HIV residual risk in Canada under a three‐month deferral for men who have sex with men

摘要

Background and objectives In Canada, the deferral for men who have sex with men (MSM) was decreased from a permanent deferral to a 5‐year then a 12‐month deferral. Current HIV testing can detect an HIV infection in donated blood within 2?weeks of exposure; thus, a 12‐month deferral may be unnecessarily restrictive. We aimed to estimate the residual risk of HIV if the deferral were further decreased to 3?months. Materials and methods Using a deterministic model with stochastic Monte Carlo simulation, residual risk of HIV was the sum of testing error, assay sensitivity and window‐period risks. Data inputs were estimated from donor surveillance, donor surveys and published data. Residual risk was modelled at baseline and using three scenarios: (1) most likely – non‐compliance, HIV prevalence and incidence rates of MSM are unchanged; (2) optimistic – non‐compliance improves by 50%; and (3) pessimistic ‐ non‐compliance, HIV prevalence and incidence rates of MSM all double. Results HIV residual risk at baseline was 1 in 36·0 million donations (95% CI 1 in 1?504?907 million, 10·5 million); in the most likely scenario 1 in 34·2 million (1 in 225?534 million, 8·7 million); in the optimistic scenario 1 in 36·0 million (1 in 282?618 million, 9·5 million); in the pessimistic scenario 1 in 16·7 million (1 in 39?469 million, 6·0 million). All confidence intervals overlapped. Conclusion With very low modelled risk under a 12‐month deferral, the additional risk with a 3‐month deferral is very low. This is true even with a pessimistic scenario.