How does influenza differ from the common cold in severity of fever and body aches?

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Influenza virus — influenza A colored transmission electron micrograph showing influenza viruses (red) at the outer surface of a host cell.

While both influenza and the common cold are contagious respiratory illnesses, they differ significantly in the intensity of their symptoms.

The common cold is generally mild and rarely causes fever or body aches. In contrast, influenza is characterized by a rapid onset of more extensive and severe symptoms. Key differences include:1

Fever: Influenza typically causes a rapid rise in body temperature, often reaching 38–40 °C (101–104 °F).2
Body Aches: Influenza is marked by severe muscular aches and diffuse headaches, whereas these symptoms are uncommon with a cold.12

Because these conditions are caused by different viruses, testing is the most reliable way to distinguish between them.1