Flu vaccine - About the flu vaccine

Flu vaccination is one of the best ways to help protect against catching and spreading flu. Protection starts around two weeks after having the vaccine.

Flu viruses are constantly changing. Each year flu vaccines are changed to match the flu viruses that are likely to be circulating.

Like all medicines, no vaccine is completely effective. You might still get flu, but your symptoms are likely to be milder. Flu vaccines do not protect against colds, other respiratory viruses, or other winter illnesses.

Flu vaccines usually become available towards the end of September or the beginning of October each year. Ideally, the flu vaccine should be given before flu starts to spread. However, it can still be given at a later date. Protection starts around two weeks after you have had a flu vaccine.

If you are in a group that has a higher risk of becoming very ill if they catch flu, you should have a flu vaccination every year.

You can see who is eligible for the flu vaccine.

You can have the flu vaccine at the same time as most other vaccines. The person giving you the vaccine can discuss this with you.

Make sure you get your vaccines as soon as they are offered to you. 

Like all medicines, vaccines can cause side effects. Most side effects are mild and short term, and not everyone gets them.

Some of the most common side effects include:

• pain, bruising, redness, hardness or swelling where you had the injection
• muscle or joint pain
• tiredness
• loss of appetite
• diarrhoea, and
• a headache.

The flu vaccine will not give you flu.

If your symptoms seem to get worse or if you are concerned, contact NHS 111 Wales by calling 111 or call your GP surgery. If you get advice from a doctor or nurse, make sure you tell them what vaccines you have had so they can assess you fully.

Rarely, people can have a severe reaction soon after the vaccination, which causes breathing difficulties and may cause them to collapse. This is called an anaphylactic reaction, and it can also happen with other medicines and food. These reactions are extremely rare, affecting less than one in a million people. Staff who give vaccinations are trained to manage these reactions.

People who have an anaphylactic reaction can be successfully treated and usually recover within a few hours.

You should report any side effects of the vaccine through the Yellow Card scheme online at Yellow Card, by downloading the Yellow Card app, or by calling 0800 731 6789 (Monday to Friday, 9am to 5pm).

For all side effects and for more information about the vaccine, please see the relevant patient information leaflet below.

• Adults aged 65 years and over 
• Adults who are at risk (including pregnant women) aged 18 to 64 years

If you are an adult in a risk group, pregnant, or aged 65 or over, you can get your flu vaccine at your GP surgery or at some local pharmacies. In some areas of Wales, pregnant women can also get the vaccine from their midwife.

If you think you might have missed the invitation for a flu vaccine, contact your GP or local pharmacy.

If your child is eligible for a flu vaccine, please see the information in the ‘Children and young people’ section further down the page.

If you work in a care home, are a domiciliary care worker (providing care in people’s homes) or a healthcare worker, go to the Influenza (flu) – information for health and social care workers webpage to find out how to get your vaccine.

Vaccination is one of the most effective ways to help prevent severe illness from flu. No vaccine is 100% effective, so it is still important to know the signs and symptoms of flu, even if you or your child are vaccinated.

For more information about flu visit the NHS 111 Wales website.

When people get flu, they tend to become ill quite quickly. Symptoms can include fever, chills, a headache and aching muscles, often with a cough and sore throat.

Around half of people infected with flu don’t even realise it, yet they can still spread the virus to others. This can sometimes cause serious illness leading to hospital care, and in rare cases, death.

Some COVID-19 symptoms are similar to flu so please check the latest advice and follow the current COVID-19 guidance.

If you have a temperature or a cough, follow the current guidance.

Flu is usually managed by resting at home, keeping warm and drinking plenty of water. You can take paracetamol (follow the advice in the packet and do not take more than the recommended dose), to lower a high temperature and relieve aches if needed.

However, if you are in a high-risk group you should speak to your GP surgery or local pharmacy straight away if you think you might have flu, as they may recommend a course of antiviral medicines.

To help stop flu and other viruses spreading, remember to:

Catch it 
Use a tissue when you sneeze or cough.

Bin it
Put the tissue in the bin as soon as possible.

Kill it
Wash your hands or use hand sanitiser.

Find out which children are eligible for a free flu vaccine.

