As a scientist collecting data during the Ebola virus outbreak in Sierra Leone in 2015, Mary-Anne Hartley watched doctors agonize about which patients among the hundreds to treat first. “How do you know who will deteriorate the fastest?” says Hartley. “You need an objective measure to decide.”
After the outbreak—which led to more than 11,000 deaths between 2013 and 2015—Hartley decided to find that measure. At the University of Lausanne, in Switzerland, where she studies infectious diseases, Hartley created a scoring system that calculates the severity of an Ebola case. If the epidemic returns—and experts say it will—this simple prognostic tool could save lives.
Hartley created two scorecards, one for diagnosis and one for daily rounds of hospitalized patients. Each assigns points for pertinent characteristics, such as age, the amount of virus in the bloodstream (the “viral load”), symptoms and how long a patient had those symptoms before coming to the clinic. A 50-year-old receives nine points for age, and seven points if he or she is disoriented. Persistent disorientation adds 10 points. The total indicates the risk of dying: A 30-year-old patient (zero points for age) without muscle pain or confusion (zero points for symptoms) would be considered low-risk, whereas the 50-year-old with confusion would be in the high-risk group. The scorecard, published recently in PLOS Neglected Tropical Diseases, correctly predicted 97 percent of Ebola deaths at or soon after diagnosis.
These tallies could help physicians better allocate their time and extremely limited funds and supplies. “If some of these patients had the benefit of more resources, they wouldn’t have died,” says Rob Fowler, a scientist at Sunnybrook Research Institute in Toronto, who treated Ebola virus disease in Sierra Leone, Guinea and Liberia during the last outbreak. In other words, inadequate resources are what make Ebola so life-threatening. Intravenous fluids, oxygen and dialysis, all scarce in West Africa, could keep a patient alive until the body finally attacks the virus.
Fowler cautions against using this scorecard to categorize patients as “so sick they’re destined to die.” That, says Fowler, “would be a misuse of the score.” Even the sickest patients may recover, and medical care may keep them alive until the patient’s immune system mounts an attack. But Fowler also emphasizes the value of scoring severity when emotions and other biases could influence medical decisions. “It keeps things more honest,” says Fowler.
The World Health Organization expects to grant emergency approval to an Ebola vaccine by mid-2017. But the inoculation will be offered only after an outbreak begins, and the virus could evolve beyond the two strains it now covers. “And it’s definitely still out there,” Hartley says. “There will be another outbreak.”