katlaughing, as a recent recoverer from pneumonia, you're probably more sensitised than most of us to the implications of such discussions; more power to your elbow!

My understanding about connections between flu, pneumonia and flu vaccinations may be a bit rusty but I'm sure others here will correct any errors I make.

Flu viruses (like cold viruses) mutate all the time, and the versions getting around any population of hosts (us) are always slightly ahead of and different from the versions to which vaccines have been developed in quantities sufficient for effective release into our population. This means some of us (the early adopters, to purloin a phrase) will get the new flu while others will get the vaccine in enough time to protect them from what us early adopters suffered.

One effect of flu is to debilitate us so seriously that we become vulnerable to other infections that, otherwise, we'd have resisted; one of these 'opportunists' is pneumonia, a bacterial infection. In the old and vulnerable pneumonia is frequently, ultimately, triumphant over our medical treatments and can take its victims quickly and relatively peacefully; often this happens in their sleep. For this reason, one of the old and traditional nicknames for pneumonia is "the old man's friend." Well, it's one "friend" I'll avoid for as long as possible. And I hope you do too.

Cheers, Rowan