Ebola cases will spiral without stronger intervention, Yale researchers say
A mathematical transmission model of the viral disease developed by a team of seven scientists from Yale's School of Public Health and the Ministry of Health and Social Welfare in Liberia was applied to Liberia's most populous county, Montserrado. The country's hard-hit capital, Monrovia, is in Montserrado.
The researchers projected as many as 170,996 cases of the disease with 90,122 deaths in Montserrado alone by Dec. 15. Those figures include cases that are reported and cases that are not. Of those figures, researchers expect that only 42,669 cases and 27,175 deaths will be officially reported by Dec. 15.
"These figures are what we'd estimate if there were to be no improvements in public health responses," said Joseph Lewnard, the lead author of the study and a Ph.D. candidate at Yale's School of Public Health. "While new interventions have been underway … which may dampen the severity of the epidemic, our findings suggest that the scale must be increased greatly to maximally avert new cases and deaths." The researchers' article is published in The Lancet Infectious Diseases journal.
On Sept. 16, the U.S. announced plans to construct 17 Ebola treatment centers to isolate and treat 1,700 patients. As of Sept. 23, there were 430 beds in Montserrado County and 625 beds in all of Liberia, Lewnard said.
"[T]he pace of epidemic growth brings into question whether the extent and timing of the commitments will be sufficient to curtail the epidemic," the researchers' article says.
Alison Galvani, professor of epidemiology at the School of Public Health and the paper's senior author, said in a statement, "Our predictions highlight the rapidly closing window of opportunity for controlling the outbreak and averting a catastrophic toll of new Ebola cases and deaths in the coming months. Although we might still be within the midst of what will ultimately be viewed as the early phase of the current outbreak, the possibility of averting calamitous repercussions from an initially delayed and insufficient response is quickly eroding."
In an accompanying comment in the journal, David Fisman and Ashleigh R. Tuite of the Dalla Lana School of Public Health at the University of Toronto wrote, "The growth of this epidemic fits so well with mathematical epidemiological ideas that it seems torn from the pages of a textbook. And thus, even as the current Ebola epidemic wastes lives, devastates economies, and causes widespread fear, it follows a seemingly well behaved epidemiological process, readily understood through the use of mathematical modelling."
Fisman and Tuite added: "[W]e have no time to waste. The urgency of timely intervention in the Ebola epidemic cannot be overstated. ... Researchers have asserted that the epidemic is proceeding in virus time, with a response on bureaucratic time."
Controlling Ebola is "not only a humanitarian duty but also a matter of crude self-interest," Fisman and Tuite said. "The report by Lewnard and colleagues shows that intervention will only be meaningful if it is timely, and so far it has not been."
The researchers found that the spread of the disease could be substantially reduced — by about 97,940 cases — if the international community steps up control measures by Oct. 31.
The authors say that would require an additional 4,800 Ebola treatment beds in Montserrado County, a five-fold increase in the speed with which cases are detected, and the allocation of protective kits with sanitation supplies such as bleach, gowns and masks to the households of patients awaiting admission to a treatment center.
If that intervention is delayed until Nov. 15, the study projects that about half as many cases — 53,957 — would be averted.
"The current global health strategy is woefully inadequate to stop the current volatile Ebola epidemic," said co-author Dr. Frederick Altice, a Yale professor of internal medicine and public health. "At a minimum, capable logisticians are needed to construct a sufficient number of Ebola treatment units in order to avoid the unnecessary deaths of tens, if not hundreds, of thousands of people."
So far, there have been almost 10,000 reported cases and 4,555 deaths from the disease in the three affected West Africa countries of Liberia, Sierra Leone and Guinea since the outbreak began with a case of a toddler in rural Guinea in December 2013. http://www.courant.com/health/hc-yale-ebola-study-1024-20141023-story.html
