Federal employees working on mental health services, disease outbreaks, and disaster preparedness were among those hardest hit by the Trump administration's mass firings over the weekend.

In Atlanta, the situation turned confusing when hundreds of Centers for Disease Control and Prevention employees who had received layoff notices learned that they had been sent in error.

Of more than 1,300 CDC employees who received reduction-in-force notices Friday, about 700 later received emails revoking their terminations, union officials said. 

A Department of Health and Human Services spokesperson told CBS News that some of the RIF notices sent to CDC employees were due to a coding error.

An uncertain future for CDC employees

CDC employee Aryn Backus said she has been laid off three times in 2025 and is not sure she'll ever return to the agency. 

"I was/am a health communications specialist in the Office of Smoking and Health at the CDC," she said.

In February, Backus said she logged into her work email and found that she had been terminated.

"They said for poor performance, which is not true. I had a stellar performance review and had just been promoted," she said.

The second time she was let go was on April 1. In that case, her entire office had received notices.

The most recent email reached her on Friday.

"Saying that we would be terminated in the reduction in force, and that one was actually rescinded 24 hours later, but that doesn't mean we have our jobs back," she said. "We're still on administrative leave."

Latest layoffs add to Health and Human Services job cuts

President Trump's government-wide reduction in force has sent waves through the U.S. Department of Health and Human Services just six months after it underwent an earlier round of cuts.

On Tuesday, the National Public Health Coalition and the American Federation of Government Employees Local 2883, which represents CDC employees in Atlanta, called on Georgia leaders to take action.

"I am terrified for the public safety of our country. The U.S. funds the most brilliant minds in the world to conduct cutting-edge science," one scientist said during the press conference.

Backus is just trying to stay hopeful. 

"Maybe at some point they'll realize, 'Hey, it's really a bad idea to really take a sledgehammer to our nation's public health institute," she said.

A Health and Human Services spokesperson said the cuts are part of an effort to "close wasteful and duplicative entities."

The department's staff was listed at just under 80,000 employees in a contingency plan before the government shutdown began, down more than 2,000 from its staffing level earlier in the year.

The Associated Press contributed to this report.