Multicenter AIDS Cohort Study (MACS) Public Data Set

The Multicenter AIDS Cohort Study (MACS) is an ongoing prospective study of the natural and treated histories of HIV-1 infection in homosexual and bisexual men conducted by sites located in Baltimore, Chicago, Pittsburgh and Los Angeles. MACS public data set has been released from CAMACS (Center for Analysis and Management of Multicenter AIDS Cohort Study) since 1994 when the MACS Executive Committee made the recommendations on the content of the public data.

The first release of the data was issued in March 1994. Beginning October 1995, the data has been released on a yearly schedule with new releases superceding previous versions. The MACS PUD had been distributed originally via the National Technical Informatiion Service (NTIS), but in recent times due to budget constraints at NTIS is now distributed via the central MACS Data Center (CAMACS). 

More information about this resource is available at Multicenter AIDS Cohort Study Public Data Set

Main Areas of Focus

Public access to MACS data allows use of the data by a wide range of scientists, in particular  epidemiologists, statisticians, and mathematical modelers seeking data sources to test novel, methodological approaches. The MACS Public Use Dataset (PUD) is also a valuable resource for masters and doctoral students. Access also ensures MACS compliance with NIH Policy for Data Sharing. The overall goals of the PUD is to:

  • To provide de-identified data (meeting HIPAA criteria) that may assist anyone interested in public health research focused on HIV
  • To provide the platform for other HIV-related NIH-funded grants
  • To enable the evolution of a substantial clinical research database


Data Components Include

  1. Original Cohort:
    • The original 4,954 gay and bisexual men volunteered since the beginning of the MACS study in 1984. They were followed up semi-annually. In each visit the data sets of physical examination, Sections 2, 3, and 4 questionnaires and laboratory results were generated. 
  2. New Recruit Cohort (Visit 75):
    • From April 1987 through September 1991, recruitment was opened to focus on minority and special target groups such as partners of the original cohort. A total of 668 new participants were recruited. Versions of new recruit baseline questionnaires of physical examination, Sections 2, 3 and 4 were initially applied to this cohort. In their follow-up visits this cohort has continued to be tested and interviewed along with the original cohort.
  3. 2001-3 New Recruit Cohort (Visit 76/36.5):
    • A third enrollment of 1,350 men [added to the Public Data Set in October 2009] took place between October 2001 and August 2003. This third cohort augments research efforts in the long term benefits and adverse effects of therapy.
    • Recruitment was opened to focus on minorities and a special target group of censored seronegatives from the 1984 cohort. After administering a series of baseline questionnaires these participants have been followed every 6 months with the other cohorts. 
  4. 2010+ New Recruit Cohort (Visit 752/52.2):
    • A fourth enrollment of 380 men [added to the Public Data Set in 2016] took place starting in May 2010 and is ongoing. This expansion will help the MACS address questions concerning the short and long-term effects of newer HAART medications, and distinguish the effects of treatment from HIV infection. Recruitment was opened to focus on men who have not yet started HAART or have started HAART on or after January 1, 2011. After administering a series of baseline questionnaires these participants have been followed every 6 months with the other cohorts. 
  5. Neuropsychological Cohort:
    • From 1987 to June 1991, the MACS centers began administering neuropsychological interviews and tests to a subgroup of the original cohort across 10 neuropsychological specific testing waves.
    • Beginning in April 1991 (Visit 15: April-September 1991) the conduct of neuropsychological tests were synchronized with the timing of the participant's semiannual MACS visit.
    • Concurrently with the expansion in 2001, the MACS began administering a battery of neuropsychological tests at baseline and every 2 years for all participants from all cohorts.

Who Can Use This Resource

  • Available for public use

How To Get Started

  • Visit the MACS website to request the most current version of the MACS Public Dataset
  • If specimens are also required, investigators should also contact the MACS for requesting accesss