The new england journal o f medicine
1836 n engl j med 369;19 nejm.org november 7, 2013
Natural Disasters, Armed Conflict,
and Public Health
Jennifer Leaning, M.D., and Debarati Guha-Sapir, Ph.D.
From the FranÃ§ois-Xavier Bagnoud Center for Health and Human Rights, Harvard
School of Public Health, Boston (J.L.); and
the World Health Organization Collaborating Center for Research on the Epidemiology of Disasters, Institute of Health
and Society, University of Louvain, Brussels (D.G.-S.). Address reprint requests
to Dr. Leaning at the FranÃ§ois-Xavier Bagnoud Center for Health and Human Rights,
Harvard School of Public Health, 651 Huntington Ave., 7th Flr., Boston, MA 02115,
or at [email protected]
N Engl J Med 2013;369:1836-42.
Copyright Â© 2013 Massachusetts Medical Society
Natural disasters and armed conflict have marked human existence throughout history and have always caused peaks in mortality and
morbidity. But in recent times, the scale and scope of these events have
increased markedly. Since 1990, natural disasters have affected about 217 million
people every year,1 and about 300 million people now live amidst violent insecurity
around the world.2 The immediate and longer-term effects of these disruptions on
large populations constitute humanitarian crises. In recent decades, public health
interventions in the humanitarian response have made gains in the equity and
quality of emergency assistance.
Natural disasters are broadly classified as biologic, climate-related (hydrometeorologic), or geophysical (Table 1). (Biologic events are not considered in this
article because they require very specific analytic approaches and are often not
directly connected to geophysical and climate-related disasters.) There were three
times as many natural disasters from 2000 through 2009 as there were from 1980
through 1989 (Fig. 1 and interactive graphic, available with the full text of this
article at NEJM.org). Although better communications may play a role in the trend,
the growth is mainly in climate-related events, accounting for nearly 80% of the
increase, whereas trends in geophysical events have remained stable. During recent
decades, the scale of disasters has expanded owing to increased rates of urbanization, deforestation, and environmental degradation and to intensifying climate
variables such as higher temperatures, extreme precipitation, and more violent
wind and water storms. The effects of disasters on populations include immediate
death and disabilities and disease outbreaks caused by ecologic shifts. For example, the 2010 earthquake in Haiti and Cyclone Nargis, which hit Myanmar in
2008, killed 225,000 and 80,000 people, respectively, in a matter of minutes; destroyed health care facilities; and left many homeless.
In contrast, armed conflicts have decreased globally, although some persist,
with entrenched internal violence lasting for years, such as in Darfur (in Sudan)
and in the eastern Democratic Republic of Congo. Advances in small-arms technology and struggles over natural resources of international value (oil and rare
minerals) make conflict resolution challenging. Civilians bear the burden. Families
are forced to move from their homes to escape internecine violence. Refugees cross
national borders and are legally entitled to assistance in United Nations (UN)â€“
managed camps. But increasingly since the mid-1980s, people have been unable to
cross international frontiers and so remain internally displaced (Fig. 2). They are
often at higher risk for malnutrition and disease than residents or refugees.3
A dva nces in Hum a ni ta r i a n Public He a lth R esponse
The early 1970s were watershed years for public health in emergencies. The Biafran
War (in Nigeria), the 1970 cyclone in Bangladesh, and the sweeping famines in Africa
from 1950 through
2012 is available
n engl j med 369;19 nejm.org november 7, 2013 1837
deeply engaged the public health community in
trying to meet the need for impartial and effective
medical aid. The use of epidemiologic methods
to reduce civilian morbidity and mortality in mass
emergencies began in earnest at this time.4,5 This
period also saw the engagement of health care
practitioners in the elaboration of international
norms on ethics, human rights, and humanitarian
law in emergency settings.6-8
Public health is a major component of the
larger operational framework of international
relief. It includes disease control, reproductive
health and maternal care, psychosocial support,
short-term or emergency medical and surgical
interventions, and sanitation and nutritional services. Although the health needs during and after
natural disasters and armed conflicts are similar, the differences arise from the political complexities of the latter, in which civilian populations serve as targets of war and human rights
abuses aggravate health and protection needs.
