CD4 and AIDS: On September 10th, 2021, the administration of a third dose of anti-SARS-CoV-2 mRNA vaccine was approved in Italy to be given after >28 days after completion of the primary vaccination cycle in PLWH (to be intended as a full additional dose vaccine) who presented with a CD4 T cell count <200/mm3 and/or previous AIDS at the time of their first dose.