Fever is a common symptom of a bacterial or viral infection

Fever is a common symptom of bacterial and viral infections. Examples include infections that cause colds and flu.3

In addition to high temperature, fever is also often associated with symptoms like sweating, shivering, chattering teeth, headache, flushed skin, aching muscles, and general weakness.1

Sickness isn’t always the reason you get a fever. Fever can also be caused by reactions to medicines or immunisations, or certain medical conditions.1,3


How fever fights infection

Fever is a part of your body’s defences/weaponry against infection.1

Your body temperature is controlled by a part of your brain called the hypothalamus. It’s like a kind of thermostat - when you’re healthy, the hypothalamus sets your body to a normal temperature of about 37°C.1

But when you’re sick with an infection, your immune system releases chemicals that make the hypothalamus reset your body to a higher temperature. You begin to feel cold, and you start to shiver. You bundle up in warm clothing. All of this causes your body temperature to rise.1

This rise in body temperature helps your body fight the bacteria or viruses that are causing the infection.1


There are practical ways to reduce a fever

To help relieve the discomfort of fever:3,4

  • Get plenty of rest
  • Drink lots of water, to stay well hydrated
  • Stay cool by wearing light clothes and sleeping with light bedclothes
  • Keep the room at a comfortable temperature
  • You could take a fever reducing medicine such as Nurofen or paracetamol.

When to see a doctor about fever symptoms

Consult with your doctor at any stage if you feel worried or concerned about your, or a child's, fever symptoms.


Seek urgent medical attention:5

Children under 3 months of age with a fever

A person of any age with a fever, headache and stiff neck, or has rash that doesn’t blanche (fade) when pressed

A person of any age with a fever who also experiences unexpected or unusual symptoms like hallucinations, muscle spasms or feels confused or drowsy.


See a doctor:

Children over 3 months of age, including adults who experience:

  • trouble breathing
  • drowsiness
  • refusing to drink and/or not urinating as often
  • stiff neck
  • sensitivity to light
  • ongoing vomiting or diarrhoea
  • looking sicker than before – more pale, lethargic or weak
  • any other symptoms that are causing you worry.


Or if you or someone you are caring for:

  • still has a fever after three days
  • are shivering or shaking uncontrollably
  • are hot but not sweating
  • are getting sicker instead of feeling better
  • have recently travelled overseas.


This article is for general information only and not intended as a substitute for medical advice. All information presented on these web pages is not meant to diagnose or prescribe. In all health-related matters, always consult your healthcare professional.


  1. Ogoina D. J Infect Public Health 2011;4(3):108-24.
  2. Chiappini E, et al. BMJ Open 2017;7(7):e015404.
  3. Institute for Quality and Efficiency in Health Care (IQWiG). InformedHealth.org [Internet] 2019. Fever in children: Overview. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279455/ (accessed 8 Apr 2020).
  4. Fever. Available from: https://www.healthdirect.gov.au/fever#doctor (accessed 11 May 2020).
  5. Queensland Government. Queensland Health. What is a fever? When should you worry about a high temperature?