Shouldn’t people be allowed to assess their own risk when they answer questions before giving blood?
In an ideal world they would. However, we know that many people living with HIV did not believe that they were at risk of contracting HIV prior to their diagnosis. People aren’t always good at assessing their own risk.
Around a quarter of men who have sex with men (MSM) in the UK who have HIV don’t yet know they have it. A fifth of this group who were diagnosed with HIV last year presented so late that they were already seriously unwell. These people were unaware they had HIV even though they may have begun to show symptoms, and came forward for testing so late that their long-term health may be damaged as a result. They did not always consider that their activities may have put them at risk of contracting HIV, though clearly that was the case.
Even people in long-term relationships that they believe to be monogamous can acquire the virus if their partner is not honest with them about the sex they are having outside of that relationship. Terrence Higgins Trust sees a significant number of men who have been infected in this way. It passes no judgement on these men to say that they are at higher risk of unintentionally donating blood containing HIV.
Penetrative sex is never completely risk-free and even though using a condom greatly reduces the risk of contracting HIV, accidents do happen and sometimes people remove a condom mid-act without telling their partner. Administering a questionnaire about recent sexual behaviour to every donor, as some have suggested, would not uncover these risks as the person may be completely unaware of them.