Can your workplace run competitions for vaccines? Is that even legal?

I'm pregnant and working in a skilled nursing facility as a patient care aide. It's hard work and the occupational health leader just told us at town hall that this year, they're running a draw for a $250 gift basket for the floor that has the most staff with the flu shot by December 1st.

Is that even legal? I told her I don't believe in the flu shot and that it's disgusting that they're pushing so heavily for it. That's coercion. It shouldn't even be legal!

Edit: But it IS coercion because they're only letting people who get the shot enter the raffle. That's forcing someone to do something. They are forcing people to get the shot to enter the raffle. So that's coercion!!! That's not fair to those of us who don't get the shot either. Where are our rewards?