BACKGROUND: Male-to-male sex is the predominant route of human immunodeficiency virus (HIV) transmission in Australia and since the early 1980s blood services in Australia have deferred donors for this practice for at least 5 years. This retrospective analysis assesses the impact on HIV prevalence of implementing an abridged 12-month deferral for male-to-male sex.

STUDY DESIGN AND METHODS: The prevalence of HIV among blood donors for 5-year periods before (Period 1) and after (Period 2) implementing the revised 12-month deferral was compared. Using deidentified data from postdonation interviews with HIV-positive donors the proportion disclosing male-to-male sex as a risk factor was compared for the two periods.

RESULTS: Twenty-four HIV-positive donations were identified among 4,025,571 donations in Period 1 compared with 24 among 4,964,628 donations in Period 2 (p = 0.468). The proportion of HIV-positive donors with male-to-male sex as a risk factor in Period 1 was 2 in 15 (13.3%), which was not significantly different from the proportion in Period 2, 5 in 16 (31.25%; p = 0.22). All five men who have sex with men risk HIV infections during Period 2 were from donors whose risk was within the 12-month criterion for acceptability, who would have been deferred had they provided a complete history.

CONCLUSIONS: We found no evidence that the implementation of the 12-month deferral for male-to-male sex resulted in an increased recipient risk for HIV in Australia. The risk of noncompliance to the revised deferral rather than its duration appears to be the most important modifier of overall risk.