Patients unaware of their HIV infection until AIDS diagnosis in Sweden 1996-2002--a remaining problem in the highly active antiretroviral therapy era.

Our objective was to analyse the characteristics of patients who were unaware of their HIV infection until they developed AIDS, in the period after introduction of highly active antiretroviral therapy. The complete national register of HIV and AIDS cases reported to the Department of Epidemiology at the Swedish Institute for Infectious Disease Control 1996-2002 was searched for cases diagnosed with HIV less than three months before AIDS diagnosis (so-called "late testers"). Of a total of 487 patients with AIDS, reported during the seven-year period, 219 (45%) were late testers. Their proportion of all AIDS cases increased from 22% in 1996 to 58% in 2002. Heterosexual route of transmission, age greater than 40 years, and foreign origin were all significant risk factors for being a late tester. Intravenous drug users were associated with a highly significant reduced risk. The group without previously known HIV infection represents an increasing part of all cases of AIDS. From a disease control and from a medical perspective, it is important to study this group further and discover what measures are needed for earlier identification and access to medical care.