Post-Vaccination Monitoring

Transcription

1 Post-Vaccination Monitoring Samia Metwally, DVM, PhD Senior Animal Health Officer (Virologist) Animal Production and Health Division FAO of UN, Rome, Italy

2 Overview Why post-vaccination monitoring (PVM)? Objectives of PVM PVM Guidelines Progress and next steps

3 Needs: Develop PVM guidelines to integrate into: vaccination programs (PCP- FMD) OIE endorsed official control program for FMD Uncertainty: Country acceptance to implement Transparency!! Challenges: Vaccine quality, availability and storage at optimum temp Animal identification Gaps: Vaccine quality control centers Validated PVM screening tools Producers awareness and incentive 3

4 Vaccine Efficacy vs. Effectiveness 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

5 Factors Impacting Vaccination Program 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

6 Informing cost effectiveness Cost of Disease Cost of Vaccine 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

7 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

8 Objectives of vaccination programs Categories of Epidemiological setting 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

9 Post vaccination monitoring guidelines Aims 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)

10 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

11 Vaccine types Chapter 1. Vaccine attributes Vaccine matching and selection of vaccine strains Vaccine quality Requirements during manufacturing process Requirements for registration process Consideration when purchasing vaccine Vaccine purchase through a tender procedure Information provided by the tenderer Information provided by manufacturers

12 Chapter 2. Vaccine delivery, Schedule and Coverage Vaccine delivery Packaging Cold change and logistics managements Vaccine schedule Booster dose Every six month till 2 years of age Annual vaccination older than 2 years of age Vaccination coverage No. animal vaccinated/no. eligible for vaccination Immunization coverage % vaccination coverage X % developed desirable antibody titers

13 Chapter 3. Evaluation of the immune response to reduce clinical FMD incidence Ab level at individual level Ab epi-unit level to maintain FMD freedom Ab level at individual level Ab level at herd level to eliminate FMD virus circulation 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

14 Field trial for evaluation of vaccine induced immune response - 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

15 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

16 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

17 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

18 PVM Expert Team Meeting Consultation Samia Metwally, FAO Sergio Duffy Susanne Munstermann, OIE Kees van Maanen Giancarlo Ferrari Kris de Clercq Phaedra Eblé Mary Joy Gordoncillo Mokganedi Mokopasesto David Paton Tim Doel Alistair King Keith Sumption Theo Knight-Jones Aldo Dekker

19 Thank you for your attention