Let's deal with your gaslighting, Poopiehead.
The flu shot is called a shot because it is given with a needle and a syringe. But the fact that it is called a shot doesn't prove it isn't a vaccine. In fact the term vaccine has always been used to classify the flu shot.
Key Facts About Seasonal Flu Vaccine
But just in case you think they suddenly decided to call it a vaccine when it isn't one, here is an article from 2009 referring to it as the flu vaccine.
https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5844a5.htm
Then here is an article from 2000 referring to it as the influenza vaccine.
https://www.aafp.org/afp/2000/0701/p233.html
A scientific article from the 1990's referring to it as the influenza vaccine.
https://www.nejm.org/doi/full/10.1056/NEJM199812173392501
It seems the one attempting to gaslight is you, Poopiehead.
The influenza vaccine has never made people immune to the flu and has never been long lasting. Anyone with their head in the real world would know that. Unfortunately as your avatar shows, your head is not outside the cow's ass but instead it is quite firmly ensconced where it works best to retain your moniker of Poopiehead.