Vaccine records are kept by States in which the vaccine was administered (it's very easy to call your Heath dept to get your complete vaccination record going back to when you were born), so it's conceivable that if necessary the government could say something like, "You can't use public services X, Y, or Z without getting this vaccine." They do that with schools to varying degrees and it works well in places where they enforce it (i.e. not on the West coast). But I don't think it would come to that. I think that the vast majority of people will see a vaccine (provided it's safe and effective) as being in their own selfish interest and therefore get it voluntarily. I will. Most people I've talked to will. We all just want to get back to normal, and if that's the path, people will take it. We don't need 100%.