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Upper respiratory tract infection

Upper respiratory infections, commonly referred to the acronym URI, is the illness caused by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx, larynx, or bronchi. It is the most common cause of days missed from work or school and one of the most common reasons for a medical visit. It is estimated that the average adult has from two to three URI-type illnesses per year and the average child six to 10. In the United States, this represents approximately one billion acute upper respiratory illnesses annually. Recent studies show that up to 98% of all cases are viral in nature.

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November 30, 2025

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