COVID vaccine FAQs

Now that the COVID-19 vaccination programme has begun here in the UK, you may have questions about this approved vaccine and how it affects blood cancer patients. We've put together a blog answering your most common questions on the COVID-19 vaccine.

Correct as of 29/11/2021. Please get in touch with us at for further help.

There are several vaccines for COVID-19, three of which has been approved for use in the UK so far; the Pfizer-BioNTech vaccine, the Oxford-AstraZeneca vaccine and the Moderna vaccine. This is positive news in the fight against COVID-19, but we understand that those affected by blood cancer may still have concerns or questions. This blog will help answer some of those.

Note: the Moderna vaccine has begun to be used in the UK. This information applies to all vaccines, unless otherwise stated.

What to do after you have your vaccine

Can I get a test to see if I have responded to the vaccine?

Tests to see if you have responded to the vaccine are not widely available on the NHS. Some people with very low immune systems may be offered antibody tests; you should only have tests under the guidance and when recommended by your haematology team. Be wary of private tests; some of these may be scams and others are not easy to interpret.

You can read our full blog on antibody testing here.

Getting a vaccine appointment

When and how will I be invited to have a COVID-19 vaccine? 

All adults in the UK, as well as children between 12 and 16, will have now been invited their COVID-19 vaccine. Many people are now eligible for a third or fourth dose. If you have not taken up this offer, we encourage you to do so.

You can read more about the extra COVID doses programme in our special blog on third doses and booster jabs here.

Where can I get a vaccine?

If you are looking to book your first or second COVID vaccine doses, you can book by calling 119 or going to this website here.

If you are booking a third dose or a booster jab, you should follow the instructions in the invitation letter. You can find more details here.

You can receive the third dose of the COVID-19 vaccine or booster vaccine alongside the flu jab if you are offered them together. According to NHS advice it is safe and doesn’t compromise the effectiveness of either vaccine to receive them at the same time.

Some GPs are still working out the logistics to administer the third dose of the vaccine. If you are eligible and have not received a letter to get your third dose, it is very unlikely you have been forgotten about and you should be contacted shortly.

Can my family/those I live with also be vaccinated at my appointment?


Everyone over the age of 18 can now book their vaccine. We would encourage everyone to have their vaccine, as this will help reduce the spread of the virus to those who are still vulnerable.

If you are immunocompromised, your household members are now eligible for a booster dose. They should receive an invitation letter in the next few weeks (September 2021). If this has not occurred, please speak to your GP so they can identify them as household contacts of an immunocompromised person and they then should receive further information.

Will I receive two doses of the same vaccine?

Each approved vaccine has only currently been trialled with two doses of the same vaccine. However, trials are ongoing to see if the vaccines will be effective if you mix one dose of one vaccine with a dose of a different vaccine afterwards.

Public Health England has stated that “every effort should be made to determine which vaccine the individual received and to complete with the same vaccine”. They have suggested that there may be circumstances in which it is not known which vaccine was used for the first dose, or if a person needs a vaccine immediately, where the second dose could be a different vaccine.

If you are concerned about which vaccine you are receiving, please discuss this with your GP or with the person administering the vaccine prior to receiving it.

The exception to this is if you are having a third dose or booster. The JCVI has recommended that people should have a different vaccine for the third dose or booster, as evidence suggests this makes the immune response stronger.

Questions for specific groups

I am currently having chemotherapy. Should I have the vaccine?

This is a group in which the vaccines have not be specifically tested. However, since the roll out, many people will have had the vaccine close to chemotherapy treatment and we are unaware of specific problems in this group. As with other vaccines, such as childhood vaccinations or the flu jab, there are specific times when these should be had whilst you are on chemotherapy, to give the vaccines the best chance of working. If you are invited for the vaccine during a course of chemotherapy, please speak to your haematology team if you are unsure when is the most appropriate time for you to have it or to discuss any other concerns.

I have had or am currently having a transplant. Should I have the vaccine?

You can have the vaccine whilst on cancer treatment, but it is preferable that it is delivered at a time when you have an immune system working at some level. For those people currently having or have recently had a transplant, there are times when it is best to receive vaccines to make sure you have all the cells in your body that you need to respond to the vaccine. If you have invited to have a vaccine, please speak to your care team for advice about when to have it.

I have already had COVID-19. Should I get a vaccine?

Natural infection with COVID-19 will generate an immune response, such as producing antibodies, as this is how your body fights off the virus. However, it is not clear how long this last in a person’s body. Initial studies have suggested that antibodies are short-lived after infection, and there have been cases of reinfection reported, although rare. Therefore, it is recommended that you still have the vaccination, as this has been designed to give strong and lasting protection.

