Someone mentioned that a one in a million risk of serious side effects should be enough of a deterrent against a vaccine. Let's suppose that you decide to take the natural course of things instead and get infected (quite often unknowingly). What's your chance of developing serious complications or dying? Even if actual COVID-19 case numbers globally have been underestimated by a factor or 10, it will perhaps still be greater than one in a million. So, no completely risk-free, gamble-free solution here.