Evaluation of the Efficacy and Safety of Peramivir in Subjects With Uncomplicated Acute Influenza.

Inclusion Criteria: * Age ≥18 years * Presence of fever at time of screening of ≥38.0 ºC (≥100.4 ºF) taken orally, or ≥38.5 ºC (≥101.2 ºF) taken rectally. However, this requirement is waived if the subject has a history of fever within the 24 hours prior to screening and has been administered antipyretic(s) in the 6 hours prior to screening. * Presence of at least one respiratory symptom (cough, sore throat, or nasal symptoms) of any severity (mild, moderate, or severe) * Presence of at least one constitutional symptom (headache, malaise, myalgia, sweats and/or chills, or fatigue) of any severity (mild, moderate, or severe) * Onset of illness no more than 48 hours before presentation. Note: Time of onset of illness is defined as either (1) the time when the temperature (either oral or rectal) was first measured as elevated (at least one ºC of elevation-oral temperature), OR (2) the time when the subject experienced the presence of at least one respiratory symptom AND the presence of at least one constitutional symptom. * Rapid Antigen Test (RAT) performed on an adequate specimen collected from an anterior nasal swab is positive. A negative initial RAT may be repeated within one hour of obtaining a negative result. A second negative RAT result will exclude the subject from evaluation for enrollment. * Females of childbearing potential must report one of the following: * Be surgically sterile * Have been sexually abstinent 4 weeks prior to date of screening evaluation and be willing to remain abstinent through 4 weeks after study drug administration * Use oral contraceptives or other form of hormonal birth control including hormonal vaginal rings or transdermal patches and have been using these for 3 months prior through 4 weeks after study drug administration * Use an intra-uterine device (IUD), or adequate barrier contraception (or double-barrier method such as condom or diaphragm with spermicidal gel or foam) as birth control 4 weeks prior to date of screening evaluation through 4 weeks after study drug administration. Exclusion Criteria: * Women who are breast-feeding * History of diagnosed chronic obstructive pulmonary disease or diagnosis of severe persistent asthma * History of chronic renal impairment requiring hemodialysis or known or suspected to have moderate or severe renal impairment (actual or estimated creatinine clearance \<50 mL/min) * History of congestive heart failure requiring daily pharmacotherapy with symptoms consistent with New York Heart Association Class II, III, or IV within the past 12 months * Immunocompromised status due to illness or previous organ transplant * Current use of systemic immunosuppressive medications (except inhaled corticosteroids) * Use of rimantadine, amantadine, zanamivir, or oseltamivir in the past 7 days * Immunized against influenza with live attenuated virus vaccine (FluMist®) in the previous 21 days * Clinical evidence of active bacterial infection at any body site requiring therapy with oral or systemic antibiotics * Clinically significant signs of acute respiratory distress * Clinically significant signs of acute cardiac disease * Screening ECG which suggests acute ischemia or presence of medically significant dysrhythmia * Presence of a chronic disease or illness(es) with either clinical or historical evidence of recent exacerbation of such disease(s) or illness(es) or lack of control of such disease(s) or illness(es) * History of hepatitis B, hepatitis C, or human immunodeficiency virus infection * History of alcohol abuse or drug addiction within 1 year prior to admission in the study * Participation in a study of any investigational drug within the last 30 days * Positive urine pregnancy test