Influenza - the flu

What is influenza?

Influenza — or ‘the flu’ — is a viral infection of your nose, throat and sometimes your lungs. Always an unpleasant illness, influenza can be particularly severe in young children, pregnant women, the elderly and those with other health problems.

The flu is usually not dangerous for a healthy person, but from time to time, new strains emerge that can cause serious illness and death even in healthy people.

How did I get flu?

The viruses that cause influenza are always around us. They constantly change, so having had the flu before doesn’t stop us getting it again. Influenza frequently occurs in epidemics, most commonly in autumn and winter. Sometimes when a new strain emerges it can spread across the globe — a so-called pandemic.

Influenza viruses are very infectious and are spread from person to person by direct contact, touching contaminated objects or the fine droplets that are shot from the nose and mouth when you cough or sneeze.

Flu symptoms

Typical influenza in adults is characterised by the sudden onset of:

  • chills;
  • fever;
  • headache;
  • tiredness and weakness (often severe);
  • cough; and
  • generalised aches and pains (especially in the back and legs).

You may also have a runny nose, sneezing and sore throat.

Children may complain of abdominal pain, nausea and vomiting, and appear generally unwell.

The illness typically lasts up to a week, but fatigue and cough may persist for longer.

People often mistakenly say they have ‘the flu’ when it is a cold — the symptoms are different. People with colds rarely have high fevers, muscle and joint pains or extreme tiredness and weakness.

Occasionally, the infection spreads to the lungs, causing bronchitis or pneumonia. This is more likely among the elderly, heavy smokers, people in poor health and people with asthma or other chest complaints.

Influenza treatment

Influenza is caused by a virus so antibiotics do not help, unless you get a bacterial infection following the flu, which sometimes happens.

Over-the-counter medicines

Analgesics (pain relievers) can be taken for pain and fever. Analgesic medicines commonly used in the treatment of flu include paracetamol, ibuprofen and aspirin. Do not give aspirin to children aged 16 years and younger, because it can cause a serious complication known as Reye’s syndrome.

Cold and flu preparations are available from your pharmacist. These medicines may contain:

  • pain relievers;
  • decongestants (to help treat a blocked or stuffy nose);
  • antihistamines (to help treat sneezing and runny nose); and
  • cough suppressants.

Take care to carefully read the ingredients of any cold or flu formulations that you take so that you don’t double up on ingredients, especially paracetamol, ibuprofen or antihistamines. If you take a combination product and then also take additional medicines, you risk overdosing on some types of medicines.

Side effects of cold and flu preparations will depend on the formulation used.

Cough and cold medicines should not be used by children younger than 6 years. For older children, always check with your doctor or pharmacist whether the product is safe for your child.

Antiviral medicines

Your doctor may prescribe antiviral medicines, which can reduce the amount of time you are unwell with influenza, reduce the severity of your symptoms and may help prevent complications. However, most people get better within a week without taking antiviral medicines.

Antivirals provide most benefit when taken within 48 hours of symptoms developing. Available antiviral medicines include oseltamivir (brand name Tamiflu) and zanamivir (brand name Relenza). Possible side effects associated with antiviral medicines include nausea and vomiting, dizziness, delirium and diarrhoea.

Self-care

The following measures can help you feel better when you have the flu.

  • Getting plenty of rest.
  • Drinking plenty of liquids (such as water, fruit juice, cordial, soups). This is very important when you are sweating and feverish. Avoid alcohol as it can lead to dehydration. Fresh lemon juice mixed with some honey and hot water can soothe a sore throat or dry cough.
  • Eat light food, only when hungry.

When should you seek medical advice?

You should see your doctor if:

  • symptoms occur in children under 12 years old;
  • symptoms occur in elderly people;
  • symptoms occur in people with heart or lung problems;
  • there is confusion or impaired mental functioning or alertness;
  • you have a very high fever (above 40°C);
  • you have shortness of breath or chest pains;
  • you are not eating or drinking;
  • you have a productive cough (a cough with phlegm);
  • the symptoms have not improved in 2 days, or have not disappeared almost completely in one week; or
  • you have reason to believe you may have been exposed to a new type of flu, such as swine flu or avian flu.

Preventing influenza

Influenza vaccines

Being vaccinated against influenza is recommended for people who want to reduce the likelihood of becoming ill with influenza.

If you are at high risk of getting influenza, more likely to have complications or are in an essential service (such as healthcare workers) your doctor may strongly recommend you have an influenza vaccination.

Influenza vaccination is provided free for:

  • anyone aged 65 years and older;
  • pregnant women;
  • those who have long-term health problems (for example, asthma or diabetes); and
  • Aboriginal or Torres Strait Islander people over the age of 15 years.

The influenza vaccine will improve your chances of not getting the flu, but does not give 100 per cent protection.

New vaccines are made each year, depending on the type of virus that is around. They are generally released for use at about the beginning of March, and to maintain protection, you should be re-vaccinated every autumn.

Influenza vaccines should not be given to babies under 6 months of age or people who have had a severe allergic reaction (anaphylaxis) to a flu vaccine before. Care should be taken in people who have extremely severe allergies to hen’s eggs.

Antiviral medicines

Antiviral medicines are sometimes given to people who have been exposed to influenza to prevent them from developing the infection. This is known as antiviral prophylaxis, and is usually considered for close contacts of people with influenza, especially if they are at risk of developing severe disease.

Infection control

To help control the spread of infections, try the following measures.

  • Frequently wash your hands using soap and water.
  • Cover your mouth and nose when you sneeze or cough. Sneeze or cough into a tissue or into the crook of your elbow, rather than into your hands. Throw tissues into the bin straight after use.
  • Stay at home and avoid school, work and other crowded places when you are sick.
Last Reviewed: 8 April 2014
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References

1. Immunise Australia. Influenza (flu) (updated 5 Mar 2013). http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/immunise-influenza (accessed Mar 2014)
2. Australian Government Department of Health and Ageing. The Australian Immunisation Handbook, 10th Edition 2013. 4.7 Influenza (updated 17 Jan 2014). http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/handbook10-4-7 (accessed Mar 2014).
3. World Health Organization (WHO). Influenza (seasonal) (updated Mar 2014). http://www.who.int/mediacentre/factsheets/fs211/en/# (accessed Mar 2014).
4. Influenza (revised June 2010). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2013 Nov. http://online.tg.org.au/complete/ (accessed Mar 2014).
5. MayoClinic.com. Influenza (flu) (updated 21 Feb 2013). http://www.mayoclinic.org/diseases-conditions/flu/basics/definition/con-20035101 (accessed Mar 2014).
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