FDA did not require the fourth season of recruitment as planned originally. Study closed.

This is a post-marketing case-controlled study of the effectiveness of a quadrivalent live attenuated influenza vaccine (Q/LAIV/FluMist® Quadrivalent) versus Inactivated Influenza Vaccine (IIV) and No Vaccine in subjects 2-17 years of age.

This post-marketing study will enroll approximately 5,200 subjects 2-17 years of age who are seeking care in an outpatient setting for febrile acute respiratory illness. This study will begin in the fall of 2013 and will be completed after 4 influenza seasons (i.e.after the 2016-2017 influenza season). No investigational product will be administered in this study. A nasal swab will be obtained and tested for the presence of influenza virus and other viral pathogens. This study will be conducted at 4 sites in the United States of America. The duration of study participation for each subject is one day.

Inclusion Criteria:

• Community-dwelling children and adolescents 2 to 17 years of age.
• Written Informed Consent or Assent.
• Acute respiratory illness documented at study visit or at home with fever (oral temperature ≥ 100.0° Fahrenheit at study visit, or history of fever reported by parents, or use of antipyretic prior to study visit)
• Symptom onset less than 5 days prior to study visit.
• Subject and/or subject's legal representative is able to understand and comply with the requirements of the protocol as judged by the investigator.

Exclusion Criteria:

• Treatment with an antiviral drug for influenza (oseltamivir or Tamiflu®, zanamivir or Relenza®) during the 14 days before enrollment
• Any condition that, in the opinion of the investigator, would interfere with interpretation of subject safety or study results
• Concurrent enrollment in another clinical study

Patient already enrolled during this influenza season

• Employees of the clinical study site or any other individuals involved with the conduct of the study, or immediate family members of such individuals.

Subjects 2 to 17 years of age who are seeking care in an outpatient setting for febrile acute respiratory illness.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.