FILE - In this Feb. 18, 2021, file photo, Clarendon Alternative Elementary School second grader Haruki Ishiyama works on his computer as students and parents attend distance learning Zoom classes at Midtown Terrace Playground in San Francisco. San Francisco Unified School District officials said in a statement that they reached the arrangement with the teachers union to "return as many students as possible in focal groups to nearly a full school day, 5 days a week," the Chronicle reported, Friday, March 5. (AP Photo/Jeff Chiu, File)

Anti-vaccination protesters hold a doll with "I don't want to be a lab rat" written on it backdropped by a Romanian national flag, during a rally outside the parliament building in Bucharest, Romania, Sunday, March 7, 2021. Some thousands of anti-vaccination protestors from across Romania converged outside the parliament building protesting against government pandemic control measures as authorities announced new restrictions amid a rise of COVID-19 infections. (AP Photo/Vadim Ghirda)

Masked with the colors of the national flag, people protest for the resignation of President Mario Abdo Benitez over his handling of the coronavirus pandemic and the state of the public health system, near his official residence in Asuncion, Paraguay, Sunday, March 7, 2021. (AP Photo/Jorge Saenz)

A health worker injects a doctor with a dose of AstraZeneca COVID-19 vaccine at Hospital for Tropical Diseases in Hanoi, Vietnam Monday, March 8, 2021. Vietnam has started the vaccination campaign with a hope to inoculate half of the population of 96 millions against COVID-19 by the end of the year. (AP Photo/Hau Dinh)

FILE - Arkansas Gov. Asa Hutchinson speaks about the coronavirus pandemic and vaccine distributions during a news conference at the state Capitol in Little Rock, Ark., on Tuesday, Jan. 12, 2021. Responding to concerns from state officials, the U.S. Treasury Department said Wednesday, March 17, 2021 that states can cut taxes without penalty under a new federal pandemic relief law — so long as they use their own funds to do so. Gov. Hutchinson said formal guidance from the Treasury Department will be critical in determining how much flexibility exists for states. (AP Photo/Andrew Demillo, file)

Elderly Indians on wheel chairs wait in a queue to receive COVID-19 vaccine in Mumbai, India, Monday, March 8, 2021. (AP Photo/Rafiq Maqbool)

A young man wearing a face mask waits for a train in the central station in Frankfurt, Germany, Sunday, March 21, 2021. On Monday, German politics will discuss further measures to avoid the outspread of the coronavirus. (AP Photo/Michael Probst)

FILE - In this Thursday, Feb. 18, 2021, file photo, Maya Peralta, right, sits with her son, Clarendon Alternative Elementary School second-grader H Suchovsky, as students and parents attend distance learning Zoom classes at Midtown Terrace Playground in San Francisco. School officials plan to reopen classrooms for some of the youngest students beginning April 12 under a tentative deal reached with the teachers union, according to a newspaper report. The agreement was announced late Friday, March 5, 2021, after months of debate over how and when kids would return to in-person instruction as coronavirus cases and hospitalizations decline statewide. (AP Photo/Jeff Chiu, File)

Anti-vaccination protesters rally outside the parliament building in Bucharest, Romania, Sunday, March 7, 2021. Some thousands of anti-vaccination protestors from across Romania converged outside the parliament building protesting against government pandemic control measures as authorities announced new restrictions amid a rise of COVID-19 infections. (AP Photo/Vadim Ghirda)

Indians are administered Covishield COVID-19 vaccine in Mumbai, India, Monday, March 8, 2021. (AP Photo/Rafiq Maqbool)