Travelers wait in the ticketing line at Salt Lake City International Airport on Monday. There have been thousands of flight delays and cancellations as the omicron variant spreads across the country. Unionized flight attendants are wary of new CDC guidelines that shorten the isolation period.

Travelers wait in the ticketing line at Salt Lake City International Airport on Monday. There have been thousands of flight delays and cancellations as the omicron variant spreads across the country. Unionized flight attendants are wary of new CDC guidelines that shorten the isolation period. / AP

Updated December 29, 2021 at 1:14 PM ET

The newest Centers for Disease Control and Prevention guidance shortening the isolation period for those with COVID-19 from 10 days to five days has led to a growing concern about its impact on essential workers such as nurses and airline staff.

CDC Director Rochelle Walensky said the decision to change the guidelines was, in part, to "keep the critical functions of society open and operating."

"We started to see challenges with ... airline flights and other areas. We started first with doing the health care workers last week to make sure that we could make — keep our hospitals functioning safely and open," Walensky told NPR on Tuesday.

The CDC says its decision is also based on the science showing that a majority of COVID-19 illnesses get passed around in the first few days of the infection. Other public health experts say that's true — but there's still a chance that transmission to others could happen after the five-day benchmark.

There's also concern that mask adherence won't be properly followed, and health experts, including Walensky, have said wearing a mask from the Day 5 to Day 10 period is critical for the new guidance to work.

Flight attendants' concerns

But some essential workers, such as flight attendants who are at higher risk of exposure to more people, say they are hoping their workplaces implement longer isolation periods, rather than following CDC guidance.

"There are holes here that give us a lot of unknowns and a lot of uncertainty, and that is the last thing we need," Sara Nelson, president of the Association of Flight Attendants, tells NPR, pointing out that uncertainty has led to violent outbursts from airline passengers, putting flight attendants at risk.

Nelson is concerned there's an emphasis in the new guidance on protecting the economy over public health.

"The problem is that we are admitting that we're going to put infectious people back into the workplace or on our planes," Nelson said on Morning Edition Wednesday. "We're very concerned about this, and we are pressing the airlines to have much better policies than what the CDC is giving us."

What Delta's CEO wanted

Nelson's position is at odds with some airlines leaders. The CDC's decision comes days after Delta Airline's CEO sent Walensky a letter advocating for a shorter isolation period.

In the letter, CEO Ed Bastian — along with the airline's medical adviser and chief health officer — asks Walensky to consider shortening the isolation period to five days for those who experience a breakthrough infection.

"With the rapid spread of the Omicron variant, the 10-day isolation for those who are fully vaccinated may significantly impact our workforce and operations," the Delta officials write.

The airline was among several in the U.S. that experienced thousands of cancellations over Christmas weekend, in part because airline staff were calling out sick with COVID-19.

On Wednesday, a spokesperson for Delta reiterated its support for the new guidance in a statement to NPR.

"Delta has always, without exception, put the health and safety of our people and customers ahead of all else throughout the pandemic," the statement said. It added, "Delta has and continues to follow the science-backed approach of the CDC."

The CDC's balancing act

Walensky, in her interview with NPR, said, "We can't take science in a vacuum."

"We have to put science in the context of how it can be implemented in a functional society. So we always do that," she said.

And the guidelines do rely on science — and people's adherence to them.

"The vast majority of transmission happens in that first five days and there's probably a little bit that might happen after those five days, which is why we've really put in the strong recommendation to mask those last five days," she said. "And I will reiterate that this guidance only works if people follow it and mask for those last five days."

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Tags: CDC COVID-19 guidance  COVID 19  Delta Air Lines  CDC  Series: The Coronavirus Crisis