You can vaccinate forever (once a year) else they wouldn't have have bothered to invent the flu jab.
You have been strongly advised to take a booster, however if you think you don't need it that's up to you.
I had a similar conversation with a taxi driver who claimed a vaccine had killed his friend. No edit that, I've had the same conversation with two taxi different drivers.
When you drill in, it becomes a friend of a friend, cousin etc...
On both occasions as the conversation went on, they were...