You can't always prevent getting the flu - but there are steps you can take to help avoid it.
It is very easy to catch flu from someone who's got the virus - even if they don't cough or sneeze near you. The virus can be picked up from touching something they've touched, like a door handle.
One medical way to help prevent flu is to have the annual flu jab.
Some people who are at a greater risk of complications from flu are offered a free flu vaccination on the NHS - usually through their GP. This includes older people, pregnant women and people with some long-term health conditions, such as diabetes.
Many children are now offered a nasal flu vaccine that's squirted into the nose. Kids are known to be 'super spreaders' of flu. This means that if a child in class has it - your child is very likely to pick up the virus and pass it on to family members - including younger children and grandparents.
If you don't qualify for the free flu jab, you can pay to have it privately, including at some pharmacies.
Flu keeps evolving - and each year experts put together a vaccine that gives protection against the strains of flu they predict will be around in autumn and winter that year. This isn't fool proof. Sometimes a strain of flu can take them by surprise and people can get flu despite being vaccinated.
We know that flu is around every year - and is usually more common in autumn and winter. That's the time to be extra vigilant with flu hygiene.
This means protecting yourself - and if somebody at home has flu - helping them try to keep it to themselves.
The main defence is to wash hands often with soap and warm water. Hand gels can be used if a sink and running water are not available.
If you share surfaces with other people - kitchen worktops, bathrooms, toilets, phone handsets, TV remote controls, door handles, computer keyboards and mice - give them a regular clean to wipe away germs.
Try to get out of the habit of touching your eyes, nose or mouth - as this spreads any germs you have - and can transmit them to you after touching a contaminated surface.
This isn't a general flu prevention measure, but it may be recommended if there's a flu outbreak and someone with a higher chance of complications, who hasn’t had the flu vaccine, has a higher risk of catching flu.
Antiviral means against viruses - as flu is a virus. They are used rather than antibiotics because antibiotics only work for bacterial infections.
The two antiviral medications the NHS uses for flu are oseltamivir (Tamiflu) or zanamivir (Relenza).
These can be used 36-48 hours after coming in to contact with a person with flu.