Flu is caused by viruses and spreads easily. Anyone can get flu, but school-aged children have the highest rate of infection and flu can be serious for them. Children under five years of age have one of the highest hospital admission rates for flu compared with other age groups.

Complications can include bronchitis and pneumonia (lung infections) and ear infections.

Some children get so ill they need to go into hospital.

For more information about the symptoms of bronchitis, pneumonia and ear infections, visit the links below.

• Pneumonia
• Bronchitis
• Ear infection

Having a flu vaccine will help protect your child from flu.

Protection starts around two weeks after having the vaccine. The vaccine usually offers children good protection against flu.

It also helps reduce the chance of children and young people spreading flu to others who are at high risk from flu, such as young babies, older adults, and those with long-term health conditions.

Some people still get flu even after having a flu vaccine, but often with milder symptoms. Flu vaccines do not protect against colds, other respiratory viruses or other winter illnesses.

Flu vaccines help protect people against flu and the possible complications caused by flu.

There are a number of flu vaccines available, for different age groups. The vaccines that are currently recommended have been proven to be effective through clinical trials and studies of their use in the UK over several years.

In the UK, the following are the two main types of flu vaccines for children.

• The live attenuated influenza vaccine (LAIV), which is given as a spray in the nostrils.
• If the nasal spray cannot be given for medical reasons, or because it is otherwise unsuitable, children can have the injectable cell-based influenza vaccine (IIVc) instead. This is given as an injection.

Both vaccines offer very good protection to children and young adults.

Different flu viruses 

There are different types of flu viruses that circulate and cause infection each year and they change over time. Because of this, it is difficult to directly compare the vaccines and say which is the most effective overall.

The three main types of flu viruses, which circulate most years, are:

• influenza A(H1)
• influenza A(H3), and
• influenza B.

During the winter of 2024 to 2025, both the nasal spray and the injection offered to children protected them from all three types of flu virus. For the two most common flu viruses that season, the nasal spray worked better for one type and the injection worked better for the other. The overall level of effectiveness was similar for both vaccines.

Sometimes flu viruses change (mutate). This makes them harder to fight, as there is a bigger difference to the ones vaccines protect against. The nasal spray might give better protection against these mutated viruses because of how it helps the body build immunity.

Final recommendation

Based on current evidence, the nasal spray is still the recommended flu vaccine for children aged two to 17, unless they cannot have it for certain medical or other reasons.

Flu nasal spray 

After the flu nasal spray vaccination, some of the most common side effects in children and young people in the first day or two include:

• • a runny or blocked nose

• • reduced appetite

• • weakness

• • a fever

• • a headache, and

• • muscle aches.

Flu vaccine injection 

If a child or young person has the flu vaccination by injection, some of the most common side effects include:

• • pain, bruising, redness, hardness or swelling where the injection was given

• • a headache

• • muscle pain

• • tiredness

• • a change in eating habits, including loss of appetite

• • irritability

• • sleepiness, and

• • diarrhoea.

Flu vaccines are very safe.

The flu vaccine will not cause flu. 

For all side effects and for more information about the vaccine, please see the relevant patient information leaflet below.

Children aged two to less than 18 years

AstraZeneca UK Limited Fluenz Trivalent LAIV (live attenuated influenza vaccine) nasal spray

Children aged six months to under two years

Seqirus TIVc (cell-based trivalent influenza vaccine – inactivated)

Note: Children aged two to 17 years who cannot have the nasal spray vaccine, for example, due to certain health conditions or because it contains pork gelatine, may be offered the flu vaccine as an injection instead.

Rarely, people can have a severe reaction soon after the vaccination, which causes breathing difficulties and may cause them to collapse. This is called an anaphylactic reaction, and it can also happen with other medicines and food. These reactions are extremely rare, affecting less

than one in a million people. Staff who give vaccinations are trained to manage these reactions.

People who have an anaphylactic reaction can be successfully treated and usually recover within a few hours.

You should report suspected side effects of the vaccine online at Yellow Card, by downloading the Yellow Card app, or by calling 0800 731 6789 (Monday to Friday, 9am to 5pm).

If your child is aged six months or older and has certain health conditions, it is important they have a flu vaccine every year as they are at an increased risk of complications from flu.

