Influenza

What is the flu?

Influenza (flu) is an infection caused by influenza viruses. It affects your upper respiratory tract (your nose, throat and mouth) and can range from mild to severe.

It can cause a range of symptoms, and usually lasts from a few days to a couple of weeks. Influenza can be very mild or considerably more serious, and often comes on very suddenly and without warning.

Most people who get flu will be fine within a few days to two weeks, but some people, particularly those classed as vulnerable such as the elderly, can get complications which can lead to conditions such as pneumonia. This may be life-threatening.

Who gets the flu?

Anyone can get the flu, but some groups are more vulnerable to it. This includes babies, pregnant women, people over the age of 65 and the elderly, and people with certain health conditions that limit their immune systems, such as diabetes and heart disease. Asthma sufferers are more prone to it too.

The flu is highly contagious, and spreads when you come into contact with another person who has it, or if you come into contact with the things that somebody coughs or sneezes on. It’s very easy to catch it as you go about your day-to-day life, so it’s important to take preventative measures to limit your chances of catching flu. These measures include washing your hands when you go to the toilet and sanitising your hands when you eat.

How common is flu?

The flu is very common. About 9% of the world population gets the flu each year. Up to one billion are infected, and there are approximately three to five million cases which are severe. Between three and five hundred thousand cases result in death.^[1]

What causes flu?

Flu is caused by catching the influenza virus. It’s highly contagious and it’s usually transmitted through infected people coughing or sneezing. This spreads the virus into the air, where people can breathe it in and become infected. The virus can also live on surfaces, and be transmitted when you touch them.

What are the symptoms of flu?

Common symptoms of flu can include but are not limited to:

• feeling nauseous and being sick
• stomach pain and diarrhoea
• appetite loss or changes in eating habits
• difficulty sleeping
• headaches
• a sore throat and dry cough
• feeling tired and achy
• a high temperature of 38°c or above which comes on quickly

Can flu lead to other problems?

The flu is usually not dangerous, and most people will recover from it without needing an intervention or medication. But if you’re in a more vulnerable health group it can create complications due to your immune system not being strong enough to defeat the virus on its own. A secondary infection may progress, such as pneumonia, or it may worsen pre-existing illnesses, such as asthma, diabetes or heart disease.

Some of the effects of flu in those of us with chronic medical conditions can be much more serious, such as a persistent pressure in the chest, difficulty breathing, seizures or dizziness and confusion.