Still wondering why previously infected individuals should still get vaccinated? This study shows why:
Single dose with mRNA vaccines boosted Ab neutralization titers vs. all variants by up to 1000-fold and elicited cross neutralizing responses ! https://science.sciencemag.org/content/early/2021/03/24/science.abg9175

Whereas sera recovered from recovered individuals who were unvaccinated were inconsistent in neutralizing virus variants of concern.
Furthermore a 2nd dose of vaccine in previously infected persons did not further boost their immune response. So one dose may be all they need.

Why should you get vaccinated if you have previously had #COVID19?
will boost the breadth and depth of your natural immune response.
provide enhanced protection vs. VOC which are on the rise and responsible for most infections currently.
Help slow spread of VOC