Smart viruses find ways around host defenses. In the case of the influenza viruses A and B, rapid genetic changes and resistance to available therapies make it hard to combat flu epidemics in humans. Mortality rates for influenza B viruses are higher than those reported for seasonal influenza A H1N1. Human monoclonal antibodies were previously shown to neutralize a wide variety of influenza A viruses, so extending that work to include influenza B viruses is critical because these flu strains cause a large proportion of the annual flu infections and are a major cause of seasonal epidemics every two to four years.
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