The risk of transfusion-transmitted HIV from blood donations of men who have sex with men, 12 months after last sex with a man: 2005–2007 estimates from England and Wales

The risk of transfusion-transmitted HIV infection under (i) permanent exclusion and (ii) 12-month deferral of MSM in England and Wales during 2005–2007 was estimated. Assuming equal compliance with both scenarios, estimated risk under a 12-month deferral (0.228/million donations [range 0·168–0·306/million donations]) was only marginally greater (0·5%) than that under lifetime exclusion (0·227/million donations [range 0·157–0.318/million donations]), with one extra-HIV infectious donation every 455 years. Poorer compliance of MSM with a 12-month deferral would be expected to increase the estimated risk, whereas improved compliance could decrease risk by up to 29·1%.