Emergency vaccination workshop presentations 30 May 2023.pdf

Preparing to use emergency
vaccination for FMD in European
Countries – Post-outbreak
surveillance
Online – 30 May 2023
Kathy Gibson (facilitator)
European Commission for the Control of Foot-and-Mouth Disease

2
Welcome & Agenda
● Emergency Vaccination Workshop
● 30 May 2023 (online)

Alternative approaches for demonstration
of freedom from FMD and their associated
waiting periods after use of a vaccinate-
and-retain policy
David Paton

4
Current WOAH Code requirements when a vaccinate-and-retain policy is
used in a FMD-free country as a response to the introduction of FMDV
● 6 mth minimum for status recovery versus 3 mth for non-vaccination or vaccinate-and-remove policy
● Does not specify the sampling frame or design prevalence for DIVA NSP testing*
● Requires follow-up investigation of all serologically positive findings to determine status
● Does not clearly elaborate on implications of different positive findings
Therefore, a vaccinate-and-retain policy results in more delay and less certainty of what is required and
whether it will be accepted
Also need to bear in mind that from experience, NSP data are often critical in status applications
* Former EU Directive (2003) required DIVA testing of all vaccinated livestock and their unvaccinated offspring (“census
testing”) to substantiate a freedom claim
Preparing to use emergency vaccination for FMD in European countries

5
Are the surveillance guidelines clear and can the minimum waiting
period after vaccinate-and-retain be reduced?
● 2014 review paper by AHG members on DIVA testing and the uncertain
impact of different diagnostic outcomes (FMD carrier issue)
○ Census NSP sero-surveillance not necessary in pigs
○ Evidence from vaccination effectiveness should substantiate freedom claims
● June 2017 AHG considered effectiveness of different surveillance
approaches including risk-based and cumulative
○ Relegated carrier detection importance in vaccinated livestock
○ Recommended enhanced surveillance approaches including abattoir surveillance
for unvaccinated animals
● Nov 2017/Aug 2018 AHG recommendations in latest FMD Chapter
○ Favored a qualitative approach to assessing surveillance and considered
unspecified waiting periods impractical
○ Suggested extra measures needed for a reduced waiting period including
possible use of virological surveillance, such as bulk milk testing, etc
○ Revised questionnaire for earlier recovery of FMD free status

6
New Draft Article 8.8.7. Recovery of Free Status
For a FMD free country or zone previously free from FMD where vaccination is not practiced*, one of the following
waiting periods is required to regain this free status:
a) 3 mths after last case disposed of with stamping-out, without emergency vaccination, and with surveillance in
accordance with Articles 8.8.40. to 8.8.42.; or
b) 3 mths after last case disposed of or the slaughter of all vaccinated animals, with stamping-out, emergency
vaccination and surveillance in accordance with Articles 8.8.40. to 8.8.42.; or
c) 6 mths after last case disposed of or the last vaccination, with stamping-out, emergency vaccination not followed
by the slaughtering of all vaccinated animals, and with surveillance in accordance with Articles 8.8.40. to 8.8.42. This
requires a serological survey based on the detection of antibodies to non-structural proteins NSP of FMDV to
demonstrate no evidence of infection transmission of FMDV in the remaining vaccinated population. This period
can be reduced to a minimum of three months if a country can submit sufficient evidence demonstrating
absence of infection in the non-vaccinated population, and absence of transmission in the emergency
vaccinated population† based on the provisions of point 7 of Article 8.8.40.
*also provision for a FMD free country or zone previously free from FMD where vaccination is practiced
† previously to demonstrate no evidence of infection in the remaining vaccinated population

7
Point 7 Draft Article 8.8.40. Additional measures for early recovery of status
free from FMD where vaccination is not practised or early recovery of status free from FMD where vaccination is practised in the
area(s) where emergency vaccination has been applied but not followed by the slaughtering of all vaccinated animals
Serosurveys required to demonstrate absence of infection in unvaccinated animals that do not show reliable clinical
signs (specified design prevalence: 1% between herds/5% within herds) and absence of transmission in vaccinated
animals
For vaccinated animals:
● Census NSP testing except pigs (specified design prevalence: all epidemiological units/5% within)
Or
● Risk-based sero-surveillance in vaccinated herds, and
● Random sero-surveillance in vaccinated herds (1% between/5% within) in each emergency vaccination area, and
● Intensified clinical and slaughterhouse/abattoir surveillance, and
● Demonstration of vaccine efficacy and vaccination effectiveness, and
● Possible use of virological surveillance

