IEEE Spectrum June, 2015 - 64

GUINEA
Population: 11.8 million
Cases: 3,589
Deaths: 2,386

SIERRA LEONE
Population: 6.1 million
Cases: 12,440
Deaths: 3,903

By the numBers

The Hot Zone
The West African Ebola
epidemic began in Guinea and
spread to Liberia and Sierra
Leone in mid-2014. To break
the chains of transmission,
health workers isolated the
sick in specialized Ebola
treatment centers, traced their
contacts, and emphasized
safe burial practices. The
epidemic is now ebbing: In the
last week of April 2015, only
18 new cases were reported.

LIBERIA
Population: 4.3 million
Cases: 10,564
Deaths: 4,716

CONFIRMED CASES

EBOLA TREATMENT CENTERS
Maintained

Closing

Scaled down

Closed

501- 4000

101 - 500

21-100

6 - 20

1- 5

Source: World Health Organization, situation report, 29 April 2015

outbreak. There was also a complicating factor not seen in most epidemics:
Traditional West African burial practices, in which untrained people often
wash and touch the dead, could act as
"superspreader" events.
As a consequence, modelers had a
hard time answering the most important question: How bad will this get?
Some wildly inaccurate forecasts
64

jun 2015

north american

prompted media criticism, which in
turn drew defensive responses. A letter in November 2014 to the journal
Nature signed by 24 workers from various modeling teams was headlined
"Ebola: Models Do More Than Forecast."
Now, with the Ebola gone from
Liberia and tamped down in the other
two countries, the global health community is taking stock of the role of

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epidemic modeling in its response. In
late March of this year, the National
Institutes of Health held a closeddoor meeting of modelers to discuss
why so many predictions were off.
Christopher Dye, director of strategy for the World Health Organization (WHO) and an epidemiologist,
said recently, "If you take modeling
out of the response to this epidemic,
would it have made any difference?
I would say very little."
Others were more sanguine. Modeling "had a substantial effect," says
Matthew Hepburn, an infectious
diseases physician at the Defense
Advance Research Projects Agency.
"It really set off alarm bells." Richard
Hatchett, chief medical officer of
the U.S. government's Biomedical
Advanced Research and Development
Authority, thinks modeling's usefulness lies in its ability to help organize
thinking. His office hosted a weekly
teleconference of modelers, which
sometimes involved 100 people from
two dozen institutions. "What decision makers are most interested in
is what risks they're facing," he said.
"They turn to modeling to help them
understand risk-the high side and
the low side-and the likely impact
of a set of interventions."
In their mathematical struggle
against a highly infectious virus that
tore through West Africa, modelers
were up against a challenge the likes
of which they had never seen. But it's
worth asking: In the fray, did they
learn enough to make such tools a
realistic hope for the next epidemic?
tHe most recent ebola outbreak

began in Guinea in December
2013. By March it had spread to neighboring Liberia and soon entered
crowded cities that had never before
experienced Ebola's ravages. Yet it
wasn't until 8 August 2014 that the
infographic By

erik Vrielink

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Table of Contents for the Digital Edition of IEEE Spectrum June, 2015