IMPACT OF INDIVIDUAL DECISIONS OF FARMERS ON THE EFFICIENCY OF VACCINATION AT A REGIONAL LEVEL: A MODELLING APPROACH

摘要

Control strategies for infectious diseases at a regional level can rely on vaccination. When the decision to vaccinate is made by each farmer on a voluntary basis, a farmer vaccinates to protect his own herd. If the vaccinated herds are protected against infection, the risk for other herds is reduced, creating a positive externality (i.e. an impact on a third party that is not directly involved in an economic decision). The two main objectives of this study were to evaluate the efficiency of voluntary vaccination at a regional level and to analyze the effect of financial incentives, considering the externalities due to vaccination. A dynamic model was developed, coupling an epidemiologic model with an economic model. It gave the proportion of farmsthat vaccinated, and the evolution of the prevalence. Assuming the farmers were fully informed on prevalence and the decision to vaccinate was made each year, the model showed that voluntary vaccination could not eradicate the disease, even in the presence of incentives for vaccination.