 The only guaranteed immunity relating to a vaccine is legal immunity for the company that produces it. Oh and sorry if you do not like it, but the link is valid. You can ask people nicely but if they decline then it is time to turn a blind eye. The Bentham-ite "greatest happiness" doctrine is immoral in practice when it involves asking people to take risks that they would not otherwise do. Also, without a direct act of parliament, there are other laws that could work against a vaccine passport than disability (data protection and harassment). P.S. (Afterthought): No medical treatment will ever be completely risk free, nor does it cease to be completely experimental. 