Modeling the effects of vaccination against multiple strains of porcine reproductive and respiratory syndrome at the barn level

Abstract

Porcine reproductive and respiratory syndrome (PRRSV) remains costly for the swine industry. Measures intended to irradicate or reduce the prevalence of PRRSV have limited effectiveness. Vaccination, the primary control strategy for PRRSV, has yet to be thoroughly investigated to ensure an optimal strategy is being implemented. Due to insufficient cross-immunity between strains, it is prudent to administer the most influential vaccine for the most dominant or threatening PRRSV strain in circulation at a given time. With this in mind, we demonstrated the benefits of targeted vaccination using metapopulation-based modeling. By using up-to-date data describing real farms to simulate the effects of variable vaccine efficacy in both a single and a double strain system, we showed that tailoring vaccines to prevalent PRRSV strains reduces infections, but using multiple vaccines may be more effective if strains vary in vaccine response. Therefore, the impact of the strain-specific effectiveness of market vaccines, paired with computational methods that allow tracking the effects on PRRVS dissemination at individual barns.