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

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. 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. 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. 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.