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Having cancer or treatment for cancer can lower your immunity and make you more likely to catch flu. We look at whether the vaccine is safe for people with breast cancer and whether it's safe to have while undergoing certain treatments like trastuzumab or chemotherapy.

The flu vaccine

Flu (influenza) is an infection caused by a virus. It generally affects people during the winter, so lots of GPs (local doctors) run flu vaccination clinics from early Autumn. The vaccine is offered free to people who are more at risk of catching flu or having more serious complications from it. This includes anyone with a weakened immune system because of cancer or cancer treatment. 

What are the benefits of having the flu vaccine?

Some cancer treatments, particularly chemotherapy, can weaken the immune system making you more prone to infections and illness. If you catch flu you might feel too unwell to attend appointments. It may also mean delays to your cancer treatment.

Although the vaccine doesn’t completely rule out the possibility of getting flu, getting vaccinated will make it less likely. Anyone diagnosed with cancer or having cancer treatment should talk to their doctor as soon as possible about having the vaccine. It takes up to 14 days to achieve immunity from your flu jab, so if in this time you have symptoms of flu the vaccination will not stop you from getting it. It also doesn’t protect you from coughs, colds or chest infections.

Is it safe to have a flu jab while having treament for breast cancer?

The flu vaccine is not ‘live’ so it cannot give you flu. You may suffer some slight aches and pains after you have had the injection. If you feel you are suffering from more serious side effects, you should contact your doctor. If you are having the following treatments for breast cancer or suffering from lymphoedema, you will need to check with your GP or specialist team before getting the vaccine.


Chemotherapy can weaken the immune system and make you more vulnerable to infection, so if you’re having (or due to have) chemotherapy you should be given the flu vaccine. Talk to your chemotherapy specialist or breast care nurse about the best time to have your flu jab.


Trastuzumab does not affect the immune system in the same way as chemotherapy, so it’s usually safe to have the flu vaccine. Talk to your specialist team about the best time to be vaccinated.

You can sometimes get flu-like symptoms with trastuzumab (usually with the first dose), but this doesn’t mean you have the flu.


If you’re having surgery soon (in the next few days) think about postponing the vaccination until afterwards. This is because the vaccine can occasionally make people feel unwell, which is best avoided around the time of your surgery.


As radiotherapy for breast cancer does not affect the immune system, you can have the vaccine at any time during your treatment. People having radiotherapy are not likely to be considered at risk of getting the flu, but you can discuss this with your GP or specialist team.

Hormone therapy

If you have finished your initial treatment for primary (early) breast cancer but are still having hormone therapy, you are not likely to be considered at risk of getting the flu. If you are considering having the flu jab, talk to your GP or specialist team.


It’s important to avoid being vaccinated in the arm on the side where you had (or are having) surgery because of the risk of lymphoedema. This is long-term swelling of the hand or arm that can happen after breast surgery. An infection or injury to your ‘at risk’ arm may increase your chances of developing it.

Do the people I live with also need a flu jab?

If you’re having treatment for breast cancer you can ask your GP about the vaccine for people you live with. If your treatment means you have reduced immunity, they may be offered a free vaccination. If any members of your family are 17 years old and under they may be offered a nasal flu spray – this does contain live viruses so if you are having chemotherapy, it may be best to avoid close contact with them for around 10 days after the spray has been given.

Will I have to pay for the flu jab?

If you are not in one of the ‘at risk’ groups you can still have the vaccine but you will need to pay for it. It's available from some high street pharmacies and supermarkets.

Further information

If you would like to have the flu jab or want to find out more, it’s important to talk to your specialist team as it will depend on the treatment you’re having (or are due to have).

You can also contact us on 0808 800 6000 to talk to a member of our experienced team, or use our email Ask our nurses service.

Find out more about flu vaccination on the NHS Choices website