The main health consequences of internal
armed conflicts are not combat-related injuries
and deaths. Mortality is driven by many direct
and indirect factors (Fig. 3); severe malnutrition,
malaria, and other common childhood diseases
are the main factors.10 Typically, health status
deteriorates as violence and insecurity lead to
population displacements and the breakdown of
health care systems and supply chains; this
breakdown, in turn, degrades essential services
such as vaccination programs, maternal care, and
The main relief needs in natural disasters are
water, food, sanitation, and shelter. Poor countries require more extensive assistance than
wealthier ones, although severe natural disasters
in wealthy regions, such as the 2011 tsunami in
Japan, create needs that challenge nation-based
responses. In disasters, unlike armed conflicts,
the need for emergency relief is comparatively
short-lived. However, in some underresourced
regions hit by recurrent natural disasters, such
as South Asia and Haiti, there is now increasing
evidence of longer-term health effects, such as
chronic malnutrition, mediated through intensifying food insecurity.11,12
In acute disasters, such as earthquakes and
cyclones, physical trauma may require specialized interventions. The probability of survival
from serious injury decreases substantially 12 to
24 hours after the disaster strikes, and good outcomes in most cases are thus highly dependent on
the rapidity of appropriate medical and surgical
responses.13 Advance preparedness of local health
care personnel in search-and-rescue capacities
and immediate emergency care are crucial for
improving victim survival. An additional requirement that is less widely recognized is for adequate local follow-up nursing care and infection
control in postoperative settings and rehabilitation services.
E x pa nding Use of Epidemiol o gic
Methods in Crises
The critical role of epidemiologic methods in
natural disasters was recognized in the 1970s
and 1980s in studies after a series of massive
catastrophes,14,15 including the Bangladesh cyclone,16 Guatemala17 and Naples18 earthquakes,
and African Sahel famines.19 These populationbased quantitative assessments identified determinants of mortality that helped improve future
preparedness and the response of medical teams.
Innovative approaches for rapid medical assessment among refugees from the Pol Pot mass killings in the Thai border camps in 1979 and 1980
also drew attention to the importance of conducting an early and accurate evaluation of needs.20
During humanitarian responses to the subsequent wave of African famines and postcolonial
civil wars in the 1980s, these epidemiologic methods were widely applied. Health analysts were
Table 1. Classification of Natural Disasters.*
Epidemic infectious disease: viral, bacterial, parasitic, fungal, prion
Mass movement (dry): rockfall, landslide, avalanche, subsidence
Flood: general flood, flash flood, storm surge or coastal flood
Mass movement (wet): rockfall, landslide, avalanche, subsidence
Storm: tropical cyclone, extratropical cyclone, local storm
Extreme temperature: heat wave, cold wave, extreme winter condition
Wildfire: forest fire, land fire
* The classification is from the Center for Research on the Epidemiology of
Disasters, University of Louvain.
The new england journal o f medicine
1838 n engl j med 369;19 nejm.org november 7, 2013
thus able to describe how mortality and morbidity differed across population groups and over
time, providing crucial insights for improving response and preparedness.21 But high population
mobility, the breakdown of vital registration or
surveillance systems, homelessness, and insecurity posed serious methodologic barriers to generalizing from epidemiologic or risk analyses
No. of Disasters
Economic Damage (billions of 2012 US $)
Figure 1. Numbers and Types of Natural Disasters, 1950â€“2012.
The effect of a disaster on the local economy usually consists of direct consequences (e.g., damage to infrastructure, crops, and housing) and indirect consequences (e.g., loss of revenues, unemployment, and market destabilization). The estimated economic damage is
for the year in which the disasters occurred and is given in billions of 2012 U.S. dollars. Data are from the EM-DAT International Disaster
Database, Center for Research on the Epidemiology of Disasters, University of Louvain (www.emdat.be/). Although this database tracks
biologic events, such events are not shown here because they require very specific analytic approaches and are often not directly connected to geophysical and climate-related disasters. No. of People (millions)
Internally displaced persons
Internally displaced persons
Total (UNHCR, IDMC)
Figure 2. Refugees and Displaced Populations, 1964â€“2011.
