Many employers already provide incentives (including cash) to participate in "wellness" programs, and many often will perform drug tests prior to and even durin

Many employers already provide incentives (including cash) to participate in "wellness" programs, and many often will perform drug tests prior to and even during employment. For most of the things you mention, it's possible for the employee to control the impact it has on their work hours. You can drink while ensuring you're not drunk or hungover at work, for example. For COVID, it's not possible to control the impact; if you have COVID, you do not work. Additionally, you can spread COVID to other employees prior to a positive test or symptoms and consequently affect the business outside of your personal availability. That's not really the case with drinking or a refusal to exercise.