“I think you have to look at the entire environment,” she noted at the Fortune Most Powerful Women Summit, referencing recent strikes by the United Auto Workers and Kaiser employees. “There’s just a lot of unrest in health care.”

Pharmacists in at least a dozen Kansas City–area CVS pharmacies walked out or didn’t show up for work for three days in late September, citing stressful and unsafe working conditions. In response, the company sent its chief pharmacy officer to the area with promises to fill open positions and increase staffing levels.

It was just one of the latest examples nationwide of workers fed up and taking action. But unlike employees in recent strikes at automakers or in Hollywood, the pharmacists weren’t demanding raises or more vacation—they simply wanted more colleagues to help them.

CVS rival Walgreens is also experiencing pharmacy staff walkouts, which began Monday and were planned to last through Wednesday. Increasing demands, like administering COVID vaccines, with insufficient staff is making it impossible to do their jobs and could put customer safety in jeopardy, employees told CNN.

This fall, drugstores are facing more challenges than usual. Customers not only expect to fill prescriptions, but to potentially receive COVID-19, flu, and pneumonia vaccines, in addition to a new RSV shot for those 60 and older. 

The federal government is no longer offering free COVID jabs for everyone, meaning insurance will have to be run for many customers receiving one. And ongoing drug shortages are keeping pharmacy workers on the phone for longer than usual.

Unexpected demand for new COVID boosters?

Making matters more difficult, CVS pharmacies are experiencing “the same level of demand that we were in 2021” for COVID shots, Lynch said Monday at the Fortune conference, held in Laguna Niguel, Calif. Coronavirus vaccines became widely available to the public for the first time that year.

“Some days we’re doing more per day than we were back then,” she said. “There’s been incredible demand.”

When asked for details on booster uptake Tuesday, CVS declined to provide additional information. So did Kroger, which said it wasn’t yet ready to release numbers. Fortune reached out to other major pharmacy chains, which did not immediately respond.

The U.S. Centers for Disease Control and Prevention also did not respond to Fortune’s inquiry Tuesday about uptake rates for the new boosters, tailored to the XBB.1.5 strain of Omicron that dominated the world late last year into early 2023. The agency stopped publishing vaccine uptake data online in May, when the U.S. COVID public health emergency ended.

But uptake for the new boosters was predicted to be low—perhaps even worse than last year, with both the federal and global health emergencies officially over. Only 17% of U.S. residents received the bivalent booster tailored to Omicron, which became widely available last year just after Labor Day.

Pfizer expects less than a quarter of the U.S. population—just 24%—will receive a COVID shot this year, chief financial officer David Denton said at a conference last month, Reuters recently reported.

Polling by Kaiser Family Foundation, a nonpartisan group that performs health policy research and polling, led to similar predictions. Nearly a quarter of Americans will “definitely” get the new COVID booster, while an additional quarter will “probably” get it, according to a telephone poll of a nationally representative sample of nearly 1,300 U.S. adults last month.

The Associated Press contributed to this report.