Effects of disease risk, vaccine efficacy, and market price on the economics of fish vaccination

Abstract Atlantic salmon ( Salmo salar ) and sea bass ( Dicentrarchus labrax ) were used as representative aquaculture species in our mathematical model to evaluate the impact of disease risk, vaccine efficacy, and market price on the value of vaccination as a management tool. This innovative and interactive spreadsheet-based model was designed to help define the risk ranges that may be encountered in a variety of intensive or extensive aquaculture systems that are vulnerable to infectious diseases. To make the risk assessments for aquaculture practical, data were generated with expected estimates of worst case, best case, and “most probable” disease impact scenarios. As an integrated system, the combination of formulas described is capable of rapidly estimating and comparing the economic value created by vaccines of different cost and potency. A key concept of this new model of disease risk is the influence of the principle of alternative cost (or opportunity cost) and its importance in understanding the true economic effect of decisions regarding health management. For example, selecting a vaccine of low cost and moderately low efficacy may actually reduce profitability and operational efficiency compared to a much higher cost vaccine that provides only moderately higher levels of protection. Calculated savings from an economically justified vaccination program should combine the value of increased survival, reduced antibiotic use, fewer compensatory fish and reduced carcass removal/disposal costs.