I have an allergy. Should I receive the vaccine?

On the 9th of December 2020, it was reported that 2 of the first recipients of the Pfizer-BioNTech vaccine had experienced an anaphylactoid reaction after receiving the vaccine; this is where the person develops a rash, breathlessness and a drop in blood pressure, but this is not the same as an anaphylaxis reaction, which can be fatal. The two people affected had severe allergies, which meant that had to carry an epi-pen at all times. The NHS is no longer giving either the Pfizer-BioNTech or the Oxford-AstraZeneca vaccine to people with history of severe allergic reactions to any of the ingredients in the vaccines.

You can find the ingredients of the Pfizer-BioNTech vaccine here.

You can find the ingredients of the Oxford-AstraZeneca vaccine here.

It is not yet clear if this will also apply to the Moderna vaccine, but will provide a further update when this information is available. If you are unsure if this applies to you, please check with your GP or care team before having the vaccine.

Are there any alternatives if I cannot be vaccinated? 

We encourage everyone who is able to have the vaccine to take up the offer. There are a small number of people who cannot have the vaccine for clinical reasons. There are other alternative protective measures in trials currently, such as an antibody treatment being developed by AstraZeneca. However, no treatment is guaranteed to protect you from COVID-19 and they are not intended to be an alternative to vaccination, but rather a back up where vaccination is not 100% effective. You can read more about treatments here.

Safety and effectiveness of the vaccines

Should I be concerned about the recent reports on the Oxford-AstraZeneca vaccine and blood clots?

On the 7th of April, the Medicines and Healthcare Regulatory Authority announced it would change its advice on who should receive the Oxford-AstraZeneca vaccine. This vaccine will no longer be offered to those under the age of 30.

If you are concerned about having the vaccine, such as due to your blood cancer or due to previous history of blood clots, please discuss with your haematology team for further information.

This change is in response to reports of very rare types of blood clots in those vaccinated. These rare effects have only come to light as more people have been vaccinated. For example, if an effect only happened to one in a million people, you need over a million people to be vaccinated before you see the effect. This shows that the system of monitoring medicine after licensing is working, as the MHRA have now addressed concerns with all the available data. As outlined by Jonathan Van Tam, Deputy Chief Medical Officer, changing advice over time is not unusual in medicine, especially in big programmes such as this.

It is important to note that all advice is that the risk is small, and the benefits of the having the vaccine vastly outweigh the benefits, especially for those older than 30 who are being offered to it. Therefore, please continue to have the vaccine if you are offered it. This includes having the second dose, unless you had a clot from the first dose; all the known cases in the UK were following the first dose.

It is important to be aware of the symptoms following your first dose and seek immediate help if you are concerned. These include:

  • Severe headache that lasts more than a couple of days
  • Shortness of breath
  • Bruising or pinprick spots away from site of injection
  • Blurred vision
  • Abdominal pain

Whilst clots are concerning, it is important to note that clots are much more common in people who have caught COVID-19, so you are protected from more clots by having the vaccine.

How do the vaccines work?

Vaccines can prevent diseases from impacting upon society in two ways; by preventing those who are vaccinated from getting severely ill and/or by preventing spread of illness. They do this by delivering a molecule that tricks your immune system into thinking you have been infected, encouraging it to develop a response that will protect you in the event you became infected with the virus itself. In the Pfizer-BioNTech vaccine, the immune system responds to a piece of genetic material called mRNA. In the Oxford-AstraZeneca vaccine, the immune system reacts to a COVID-19 protein, which is delivered into the body by being attached to a different virus. Neither vaccine is a live vaccine, as neither contain whole COVID-19 virus, and neither can give you COVID-19. You can read more general information about vaccination and blood cancers here.

Clinical trials of the COVID-19 vaccines announced so far in the media, have shown that the vaccines reduce severity of illness and the number of people who require hospital treatment. However, it is not yet known whether any of these vaccines can prevent people from passing on the virus to other people who not yet been vaccinated. Therefore, if you do receive a vaccine, it is important you continue to observe social distancing and other actions to make sure that you do not spread COVID-19 unknowingly to non-vaccinated people (see “can I stop following guidelines if I have the vaccine” below). Scientists expect the vaccine will impact on transmission, but this will not be known for sure until more people have been vaccinated.

What is the difference between the various vaccines?

As mentioned in “how do the vaccines work?”, the vaccines use different methods of encouraging the immune system to react. As you may have heard in the media, they also differ in how they need to be stored, meaning they will be delivered to different groups of people in different locations. It is unlikely that you will be able to choose which vaccine to have; both the Pfizer-BioNTech and Oxford-AstraZeneca vaccines are considered safe (see “Have the vaccines been tested in people with blood cancer” below).

