The choice of some Transportation Security Agency (TSA) employees to not get vaccinated against COVID-19 could mean longer lines at some airports just ahead of the holiday season.

Dave Pekoske, the head of the TSA, says 40% of workers, including screeners, remain unvaccinated.

However, the Biden administration is mandating civilian government workers be fully vaccinated by Nov. 22.

Pekoske says he is “very hopeful” that employees can meet the deadline and there will be no worker shortages, but says the agency is building plans if there is fewer staff because workers refuse to comply with the federal mandate.

A TSA spokesperson added that the agency is working to comply with the mandate, saying in part that “the current percentage reflects employees TSA doesn’t yet have vaccination information on, and is not an accurate reflection of its vaccination rate.”

A representative from MacArthur Airport says they don’t think they be short staffed for the upcoming holiday travel season.

The head of the agency says he’s been holding employee Town Hall meetings to convince workers to get vaccinated in the hopes of avoiding any disruptions.