Nurses and health care workers across the country are finding strength in numbers and with labor actions not seen in years.

In California, which has a strong union tradition, Kaiser Permanente management misjudged workplace tensions during the COVID-19 crisis and risked a walkout of thousands when union nurses balked at signing a four-year contract that would have slashed pay for new hires. In Colorado, Pennsylvania, North Carolina and Massachusetts, nurses have been embroiled in union battles over staffing and work conditions.

As deadly coronavirus cases spiked this year, daily pressures intensified on hospital floors. Some nurses retired; some became travel nurses, hired by agencies that advertised more than double, even triple, the day rates for intensive care unit, telemetry and emergency room nurses. Others gave up their jobs to avoid possibly carrying the COVID virus home to their families.

“Things had gotten particularly stark for nurses,” said Rebecca Kolins Givan, an associate professor of labor studies at Rutgers University.

It was so grim in Pittsburgh that registered nurses at West Penn Hospital, part of the Allegheny Health Network, voted this year to authorize a strike — less than a year after they unionized with SEIU Healthcare Pennsylvania. Chief among their complaints: The hospital system had balked at improving staff ratios even as it offered bonuses, up to $15,000 for some, to hire registered nurses to fill vacancies.

Kathleen Jae, a member of the bargaining team that reached a pact without a work stoppage, said nurses wanted management to work harder to retain veteran staff members.

Allegheny Health Network said the first-ever pact with RNs at West Penn provides “competitive wages and benefits” to help it “recruit and retain talented, experienced nurses.”

Liz Soriano-Clark, a teacher-turned-nurse on the bargaining team, said the pandemic had made workers across the health sector more careful and choosier about what jobs they’ll take.

“There’s a nursing shortage and a shortage of nursing instructors, nationwide. They’ve seen aides leave. They’ve seen cleaners leave,” Soriano-Clark said. “Why is that? Because they can make more at McDonald’s and not have to clean up vomit.”

In September, the American Nurses Association alerted the Biden administration to an “unsustainable nurse staffing shortage facing our country” in a letter to the Department of Health and Human Services. The ANA said a “crisis-level human resource shortage” was evident: Mississippi had 2,000 fewer nurses than it did at the beginning of 2021. Tennessee called on its National Guard to reinforce hospital staffs. Texas was recruiting 2,500 nurses from outside the state.

Union membership among U.S. nurses has inched up over the past 15 years and held steady, at about 17%, for five years, according to unionstats.com, an academic website. But 2021, a year of union organizing and holdouts in such disparate workplaces as Starbucks cafes and John Deere tractor plants, might well be a turning point for essential workers in health care.

“If you ask nurses what they want,” said Givan, who interviewed dozens of nurses for a 2016 book on health care workers, “they want working conditions where they can provide a high level of care. They don’t want appreciation that is lip service. They don’t want marketing campaigns. They don’t want shiny new buildings.”

A recent poll by Gallup, the global analytics firm, found that the share of Americans who say they approved of unions was at 68%, its highest point since 1965.

Sal Rosselli, president of the National Union of Healthcare Workers, said that in the past year “there has just been an explosion of leads,” queries from health workers exploring how to unionize.

Rosselli, whose organization represents about 15,000 health workers, said the pandemic exposed practices that had long antagonized employees.