An upper respiratory infection (URI) is an infection that affects the nose, throat, and sinuses. Common causes include viruses, such as the common cold and influenza, as well as bacteria. Symptoms often include a runny or stuffy nose, sore throat, cough, and sometimes a mild fever. URIs are typically mild and resolve on their own within a week or two. These infections are highly contagious and can spread through respiratory droplets when an infected person coughs or sneezes. While most URIs do not require medical treatment, staying hydrated and resting can help alleviate symptoms. In some cases, over-the-counter medications may provide relief.