Therein lies the issue. Immunity is being defined away.
Test case. Your small pox vaccination requires a second does and then a booster in the US, and then the public is told the “immunization” — their word “wanes,” all the while in Europe a second booster and perhaps third is being encouraged. How many injections of “immunogenic material” is/will be required to find “active immunity” all the while the immunity “wanes?”
When a medical issue becomes all about definitions and semantics and estimates and assumptions and anomalous data collection and reporting, the argument also “wanes.”
The longevity limitations of mRNA vaccines were known in October 2019 and disclosed in the leading scientific magazine Nature:
https://www.nature.com/articles/d41586-019-03072-8
Many people got flu shots annually in years past. There was not a never-ending birthing of “cows” as a result.
It is has been known for quite a number of years that tetanus jabs wane and that booster shots are needed to restore immunity to tetanus.
Governments have to rely on what private enterprise cooks up.