For more information, visit Eligibility for the vaccine – Public Health Wales

Children who are aged two or three years (on 31 August 2025) are generally invited to have their flu vaccine at their GP surgery.

In some areas, three-year-olds and some four-year-olds are offered the vaccine in nursery.

If your child is in this age group and hasn’t had an invitation for the vaccine by mid-November, contact their GP surgery.

Children and young people who attend school will usually have their flu vaccine in school. Parents will be given information about the vaccine, along with a paper or digital consent form. Please read the information, then fill in and return the consent form as soon as possible.

In some cases, young people under the age of 16 may be able to give consent themselves, if they are mature enough to fully understand what is being offered. The person giving the vaccination will be able to answer any questions.

Children and young people aged four or older who are not in school or mainstream education can have their flu vaccine at their GP surgery or community vaccination centre. You will need to make an appointment and ask your local health board what to do next.

If your child is aged under two, or 16 or 17 years of age, and is at greater risk of complications from flu due to a health condition, their GP surgery should invite them to have their vaccine.

Ideally, the flu vaccine should be given in the early autumn before flu starts to spread. However, it can still be given at a later date.

If your child misses their flu vaccine, speak to their health visitor (if the child is under five years old), school nurse or GP surgery about getting the vaccine. 

Most children and young people will get a nasal spray vaccine at school. It is a fine mist sprayed up the nose and can be given from the age of two. The vaccine is painless and safe, and most children and young people are not usually upset after having it.

Children and young people in the age ranges above who are homeschooled or not in mainstream education can also have the flu vaccine.

If your child misses their flu vaccine, speak to their health visitor (if the child is under five years old), school nurse, GP or practice nurse about getting the vaccine.

The nasal spray vaccine can’t be given to children and young people who:

• are under two years old
• are on long-term aspirin (salicylate) treatment
• have had a severe life-threatening allergic reaction to the vaccine or its ingredients
• have a weakened immune system due to a disease or treatment
• are pregnant
• have a wheezy chest on the day of the vaccination or in the previous three days, or
• have increased the use of their asthma inhalers in the previous three days.

A flu vaccine injection is available from GP surgeries for children and young people who can’t have the nasal spray vaccine.

There are some situations where you should get advice about your child having the nasal spray vaccine. If any of the following apply, speak to your health visitor, school nurse, GP or practice nurse for more advice before your child has the flu vaccine.

• Your child has asthma and needs regular oral steroids or they have needed intensive-care treatment for their asthma in the past. In this case they should get advice about the nasal spray vaccine from a specialist. They may be offered a flu vaccine injection instead or they may need to have the nasal spray vaccine in hospital.
• Your child is having a cochlear implant in the week before their nasal spray vaccination appointment, is due to have the vaccination in the two weeks after having their implant, or there are problems related to the implant.
• Your child has an unrepaired craniofacial malformation (a difference in the shape of the face or skull that hasn’t been corrected with surgery).
• Your child cannot avoid contact with someone who has very weakened immunity, such as someone who has recently had a bone marrow transplant.

In these situations, your child can have the flu vaccine by injection instead. Your health professional will make an assessment before giving the vaccine.

A cold or other minor illness is not a reason to delay a flu vaccination. If your child is unwell with a high temperature, it is best to delay their vaccination until they are feeling better.

Remember to follow the latest advice if your child has any COVID-19 symptoms.

The nasal spray vaccine can be safely given to most children with an egg allergy. If your child has had a serious (life-threatening) reaction to egg that needed intensive-care treatment, they should be offered an appropriate flu vaccine by injection.

Speak to your health visitor, school nurse, GP or practice nurse for more advice.

The nasal spray flu vaccine contains small traces of highly purified pork gelatine.

It is the recommended flu vaccine for most children and young people.

Some people don’t eat pork gelatine because of their faith. Both Muslim and Jewish communities have approved the use of the flu nasal spray vaccine. This is because the flu nasal spray is a non-oral product and a medicine.

If you decide you do not want your child to have the nasal spray, they can have an injection instead. This does not contain pork gelatine. You can highlight this on your consent form. Or you can contact your health visitor, school nurse, immunisation team or GP surgery to discuss with them how to get the injection.

Find more information on pork gelatine.