PUBLISHED ON: 11 March 2021

With the COVID-19 vaccination programme being rolled out across the country Dr Sheeba Irshad, senior clinical lecturer, breast cancer medical oncologist and clinical deputy head of the Breast Cancer Now Research Unit at Kings College London, answers some common questions about the current vaccines and if they are safe and effective for people with breast cancer.  

Dr Irshad

Is the coronavirus vaccine safe if I’m having breast cancer treatment?

For most people, it’s much safer to have the vaccine than not to have it and risk catching coronavirus.

Some vaccines use a ‘live’ but weakened virus to give an immune response, which may be a risk to people with weaker immune systems.

However, that’s not the case for the three available Covid-19 vaccines, which are considered safe for people having treatments that can weaken the immune system, such as chemotherapy.

You should discuss having the vaccine with your treatment team if you are having an immunotherapy treatment like atezolizumab.

Can I have the vaccine if I’m taking hormone therapy?

Hormone therapy, such as tamoxifen, letrozole, anastrozole or exemestane, does not typically affect your immune system. Therefore, it shouldn’t reduce the effectiveness of the vaccine, and it should be safe to have the vaccine if you’re taking one of these treatments.

Some people have asked if it’s safe to have the AstraZeneca vaccine if they are on hormone therapy. This follows news stories about a rare type of blood clot in a small number of people who had this vaccine. Blood clots can be a side effect of tamoxifen.

However, as far as we’re aware there’s no increased risk of blood clots in people who have the AstraZeneca vaccine while taking hormone therapy. 

Will the vaccine be effective if I’m having treatment?

Although we don’t know for certain how effective the vaccine will be for people having treatments such as chemotherapy or targeted cancer therapies, it’s likely to still offer some protection against the virus.

During treatment you will usually have regular blood tests to check your white blood cell count. A reduced white blood cell count may mean you’re more at risk of infection.

However, it doesn’t mean that your body is less capable of developing immunity from the vaccine. This is because different parts of the immune system are involved in this process.

You may be advised to have the vaccine at a specific point during your treatment cycle when your immune system is at its healthiest.

As the vaccine continues to be rolled out, it should become clearer how it may work for people with cancer and those with a reduced immune system.

A very small study has suggested some cancer patients had less protection after their first dose of the Pfizer vaccine compared to people without cancer.

People with cancer are advised to follow their doctors’ advice about having the vaccine.

When should I have the vaccine?

If you are having treatment, when you have your Covid-19 vaccination may depend on the type and timing of your cancer treatment.  Your treatment team will be able to offer advice based on your individual situation.

The government has set out an order of priority for who will be offered the vaccine, so those most in need get it first. Where you fit on the priority list will depend on your age and individual situation. Your GP will be in touch by text, email or letter when it’s your turn to be offered the vaccine.

Can I have a Covid-19 vaccine if I’ve finished my breast cancer treatment?

Yes. When you have completed your breast cancer treatment, your immune system gradually recovers from any side effects of chemotherapy or other treatments. There’s no reason to think the vaccine won’t be effective if you have had breast cancer and have finished your treatment.

What should I do after I’ve had the vaccine?

People considered to be clinically extremely vulnerable, which may be the case if you’re having or have recently completed treatment, are advised to take extra precautions to protect themselves.

This includes minimising the number of social interactions you have and reducing the amount of time you spend in places where you cannot maintain social distancing.

While the vaccine is expected to offer some protection against the virus, we don’t yet know what that level is, especially if your immune system is weakened by cancer treatments. This is a precautionary measure to keep you as safe as possible.

I have had lymph nodes removed as part of my surgery, can I still have the vaccine?

If you have had surgery to remove some of or all of your lymph nodes in your armpit, you may be worried that having the vaccination will increase your risk of lymphoedema

There’s no strong evidence that having injections in your ‘at risk’ arm will cause lymphoedema. However, you may prefer to use your other arm.

If you have had lymph nodes removed from both sides, the vaccine can be given safely into your thigh.

You’ll need to talk to the vaccination team on the day of your appointment if you’re worried about having an injection on your affected side.


You can view a Facebook video of Dr Irshad talking to our clinical nurse specialist, Louise, about coronavirus vaccines. If you have questions about COVID-19 vaccinations and breast cancer, contact our Helpline team on 0808 800 6000.

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