Has the switch to sexual risk behaviour screening impacted deferrals for pre- and post-exposure prophylaxis therapy for human immunodeficiency virus?

Background and objectives: Canadian Blood Services defers donors during and for 4 months after oral pre-exposure or post-exposure prophylaxis (PrEP/PEP) for human immunodeficiency virus (HIV) because of concerns about altered viral kinetics. We assessed the impact of the switch from a time-based deferral for men who have sex with men (MSM) to sexual risk behaviour criteria on PrEP/PEP deferrals.

Materials and methods: Data on PrEP/PEP deferral codes were extracted from our National Epidemiology Database for the 22 months before (Period 1) and after (Period 2) the criteria change.

Results: PEP deferrals remained stable (2.3 vs. 1.7 per 100,000 donations in Periods 1 and 2, p = 0.2892), about 45% and 33%, respectively, of these donors who reported a recent needle stick injury. PrEP deferrals increased from 5.9 to 12.4 per 100,000 (p = 0.0001); approximately 30% of donors in both periods had other HIV risk factor deferrals. Donors deferred for PrEP use alone were more likely to be male, first-time users and younger than other donors.

Conclusion: The switch to sexual risk behaviour led to a small increase in deferrals for PrEP. We may not be measuring the full impact of deferral criteria because potential donors may self-defer and PrEP use is increasing.