What is influenza? Flu symptoms and how long they last
INFLUENZA - or flu to most of us - is a highly contagious virus that has millions of Brits bedridden for a few days or longer each year.
While it's nasty to catch, there are ways of avoiding it and treating the symptoms if you get it.
What are the symptoms of flu?
The NHS explains that the main symptoms include a fever of more than 38C, a chesty cough, headache, tiredness and aching muscles as well as a sore throat, runny nose and sneezing.
Some people can also experience nausea and vomiting, diarrhoea or joint and limb pain.
It usually takes between one and three days for flu symptoms to develop after catching the virus.
In most cases people feel better after a week.
How contagious is it?
It is spread in droplets, meaning that anyone sneezing, coughing or talking up to six feet away from you can spread it to you.
People who have been vaccinated have a much better chance of fighting it off. The NHS offers vulnerable people free vaccinations.
The incubation period (between exposure and symptoms) is between one and four days.
After symptoms have begun, adults are contagious for five to 10 days but children can be contagious for longer.
What's the difference between flu and the common cold?
Influenza and the common cold are both respiratory illnesses but they are caused by different viruses.
On the whole, flu symptoms are more intense than those caused by the common cold and leaves you feeling exhausted and too unwell to continue your usual routine.
People who are suffering from a cold are more likely to have a runny or stuffy nose but those with flu experience more than just nose and throat problems.
How can I treat influenza at home?
As influenza is viral, you need to wait for the symptoms to pass, but there are some things you can do to make yourself more comfortable.
It's best to get as much rest as possible to allow your body to recuperate.
You should also keep warm and drink plenty of water to avoid getting dehydrated.
Taking paracetamol or ibuprofen can help to lower your temperature and treat aches and pains.
If you're pregnant, over 65, have a long-term medical condition or weakened immune system you should consider visiting a GP if you are struck down by the flu.
The NHS also advises seeking medical attention if you develop chest pain, shortness of breath, difficulty breathing or begin coughing up blood, as well as if symptoms are not improving after a week.