Even if they could find a commonality in flu which would allow development of a vaccine with long term protection, I doubt that they would. We’re talking a couple hundred billion dollar industry that has a monopoly with recurring guaranteed income.
“Even if they could find a commonality in flu which would allow development of a vaccine with long term protection, I doubt that they would.”
It has really nothing to do commonality between influenza viruses. Influenza viruses are ‘enveloped’ RNA viruses, and have a lipid envelope ‘coating’. There are proteins embedded in this lipid envelope, and these proteins are what the antibodies/immune system react against. Unfortunately, these proteins have a high rate of mutation and rearrangement, and so every year the proteins are a little bit different. This allows the virus to escape the immune system of the host (e.g. us). It makes it extremely difficult to develop a vaccine that will work year after year.