The British government is thinking of vaccinating children against drug addiction. Except that when you read it, it's not addiction per se they're vaccinating against, but the ability to have fun with drugs. And their list of drugs to vaccinate against includes at least one which is currently perfectly legal: nicotine.
This is something I'm deeply uncomfortable with. Not because I think addiction is a Good Thing, but because this way of dealing with it simply too gross an invasion of personal autonomy - it's literally denying the ability to choose, by artificial means.
Now, any conception of autonomy has to allow for future choices to be limited; such limitation can itself be a deep expression of who you are. But in order to be autonomous, those limitations have to be voluntary, your choice, not the government's. It's OK for individuals to choose to limit their future ability to get high (as part of a rehab program, or a better way of giving up smoking), but it's not OK for the government to permanantly and irreversibly take that choice away from people.