Estimates are from the Office of the United Nations High Commissioner for Refugees (UNHCR), the U.S. Committee for Refugees and Immigrants (USCRI), and the Internal Displacement Monitoring Centre (IDMC).
n engl j med 369;19 nejm.org november 7, 2013 1839
conducted with small samples. Emergency health
assessments also suffered from the lack of baselines against which to calculate excess deaths
(Fig. 3) and calibrate the criticality of a situation.22
In response to growing concerns regarding
equity and needs-based response, public health
analysts within the humanitarian aid community worked to identify thresholds of key indicators of mortality and malnutrition in order to
classify situations as critical and establish triggers for the provision of emergency relief.23 Recognizing the major implications of using such
thresholds,24 a group of academics, nongovernmental organizations, and UN agencies developed Standardized Monitoring and Assessment of
Relief and Transitions (SMART), a rapid clustersampling method that divides the population
into groups, or clusters, and randomly selects a
sample among these clusters for data collection,
in order to provide statistically sound estimates
of mortality and malnutrition.25 Now widely used
by relief agencies,26 this method generates comparable epidemiologic data to quantify crisis
thresholds and monitor the effectiveness of the
relief,27 strengthening the evidence-based response.
Collecting reliable epidemiologic information
still presents unique challenges in these disrupted field contexts.28 Because the SMART method
does not require household listing, it has advantages over random sampling.29 However, the
relative uncertainties of cluster sampling (lower
levels of precision and constraints on extrapolation of key variables such as mortality) can prove
problematic, because risks are highly variable
across small areas.30 Given the importance of
correctly measuring malnutrition and mortality,
on the one hand, and the shortcomings of cluster sampling in transient settings, on the other,
alternative methods, such as lot quality assurance
sampling (which involves taking a large number
of unusually small random samples from each
set in the population to determine whether they
meet an established standard) or collection of
data from key informants, are increasingly used.31
For insecure settings (e.g., in a zone of conflict),
these alternatives show promising advantages
because of ease of implementation and the provision of nearly real-time estimates of mortality.
Although these advances have contributed to
a greatly improved understanding of the determinants of mortality and morbidity and the effectiveness of aid, the Haiti earthquake response
(2010) revealed persistent weaknesses in international emergency relief, particularly with regard
to initial assessment and coordination. An authoritative evaluation has noted the long delay in
obtaining a â€œrapidâ€ health assessment (reported
on day 45 vs. day 12, which is the standard32),
owing to the widespread initial chaos but also
explicitly to the bureaucratic complexity of the
Total mortality in period of conflict
Expected (normal) mortality
(based on factors such
as regional or preconflict death rates)
(deaths attributable to the conflict in
addition to expected [normal] mortality)
Direct combat-related deaths
(e.g., from massacres, killings, and
bombings), mostly in adults
(e.g., from epidemics, breakdown
in food supply, and inaccessibility
of health and other essential services),
mostly in civilians and children
Figure 3. Conflict-Related Deaths.
Adapted from Guha-Sapir and van Panhuis.9
The new england journal o f medicine
1840 n engl j med 369;19 nejm.org november 7, 2013
UN Health Cluster system.33 Trauma response by
foreign field hospitals in a recent review was
found to be completely uncoordinated and poorly documented. The field units arrived in unprecedented numbers (44 total vs. 41 for the 2005
Pakistan earthquake) but much later than recommended for clinical efficacy (a mean of 10.2 days
after the earthquake rather than the standard of
1 to 5 days) and left scant and scattered information on surgical outcomes and patient follow-up.34
Evolving Norms and Practice Guidelines
for Public Health Response
Much of the progress described above has been
driven by the ethical imperatives of medical and
public health interventions in humanitarian emergencies. Ensuring unimpeded access to all victims of a disaster or conflict, providing relief according to need rather than political expediency,
and documenting or sounding the alert on grave
human rights abuses are central to the engagement of health care professionals in responding
to humanitarian emergencies. The global health
community has made major advances on these
issues by working within the international humanitarian framework of law and practice.35,36
Normative and operational guidance for health
care responders within the humanitarian community has been codified in a number of key publications (see the Supplementary Appendix, available
Medical responders37 in disaster or conflict
zones face stressful situations that demand experience and seasoned judgment beyond medical
skills. For example, impartial provision of medical care to victims requires negotiating humanitarian space to prevent hostile interference from
local authorities and armed combatants who are
the perpetrators of the violence. Delivering food
