The US Centers for Disease Control and Prevention recommends that every individual should get a COVID-19 vaccine, even if they′ve had the infection previously. 

A study published in Morbidity and Mortality Weekly Report has shown that people who have recovered from COVID-19 but haven′t yet received a vaccine have over two-fold increased risk of testing positive for the virus again, compared to an individual who was vaccinated after a previous infection.

Investigators assessed 738 residents of Kentucky who had COVID-19 infection in 2020. About 250 of them again tested positive for COVID-19 from May through July 2021, when the Delta variant was dominant. People who were unvaccinated had more than double the risk of contracting the infection again during the Delta wave. Partial vaccination had no significant effect on the risk of reinfection… (Medscape)