All patients who present with ILI and/or signs/symptoms of RSV Infection who have met all the inclusion and none of the exclusion criteria are considered eligible to participate in the sample collection phase of this study. Specimens may be collected from subjects in either an inpatient or outpatient setting. An outpatient setting includes facilities such as emergency rooms associated with hospitals, large decentralized hospital/commercial labs, urgent cares and/or physician practices currently undertaking diagnostic testing. An inpatient setting is defined as a hospital where patients are admitted (does not include the emergency room associated with the hospital as this will be considered "outpatient" setting). Patient populations from the United States will be evaluated.