What is influenza (the flu)?

Everyone thinks they've had influenza (the flu), when all they've had is the common cold. Influenza is not a cold. Influenza is a viral infection of your nose, throat and sometimes your lungs, but it can affect your whole body. It is a serious viral infection that carries the risk of hospitalisation or even death. Special care is needed when children, the elderly or those with other health problems (see bottom of page) get influenza - in these people it can be serious and life-threatening.

According to a 2001 publication in the New Zealand Public Health Report, during the 1990s:

• an average of 278 New Zealanders ended up in hospital each year because of influenza 
• an average of 34 died each year as a result of being infected with influenza.

These data are likely to underestimate the actual effects associated with influenza.

For the vast majority, influenza will also make you unable work, play sport or take planned holidays. It can infect your family or leave them looking after you.

How do you get the flu?

The influenza virus is very infectious and is spread from person to person by the fine spray expelled from the nose and mouth when you cough or sneeze. The strains of virus that cause influenza are always around us. They constantly change, so having had the flu before does not stop you getting it again.

What does having the flu feel like?

You are likely to have a combination of symptoms including cough, sore throat, runny nose and eyes, headache, and usually high fever or chills, fatigue, aching muscles and joints and, in some people, breathing difficulties.

These symptoms can last for up to a week and will keep you in bed for a number of days. It will probably be a few weeks before you feel like you've fully recovered from the flu.

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

What makes the symptoms of flu better?

• Resting in bed until you feel better and the fever goes.
• Drinking at least eight glasses of fluid (water, fruit juice, cordial, iceblocks) a day. This is very important when you are sweating and feverish. Avoid tea, coffee and alcohol - they dry you out even more (fresh lemon juice mixed with honey, some hot water and a little olive oil, well shaken then sipped, can soothe a sore throat or dry cough).
• Eating only light food when you are hungry. 
• Taking medicine for fever and pain (do not give aspirin to children aged under 16 years; ask your pharmacist for product advice, eg, children's paracetamol, and follow instructions on the bottle carefully). 
• The New Zealand Medicines and Medical Devices Safety Authority (Medsafe) recommends NOT to give cough and cold medicines to children aged less than six years - ask your pharmacist for advice on treating young children with these symptoms.
• Talking to your doctor about an antiviral medication that can reduce the amount of time you are unwell. This medicine needs to be taken within 48 hours of getting the symptoms of the flu (aching joints and fever) to be effective. You will need to pay for this medicine as it is not subsidised by the government.

How can my doctor help?

See your doctor if you have not improved after four days, you are elderly or you have other long term health problems. Young children with flu also need to see their doctor.

Influenza is caused by a virus so antibiotics do not help unless you get a secondary bacterial infection (eg, pneumonia or chronic sinusitis) following the flu.

How do I protect against influenza?

If you do not want to risk getting influenza you should have the influenza vaccination in the autumn each year. This will protect you from the most common strains of flu virus that are around over the peak flu season (winter).

The influenza vaccine is provided free, until the end of June each year (end of September in 2009), for those at high risk of complications from the flu - ie, those aged 65 years and over and those who are under 65 years and have long term health problems such as:

• Heart disease 
• Stroke and related diseases 
• Long term respiratory diseases such as chronic bronchitis and asthma needing regular preventive medicine 
• Diabetes 
• Ongoing kidney (renal) disease 
• Most cancers 
• Autoimmune diseases and conditions such as rheumatoid arthritis, organ transplant recipients and HIV/AIDs 
• Neuromuscular and central nervous system diseases
• Haemoglobinopathies and children on long term aspirin.

For more information see our topic on Influenza vaccination

Further information and support

To find out more about the influenza vaccine call your doctor or contact:
The Immunisation Advisory Centre (IMAC) on freephone 0800 IMMUNE (0800 466 863)

Useful websites www.immune.org.nz and www.influenza.org.nz

Written by the everybody editorial team. Reviewed by IMAC.