Ebola vaccine nearly 98% effective in preventing disease 

A vaccine being developed by Merck is 97.5% effective in protecting people against Ebola in the Democratic Republic of the Congo, according to new data released late last week. More than 90,000 people were vaccinated in an effort to limit the current outbreak, and only 71 developed Ebola. The vast majority of people who developed the disease despite being vaccinated — including nine people who died — developed symptoms fewer than 10 days after being vaccinated, suggesting the vaccine had not yet had time to fully protect them.

The data were released shortly after the WHO, advised by a panel of outside experts, concluded that the outbreak, though increasingly serious, does not constitute a public health emergency of international concern. As of Saturday, there have been 1,240 cases and 792 deaths.