, 2021. (AP Photo/Andrew Medichini)

A healthcare worker, wearing a protective face mask with a message that reads in Spanish: "We demand vaccines now!", attends a march demanding a more equitable and faster distribution of COVID-19 vaccines, in the Los Palos Grandes neighborhood of Caracas, Venezuela, Saturday, April 17, 2021. (AP Photo/Matias Delacroix)

A health worker takes a swab sample to test for COVID-19 in Prayagraj, India, Saturday, April 17, 2021. The global death toll from the coronavirus topped a staggering 3 million people Saturday amid repeated setbacks in the worldwide vaccination campaign and a deepening crisis in places such as Brazil, India and France. (AP Photo/Rajesh Kumar Singh)

People enjoying outdoor restaurants in Chinatown, London Saturday, April 17, 2021. (AP Photo/Rui Vieira)

Prisoners are briefed about the dangers of the coronavirus following their release from Chikurubi prison on the outskirts of Harare, Saturday, April 17, 2021. Zimbabwe began the release of about 3,000 prisoners under a presidential amnesty aimed at easing congestion and minimizing the threat of COVID-19 across the country's overcrowded jails. (AP Photo/Tsvangirayi Mukwazhi)

A man sits down during a protest in the central Puerta del Sol to protect the national health service during and after the pandemic, in Madrid, Spain, Saturday, April 17, 2021. Spanish Prime Minister Pedro Sanchez says he is "very hopeful" that Spain can come up with its own COVID-19 vaccine by the end of the year. (AP Photo/Paul White)

A woman flashes a V sign as police break up a social gathering during an operation against illegal and clandestine gatherings that authorities believe are partly responsible for fueling the spread of COVID-19, at a party hall in Sao Paulo, Brazil, early Saturday, April 17, 2021. (AP Photo/Marcelo Chello)

Entertainment workers gather in Piazza del Popolo Square to protest against the Italian government's economic policies to combat the spread of COVID-19 and to demand to reopen their business, in Rome, Saturday, April 17, 2021. (AP Photo/Andrew Medichini)

A health worker takes a swab sample to test for COVID-19 in Prayagraj, India, Saturday, April 17, 2021. The global death toll from the coronavirus topped a staggering 3 million people Saturday amid repeated setbacks in the worldwide vaccination campaign and a deepening crisis in places such as Brazil, India and France. (AP Photo/Rajesh Kumar Singh)

Residents wearing masks walk in downtown Lake Oswego, Ore., on Sunday, April 11, 2021. Tens of thousands of Oregon residents are angry about a proposal to make permanent an emergency rule that requires masks and social distancing in the state's businesses and schools to prevent the spread of COVID-19. Opponents worry about government overreach and fear that state officials won't remove the mask requirements for businesses even after threat of the virus has receded if the emergency rule becomes permanent. (AP Photo/Gillian Flaccus)