Flu Jab

The flu vaccine campaign begins every autumn in the UK and is one of the most important public health interventions that the NHS undertakes. In this blog, we answer a number of common questions we get from blood cancer patients about the vaccination programme.

The flu vaccine campaign begins every autumn in the UK and is one of the most important public health interventions that the NHS undertakes. Flu hospitalises and even kills a large number of people every year. The vaccine can help prevent transmission of the virus to those most likely to get severely unwell, as well as reduce the severity of the flu. Here are a number of common questions we get from blood cancer patients about the vaccination programme.

What is the flu?

“Flu” is the name given to the illness that occurs in people who have been infected with the influenza virus. Influenza is an extremely common virus. It is often confused with a cold, but influenza, or flu, comes on quicker and makes you feel more unwell. It should not be dismissed. Most healthy people recover from flu after a few days and don’t need to see their GP. However, some complications can arise from flu, such as pneumonia and bronchitis, which can be especially serious in certain populations.

Who is more likely to develop complications from flu?

There are certain groups that are most at risk from complications related to flu. These include the elderly, the young, pregnant women and those with certain medical conditions, such as asthma. These groups are chosen because they are more likely to have a serious illness from the virus, often due to a reduced or compromised immune system.

Therefore, these groups are eligible for the free flu vaccine on the NHS each year and it is more important for these people, and those around them, to take action to prevent themselves catching the flu

What about those with blood cancer?

If you have a blood cancer, such as a leukaemia, you will likely have at least some reduction in your ability in fight infections (although this depends on your leukaemia type, among other things). Therefore, it is recommended you also have the flu vaccine, as blood cancer can hinder your ability to fight off the flu. Even if you are currently not undergoing treatment, such as you’re on watch and wait, you should still speak to your GP or medical team about having the jab.

What if I am undergoing treatment? Should I have the vaccine?

Yes. Treatment such as chemotherapy, radiotherapy and steroids can also lower your immune system, so you are still at risk of developing flu-related complications. It is safe to have the vaccine whilst you are undergoing treatment.

Should children with leukaemia have the vaccine?

If your child is undergoing treatment for leukaemia, please consult with their medical team about the need for a flu jab. Children typically receive a live virus treatment in either a spray or injection format; this type of vaccine can be unsafe for children with an especially low immune system.

My immune system is low. Will the vaccine make me ill?

The flu jab that is given to adults does not contain any live flu virus; it instead contains inactive pieces of protein that the virus has on its surface. These proteins are what alerts the immune system to the presence of a virus. The vaccine works by preparing the immune system in advance by showing it these proteins. If you come into contact with the flu virus afterwards, this means your immune system can protect you more quickly, because it has seen the proteins before. This process is called “priming” the immune system. Importantly, have the proteins on their own cannot give you flu, so you will not develop the flu after the vaccine.

Some people develop some symptoms after the virus, but this is due to the immune response to the vaccine proteins and not the flu itself. (see “are there any side effects?” below).  You should also not have the flu jab if you’ve had a severe reaction to a vaccine in the past.

Additionally, you should not have the flu vaccination if you have an egg allergy, as some of the vaccines contain egg. Speak to your doctor about your allergy, as an egg-free vaccine may be available.

Are there any side effects?

Side effects from the flu jab are uncommon. However, some people report a feeling of soreness around the site of injection, as well as a slight fever and aching joints. These side effects do not mean you have, or will develop, flu; they are a side effect of your immune response responding to the vaccine.

Severe reactions, such as allergic reactions, are rare, but seek medical help if you concerned about symptoms or feel very unwell within 24 hours of the vaccine.

I had the flu jab last year. Do I need to have it again this year?

Yes, as the viruses that cause flu can change each year. If you were to skip this year’s vaccine, you may be protected if you encounter the virus that was most common last year. However, this year, a different virus might be the most common one and you will not be protected against those newer viruses without the updated vaccine.

Here is a quick overview about why the vaccine changes each year, to help explain why you need to have a vaccine every year.

