A Study of MHAA4549A in Healthy Volunteers in an Influenza Challenge Model

This randomized, double-blind, placebo-controlled study will evaluate the efficacy and safety of MHAA4549A in healthy volunteers in an influenza challenge model. Subjects will be intranasally oculated with the challenge virus and will be randomly assigned to receive a intravenous dose of either MHAA4549A or placebo. In the stage 5 cohort, subjects will be randomly assigned to receive doses of MHAA4549A or placebo or Tamiflu (oseltamivir) orally twice daily for 5 days. All subjects in all cohorts may take Tamiflu twice daily from Day 7 to Day 11.