To illustrate my understanding of the situation, I had polio back in 1950 when I was two years old. Salks vaccine wasnt announced until April of 1955 but I can assure you that my brothers and sister were vaccinated as soon as it was available to the public. It certainly wasnt because the government mandated it. If something works it will be used without the need of government intervention or mandates. Your attitude about needing the government to somehow mandate anything is scary and indicates your propensity to give over freedoms without view to repercussions. Give me liberty or give me death. He who gives up liberty for security deserves neither.
And these days, we also have the folks who are convinced that every vaccine is a health threat and that all vaccination programs are a conspiracy. Their spiritual ancestors were convinced that Jenner's inoculations would cause them to break out in cows.
If everybody were as sensible as you and I on such matters, it wouldn't be a problem. And if the folks who refuse to take precautions infected only themselves, it still wouldn't be a problem. But they infect other people -- including those who do get vaccinated (although generally the disease will be milder). That's why herd immunity is important.
And mandatory vaccination goes back to 1807. I'm not a big fan of government intervention, but preventing epidemics is a traditional, core governmental function along with keeping the peace and regulating trade. There's a lot of other government interference that needs to go before we interfere with public health mandates.