A research study involving 30,454 individuals, from 34 European countries, estimated the prevalence of late onset (which can express late diagnosis or late entry to care), in the period from 2010 to 2013, at 47.9%, using the as a parameter a CD4 count below 350 cells/mm3 or an AIDS diagnosis within 6 months after HIV diagnosis(15). Here, CD4 is linked to AIDS.