Inclusion Criteria:

• Southeast Minnesota (SEMN: Olmsted County and nearby counties including Dodge, Goodhue, Mower, Fillmore, Winona, and Wabasha,) residents (residency established at least one year prior to consent) aged 50 years or above at the time of consenting.
• Those who have primary care physician at Mayo Clinic and a history of primary care visits to Mayo Clinic.
• Those who authorizes use of their medical record for research.
• Those who provide written consent to participate in the study.

Exclusion Criteria: 

• Subjects without authorization for use of medical records for research.
• Those who do not reside in SEMN at the time of enrollment.
• Those who may go to health care providers other than Mayo Clinic Rochester (eg, Mayo Kasson, Olmsted Medical Center).
• (This will not be applicable to Phase II study). Those who develop ARI after October 1, 2019 but prior to enrollment and are not able to come in for enrollment and swabbing within 7 days of symptoms.
• Those who opt out for swab test and other study procedures.
• Those who cannot ambulate or those who are bedridden (absolute or perhaps relative contraindications to the 6 minute walk such as uncontrolled/unstable cardiovascular, pulmonary, renal, endocrine, immunological or hepatic disorders).
• Those with known cognitive impairment.
• Those who had evidence of an ongoing systemic bacterial, fungal, or viral infection within 7 days prior to enrollment.
• Those who reside out of Olmsted, Dodge, Goodhue, Mower, Fillmore, Winona, and Wabasha County, MN > 2 weeks during winter season the RSV season (Oct-April) and/or > 4 weeks during summer season (May-Sep).
• Any reason in the opinion of the study PIs that someone would not be able to complete the requirements of the study for safety or other reasons.