The nation’s biggest immunization rollout in history is facing pushback from an unlikely source: health care workers who witnessed COVID-19′s devastation firsthand but are refusing shots in surprising numbers.

It is happening in nursing homes and, to a lesser degree, in hospitals. Some employees expressing what experts say are unfounded fears of side effects from vaccines that were developed at record speed.

Alarmed by the phenomenon, some administrators have dangled everything from free breakfasts at Waffle House to a raffle for a car to get employees to roll up their sleeves.