CD4 and AIDS: Overall, it is estimated that 44-64% of HIV-positive people in Germany are diagnosed at an advanced stage of disease, hence they are considered late presenters according to the definition of Antinori et al. from 2011 (AIDS-defining disease and/or CD4 cell count below 350 per microliter at the time of initial diagnosis) (an updated consensus definition was published in November 2022) [7–13].