A viral infection is an illness caused by a virus entering your body, attaching to your cells, and using those cells to make more copies of itself. Viral infections can range from mild to severe and may affect the respiratory system, digestive system, skin, nerves, or other parts of the body.

How it works

A virus is much smaller than bacteria and must live inside a host cell to reproduce. Once inside, it hijacks the cell’s machinery, which can damage or kill the infected cell and spread new virus particles to nearby cells.

Common examples

Examples of viral infections include the common cold, flu, COVID-19, norovirus, herpes, HPV, and rabies.

Symptoms

Symptoms depend on the virus and the body part affected, but common signs include fever, fatigue, cough, sore throat, body aches, rash, vomiting, or diarrhea. Some viral infections cause no symptoms at all, while others can become chronic or life-threatening.

Treatment

Many viral infections improve on their own, but some need antiviral medicine, vaccines, or other supportive care such as fluids and rest. Antibiotics do not treat viruses.

TL;DR

A viral infection is when a virus gets into your body, multiplies inside your cells, and makes you sick.