Effect of Oseltamivir on Cognitive Function in Subjects With Influenza

Inclusion Criteria: 1. Adult men and women, 18 - 65 years of age (inclusive) 2. Indicative symptoms/signs of uncomplicated acute illness due to influenza infection (A or B strains) that started within a maximum of 2 days prior to Visit 1 as per the Tamiflu® Canadian product label. Signs and symptoms may include the following: * Fever * Respiratory symptoms (cough, coryza, sore throat, rhinitis) * Constitutional symptoms (headache, malaise, myalgia, sweats and/or chills, fatigue) 3. Positive rapid antigen test for influenza (A or B strains) at Visit 1 4. Negative urine pregnancy test at Visit 1 for women of childbearing potential; women of childbearing potential who are sexually active must agree to use a suitable form of contraception during the study. Acceptable birth control measures include: hysterectomy, birth control pills, tubal ligation, intrauterine device, hormonal injections and implants, double barrier methods (such as a condom with a diaphragm or a condom with spermicide), and abstinence. Oral contraceptives must be in stable use for 2 or more cycles prior to screening. Intrauterine device (IUD) must be in use at least 30 days prior to study drug administration. Barrier methods must be in use at least 14 days prior to study drug administration. 5. Subjects must: * have daily access to a computer at home with: internet access (preferably high-speed for optimal performance but dial-up can be used as well); Microsoft operating system; Internet Explorer browser capability and an e-mail account. A Macintosh (Mac) computer cannot be used. * be capable of and willing to complete the required online assessments in English according to the protocol schedule * be willing to abstain from the use of an antiviral medication if they are randomised to the standard of care treatment arm * have provided written informed consent prior to the initiation of any study procedures Exclusion Criteria: 1. More than 2 days since the onset of influenza symptoms 2. Subjects who, in the Investigator's judgment, require treatment with an antiviral medication as per the Canadian "Clinical Recommendations for Patients Presenting with Respiratory Symptoms During the 2009 - 2010 Influenza Season" (see Appendix D) 3. Clinical suspicion of infection with a respiratory virus other than influenza 4. Any medical condition that is sufficiently severe or unstable such that the subject is considered to be at imminent risk of requiring hospitalisation 5. History of conditions that may potentially affect cognitive function during the study, such as underlying neurologic conditions, depression or depressive disorders (unless the condition and treatment have been stable for 3 months), seasonal affective disorder (SAD), or any other cognitive impairment or dementia 6. Intermittent use of sedative-hypnotics; subjects who have been taking a fixed dose of a sedative-hypnotic every day for a period of at least 30 days may be included provided that they continue the same regimen throughout the study. 7. Intermittent or chronic use of psychiatric medications (with the exception of antidepressants that have been stable for 3 months) or anti-epileptic drugs 8. Nursing home residents 9. Known allergy to oseltamivir phosphate or any of the inactive ingredients of Tamiflu® 10. Women who are pregnant, or planning to become pregnant, or who are lactating 11. Current alcohol or drug abuse or substance dependence 12. Participation in another clinical trial with an investigational drug within the last 30 days 13. Patients vaccinated for influenza within 6 months of study enrollment 14. In the Investigator's judgment, the subject will not be able to adhere to the protocol requirements or is not suitable for study participation for any reason