Why does COVID-19 cause fever?

A fever is an increase in body temperature caused by signals released during infection. You may feel hot, cold, sweaty, shivery, weak, or thirsty while your temperature changes. Fever is a very common presentation of COVID-19, yet fever also has many causes, including other viral illnesses, bacterial infections, and inflammatory conditions. The number on a thermometer is useful context, but your breathing, alertness, fluid intake, and overall trend matter too.

Drink fluids regularly and wear light, comfortable clothing. Rest in a room that is not too warm, and take your temperature if doing so helps you track the pattern. Use a fever medicine only as directed on its label or by a clinician, checking first if you have liver or kidney disease, are pregnant, or take regular medicines. Do not use an ice bath or alcohol rubs; shivering can make you feel worse.

Get urgent help for severe breathing difficulty, chest pain or pressure, confusion, a seizure, a stiff neck with severe illness, or difficulty waking. Seek prompt clinical advice if fever is accompanied by dehydration, a worsening cough, or a marked decline in how you are functioning. Parents and carers should obtain advice for a baby with fever, or for a child who is hard to rouse, has laboured breathing, or is not drinking.

Ask how to monitor your illness at home, whether a medicine is safe alongside your prescriptions, and which symptoms make your personal situation more urgent.