Yes, because of the concern about the anthrax spores after 9/11. They needed a volunteer who would see potential small pox patients, and I knew I had been vaccinated twice as child. And then once again in 2001. I had a mild fefer, and a distinct viral prodrome - aching, felt sick, tired, yucky. But after 36-48 hours it left and I was fine, as I expected, but wondered a bit about it, for several hours.
Taught me to be more careful when I choose to volunteer 😇 Still, I would do it again, under similar circumstances.