ANTICIPATING EPIDEMICS
Epidemics are common occurrences in the world of the 21st century. Every country on earth has
experienced at least one epidemic since the year
2000. Some epidemics, such as the H1N1 2009,
Avian Flu and SARS pandemics, have had global
reach, but far more often, and with increasing
regularity, epidemics strike at lesser geographic
levels. Devastating diseases such as the Marburg
and Ebola haemorrhagic fevers, cholera, plague,
and yellow fever, for instance, have wreaked
havoc on regional and local scales, with much loss
of life and livelihoods.
Epidemics are contemporary health catastrophes.
Tornado striking in the countryside
Improvements in the technology and infrastructure of surveillance and diagnostics have made it
possible to detect epidemics earlier than in the past. Early detection enables a faster response, and
occasionally this has led to containing a disease before it spread to the wider community, a very
significant result. No matter how beneficial a quick response might be, however, it is still a form of
reactive disease management, comprised of a portfolio of measures enacted only when the outbreak
is already under way. How much more effective and timely might these measures be if they
anticipated specific outbreaks?
Close collaboration between health experts and meteorologists would open up new possibilities
for anticipating epidemics. There are connections between the dynamics of epidemics, weather, and
climate, not the least of which is that weather and climate factors are often associated with the
beginning of disease outbreaks. For example, the arrival of cold, humid weather tends to trigger the
onset of influenza, while flooding encourages the rapid spread of water-borne and rodent-borne
diseases such as cholera and leptospirosis.
From the point of view of populations and health services, outbreaks of epidemics at the community
level are often experienced as though they were natural disasters. Their onset is so swift and
powerful that people feel like a tornado or a flash flood has struck. Health service disorganization can
too often be the result.
As is true for meteorological disasters, earthquakes and the like, the impact of epidemics on the
affected populations varies considerably depending on the degree of vulnerability and
preparedness in each locale. For instance, in disadvantaged communities that have little or no
patient surge capacity, routine interventions and surgery are postponed or cancelled during
epidemics. Epidemics thus have a greater negative impact on the viability and future development of
the health service in these places than they do in communities that are materially better off.
Anticipating Epidemic
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May 2014
Being able to anticipate the outbreak of epidemic-prone
diseases accurately would mark a great improvement in
epidemic and pandemic management, shifting the
approach from reaction to anticipation and allowing for
more orderly and effective preparedness, both in terms of
the availability of materials and of the readiness of human
and organizational resources. Forecasting disease
outbreaks is still in its infancy, however, unlike weather
forecasting, where progress in recent years has been
substantial. For example, weather forecasters can now
provide reliable predictions covering periods of up to ten
days.
Weather forecast, African Region
It will take time to get to the point where forecasting epidemics is sufficiently accurate. This is not
surprising: weather forecasting did not attain its present level of reliability overnight. Meteorological
scientists have had to pass through many stages to reach this level, including observing a wide
variety of variables over long periods of time, gaining experience in forecasting techniques, and
integrating a large number of environmental and climatic factors into mathematical models.
Most significantly, meteorologists, whether they are climate scientists or weather forecasters, have
recognized that the past is no longer a good indicator of future climate evolution. This has resulted in
a shift in the orientation of meteorological science to emphasize forward-looking research and
modelling that feeds into scenario building and supports the creation of user-oriented climate
services. Learning this and other lessons available from the meteorological sector and configuring
some of their tools so that they can be used for epidemic prediction would be extremely valuable
for accelerating progress in epidemic management.
For one example, being able to predict the place of outbreak of a new influenza virus and to
anticipate the speed of its spread would allow for timely preparations that might keep an epidemic
from becoming pandemic. For another, creating visualization tools similar to those used in
meteorological bulletins would make it possible to disseminate complex scientific information to a
large audience and thus improve risk communication during a global health crisis.
Health forecasting depends on interpreting epidemiological data that are still too scarce for these
interpretations to be reliable for decision making and will never be sufficient by themselves. The
reason for this is that epidemics issue from the combination of a wide range of factors extending well
beyond those captured in epidemiological data. Many of these factors reside outside the health
sector per se, but all must be inventoried and incorporated in any effective health forecasting tool or
protocol. Some of them include selected climate variables, which is why collaboration between
health and climate scientists is so critical to anticipating epidemics.
Ongoing collaboration between meteorologists and health sector experts would establish the
scientific basis for jointly developing epidemic forecasting tools. By working together, these groups of
scientists and public health experts would create a collective reservoir of operationally-oriented
Anticipating Epidemic
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May 2014
knowledge that would be greater than the sum of their separate contributions. The resulting crossfertilization of ideas would generate possibilities for research and applications that would speed up
the evolution of this knowledge. It would also accelerate progress in research initiatives that already
exist by building on them where possible and giving them an operational orientation.
World airline routemap, 2009
Already, concerns for how climate - especially changing climate - will affect health and other areas
motivated the establishment of the Global Framework for Climate Services. The GFCS will provide a
worldwide forum for exchange between climate scientists and stakeholders in areas sensitive to
climate such as health.
To move forward this kind collaboration, we propose establishing a worldwide forum for
discussion and scientific exchange, including researchers, modellers, decision-makers, and research
funding agencies representing both the health and meteorological sectors. The forum would
identify pilot projects in priority areas such as influenza pandemic prediction, cholera outbreak
forecasting in countries where cholera is endemic, and major vector borne diseases (dengue, yellow
fever, zika virus and chikungunya). The point of its work would be to create operational tools for
anticipating epidemics, identifying the indicators required for these tools to work, and adapting
surveillance and data collection systems accordingly. As progress is made, it will be necessary to
create or reconfigure communication platforms to disseminate the forecasts produced.
Anticipating Epidemic
© World Health Organization 2014. All rights reserved.