I seriously have my doubts that it’s only effective for a few months or a year for the viruses in the vaccine. The problem is, each year it can be different strains of flu floating around, and so you need the new vaccine to protect you from the specific strains in that year.
@Caravanfan Have you actually seen information that says the antibodies for a specific flu virus wane that fast? I’m not challenging you, I’m asking because I’m interested. I tried to find that information a while back, and couldn’t find that information. It’s always worded in terms of the vaccine being good for one flu season.
I just don’t understand why flu would be so different from all the other vaccines that protect against specific viruses for years.
Again, I realize flu is not stable like polio or measles, the flu virus has a tendency to mutate and there are many strains.