Demonstrating vaccine efficacy and vaccine effectiveness
Vaccine efficacy
● 6PD50 and good match, or
● Vaccine/heterologous challenge study to
demonstrate protection and establish cut-off for
population immunity studies
Vaccination effectiveness
● Strategy and timeliness
● Delivery
● Post-vaccination population immunity

9
Summary of changes
● Possible to regain free status sooner after implementing a vaccination-to-retain policy
● More clarity on infection and transmission
● Design of surveys more prescriptive
● Additional safeguards concerning clinical surveillance and vaccination

10
Any questions?

Australia’s National Science Agency
Methods of post-vaccination
surveillance to demonstrate
absence of transmission of
FMD virus in vaccinated and
non-vaccinated livestock
populations
Wilna Vosloo | 30 May 2023

Proposed changes in Code states: This period can be reduced to a minimum
of three months if a country can submit sufficient evidence demonstrating absence of
infection in the non-vaccinated population, and absence of transmission in the
emergency vaccinated population based on the provisions of point 7 of Article 8.8.40.
• Collecting and testing large numbers of sera to support regaining FMD freedom –
labour intensive and expensive
• Can PO surveillance be more effective using new technologies to add confidence
that virus is not present?
o quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR)
detection of the FMDV genome
o oral fluids (swabs and/or rope tethers), bulk milk testing (BMT) of dairy cattle
Introduction

Methods
• FMD outbreaks in Australia simulated using the
Australian Animal Disease Spread (AADIS) model
• Victorian outbreak scenario (V2) – dairy farm,
September
• Control
o Stamping out with and without emergency ring
vaccination (5 km)
o Two approaches to managing vaccinated animals
(remove or retain)
• Approaches were compared - resources required,
time taken, cost, and effectiveness
Stamping
out without
vaccination
Stamping
out with
vaccination
Remove
vaccinated
animals
Retain
vaccinated
animals
3 months
3 months 6 months

Post outbreak surveillance
• Baseline PO surveillance
approaches based on
previous European FMD
directive
o Non-vaccinated animals -
clinical inspections (cattle
and pigs) and serological
surveillance (sheep)
o Vaccinated animals -
(census) surveillance using
blood samples/NSP tests
Control Areas
Restricted Areas
Infected Premises
Restricted Area Sampling intensity
(herds)
Test procedure within herds
cattle all clinical inspection only
sheep all clinical + 95:5 animal sampling (serology)
pigs all clinical inspection only
Control Area
cattle 95:2 clinical + 95:5 animal sampling (serology)
sheep 95:2 clinical + 95:5 sampling (serology)
pigs 95:2 clinical inspection only
Vaccination zone
cattle all clinical +all animals (serology)
sheep all clinical +all animals (serology)
pigs all clinical + 95:5 animal sampling (serology)*
*While EU Directive requires census sampling, sampling all pigs is considered impractical (Anon.
2007)

• Replace serological testing
• Dairy farms with bulk milk testing
• Piggeries with saliva testing (rope tethers)
• Sheep farms with saliva testing (swabs)
• However, this a modelled example and not the approach for this
workshop
Alternative PO surveillance approaches

• FMDV can be detected in saliva samples up to 14 days post
infection*
• RT-qPCR – detects viral RNA at high Se and Sp
• Serological tests (different Se and Sp in vaccinated and unvaccinated
populations)
• c-ELISA - detects abs due to infection and vaccination (serotype specific)
• NSP ELISA – detect abs due to past and present infection all 7 serotypes
Assumptions in study
*Based on numerous experimental infection studies in different vaccinated and unvaccinated species

Results that informed the study
•Possible to identify one acutely-infected
milking cow in a typical-sized dairy herd
(100–1000 individuals) using milk from bulk
tanks or milk tankers (Reid et al., 2006; Armson
et al., 2018)
Bulk milk
testing
•Experimental: oral fluids (saliva), can be
used to diagnose FMD using RT-qPCR (Grau et
al., 2015; Senthilkumaran et al., 2017)
•Good agreement in experimental studies
comparing ropes to collect oral fluid
samples to individual swab sampling (Vosloo et
al., 2015)
Saliva testing -
pigs
•Can detect one positive sample in a pool of
ten oral swabs - first week of infection
•Can detect one positive in a pool of - one
month after infection (Kirkland, 2016)
Saliva testing
and pooling -
sheep

