FILE - In this May 2, 2021, patrons at a sidewalk cafe are seated without masks in Boston. COVID-19 deaths in the U.S. have tumbled to an average of just over 600 per day — the lowest level in 10 months — with the number of lives lost dropping to single digits in well over half the states and hitting zero on some days. (AP Photo/Steven Senne, File)

A man waits after receiving the Pfizer vaccine, during a COVID-19 vaccination campaign, in Pamplona, northern Spain, Tuesday, May 11, 2021. (AP Photo/Alvaro Barrientos)

FILE - In this May 2, 2021, file photo, pedestrians walk along Boston's fashionable Newbury Street. COVID-19 deaths in the U.S. have tumbled to an average of just over 600 per day — the lowest level in 10 months — with the number of lives lost dropping to single digits in well over half the states and hitting zero on some days. (AP Photo/Steven Senne, File)

FILE - In this Friday, April 9, 2021 filer photo, medical staff members administer shots of Russia's Sputnik V vaccine for COVID-19, at the San Marino State Hospital, in San Marino. The tiny Republic of San Marino on Wednesday announced a plan to offer vaccines to tourists, on the heels of its successful vaccination campaign with the Russian Sputnik V. Under the plan, tourists can get vaccinated as long as they reserve two stays of at least three nights, with the second coming three to four weeks after the first for the second jab. The program launches on Monday. (AP Photo/Antonio Calanni, File)

A man wearing a face mask to prevent the spread of the coronavirus walks past a huge poster on a street in Hong Kong, Wednesday, May 12, 2021. (AP Photo/Vincent Yu)

Bodies of people who died of COVID-19 are cremated at an open crematorium on the outskirts of Bengaluru, Karnataka state, India, Wednesday, May 12, 2021. (AP Photo/Aijaz Rahi)

Jacob Conary, 15, listens to advice from a medical assistant after receiving his first shot of the COVID-19 vaccination, Wednesday, May 12, 2021, in Auburn, Maine. Vaccination clinics in Maine recently opened up to 12 to 15-year-olds. (AP Photo/Robert F. Bukaty)

Middle school student Meredith Rogers, center, waits to receive her first coronavirus vaccination on Wednesday, May 12, 2021, in Decatur, Ga. Hundreds of children, ages 12 to 15, received the Pfizer vaccine at the DeKalb Pediatric Center, just days after it was approved for use within their age group. (AP Photo/Ron Harris)

Middle school student Meredith Rogers, left, waits outside the DeKalb Pediatric Center after receiving her first coronavirus vaccination on Wednesday, May 12, 2021, in Decatur, Ga. Hundreds of children, ages 12 to 15, received the Pfizer vaccine at the center, just days after it was approved for use within their age group. (AP Photo/Ron Harris)

Motorists queue up to cross Suramadu Bridge connecting Java and Madura Island, as they head to their home villages to celebrate Eid al-Fitr holiday that marks the end of Ramadan, in Surabaya, East Java, Indonesia, Wednesday, May 12, 2021. The mass exodus out of major cities in the world's most populous Muslim country is underway despite travel prohibition imposed by the government ahead of the holiday to prevent spikes in COVID-19 cases. (AP Photo/Trisnadi)

Nouf Albarakati, left, of Narberth Pa., comforts her son Manaf Albarakati, 14, before he receives a Pfizer COVID-19 vaccination from registered nurse Alicia Jimenez at a Montgomery County, Pa. Office of Public Health vaccination clinic at the King of Prussia Mall, Tuesday, May 11, 2021, in King of Prussia, Pa. (AP Photo/Matt Slocum)

FILE - In this March 30, 2021, file photo, second grader Ernesto Beltran Pastrana puts on his face mask while attending class during the first day of partial in-person instruction at Garfield Elementary School in Oakland, Calif. Dozens of school districts around the country have eliminated requirements for students to wear masks, and many more are likely to ditch mask requirements before the next academic year. (Jessica Christian/San Francisco Chronicle via AP, File)