I've had quite a few influenza shots, but each year, until I'm vaccinated for the current strain of influenza, I'm consider "unvaccinated." Go figure. Or maybe you already understand now. COVID viruses, including COVID-19, are like that.I mean people with two shots and two boosters are listed as“unvaccinated” if enough time has past.
Viruses mutate. And to be immunized, you have to be immune to the current strain. That's the science. Learn about it here:It isn’t science.
Selecting Viruses for the Seasonal Flu Vaccine
Vaccine composition is reviewed each year and updated as needed based on which influenza viruses are making people sick.
www.cdc.gov
I've been told by someone still in the field that there is some possibility of developing a universal influenza immunization. Sounds like a great idea if it works. I'll have to take a look at that.