There’s growing research which proves that recovered patients may have antibodies that last for 6-8 months, and sometimes, may even last for years.
However, with no clinical evidence to support the presence of immunity granting antibodies, it is tough to say who should or who shouldn’t get two doses of current vaccines offered right now. The prioritisation may be done on a case-to-case basis right now
However, since antibodies tend to taper with the passing of months, the ones who may have had COVID more than eight months ago may be asked to get both doses of vaccine for enhanced protection.
Similarly, since people with certain comorbidities, such as diabetes, and the ones who suffer from asymptomatic infection are at a higher risk of waning immunity, opting for a two-dose regime may be strongly advised to ward off infection risk.