CDC revises HIV classification system, AIDS definition.
D000163:Acquired Immunodeficiency Syndrome / Q000145:classification* / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D002487:Centers for Disease Control and Prevention, U.S.; D015658:HIV Infections / Q000145:classification* / Q000453:epidemiology; D006801:Humans; D011159:Population Surveillance; D014481:United States