Potential benefits and limitations of various strategies to mitigate the impact of an influenza pandemic

The recent avian influenza outbreaks underscore the importance of improving our preparedness for an impending influenza pandemic. Various strategies, including pharmaceutical interventions (such as vaccines and antivirals) and nonpharmaceutical interventions (such as quarantine, isolation, and social distancing) may be implemented to mitigate the impact of a pandemic. It is necessary to understand the potential benefits and limitations of each strategy to determine the most appropriate strategies to be implemented. In this article, each strategy is reviewed to define its potential benefits and limitations during a pandemic. Vaccines are probably the most effective measure to reduce morbidity and mortality. However, vaccines are not likely to be available at an early stage of a pandemic. The supply of vaccines is most likely to be insufficient due to limited worldwide production capacity. Antivirals, particularly neuraminidase inhibitors, are expected to be effective against a pandemic influenza strain and are the only available pharmaceutical intervention until enough vaccines are produced. Shortage of supply and high cost is still a major limiting factor in amassing large stockpiles of neuraminidase inhibitors. The possible emergence of resistant strains should also be considered. Nonpharmaceutical interventions can be effective in preventing the spread of the virus under certain conditions. The effectiveness of nonpharmaceutical interventions depends on how influenza viruses are transmitted. There are still significant gaps in the scientific evidence of the way in which influenza viruses are transmitted. Further studies should be conducted to define the basic transmission patterns of influenza viruses.