The immune system relies on the ability to recognise a virus as foreign and something to be got rid of. Therefore, it looks for things that appear on every virus, known as antigens, and creates antibodies that recognise those antigens. Vaccination relies on these antigens staying the same with every attack, speeding up your response to something your body has seen before. When the immune system detects an influenza virus, the antigens it reacts to are proteins called haemagglutinin (H) and neuraminidase (N). These proteins stick out of the surface of the virus.

However, influenza virus can change the H and N proteins slightly. This is because it has a genome made of RNA, which is prone to mistakes when it is copied. That means future virus may have slightly different looking H and N proteins. One small change will dampen down your immune response, but your antibodies should still work a bit. These small changes build up over time until the H and N proteins are unrecognisable to the antibodies you’ve already got, and then your immune system must start from scratch.

Scientists look at which H and N the viruses in the environment have throughout the year and try to work which H and which N this winter’s viruses will have. They include these H and Ns into the vaccine. The World Health Organisation is the body that works out which flu strains are most likely the following year and publishes the 4 types that should be included in the vaccines that year. Pharmaceutical companies then produce viruses for purchase.

For further information, you can watch the following YouTube videos:


Can you still get flu even if you have had the vaccine?

Yes, it is still possible you may catch flu. Even if scientists identify the correct strain of virus that initially appears, the virus can mutate and change over time as it circulates around the human population during the flu season. This means that those who get the slightly changed virus later in the season may have less immunity to it.

Additionally, your immune system may not react strongly enough to the vaccine to give you lasting protection in the first place; this can happen if your immune system was low at the time of having the vaccine.

Regardless of the reason the virus wasn’t stopped completely, the vaccine should still make your flu less severe, so you are much more likely to recover more quickly and less likely to develop complications than if you never had the virus .

I am a relative of someone with blood cancer. Should I get the flu jab?

Yes, so as to prevent any chance of you passing the flu on to your vulnerable relative. Speak to your GP or pharmacist about having the vaccine. You will have to pay a small amount (approximately £20) for the vaccine if you are not included on the list of people entitled to a free vaccine; it may be easier for you to get an appointment at a pharmacy for this as demand on GP appointments is high in flu season. The vaccine you receive if you pay for it is the same as the free version available on the NHS for the vulnerable groups.

Please note: Children have a live version of the vaccine as a spray or injection. A live vaccine means the vaccine contains a whole virus that has been weakened (known as being attenuated) so it is less likely to cause the flu, but can still cause an immune response. This type of weakened virus can also be passed on to others. It is not known for sure whether a person who is extremely immune compromised could get still become unwell if they were to catch this weakened version of the virus. Discuss this with your medical team if you have a particularly low immune system and are in contact with children who are having the flu jab.

I am a medical professional. Should I have the flu jab?

If you work with haemato-oncology patients, then you should certainly have the flu jab, as this helps prevent you spreading flu to those who may be vulnerable. NHS-employed front-line healthcare workers can get the flu jab for free, and your employer will organise this for you.

How do I get the flu jab?

Flu vaccine clinics usually start running from the end of September, so simply speak to your GP about the clinic times. Alternatively, if you are visiting hospital regularly, you might be able to have the vaccination there. You can also often get your free vaccine through a pharmacy; both independent pharmacies and well-known chains such as Boots offer appointments. This can ease pressure on the GP appointments and may offer you more convenient times, such as evenings and weekends.

If you are in the middle of treatment, speak to your consultant or cancer specialist about the best time to have the jab. Certain cancer treatments can make your immune system especially low, which may mean our immune system doesn’t respond as well as it needs to in order to give you lasting protection from the virus. Your consultant or specialist will be able to tell you the best time for you to have the vaccine to ensure you have the best response.

What other vaccines should I have?

It is important that blood cancer patients do not have any live vaccines, such as the shingles vaccine. There are a number of other vaccines that are relevant to blood cancer patients, depending on the type of leukaemia you have and what stage of treatment you are at. Some patients may also require a repeat of old vaccinations following treatment. If you think you are missing a vaccine or are unsure about whether you should have a particular vaccine when offered it, please speak to your consultant or to your GP for further advice.