A new model by David Fisman and Ashleigh Tuite of the University of Toronto in Canada – the first to take account of efforts to fight infections – suggests that if things continue as they have been up until now, 700,000 people could have had the virus by the time the epidemic in Liberia, Guinea and Sierra Leone subsides – in early 2016. Fisman’s prediction is based on reported cases of Ebola. (The previous prediction of more than a million cases by this coming January had assumed that the actual number of cases is 2.5 times the reported cases. Factoring in underreporting results in Fisman’s model having 1.75 million cases. 50-70% of those cases would result in death so around 900,000-1.23 million deaths.
But Fisman’s work shows that even the measures taken so far have been worthwhile. In a commentary with Galvani’s report, he says it has been hard to predict how big epidemics will get, because they often decelerate faster than their initial growth suggests.
He modelled what would happen if efforts to control the disease faltered, which could happen as a result of civil disturbance as cases mount. Such faltering would mean the discounting term shrinks. A 40 per cent reduction in the term made predicted Ebola cases balloon from 700,000 to 12 million [adjusted for underreporting 1.75 million to 30 million]. Because this is a derived term, it’s hard to know how it translates to what’s happening on the ground.
More optimistically, if currently experimental drugs and vaccines work against Ebola, significant quantities should become available in 2015, when the model says the epidemic will peak. This could lead to a much faster decline in cases than currently predicted.
Representatives of the GlaxoSmithKline, meeting with WHO officials in Geneva this week, say that by December 2015 they should be able to make a million doses of vaccine a month.
The Yale model developed by the researchers projects as many as 170,996 total reported and unreported cases of the disease, representing 12 percent of the overall population of some 1.38 million people, and 90,122 deaths in Montserrado alone by Dec. 15. Of these, the authors estimate 42,669 cases and 27,175 deaths will have been reported by that time.
The Yale research also predicts that roughly 97,940 cases of the disease could be averted if the international community steps up control measures by Oct. 31.
These measures include additional Ebola treatment center beds, a five-fold increase in the speed with which cases are detected and allocation of protective kits to households of patients awaiting treatment center admission. If intervention is delayed to Nov. 15, the number of lives saved would be cut nearly in half, to 53,957, according to the research.
SOURCES – Yale, Lancet, Science Direct, Greenwhich Time, New Scientist