• Alternative approach replaces:
o on-farm clinical inspection of dairy herds with BMT
o on-farm clinical inspection of pigs with saliva collection using rope tethers
o blood sampling of sheep with oral swabs
o serology is replaced by pooled qRT-PCR
• Alternative, on average:
o reduced the time to complete the surveillance by 12% (12 days less)
o reduced cost by 31% (saving of $AUD 4.3 million).
o no reduction in effectiveness of the surveillance (reduced number of false
positives and reduced likelihood of missing a positive herd)
PO surveillance – no vaccination

• Alternative surveillance approaches for vaccinated and retained animals
o Alt 1: reduced sampling intensity (keep serology)
o Alt 2: replace serology with oral swabs and pooled qRT-PCR
o Alt 3: as for Alt 2 plus replaces on-farm visits and sample collection for dairy herds with BMT
and pig herds with saliva sampling ropes
• Alternative approaches took less time (1-3.8%) and were less expensive (1.5-7.3% ) than
the baseline.
o Alt 2 and Alt 3 - could reduce the number of false positives and false negatives
o Alt 3 consistently performed the best (reduced average cost of surveillance by 7.3%)
PO surveillance - vaccination

• Combining the alternative approaches for unvaccinated and vaccinated animals (unvacc alt +
vacc alt3)
o Reduce average surveillance time by 12% (11 days) and average surveillance cost by 27% (AUD 3.7
million)
Combining the outputs

• Alternate sampling detects active infection whereas serology
indicates previous infection of unknown time points
• Alternative approaches based on non-invasive sampling methods
and qRT-PCR tests - potential to enable post outbreak surveillance
to be done more quickly and less expensively than traditional
approaches based on serological surveys
Conclusions

Australia’s National Science Agency
Health & Biosecurity
Wilna Vosloo
Group Leader
+61 3 5227 5015
Wilna.Vosloo@csiro.au
https://research.csiro.au/fmd
Thank you
Acknowledgement
Graeme Garner
Sorada Tapsuwan
Richard Bradhurst
Ann Hilberg Seitzinger
Andrew Breed
Tim Capon
DOI: 10.1016/j.prevetmed.2021.105441

23
Epidemiological Modelling
The European Foot-and-Mouth Disease Spread Model (EuFMDiS)
● Multi-country FMD spread simulation model supporting
contingency planning in FMD-free countries
● Models within-herd and between-herd spread of infection
● Incorporates European approaches to control measures
● Detailed output information on epidemiological and
economic implications, including required capacity of human
resources
Emergency Vaccination Workshop
30 May 2023 (online)

24
Post-outbreak Management
EuFMDiS allows:
○ Comparison of different approaches to managing vaccinated animals when vaccination
has been used as part of the response
○ Study of different approaches to surveillance in vaccinated and non-vaccinated
populations to help regain FMD-free status
FMD
incursion
First
detection
End of control phase;
Lifting of control
measures and restrictions
Official
FMD-free
status
Post-outbreak Management
Control phase
Silent phase
Post-outbreak Management in EuFMDiS
Webinar, 15 November 2022

25
Post-outbreak Surveillance in EuFMDiS
• According to OIE/WOAH Code (and EU legislation where relevant)
• Clinical inspections, epidemiological surveys and laboratory testing of vaccinated and non-
vaccinated animals
• Sampling should not begin until at least a month after the last outbreak or last use of emergency
vaccine; Cleaning and disinfection of infected holdings are completed
• For this workshop: Level of surveillance in vaccinated and non-vaccinated populations as
specified in current and draft WOAH Code Articles 8.8.40
Principles

26
Introduction to breakout room activities
Scenarios and assumptions
● Scenario: FMD outbreak in Austria/Denmark/Ireland
● Decision has been made to use emergency vaccination
● Other control measures include:
○ Culling of livestock on infected holdings, disposal
& decontamination
○ Movement restrictions
○ Tracing and surveillance
● High potency vaccines used (≥6 PD50/dose);
○ good match to field strain;
○ onset of immunity 4-6 days
● Vaccination commences at 14 days

