Could a heroin vaccine cure the west’s drug epidemic?

There are a million heroin users in the US, and the UK has Europe's highest rate of use. It is a huge problem. But can there be a chemical answer to a social issue?

The effect of heroin has been described as "a warm blanket on the brain". Within seconds of the drug entering the bloodstream, it hits receptor molecules in the brain's neurons that induce a surge of euphoria, followed by a prolonged sense of tranquillity. Yes, it feels good - and that's the problem.

But what if you took heroin and felt nothing? What if there was a treatment that cancelled its effects on the brain? Who then would bother to take it?