After getting HIv, when does a person have AIDs There is no clear-cut answer but doctors agree that a person has aids if he or she has hiv and bOtH of the following happen The cd4 helper lymphocyte count is 200 or less He or she has a serious infection or cancer because the immune system could not fight it offAfter getting HIV, when does a person have AIDS? There is no clear-cut answer but doctors agree that a person has AIDS if he or she has HIV and BOTH of the following happen: • The CD4 helper lymphocyte count is 200 or less • He or she has a serious infection or cancer because the immune system could not fight it off