The purpose of this study is to determine the antiviral activity and safety of VX-787 given to healthy adult volunteers that have been inoculated with the influenza virus.

Inclusion Criteria:

• Negative human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C(HCV) antibody screen
• Have not been vaccinated for influenza virus since 2006 or had a known influenza-like illness in the current season (as determined in the medical history), defined as in the last 12 months before Screening

Exclusion Criteria:

• Subjects who are pregnant or nursing, or who are male and have a female partner who is pregnant, nursing, or is planning to become pregnant during the study period (from at least 14 days before the first dose until 90 days of the last dose of study drug)
• Presence of any significant acute or chronic, uncontrolled medical or psychiatric illness
• Abnormal pulmonary function as evidenced by clinically significant abnormalities in spirometry
• Health care workers (including doctors, nurses, medical students and allied healthcare professionals) anticipated to have patient contact within two weeks of viral inoculation
• Intending to travel(to countries for which vaccinations are recommended or where high risk of infections exists)
• Subjects with a history of asthma, COPD, pulmonary hypertension, reactive airway disease, or any chronic lung condition of any etiology; any history during adulthood of asthma of any etiology, COPD, or any use of a bronchodilator or other asthma medication during adulthood
• Regular daily smokers
• History or evidence of autoimmune disease or known impaired immune responsiveness
• History of heart failure or any other severe cardiac abnormality including clinically significant arrhythmia
• Receipt of any investigational drug within 3 months, or prior participation in a clinical trial of any influenza vaccine, medication, or experimental respiratory viral challenge delivered directly to the respiratory tract within 1 year before viral inoculation
• Previous exposure to study drug or similar substance(s)