Which virus is known for causing common colds and upper respiratory infections?

The rhinovirus is recognized as the primary cause of common colds, which are frequent upper respiratory infections. This virus is highly prevalent, especially during the fall and spring months, contributing to a significant number of cold cases each year. Rhinoviruses ensure a multitude of strains, meaning they continually adapt and can lead to recurrent infections in individuals throughout their lives.

In contrast, while the flu virus can also cause upper respiratory symptoms, it is more strongly associated with seasonal influenza and presents with more severe symptoms. HIV is primarily linked with immunodeficiency and does not typically cause the mild symptoms associated with a common cold. The herpes virus, on the other hand, is associated with specific clinical presentations such as sores and infections but not with the typical symptoms of the common cold. Thus, rhinovirus is the correct choice for this question.