The CFR doesn't tell you how contagious a disease is. Ebola, transmitted through contact with bodily fluids, is much less contagious than airborne diseases such as influenza or measles. What it can do is indicate how serious the disease is, for those patients infected with it. But as we've seen, this varies.
"When you have large ranges of CFR like you do with ebola, it isn't really appropriate to give one extreme or the other," Majumder says. "I think if we were to use a CFR for ebola we really ought to give the case average since initial emergence of the disease in 1976 - and that is significantly less than the 90% estimate that we hear a lot of in the media."
And which we also hear about on the WHO website