I've had some experience with sore throats in the past which always developed into something more serious, including one case of pneumonia. The only, repeat only cure I have found has been the repeated use (in coffee or on foodstuffs) a strong preventative measure involving a natural herb ...
That's the interesting thing that we've seen hints of. It's pure speculation, but it looks like it might be deadly only when you get the double-whammy that you're describing. If so, that would be great news.