Emergence of drug resistance during an influenza epidemic: insights from a mathematical model.

A model was developed for the emergence of drug-resistant influenza viruses during a closed population influenza epidemic that occurs in a single wave. The model was used to consider several treatment and chemoprophylaxis strategies and to determine their effects on the spread of the infection. The model predicts frequent emergence and transmission of drug-resistant viruses with certain treatment scenarios. According to the model, chemoprophylaxis of susceptible persons (without treatment of those who are symptomatic) may be the best way to reduce the force of an epidemic and to keep development of drug resistance low. The model predictions indicate that the relative transmissibility of resistant variants compared with wild type virus and the choice of the treatment or chemoprophylaxis strategy can be decisive for the spread of drug-resistant viruses, a feature that may be crucial in a pandemic.