A Study to Explore the Incidence of Influenza and Respiratory Syncytial Virus (RSV) in Adults Hospitalized With Acute Respiratory Tract Infection

Inclusion Criteria: Main Study:

• Participants (or their legally acceptable representative) who signed an informedconsent form

• Hospitalized

• Participants with clinical diagnosis of acute respiratory tract infection (ARTI)during the influenza/respiratory syncytial virus (RSV) season, with or withoutassociated complications or other diseases (such as, but not limited to: acuteexacerbation of asthma or chronic obstructive pulmonary disease [COPD], malignancy,hypoxemia, congestive heart failure, sepsis, septic shock, pregnancy,immunodeficiencies) Substudy:

• Participants with confirmed diagnosis of influenza and/or RSV infection using aPCR-based influenza/RSV test

Exclusion Criteria: Main study and Substudy:

• Participants who participated in another clinical study, with the exception ofregistry and epidemiology studies involving minimum sampling done prior to theparticipant screening for the proposed study

• Participants not able to comply with study-related procedures, due to their mentalstatus or severe clinical condition, based on clinical judgement of the investigator

• Participants who received an experimental RSV vaccine