Why we need a practicaldisaster epidemiology

Why we need a practicaldisaster epidemiology

David AlexanderUniversity College London

Analysis

• registered• archived• forgotten• ignored

Vulnerabilitymaintained-

• utilised• adopted• learned

Disasterriskreduced

+

Lesson

s

Pastevent

s

The process ofdisaster riskreduction(DRR)

Learningprocesses

Improved

safety

Lessonlearned

Change andinnovation

Experienceand theory

Recognition andcomprehension

Lesson tobe

learned

• Unexpected event

• New circumstance

• Error• New

practice

Self-protectivebehaviour

Hospitalmass-casualty

response

Urban searchand rescue

(USAR)

A practical disaster epidemiology

Focus Potential benefit to...

How, whereand why

people died;who they were;

how theyreacted to

the disaster

Sendai Framework for DisasterRisk Reduction, para. 24(1), 33(n)Promote the collection, analysis,

management and use of relevant dataand practical information. Ensure its

dissemination...

Establish a mechanism of case registryand a database of mortality caused by

disaster in order to improve theprevention of morbidity and mortality;

Physical injury (physical trauma):-• short-term condition• long-term injury or disease• fatal injury• premature death.

Psychological impairment:-• depression• anxiety• post-traumatic stress (including long-term).

Disaster injury epidemiology

DISASTERVICTIM

NOT INJURED INJURED

HEALTHY INFECTEDWORSENINGOF PATIENT'SCONDITION

IMPROVEMENTOF PATIENT'SCONDITION

RECOVERS

IMPROVEMENTOF PATIENT'SCONDITION

DISEASES INJURIES

Public health measures

Search and rescue

Mortuaryand funeral

services

WORSENINGOF PATIENT'SCONDITION

DEATH

Medical assistance

Medical assistance

• failure to collect data [systematically]

• post-event data collection is not reliable enough

• few epidemiological researchers are specialists in this field

• most research consists of isolated clinical studies

• patient confidentiality issues.

Constraints on progress

Earthquakes as archetypicalsudden-impact disasters: toward

an evidence-based approachto earthquake epidemiology

After more than 30 years of study,

the causes and patterns ofinjury are still poorly

understood.

Magnitude Location Date Deaths Injuries D/I

6.7 Northridge, California

17.01.1994 57-72 8,700

0.0007

7.3 Kobe, Japan17.01.199

5 6,434 14,678 0.44

7.4-7.5 İzmit, Turkey17.08.199

917,127-45,000 43,959 0.39

9.1-9.3(*tsuna

mi)

Indonesia, Indian Ocean*

26.12.2004

184,167-

276,025125,000 2.21

7.6 Kashmir, Pakistan

08.10.2005 74,702 106,280 0.70

7.9 Wenchuan, China

12.05.2008 69,180 374,176 0.19

7.9 Padang, Indonesia

30.09.2009 1,115 2,902 0.38

7.0 Haiti12.01.201

046,000-316,000

uncounted --

6.3 Christchurch, New Zealand

11.02.2011 185 6,800 0.03

9.0 Eastern Japan*

11.03.2011 19,009 26,992 0.70

• no standard definitions (regarding incidence and prevalence)

• lack of comparability and compatibility of existing data

• regularities exist but are poorly known

• to what extent is injury predictable?.

What is an earthquake-related injury?

Injury distribution reported in 67 earthquakes

Poor buildingquality

(low seismicresistance)

Proximityto epicentre

and faultrupture

Topographicamplification

Sedimentaryamplification

Q E

T S

Concentrationof casualties

C

Casualties = f { E,Q,S,T }

Deaths

InjuriesQ E

T S

The ratio of deaths to collapsedbuildings varies from 8:100 to 32:100

Entrapment increases the riskof death by 35-100 times

• respiratory difficulties caused by pressure of fallen objects on the thorax or ingestion of large amounts of dust

• 2-6 hours after the earthquake fewer than half of trapped people are still alive.

No damageto buildings

Damageto buildings

InjuriesEmergency roominjuries

Hospitaladmissions

Source: Linda Bourque, UCLA

Axiom: building collapse(structural failure) is the main

source of damage in earthquakes

What impact does self-protectivebehaviour have on injury rates? .

Behaviour

Vulnerability of thebuilt environment

Interaction

Force majeure:the earthquake

Perception

Knowledge, habit,custom and training

Active behaviour:• journey to and from work• recreational activities, etc.• family life at home

Active behaviour:• journey to and from work• recreational activities, etc.• family life at home

Passive behaviour:• sleeping at night• role, efficiency and rapidity of search and rescue and medical assistance after the earthquake.

Passive behaviour:• sleeping at night• role, efficiency and rapidity of search and rescue and medical assistance after the earthquake.

Behavioural influence on casualties

Seekplace ofrefuge

Remainin situ

Seekpotential

cavityRushoutside

Unexpected earthquake

Mildimpact

Severeimpact

Catastrophicimpact

Verylimiteddamage

Fall ofheavy

objects

Partialcollapse

Totalcollapse

Absolute immobility Frantic egress

UninjuredLightlyinjured

Seriouslyinjured Killed

Expected pattern of injuries

minor injuries:bruises, lacerations, etc.

simple fractures

seriousmultiple injuries

Ratio of serious to slight injuries: from 1:9 to 1:30

dead

Spatial model of deathsand injuries in earthquakes

Four hypotheses of earthquake casualty distribution

• differences in exposure to risk, perception and behaviour

• social constraints on self-protection

• higher psychological burden

• demographic preponderance in old age.

Why are women and girls moreat risk than men and boys?

• ability to prepare for incidence of particular injuries

• need for mass-fatality planning

• social benefits of behavioural modification to avoid injury

• bolster arguments for investing in stronger buildings.

Better death and injury data

Dead bodies do not cause epidemics.

Hasty mass burial is not a goodresponse to a mass fatality situation

This simple observation has taken decadesto establish and is still not known

or accepted by all decision-makers.

Thank you foryour

attention!

david.alexander@ucl.ac.ukemergency-planning.blogspot.comwww.slideshare.net/dealexander