Are any of the vaccines currently available in the UK live vaccines?

No. One of the vaccines currently available, the Oxford-AstraZeneca vaccine, contains whole virus particles, but these are not whole COVID-19 viruses. It is a different virus that has been used to deliver a part of the COVID-19 vaccine that the immune system can respond to; this type of vaccine is called a viral vector.

The virus used as the vector is called an adenovirus, and it usually causes the common cold in monkeys. It has been modified so it cannot replicate. Therefore, you are not able to become ill from either the adenovirus or COVID-19 from this vaccine.

Are the vaccines safe for people with blood cancers?

The advice from the Joint Committee for Vaccine and Immunisation (JCVI), the group which advises the government on vaccines, is that everyone who is offered either the Pfizer-BioNTech vaccine or the Oxford-AstraZeneca vaccine should have it. Our clinical advisers have also confirmed that this is the case. Additionally, neither vaccine is a live vaccine, so does not pose a risk to immunocompromised people as some live vaccines can (see our vaccines web page for further information on the different types of vaccines). We will provide further information should this be different with other vaccines in development.

If you have any concerns about receiving the vaccine, we advise that you speak to your haematologist about it once you have received your invitation.

Have the vaccines been tested in people with blood cancer?

Pfizer has confirmed that their vaccine was not tested in immunocompromised populations, which includes blood cancer patients. However, further research is underway in the blood cancer population now many people have started their vaccinations.

The Oxford-AstraZeneca vaccine is not thought to have been tested in people with blood cancers specifically. Like with the Pfizer vaccine, it was tested in elderly people, who are also immunocompromised due to age, as well as being tested in people with other comorbidities.

A spokesperson from the MHRA stated that data in some of the trials did include some people with a history of leukaemia, but these were likely people who had recovered from leukaemia some time ago.

Both the Pfizer and the Oxford vaccines are considered safe for blood cancer patients, based on currently available information, and therefore those who are offered the vaccine should take up the offer.

Will the vaccines work for me?

We know from other studies that people with leukaemia or similar blood cancers do not always respond as well to some vaccines as those with fully functioning immune systems. This may also apply to COVID-19 vaccines but we do not yet know if this is the case for those approved or those still in development. However, having a weak immune system does not mean that you will not respond at all; a small amount of protection is better than none at all, which is why you are encouraged to continue to take the vaccine when it is offered.

You may have seen media reports about some early research into the response of some cancer patients to the Pfizer vaccine. One piece of unpublished research suggested that cancer patients had a reduced amount of antibodies after the first doses compared to the non-cancer patients; blood cancer patients had the worst antibody responses of all. However, antibodies are not the only thing that is important. When you have a vaccine, you also make a response using your T cells; this T cell response is thought to be more important for immunity to viruses. Blood cancer patients did show a good T cell response, which was less than non-cancer patients but much higher than their antibody response. Therefore, we need to conduct further research to see if this T cell response is enough to prevent severe illness, hospitalisation and death.

It is important that you get all the doses of the vaccine that you are scheduled to receive, as this gives maximum protection. Both the Pfizer and Oxford vaccines involve a two-dose strategy.

Should I be concerned about recent reports about how well vaccines work against variants of the virus?

There have been some recent reports that some of the vaccines are thought to be less effective against more infectious variants of COVID-19, such as the South African variant. Whilst this is concerning, we would encourage everyone who is eligible to continue to receive any vaccine you are offered. You are unlikely to get a choice about which vaccine you receive.

The South African variant is not the most common version of the virus circulating in the UK at the time of writing, and it is unlikely to become so, according to Deputy Chief Medical Officer Jonathan Van-Tam. The South African variant has only caused 100’s of cases in the last few months, whereas there have been 1000s of cases of other variants every day. Therefore, the current vaccines protect you against the virus you are most likely to catch. Additionally, the vaccines do not stop working altogether against other variants; they have been shown to still protect against severe disease, preventing hospitalisation and death.

Will I have side effects?

The side effects of these vaccines are minor and are not expected to be any worse for those with blood cancers. You can read about these here. If you do experience side effects, we encourage you to report these to the MHRA via the Yellow Card Scheme; there is a specific version for the vaccine here. They are particularly keen to hear from certain groups, such as those with blood cancers, to monitor the response of these people.

If you have any additional questions about the COVID-19 vaccine, please email

You can also call our helpline: 08088 010 444, or use our WhatsApp service: 07500068065

For a patient’s experience of receiving a COVID-19 vaccination, read Hannah Mahoney’s blog by clicking here.

Blog post published on: 15th March 2021

Blog post last updated on: 29th November 2021

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