The unions that represent health workers in the country have emerged as increasingly powerful voices during the still raging pandemic.

With more than 100,000 Americans in hospital and many infected in their ranks, nurses and other health workers remain on a precarious front against the coronavirus and have reached out to unions for help.

Nurses from various unions across the country take part in dozens of strikes and protests. National Nurses United, the largest registered nurses union in the country, held a “day of action” on Wednesday with demonstrations in more than a dozen states and in Washington, DC as negotiations began in hospitals, major systems like HCA, Sutter Health and belong to CommonSpirit Health.

“It’s so overwhelming. It’s unlike anything I’ve ever seen before, ”said Erin McIntosh, a nurse at Riverside Community Hospital in Southern California, a part of the country that in some cases has been hit hardest by the surge. “Every day I’m waist-deep in death and dying.”

Hospitals said the unions were playing public health policy during a public health emergency, saying they had no choice but to ask more of their workers.

However, healthcare workers are bitterly disappointed with the response of their employers and government agencies to the pandemic. Lack of staff, inadequate and persistent supplies of protective equipment, limited virus testing and work pressure even when they might be sick have led many workers to turn to the unions as their only ally. The virus has killed more than 3,300 healthcare workers across the country, according to a census.

“We wouldn’t be alive today if we didn’t have a union,” said Elizabeth Lalasz, a nurse and steward at National Nurses United in Chicago.

Despite the decade-long decline of the labor movement and the low number of unionized nurses, labor officials have used the effects of the pandemic to organize new chapters and contract negotiations for better terms and benefits. National Nurses organized seven new negotiating units last year, compared to four in 2019. The Service Employees International Union, which Ms. McIntosh represents, also said interest has increased.