Cluster bombing

THE outbreak of Ebola fever in Guinea, Liberia and Sierra Leone, which has killed more than 11,000 people, has dropped out of the news as it has been brought under control. Although new cases are now measured in dozens, rather than hundreds, a week, the disease has not been stamped out--and a new epidemic could flare up somewhere else at any time. A vaccine against the virus responsible would be of enormous value. And a paper in the Lancet suggests one is now available. The vaccine, developed by...