The Transportation Security Administration has a mandate that employees need to be fully vaccinated by November 22nd. As of this week, 4 out of 10 workers remain unvaccinated. This deadline is the Monday before Thanksgiving which is one of the busiest travel times of the year, so a TSA representative says they are “building contingency plans, for if we do have some staffing shortages as a result of this.” The TSA has also been holding town hall meetings to encourage employees to get vaccinated.
See "40% of TSA employees remain unvaccinated", Gregory Wallace and Pete Muntean, CNN, October 14, 2021