STD isn’t my expertise, but I don’t see why it would be a problem to offer benefits incentives to vaccinated employees, as long as you accommodate those who can’t get vaccinated due to a disability, legitimate religious objection or other grounds protected from discrimination by human rights laws. My fear, however, is that there may be some technical rule in benefits law that I’m unaware of; but as a matter of discrimination liability, I think  you’re OK. Hope that helps. Glenn