what determines the longevity of antibodies?


Why do some vaccines only require a single shot while others nessessitate a booster in order for the antibodies to remain within protective levels?

In: Biology

Basically it just depends on how angry the body (immune system) is with the vaccine (a cocktail of foreign molecules). The angrier, the more antibodies it makes for a longer time. But you don’t want it too angry, or else it starts to harm your own tissue. And this balance is different for every vaccine, and some need boosters to make the body less angry but multiple times instead!

In the event of vaccines that need to be readministered on a yearly basis, such as the flu, it is because there are new variants of such viruses that are created through mutations, and new forms of vaccines are required to develop immunity to those variants.

New strains of viruses are always evolving, and the vaccine must evolve alongside them.