Buoyed by a surge in vaccine shipments, states and cities are rapidly expanding eligibility for COVID-19 shots to teachers, Americans 50 and over and others as the U.S. races to beat back the virus and reopen businesses and schools.

Indiana and Michigan will begin vaccinating those 50 and over, while Arizona and Connecticut have thrown open the line to those who are at least 55. Pennsylvania and Wisconsin are reserving the first doses of the new one-shot vaccine from Johnson & Johnson for teachers. And in Detroit, factory workers can get vaccinated starting this week, regardless of age.

Giving the vaccine to teachers and other school staff “will help protect our communities,” Pennsylvania Gov. Tom Wolf said. “It’s going to take burdens off our parents and families. It’s going to make our schools get back to the business of teaching our kids.”

Until now, the vaccination campaign against the outbreak that’s killed over a half-million Americans has concentrated mostly on health workers and senior citizens.

Around the U.S., politicians and school administrators have been pushing hard in recent weeks to reopen classrooms to stop students from falling behind and enable more parents to go back to work. But teachers have resisted returning without getting vaccinated.

The Department of Health and Human Services has ordered all states to make teachers, school staff, bus drivers and child care workers eligible for shots. That’s a major shift for the Biden administration, which controls access to COVID-19 vaccines but previously allowed states to set their own guidelines.

Jody Mackey, 46, a middle-school digital media and history teacher in Traverse City, Michigan — where students have attended mostly in-person since September — received her second dose nearly two weeks ago after teachers in her district were designated essential workers.

Before that, she kept her classroom windows open and used space heaters.

“If you want schools to be successful and safe and you want your teachers to have their heads in the game, get them the vaccination,” she said. “Putting teachers in a situation where they feel scared all the time, where they’re going to want to avoid their kids, how is that good for kids or teachers?”

Arizona Gov. Doug Ducey on Wednesday ordered students and teachers to return to school this month, saying many teachers have already received their second dose.

“The science is clear: It’s time all kids have the option to return to school so they can get back on track and we can close the achievement gap,” Ducey said in a statement.

The U.S. has administered over 80 million shots in a vaccination drive now hitting its stride, according to the Centers for Disease Control and Prevention. More than 20% of the nation’s adults, or close to 52 million people, have received at least one dose, and 10% have been fully inoculated.

President Joe Biden said Tuesday that the U.S. expects to have enough vaccine by the end of May for all adults — two months earlier than anticipated — though it is likely to take longer than that to administer those shots. He also pushed states to give at least one shot to teachers by month’s end and said the government will provide the doses through its pharmacy program.

In Wisconsin, teachers will get priority when the state receives its first shipment of about 48,000 doses of the J&J vaccine, health authorities said. Pennsylvania teachers will likewise be first in line when an expected 94,000 doses of that formula arrive this week.

Washington Gov. Jay Inslee announced this week that educators, school staff and child care workers can now get shots. In Texas, where teachers have been battling to gain access to shots, state officials on Wednesday ordered vaccine providers to begin administering shots to school workers.

And in Massachusetts, about 400,000 teachers, child care workers and school staff can register for vaccinations starting March 11, Gov. Charlie Baker said, though he warned it could take time to book appointments because supplies remain limited.

Tennessee will open vaccinations Monday to an estimated 1 million people over 16 who have high-risk health conditions and those in households with medically fragile children.

The rush to vaccinate comes as many states ease restrictions on people and businesses, despite repeated warnings from health officials that the U.S. is risking another lethal wave. Biden called out the Republican governors of Texas and Mississippi for lifting mask rules.

“We are on the cusp of being able to fundamentally change the nature of this disease,” the president said Wednesday. “The last thing we need is Neanderthal thinking that in the meantime, everything’s fine, take off your mask, forget it. It still matters.”

Mississippi Gov. Tate Reeves snapped back on Twitter. “Mississippians don’t need handlers. As numbers drop, they can assess their choices and listen to experts,” he said. “I guess I just think we should trust Americans, not insult them.”

While deaths and newly confirmed infections have plummeted from their peaks in January, they’re still running at high levels. The U.S. is averaging close to 2,000 deaths and 66,000 cases per day.

CDC Director Dr. Rochelle Walensky encouraged Americans to “do the right thing” even if states lift their restrictions.

Vaccinations are seen as key to getting people back to work and revitalizing the battered economy.

“The more people we can get the safe and effective vaccine, the faster we can return to a sense of normalcy,” Michigan Gov. Gretchen Whitmer said in a statement Wednesday announcing that people 50 to 64 can start getting vaccinations March 22.

Cindy Estrada, a vice president at the United Auto Workers, said there have been illnesses and deaths among factory workers, so Detroit’s decision to offer them shots “is incredibly important.”

“It’s going to give them some peace of mind,” she said, baring her arm for a shot.