London School of Hygiene & Tropical Medicine

Professor Peter Piot, Director of the London School of Hygiene & Tropical Medicine and co-discoverer of the Ebola virus, said:

"It is really impossible to predict how many cases of Ebola infection there will be in four months. The range of uncertainty is enormous because there are so many unknowns, and we should certainly not assume that our collective efforts won't have any impact. Unless CDC has data nobody else has, this is not a useful estimate."

Dr Adam Kucharski, Research Fellow in Infectious Disease Epidemiology at the London School of Hygiene & Tropical Medicine, said:

"Models can provide useful information about how Ebola might spread in the next month or so, but it is near impossible to make accurate longer-term forecasts. Travel patterns and human behaviour will undoubtedly influence the dynamics of the infection over coming months - for better or worse - and the results will be extremely difficult to predict. Even with accompanying caveats, a single number cannot capture the huge amount of uncertainty involved."