Post-Vaccination Monitoring

Samia Metwally, DVM, PhD Senior Animal Health Officer (Virologist) Animal Production and Health Division FAO of UN, Rome, Italy samia.metwally@fao.org

• Why post-vaccination monitoring (PVM)?

• Objectives of PVM

• PVM Guidelines

• Progress and next steps

Overview

• Challenges: – Vaccine quality, availability and

storage at optimum temp – Animal identification

• Uncertainty: – Country acceptance to implement – Transparency!!

• Gaps: – Vaccine quality control centers – Validated PVM screening tools – Producers awareness and incentive

3

Needs: – Develop PVM guidelines to

integrate into: – vaccination programs (PCP-

FMD) – OIE endorsed official control

program for FMD

• Vaccine efficacy: percent reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions

• Vaccine effectiveness: ability of vaccine to fulfill outcomes of interest in the “real world” = field efficacy

Vaccine Efficacy vs. Effectiveness

Host factors • age • health condition • prior exposure • time since

vaccination

Vaccine characteristics • potency

• stability • shelf life • purity • vaccine

composition • adjuvant

Application • vaccination

strategy • vaccination

campaign • trained

vaccinators • cold chain

Match to circulating

virus

Factors Impacting Vaccination Program Effectiveness

Informing cost effectiveness

• Where the balance rests depends upon understanding the proportion of the disease burden that is vaccine preventable

= VACCINE EFFECTIVENESS

• At any vaccine cost, the greater the burden of disease and the greater the proportion that is vaccine preventable, the more cost effective a program will be

Cost of Vaccine Cost of Disease

Incentives for post-vaccination monitoring

• PVM is critical to: – Optimize vaccination programs – Optimize use of limited resources – Demonstrate impact of vaccination program on disease

burden (justify cost) – Stimulate production of quality vaccine and/or

development of improved vaccines

A. Vaccinating to reduce clinical FMD incidence (PCP-FMD stage 2)

B. Vaccination to eliminate FMD virus circulation (PCP-FMD stage 3)

C. Vaccination to maintain FMD freedom (PCP-FMD stages 4 & 5)

D. Vaccination to regain FMD freedom

Objectives of vaccination programs Categories of Epidemiological setting

• Practical guidance on how to evaluate the effectiveness of

FMD vaccination program

• Tailored to needs of countries at different stages of FMD

control (PCP-FMD stages freedom reintroduction)

Post vaccination monitoring guidelines Aims

Structure of the guidelines currently in draft

»Preamble • Chapter 1. Vaccine attributes • Chapter 2. Vaccine delivery, schedule and coverage • Chapter 3. Evaluation of the immune response • Chapter 4. Monitoring the impact of vaccination and

other control measures » Annexes » References

Chapter 1. Vaccine attributes

• Vaccine types • Vaccine matching and

selection of vaccine strains

• Consideration when purchasing vaccine – Vaccine purchase through a

tender procedure • Information provided by the

tenderer • Information provided by

manufacturers

• Vaccine quality – Requirements during

manufacturing process – Requirements for

registration process

Chapter 2. Vaccine delivery, Schedule and Coverage

• Vaccine delivery – Packaging – Cold change and logistics

managements

• Vaccination coverage No. animal vaccinated/No.

eligible for vaccination

• Vaccine schedule – Booster dose – Every six month – till 2 years

of age – Annual vaccination older

than 2 years of age

• Immunization coverage % vaccination coverage X %

developed desirable antibody titers

Chapter 3. Evaluation of the immune response • to reduce clinical FMD

incidence – Ab level at individual level – Ab epi-unit level

• to eliminate FMD virus circulation – Ab level at individual level – Ab level at herd level

• to maintain FMD freedom

– Ab level at individual level – Ab level at herd level

• to regain FMD freedom – Ab level at individual level – Ab level at herd level

• For all: points of sample collection, suggested values for expected proportion of animals with desirable level of antibodies at a given age group

- Objective to evaluate immune response to vaccine batch under local condition and using locally available lab tests, when vaccine quality is uncertain

- Study design: - 50 vaccinates and 5 control - Monitored for 6 month under good farm biosecurity - Determine SP and NSP at 5, 21, 30, 60, 120 and 180 days

Field trial for evaluation of vaccine induced

immune response

Chapter 4. Monitoring the impact of vaccination and other control measures

• Monitoring vaccination program with expected outcomes: 1. The incidence of disease or FMDV infection is reduced. 2. The incidence of disease or FMDV infection is below a defined target value. 3. The incidence of disease or FMDV infection is shown to be absent.

• Monitoring FMD clinical outbreaks

• Monitoring FMD infection

Some challenges to overcome

Correlation between protection and antibody titers not disclosed for some virus strains – Potential solution to request these information from manufacturers

and reference sera upon purchasing the vaccines – Pilot study protocol included in the document

Tests for PVM using homologous vaccine strains – currently addressed with Reference Labs

Next Step

Review draft by expert team then the working group Publication (end of 2014)

FAO manual OIE publication Peer-reviewed journal

Revision, if need be, after validation in countries - FAO and EuFMD projects.. any other projects Provide training

• FMD roadmap meetings • PCP trainings • Others

PVM Expert Team Meeting Consultation • Samia Metwally, FAO

• Susanne Munstermann, OIE

• Kees van Maanen

• Giancarlo Ferrari

• Kris de Clercq

• Tim Doel

• Alistair King

• Keith Sumption

• Sergio Duffy

• Phaedra Eblé

• Mary Joy Gordoncillo

• Mokganedi Mokopasesto

• David Paton

• Theo Knight-Jones

• Aldo Dekker

Thank you for your attention