Seasonal flu
Flu is a common infectious viral illness spread by coughs and sneezes. It can be very unpleasant, but you'll usually begin to feel better within about a week.
You can catch flu short for influenza all year round, but it's especially common in winter, which is why it's also known as "seasonal flu".
It's not the same as the cold. Flu is caused by a different group of viruses and the symptoms tend to start more suddenly, be more severe and last longer.
Cold-like symptoms such as a blocked or runny nose, sneezing, and a sore throat can also be caused by flu, but they tend to be less severe than the other symptoms you have.
Flu can make you feel so exhausted and unwell that you have to stay in bed and rest until you feel better.
You can take paracetamol or ibuprofen to lower a high temperature and relieve aches if necessary.
Stay off work or school until you're feeling better. For most people, this will take about a week.
Your doctor may recommend taking antiviral medicine to reduce your symptoms and help you recover more quickly.
Children and people with weaker immune systems may remain infectious for longer.
Most people will make a full recovery and won't experience any further problems, but elderly people and people with certain long-term medical conditions are more likely to have a bad case of flu or develop a serious complication, such as a chest infection.
They hang suspended in the air for a while before landing on surfaces, where the virus can survive for up to 24 hours.
Anyone who breathes in the droplets can catch flu. You can also catch the virus by touching the surfaces that thedroplets have landed on if you pick up the virus on your hands and then touch your nose or mouth.
Everyday items at home and in public places can easily become contaminated with the flu virus, including food, door handles, remote controls, handrails, telephone hand sets and computer keyboards. Therefore, it's important to wash your hands frequently.
You can catch flu many times, because flu viruses change regularly and your body won't have natural resistance to the new versions.
You can help stop yourself catching fluor spreading it to others with good hygiene measures.
Always wash your hands regularly with soap and warm water, as well as:
You can also help stop the spread of flu by avoiding unnecessary contact with other people while you're infectious. You should stay off work or school until you're feeling better.
In some people at risk of more serious flu, an annual flu vaccine (see below) or antiviral medication may be recommended to help reduce the risk of becoming infected.
If you think you might need it, contact your local GP surgery.
You should have the flu vaccination every year so you stay protected, as the viruses that cause flu change every year.
For more information on who should have the flu vaccine and how to get it,read the sections on the flu jab for adults, the flu jab for pregnant women and the children's flu vaccine.
Flu is a common infectious viral illness spread by coughs and sneezes. It can be very unpleasant, but you'll usually begin to feel better within about a week.
The symptoms of flu usually develop within one to three days of becoming infected. Most people will feel better within a week. However, you may have a lingering cough and still feel very tired for a further couple of weeks.
Usually, you can manage flu symptoms yourself at home and there's no need to see a GP. Most people feel better within a week. You can look after yourself at home by resting, keeping warm and drinking plenty of water.
Complications of flu mostly affect people in high-risk groups, such as the elderly, pregnant women and those who have a long-term medical condition or weakened immune system.
There are three main ways of preventing flu: good hygiene, such as handwashing and cleaning, the flu vaccination and antiviral medication.