Influenza, or flu, is a respiratory illness caused by a virus. Flu is highly contagious and is normally spread by the coughs and sneezes of an infected person. A person can also catch flu by touching an infected person, for instance, by shaking hands. Adults are contagious 1–2 days before getting symptoms and up to 7 days after becoming ill. This means that you can spread the influenza virus before you even know you are infected. In this article, we explain the symptoms of flu, how it is treated, how it differs from a cold, and the best ways to prevent flu occurring.

Fast facts on flu

Here are some key points about flu. More detail and supporting information is in the main article.
  • Antibiotics cannot treat flu, but some antivirals can.
  • Experts agree that the best way to prevent flu is to get vaccinated each year.
  • The flu vaccine is not suitable for certain groups of people, such as those who have a severe allergy to chicken eggs.


Flu can be uncomfortable, but it is rarely life-threatening. Confusing flu with a bad cold is common.
Flu and cold symptoms may both include:
  • a runny or blocked nose
  • a sore throat
  • a cough
To help you tell them apart, below are some symptoms of flu that are different from a heavy cold:
  • high temperature
  • cold sweats and shivers
  • headache
  • aching joints and limbs
  • fatigue, feeling exhausted
There may also be gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. These are more common in children than in adults. Normally, symptoms linger for about 1 week. However, the feeling of tiredness can continue for several weeks. It is worth noting that not every person with flu will have all of the symptoms. For instance, it is possible to have flu without a fever.

Bulk Billing Eligibility Criteria

All kids aged under 16

All Pension card holders

All valid Healthcare card holders

All Chronic disease management plans

All Health assessments.