27
Introduction to breakout room activities
Comparisons of post-vaccination surveillance options
● Vaccinated population removed (culled) (A)
○ Proof of freedom surveillance for unvaccinated
populations as per WOAH Terrestrial Code
● Vaccinated population not removed (retained)
○ 6 month recovery period with census surveillance (B)
○ 3 month recovery period with census surveillance (C)
○ 3 month recovery period with risk-based surveillance (D)
● Post-outbreak resourcing
○ Capacity to depopulate vaccinated animals (if removing)
○ Human resourcing for surveillance
○ Laboratory capacity for NSP testing
Total cost of outbreak
Example data

28
Median
Outliers
}Whiskers
Credit: Wikimedia commons
}
Whiskers
Data presentation
Total cost of outbreak

Definitions used in this workshop
● Vaccinate-to-remove ("vaccinate to kill"): all vaccinated livestock are removed (culled) post-outbreak
● Vaccinate to retain ("vaccinate to live"): vaccinated livestock remain in the population
● Recovery period: time to recover the animal health status in place prior to the outbreak
● Time 'out of market’: time between first detection of FMD and eligibility to regain FMD-free status
● Loss of trade: – estimated value (€) of international trade as reported in the model
● Post-outbreak management: includes surveillance of vacc and non-vacc populations; removal of
vaccinates under vacc to remove policy)
● Epidemiological impact: number of infected farms and duration of control of outbreak
29

Breakout room instructions
For each scenario
● Room facilitator will present the scenario
● Discuss the effect of post-outbreak surveillance alternatives on:
○ Time to complete post-outbreak management
○ Number of animals culled
○ Animals sampled/tests done
○ Cost of post-outbreak management
○ Minimum time to support proof of FMD freedom without vaccination
○ Trade losses
○ Total cost of outbreak
● Return to plenary at approximately 12.30 CEST*; discuss results AFTER LUNCH.
30

Report back on scenario discussions
31

Conclusions (Austria scenario breakout room 1)
6
• Employing emergency vaccination to control FMD outbreaks has a substantial impact on the intensity of post-
outbreak surveillance which can be reduced by replacing the current standards with alternative surveillance
approaches
• Sufficient surveillance, laboratory, and removal capacities are essential for the effective employment of emergency
vaccination strategies and post-outbreak management
• Removing vaccinated animals had the highest post-outbreak management cost and highest total cost due to time
required and cost of slaughtering and disposing of vaccinated animals and compensation payments
• Risk-based surveillance approach (acc. to WOAH Code draft article 8.8.40) leads to the highest economic efficiency
with no reduction in the effectiveness of the post-outbreak surveillance
• Increasing the capacity of human resources for post-outbreak surveillance leads to a significant reduction of its length
and therefore contributes to a faster free-status recovery

Break-out Group Discussion
(Austria scenario breakout room 1)
6
• Export losses amount to ~90 % of total losses -> recovery periods should be subject to further discussion
• It was surprising that the difference in samples taken between ‘B’, ‘C’ and ‘D’ wasn’t even more significant
• Comparing the results with larger outbreaks would lead to clearer differences between the scenarios
• The surveillance was based on serological testing
• Can laboratory capacities be increased?
• Wildlife component was not considered
• Depending on a situation, in a potential FMD-outbreak in Austria, emergency vaccination as a control measure would
be implemented under careful consideration

Conclusions (Austria scenario breakout room 2)
6
• Employing emergency vaccination to control FMD outbreaks has a substantial impact on the intensity of post-
outbreak surveillance which can be reduced by replacing the current standards with alternative surveillance
approaches
• Sufficient surveillance, laboratory, and removal capacities are essential for the effective employment of emergency
vaccination strategies and post-outbreak management
• Removing vaccinated animals had the highest post-outbreak management cost and highest total cost due to time
required and cost of slaughtering and disposing of vaccinated animals and compensation payments
• Risk-based surveillance approach (acc. to WOAH Code draft article 8.8.40) leads to the highest economic efficiency
with no reduction in the effectiveness of the post-outbreak surveillance
• Increasing the capacity of human resources for post-outbreak surveillance leads to a significant reduction of its length
and therefore contributes to a faster free-status recovery

