I’ve had these questions/ideas (attached image) after reading  “The Great Influenza” by John Barry and was wondering if anybody could add anything or point me in a direction where I could find more information.

Well, simply put the common antigens recognized in bacteria as well as viruses have a high variation, no doubt to some extent due to the selective pressure exerted by immune responses. As for reading, some textbooks on bacterial cell hulls are probably a good start. I would recommend looking at the diversity of LPS structure and specifically the O-antigen as a model for what you are thinking about (and why it is unlikely to work).

Interesting, thank you