A Simulation Study of the Use of Vaccination to Control Foot-and-Mouth Disease Outbreaks Across Australia

Abstract

This study examines the potential for foot-and-mouth disease (FMD) control strategies that incorporate vaccination to manage FMD spread for a range of incursion scenarios across Australia. Stakeholder consultation was used to formulate control strategies and incursion scenarios to ensure relevance to the diverse range of Australian livestock production regions and management systems. The Australian Animal Disease Spread model (AADIS) was used to compare nine control strategies for 13 incursion scenarios, including seven control strategies incorporating vaccination. The control strategies with vaccination differed in terms of their approaches for targeting areas and species. These strategies are compared with two benchmark strategies based on stamping out only. Outbreak size and duration were compared in terms of the total number of infected premises, the duration of the control stage of an FMD outbreak, and the number of vaccinated animals. The three key findings from this analysis are as follows: (1) smaller outbreaks can be effectively managed by stamping out without vaccination, (2) the size and duration of larger outbreaks can be significantly reduced when vaccination is used, and (3) different vaccination strategies produced similar reductions in the size and duration of an outbreak, but the number of animals vaccinated varied. Under current international standards for regaining FMD-free status, vaccinated animals need to be removed from the population at the end of the outbreak to minimize trade impacts. We have shown that selective, targeted vaccination strategies could achieve effective FMD control while significantly reducing the number of animals vaccinated.

Modeling foot-and-mouth disease dissemination in Brazil and evaluating the effectiveness of control measures

“…Several modeling works have demonstrated the effectiveness of the combination of vaccination with depopulation in FMD elimination (Capon et al, 2021; Dürr et al, 2014; Sanson et al, 2017), with some exceptions in highly dense livestock areas such as in The Netherlands in which vaccination combined with ring culling was not sufficient (Boklund et al, 2013). Among the simulated scenarios, implementing vaccination in conjunction with depopulation was always more effective when compared with depopulation alone (Figures 7 and 8).…”

“…Nevertheless, there are uncertainties about the implementation of control measures, and future work could include delays in response times. Additionally, given the volume of vaccines necessary to vaccinate all animals within infected and buffer zones, further work should consider restricting vaccination to each species, thus allowing for benchmarking and better estimation of vaccine stockpiles (Capon et al, 2021; Dürr et al, 2014; Roche et al, 2015). Another limitation was the assumption of instantaneous vaccination efficacy; future work should consider a variation in vaccination waning (Ringa and Bauch, 2014).…”

Economic benefits of implementing trading zones for Australian livestock disease outbreaks of limited duration

“…Additional simulations of control strategies included depopulation of dangerous contact herds and alternative targeted vaccination programmes to the stamping‐out response. The vaccination strategies were less effective than applying a traditional stamping‐out approach for controlling the 11 small incursion scenarios included here 10 . Only the stamping‐out control option results were used as inputs into the economic analysis presented in this paper.…”

“…This economic analysis is based on outputs from previously reported epidemiological model development exploring the extent of potential FMD outbreaks in Australia 10 and historical trade data. Figure 1 labels and details 11 incursion scenarios, selected through jurisdiction and industry stakeholder consultations, which were simulated.…”

“…The vaccination strategies were less effective than applying a traditional stamping‐out approach for controlling the 11 small incursion scenarios included here. 10 Only the stamping‐out control option results were used as inputs into the economic analysis presented in this paper. Separate economic analyses were undertaken for one additional incursion scenario in Victoria where much larger outbreaks were simulated by AADIS, and multiple vaccination strategies led to statistically significant reductions in duration and animals culled.…”