My other car's a Porsche
The question wasn’t about flu vaccines, it was about the covid vaccine... are you having trouble answering the question?The answer to both questions is, if not identical, at least overlapping. Are you having trouble answering it for the flu?
It's a fair question, but the truth is that no-one really knows for sure how long immunity lasts after either an infection or a vaccination. Evidence so far suggests that protection from a subsequent infection might only last around 6 months, but there's very little evidence (though it is certainly possible) that people can be infected again... it's still too early to say, but vaccination after infection makes as much sense as vaccination without an infection, esp. if one was infected some time ago.
edit: As @Danoff alludes to as well, vaccinations/boosters against future variants of SARS-CoV-2 will almost certainly be needed to prevent new variants from creating new waves of severe illness. There are already booster shots for the Delta variant in the pipeline, for example.
The current vaccine seems to work against all variants we’ve seen so far despite being developed only for the original strain... maybe not for cases, but at least as far as preventing serious illness and death.
I understand boosters and new variant vaccines may follow, but at this stage, why would anyone take the risk of side effects if they have antibodies from prior infection. There’s zero benefit as far as I can see.
Plus, at this stage there also seems no evidence to for the need for boosters other than the lines of Pfizer wanting to make even more money.