I don’t know where I saw 90 days but my wife was told that when her work was vaccinating everyone. But I just googled and the WHO says you might want to wait 6 months though that is based on availability, probably to give those with no immunity first choice.
People who have or had COVID-19 already
Vaccination can be offered to people who have had COVID-19 in the past.
But given the limited vaccine supply, individuals may wish to defer their own COVID-19 vaccination for up to 6 months from the time of SARS-CoV-2 infection. As more data becomes available on duration of immunity after infection, this time period may be adjusted.
Testing for prior infection is not recommended for the purpose of vaccine decision-making.
BTW, those at Mrs. 321’s work who are vaccinated can enter the side door and bypass the temperature check and questioning, while those not vaccinated, including her who they refused to vaccinate because she had recently tested positive, have to go through those protocols.