The Role of Risk Analysis in theJudgement of Equivalence

Zero risk and trade

• Zero risk does not exist

• Trade implies risk

• Lack of trade also implies risk• Unregulated trade

Risk analysis

• A process composed of:

– Hazard identification

– Risk assessment

– Risk management

– Risk communication

Definition of Risk Assessment

Evaluation of the likelihood of entry, establishment and spread of a disease and

the associated potential biological and economic consequences and its impact on

public health

Three questions:

• What can go wrong?

• How likely is it?

• If it happens, what is the magnitude of the consequences?

Hazard

• Source for potential damage

• Cause of the adverse event

Probability of occurrence of an adverse event

and

the magnitude of consequences

Definition of Risk

Is disease exotic to

importing country?

Yes

Requires scientific

demonstration

Legitimate SPS

measure

NoIs disease under

official control?

Yes

Invalid SPS

measure

Are same SPS measures

required internally?

No

Are countries with equivalent

health status treated equally?

(non discrimination)

Are SPS measures based on

international standards (OIE Code) or

on a scientifically valid risk

assessment?

Yes

No

YesNo

Risk assessment

• Release assessment

• Exposure assessment

• Consequence assessment

• Risk estimation

Release assessment

Exporting country

Exposure assessment

Importing country

Consequence assessment

Release assessment

• Describes possible pathways for the introduction of a disease agent• Biological factors

• Country factors

• Commodity factors

Exposure assessment

• Describes the pathways leading to an outbreak• Volume and use of the commodity

• Density and distribution of susceptible animal populations

• Immunity

• Vectors

• Seasonality

Scenario trees

Herd infected?

yes

no

No risk

Importation of meat from country x

Initial event

Scenario trees

Herd infected?

Animal infected?

yes

yes

no

no

No risk

No riskImportation of meat from country x

Initial event

Scenario trees

Herd infected?

Detected during inspection?

Animal infected?

yes

yes

yes

no

no

no

No risk

No risk

No riskImportation of meat from country x

Initial event

Scenario trees

Herd infected?

Detected during inspection?

Animal infected?

Agent survives process?

Susceptible species exposed?

yes

yes

yes

yes

Riskyes

no

no

no

no

no

No risk

No risk

No risk

No risk

No riskImportation of meat from country x

Initial event

Risk management

• Risk evaluation

• Determination of the appropriate level of protection

• Option evaluation

• Implementation

• Monitoring and review

Exposure probability

Relea

se pro

bab

ility

Insignifi-

cant

Extre-

mely

low

Very

low

Low Slight Modera

te

High

High I EL VL L S M H

Moderate I EL VL L S M M

Slight I I EL VL L S S

Low I I I EL VL L L

Very low I I I I EL VL VL

Extremely low I I I I I EL EL

Insignificant I I I I I I I

Consequences

Insignifi-

cant

Very

low

Low Modera-

te

High Extreme

Relea

se an

d ex

po

sure

pro

ba

bility

High I VL L M H E

Moderate I VL L M A E

Slight I VL L M A E

Low I I VL L M A

Very low I I I VL L M

Extremely low I I I I VL L

Insignificant I I I I I VL

Equivalence

• Recognition that different SPS measures may achieve similar results

• Allows for flexibility in the organization of veterinary services, surveillance systems, etc.

Role of epidemiology in equivalence

• Develop methods to compare the effect of mitigation measures

• Develop criteria to define the appropriate level of protection

• Focus on outputs rather than approaches

Equivalence of surveillance systems

Surveillance component Sensitivity (SE) of each component

Country A Country B Country C

Passive surveillance 0.6 0.7 0.6

Survey 0.95 0.90 0.73

Slaughter surveillance 0.75 0.75 0.5

Overall system SE 0.995 0.992 0.947

1-((1-SE1)*(1-SE2)*(1-SE3))

Overall probability of detection

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0.91 0.9325 0.955 0.9775 1

Country A

Country C

Country B

Disease freedom

• Is disease freedom the only answer?

– Traditionally has been the goal

– May not be achievable in a reasonable time frame

– For some diseases may not be achievable at all

• Are there other options?

A shift in approach

FREE

NOT

FREE

Alternatives

• Country freedom– Does the country present

negligible risk?

• Regionalization– Does the geographical area

present negligible risk?

• Compartmentalization– Does the management

system present negligible risk?

• Commodity-based trade– Does the product present

negligible risk?

All depend on

• Effective veterinary services– Veterinary accreditation

– Para-vets, CAHWs

• Producer participation

Commodity-based trade

• The OIE Code explicitly mentions for each listed disease:

– Commodities for which no measures are required• e.g. milk and BSE

• Hides and skins and RVF

– Commodities for which specific requirements have been established• e.g. beef and Foot-and-Mouth disease

Commodity-based trade

• Different approaches depending on the presence or absence of the agent in the commodity

• CBT allows to trade from countries or zones where disease is still present

• CBT is NOT a substitute for efficient official veterinary services– Certification processes still required

Example of layered mitigations in CBT

Country or zone level – Outbreak prediction and surveillance– RVF mitigation program based on risk-based decision

making Herd-level

Surveillance or vaccination

Animal level Ante and post-mortem inspection

Commodity level Maturation Deboning

Stepwise approach

• How do we improve existing systems?– Are there ecosystems or time periods where the

prevalence of disease is naturally lower?

– Do the existing production systems lend themselves to compartmentalization?

– How can we provide assurances to trading partners that trade is “safe” i.e. with an acceptable level of risk?

Risk, trust and trade

• Trade is based on trust

• Trust is a very delicate commodity

– It takes a long time to develop

– It takes very little to lose it

Transparency

• Trust is based on transparency

– Structure of veterinary services

– Surveillance systems

– Disease reporting

– Production systems

Building trust

• High-level bilateral visits and negotiations

• Accept limitations and plan for improvements

• Establish mechanisms to reinstate trade– Commodities

– Compartments?

Regional approaches

• Regional problems require regional solutions

– Coordinated efforts across borders

• However, certification is still a national responsibility