Life or death decision

摘要

After more than a decade of false starts, the day is finally approaching when we will have a vaccine to fight AIDS. But already debate is raging over how - or even if- it should be used. The trouble is that the first vaccines to be approved almost certainly won't work very well. They are likely to prevent fewer than half of the people who receive them becoming infected, and this protection might only last a few years. And that creates a dilemma. Should we dish out these vaccines anyway, so that at least some people will be protected? Or could they make HIV spread faster by giving vaccinated people a false, and potentially fatal, sense of security? Scientists and policy makers face a very difficult decision. If they get it wrong, they'll not only fail to curb the most destructive plague in modern history, they might actually make it worse. Yet there's still no clear consensus on whether and how the first vaccines should be used.