Remarks from group discussion
(Austria scenario breakout room 2)
6
• Trading partners unwilling to accept vaccinated animals and products
• There may be seasonal differences in efficiency and costs of surveillance
• Resources for vaccination remains an issue, but scenario shows that vaccination-to-retain is a good approach to
consider and overcome limited culling capacity
• Bottlenecks for vaccination-to-cull is culling capacity (reputational impact for slaughterhouses) and ethical implications
• Still looking for the threshold in size of outbreak to decide for vaccination

Conclusions Denmark scenario
6
• Laboratory capacity with N=3570 nsp ELISA and 286 PCR per day is sufficient in order to perform
post-outbreak surveillance (no impact by doubling the laboratory capacity)
• Sufficient surveillance, and removal capacities are essential for the effective employment of
emergency vaccination strategies and post-outbreak management -> recommendation to invest in
human resources for post-outbreak surveillance and increase the rate at which vaccinated animals
can be removed
• Increasing the capacity of human resources for post-outbreak surveillance leads to a significant
reduction of its length and therefore contributes to a faster free-status recovery
• Vaccination-to-retain (3-month recovery, risk-based surveillance) was the most beneficial strategy for
Denmark. This includes also the comparison with the stamping-out policy- without vaccination
• Removing vaccinated animals caused the highest length of post-outbreak management, post-
outbreak management costs and highest total cost due to time required and cost of slaughtering and
disposing of vaccinated animals and compensation payments

Discussion Denmark scenario
6
•Difficulty of knowing if strategy D accepted by WOAH/other countries. Transition from technical
decision making to global trade politics is difficult to comment on. It may take several years before
accepted by international community - this may not be acceptable to policy makers
•“Worst case scenario”: Importance of the type of index case and the individuality of each outbreak –
decisions are made at the time and not in hindsight and therefore need to take into account results of
multiple epidemics/index herds scenarios – a full picture in order to make a decision
•Importance of resources and the reality of having discreet human resource pools for each function,
and how resourcing during the control phase is managed
•Ensuring that each time period was clearly defined (i.e control vs surveillance) and where the model
allowed movement between these phases (i.e. if a case was identified in the surveillance phase and so
would move back to control phase), and how this was parameterised, especially with respect to
sensitivity/specificity of testing.

Conclusions Ireland scenario
6
• The reduction in time to regain FMD freedom status is only significant when the post-outbreak
surveillance can be completed in the same amount or less time than the recovery period. Therefore,
sufficient surveillance, laboratory, and removal capacities are essential.
• Risk-based surveillance approach (acc. to WOAH Code draft article 8.8.40) leads to the highest
economic efficiency with no reduction in the effectiveness of the post-outbreak surveillance
• Increasing the capacity of human resources leads to a significant reduction in the duration of an
outbreak and therefore contributes to a faster free-status recovery
• Removing vaccinated animals was completed quicker than completing post-outbreak surveillance
sampling but incurred the highest post-outbreak management cost, total outbreak cost and longest
time out of market. This strategy was not deemed to benefit the country in any way and resulted in a
lot more animals being culled. There may also be increased risk involved in transporting the
vaccinated animals to slaughter plants.

Break out discussion Ireland scenario
6
• Investigate options on how human resources could be increased exponentially. This could be through
sharing emergency response staff including veterinary professionals between countries and training
paraprofessionals in relevant skills related to outbreak control and surveillance. Similarly, options on
how lab capacity might be increased should be examined.
• It is important to acknowledge that the opinion of the product destination when it comes to trade
may be different from WOAH and they may decide not to immediately accept the FMD-free status
even if it is determined as such by WOAH.
• It is important to acknowledge, that while this workshop assumes that a good vaccination matching
the field strain is available to use in 14 days, it is possible that proving the efficacy of this vaccine
may take longer than the recovery period.

Break out discussion Ireland scenario
6
• Surprising the small difference between census surveillance approach and risk-based surveillance.
Again, this emphasizes the importance of resource.
• Difficult to predict how markets will react – Belgium commented how they are free of ASF for 2
years but still trying to recover trade.

fao.eufmd.org eufmdlearning.works eufmdvirtual.com EuFMD Trello board
Thank you !.
#eufmd #movefast

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