Flu is a highly infectious illness that spreads rapidly through the coughs and sneezes of people who are carrying the virus.
If you're at risk of complications from flu, make sure you have your annual flu vaccine, available each year usually from October onwards.
There are two types of flu vaccine:
Because flu is caused by a virus and not bacteria, antibiotics won't treat it.
Anyone can get flu, but it can be more serious for certain people, such as:
If you are in one of these groups, you're more vulnerable to the effects of flu (even if the condition is well managed and you normally feel well). You could develop flu complications, which are more serious illnesses such as bronchitis and pneumonia, which could result in hospitalisation.
Flu can also make existing medical conditions worse.
Read more about flu.
See your doctor about the flu jab if you're 65 or over, or if you have any of the following problems (however old you are):
If you're pregnant, you should have the flu jab, regardless of the stage of pregnancy you've reached. Pregnant women are more prone to complications from flu that can cause serious illness for both mother and baby.
If you are pregnant and catch flu, talk to your doctor urgently as you may need treatment with antiviral medicine.
The flu vaccine for children is a nasal spray and is available each year on the NHS for two- and three-year-olds plus children in reception class and school years one, two, three and four.
Over the next few years the programme will be extended to children in other year groups.
Children with a long-term health condition should also have a flu vaccination because their illness could get worse if they catch flu. This includes any child over the age of six months with a long-term health problem such as a serious respiratory or neurological condition.
If you have a child with a long-term condition, speak to your doctor about whether they should have the flu vaccination. Some children with a long-term health condition may be advised to have the flu vaccine injection rather than the nasal spray.
This NHS leaflet gives you five reasons to vaccinate your child against flu (PDF, 408kb).
If you're the main carer of an elderly or disabled person, make sure they've had their flu jab. As a carer, you could be eligible for a flu jab too. Ask your doctor for advice.
The injected flu vaccine contains inactivated, or killed, strains of the flu virus and therefore cannot cause flu.
The nasal spray flu vaccine for children contains live, but weakened forms of flu virus but again this vaccine does not cause flu.
The flu virus in both the injected and nasal spray vaccine is grown on fertilised hens' eggs so anyone with an egg allergy should have an alternative egg-free vaccine.
If you think you or your child needs a flu vaccination, check with your doctor, practice nurse or local pharmacist.
The best time of the year to have a flu vaccination is in the autumn from the beginning of October to early November. Most doctor surgeries arrange flu vaccination clinics around this time. It's free and helps to protect you against the latest flu virus strains.
Some community pharmacies now offer flu vaccination on the NHS to adults (but not children) at risk of flu including pregnant women, people aged 65 and over, people with long-term health conditions and carers.
If you have your flu jab at a pharmacy, you don't have to inform your doctor – it is up to the pharmacist to do that.
Even if you've already had a flu vaccine in previous years, you need another one each year. The flu vaccine may only protect you for a year because the viruses that cause flu are always changing.
When you see your doctor for a flu jab, ask whether you also need the pneumococcal vaccine, which protects you against some forms of pneumococcal infection, including pneumonia.
Like the flu jab, the pneumococcal vaccine (also known as the pneumonia vaccine or "pneumo jab") is available free on the NHS to everyone aged 65 or over, and for younger people with some serious medical conditions. But it's a one-off jab rather than an annual one.
No vaccine is 100% effective, however, people who have had the flu jab are less likely to get flu. If you do get flu despite having the jab, it will probably be milder than if you haven't been vaccinated.
The flu jab doesn't cause flu as it doesn't contain live viruses.
However, you may experience side effects after having the jab, such as a temperature and aching muscles for a couple of days afterwards. Your arm may feel sore at the site where you were injected. More severe reactions are rare.
The flu vaccine only protects against flu, not other illnesses caused by other viruses, such as the common cold.
You shouldn't have the flu vaccination if:
Not all flu vaccines are suitable for children, so discuss this with your doctor beforehand.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.