Multicenter AIDS Cohort Study (MACS)

The Multicenter AIDS Cohort Study (MACS) provides important information about the changing
nature of HIV-mediated disease progression, the impact of antiretroviral treatment, the
nature of HIV pathogenesis, and viral and host genetic factors. This study will also assess
the long-term patterns of therapy use and risk-taking behaviors.

Patients will have study visits every 6 months. The visits will include interviews, specimen
collection, and a physical examination.

Inclusion Criteria:

- HIV negative, or

- HIV positive and no history or current use of highly active antiretroviral therapy
(HAART), or

- HIV positive HAART recipient with documentation of HAART initiation, no AIDS diagnosis
prior to HAART initiation, and a CD4 cell count and HIV-1 RNA measurement within 6
months prior to first HAART use.

- Sexual intercourse with men or at least 5 male or female partners in the 5 years prior
to enrollment.

Exclusion Criteria:

- Injection drug use within 1 year of enrollment.

- Perinatally acquired HIV infection.