R. Sanson - Evaluating vaccination strategies to control FMD: a country comparison study

R. Sanson - Evaluating vaccination strategies to control FMD: a country comparison study

Open Session of the EuFMD – 2018 – Increasing Global Security in the supply of effective vaccines – 29-31 October 2018 -Borgo Egnazia, Italy

Introduction
Vaccination is increasingly being recognised as a potential tool to supplement ‘stamping out’ for controlling foot-and-mouth disease (FMD) outbreaks in non-endemic countries. Infectious disease simulation models provide the opportunity to determine how vaccination might be used in the face of an FMD outbreak. Previously, consistent relative benefits of specific vaccination strategies across different FMD simulation modelling platforms have been demonstrated, using a United Kingdom FMD outbreak scenario. We extended this work to assess the relative effectiveness of selected vaccination strategies in five countries: Australia, New Zealand, the United States, the United Kingdom and Canada.

Materials and Methods A comparable, but not identical, FMD outbreak scenario was developed for each country with initial seeding of Pan Asia type O FMD virus into an area with a relatively high density of livestock farms. A series of vaccination strategies (in addition to stamping out) were selected to evaluate key areas of interest from a disease response perspective, including: timing of vaccination, species considerations (e.g. vaccination of only those farms with cattle), risk area vaccination, and resources available for vaccination.

Results
The study found that vaccination used with stamping out was effective in reducing epidemic size and duration in a severe outbreak situation. Early vaccination and unconstrained resources for vaccination consistently outperformed other strategies. Vaccination of only those farms with cattle produced comparable results, with some countries demonstrating that this could be as effective as all species vaccination. Restriction of vaccination to higher risk areas was less effective than other strategies.

Discussion
This study demonstrated consistency in the relative effectiveness of selected vaccination strategies under different start up conditions. We conclude that the preferred approach to FMD control depends on clearly defining outbreak management objectives, while having a good understanding of logistic requirements, and the socio-economic implications of different measures.