or medical aid to vulnerable or high-risk persons
or groups may require population-based triage
decisions that can be technically complex and
The collection of data on sensitive topics such
as mortality estimates, combat injuries, or witnessed human rights violations requires adherence to standards of informed consent, confidentiality, and informant protection. In oppressive
and hostile settings, these standards are difficult
to maintain because of risks to those who provide
information and to those who collect it.39
Norms of equity, particularly in areas of severe need, dictate that the provision of emergency
health care cannot be restricted to the survivors
but must extend to the surrounding poor communities that help take them in.40 Broader societal issues related to humanitarian response are
often neglected, such as the need to maintain
respect for cultural practices regarding death
and grief.41 On occasion, mass emergency interventions may still violate human rights norms of
mutual respect and cause discontent in local communities whose cooperation with external assistance is vital. Experiences from massive earthquakes have shown that the longer-term, social
consequences of such oversights can be severe.42
For instance, the citizens of Soviet Armenia (sensitive to the historical echoes of genocide) were incensed at the Soviet Union for offering to take
orphans in the immediate aftermath of the December 1988 earthquake that killed at least 25,000
people â€” an affront that lingers to this day43
and that foreshadowed the controversy about postdisaster international child adoption that surfaced with the earthquakes in Haiti44 and Japan.45
Much has been learned in the past few decades,
but some important issues need urgent attention.
The rapidity of emergency health care intervention has greatly improved, with teams on the
ground within days, but coordination of health
needs assessments performed by multiple groups
is weak. Although coordination of health data
has been widely recognized as an ongoing problem through in-depth evaluations of the Rwanda
genocide and Haiti earthquake, little progress has
been made in addressing this problem.
Bridging the transition from emergency health
response to local health systems has not been
adequately addressed in most post-conflict or
post-disaster settings and especially in poor regions afflicted by recurrent conflicts or natural
disasters. Sudden infusions of outside aid and
expertise can compromise existing community
public health operations by setting up parallel
systems with different norms and resources.
Abrupt departures of emergency teams may also
leave patients without locally viable follow-up
nursing care. Resolving such transitional issues
by reducing vulnerabilities and strengthening the
n engl j med 369;19 nejm.org november 7, 2013 1841
resilience of local systems will inform the strategies needed to address root causes of these crises.
Finally, humanitarian health care personnel
regularly face political and military barriers to
providing humane and appropriate care for those
most in need.46 These crises often uncover deep
fissures in societies. In particular, humanitarian
health care providers confront the need to maintain silence about witnessed violations of international humanitarian and human rights law in
order to maintain access to stigmatized or oppressed populations.47 These ethical dilemmas
have provoked sustained controversy and require
health care personnel to possess not only medical and public health expertise but also a practical
understanding of when to negotiate or speak out
on the basis of applicable humanitarian norms
and legal principles.48 Health care personnel
need adequate training in these aspects of the
humanitarian response as situations become
increasingly politicized and neutral space constricts.49
The effects of armed conflict and natural disasters on global public health are widespread.
Much progress has been made in the technical
quality, normative coherence, and efficiency of
the health care response. But action after the fact
remains insufficient. In the years ahead, the international community must address the root causes
of these crises. Natural disasters, particularly
floods and storms, will become more frequent
and severe because of climate change. Organized
deadly onslaughts against civilian populations
will continue, fueled by the availability of small
arms, persistent social and political inequities,
and, increasingly, by a struggle for natural resources. These events affect the mortality, morbidity, and well-being of large populations. Humanitarian relief will always be required, and
there is a demonstrable need, as in other areas of
global health, to place greater emphasis on prevention and mitigation.
No potential conflict of interest relevant to this article was
Disclosure forms provided by the authors are available with
the full text of this article at NEJM.org.
We thank Peter Louis Heudtlass, Ph.D. candidate, World Health
Organization Collaborating Center for Research on the Epidemiology of Disasters, Institute of Health and Society, University of
Louvain, Brussels, and Bonnie Shnayerson and Angela Murray,
FranÃ§ois-Xavier Bagnoud Center for Health and Human Rights,
Harvard School of Public Health, Boston, for their help in the
preparation of the manuscript.
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