Re: Doesn't check out
We first have to understand the nature of the reinfection. I believe that strep has three sections in the binding protein. The outer one frequently mutates, the middle occasionally. As someone is repeatedly infected, their immune system eventually learns the inner section, and they don't get sick any more.
If this virus behaves in this fashion, then a vaccine that trains against an inner, non-changing section will be the fix. If not... well, I'm not an immunologist.