Groupe d’études et de recherche en analyse des décisions

Open Access to the Resource of Antibiotic Treatment Efficacy Subject to Bacterial Resistance

Bruno Nkuiya

In this paper, we are interested in how a pharmaceutical industry manages existing antibiotic drugs in the context of bacterial resistance. We consider a model based on an epidemiological framework where antibiotic recovery rates, and thus intrinsic qualities, may differ. Antibiotic efficacy is modeled as a common pool of a non-renewable resource to which antibiotic producers have open access. The paper derives antibiotic demands within a vertical differentiation model and characterizes the dynamics of infected individuals, antibiotic efficacy and treatment rates under the open-access and the socially optimal allocation. We show that the high-quality antibiotic drug loses its comparative advantage over time under both allocations, such that the low-quality drug should be used longer. This occurs at a later point of time in the social optimum and allows for a better control of infection in the longer run. In contrast with the ambiguous outcome reported in the literature, the socially optimal steady-state level of antibiotic efficacy is lower than that of the open-access allocation. We also extend our analysis to a strategic, duopolistic context.