COVID-19 vaccine programme next steps for leukaemia patients: third doses and boosters

There has been much discussion in the media of both a third dose of COVID-19 vaccine and booster programmes. This has caused some confusion; this article aims to explain who is eligible for each programme and how they differ from each other. Note: to the best of our knowledge, this advice applies across the UK.



Third dose of vaccine for the immunocompromised:

On the 1st of September, the governments of the UK have accepted advice from the JCVI to offer a third dose of the vaccine to the immunocompromised. This is separate from booster vaccines, and is considered part of their primary course. This is with the hope of further building the immunity of those with suppressed immune systems.

Who needs a third dose?

The third dose can be given to anyone aged 12 and over who is considered clinically immunocompromised at the time they were first vaccinated. The third dose must be 8 weeks or more after the second dose of the vaccine. The JCVI advice says this should include people with acute and chronic leukaemias who are undergoing treatment or who will not achieve a cure within 12 months. Also included is anyone who has had a stem cell transplant in the last 2 years and those who received immunosuppressive chemotherapy or radiotherapy in the 6 months prior to vaccination. Please check with your consultant or specialist nurse if you are unsure if this applies to you.

What is the evidence for needing a third dose of the vaccine if you are immunocompromised?

As many of you will know, blood cancer patients were prioritised for the COVID-19 vaccine earlier this year, due to many patients being clinically extremely vulnerable to COVID-19. Unfortunately, further research has shown that those blood cancer patients who are also immunosuppressed due to their condition and/or treatments are less likely to have responded to the vaccine than other blood cancer patients with working immune systems. More work is needed to know which blood cancer patients are most likely to benefit from this news; the studies on the impact of the third vaccine dose focused on people who have had transplants. However, some protection is better than none, so it is recommended that you get the third dose you are offered in the hope you will see some benefits. You can read some studies published so far here and here.

Should I bother with a third vaccine if I have not made antibodies to the vaccines so far? Do I need to find out my antibody levels before I have the third vaccine?

We would encourage everyone who is eligible to take up the offer of the third vaccine. There is some evidence that it increases an immune response, including in people who did not make many antibodies. Some protection is better than none. 

You do not need to test for antibodies before you have the third vaccine. Even if you have responded to the first two vaccines, we would encourage you to take up the third. Antibodies are only part of the immune system and the role of other parts of the immune system isn’t yet fully understood. It is possible that the third vaccine may yet boost your immune response further.

Is the third dose the same as the booster vaccine?

The third dose for the immunocompromised is an addition to the primary course (first two doses of the vaccine) to try and raise the level of immunity among the immunocompromised to match the immunity of the rest of the population. The vaccine you get is the same as you would get for a booster, but the purpose of having the 3rd dose is different to the purpose of a booster, in terms of the impact on your immune system.

For the third dose programme the vaccine given will be a full shot of either Pfizer or Moderna.  This is because most people who are immunocompromised received AstraZeneca as their first vaccine, and evidence suggests that a different vaccine for the third dose makes for a better immune response. Under 18’s will only receive Pfizer.

Do not worry if you were offered a booster around September/October time and took up this offer. This will still count as a third dose of the vaccine and the NHS is trying to change your medical records to be marked as third doses instead. You now need a booster 3 months after your last dose of the vaccine – see the next section for how to arrange this.

If you are not eligible for a third dose as per the criteria outlined in the next section, please go to the third section of this blog about booster vaccines for those who only need 2 doses. Please contact your specialist consultant or nurse if you are not sure which group you fall into, as they are responsible for identifying people who need the third dose.

When and where will I receive my third vaccine?

Most people who need a third dose have now been contacted. You need to have a confirmation letter or text before you can book this, so if you have only had 2 doses of the COVID-19 vaccine so far, contact your GP or haematology team to ask for a letter about the third dose so you can book.

Once you have the confirmation that you need a third dose, you can now book this online, via 119, a walk in clinic, or book via your GP if they are offering appointments. Regardless of where you go, make sure you take the invitation letter as evidence that you need the third dose.

Important: Make sure you make it clear that you need a third full dose of the vaccine when you go to the walk in clinic.

Will I get a booster vaccine later too?

Yes. Please see the next section for advice on getting a booster/4th dose of the COVID vaccine.

Important: anyone who lives in the same household as you is now eligible for a booster dose, if it has been more than 3 months since they had their second dose. See next section for details.

Getting a booster vaccine if you have had 3 primary doses

Who is eligible for a booster?
All adults are now eligible for a booster dose of the vaccine 3 months after their lasrt dose of the COVID vaccine. We have received confirmation this includes people who have already had 3 doses because they are immunocompromised. This also includes people who had a booster but were eligible for a third dose (e.g. they booked a booster because they didn’t know they needed a third dose at the time, or bacauseit was quicker to book a booster at the time). 

Important: anyone who lives in the same household as you is now eligible for a booster dose, if it has been more than 3 months since they had their second dose. See next section for details. 

Is it worth getting another dose if I have already had 3?
With the emergence of the omicron variant, it has been shown that the more recently you have had a COVID-19 vaccine, the better you are protected. 

How do I get my booster/4th dose?
Unfortunately, if you have had 3 doses of the COVID-19 vaccine already, it’s not currently possible to book online for your booster. You need to wait to receive an invitation. Once you have your invitation for your booster, you can then book. How to do this will be included in the invitation, or call 119 for help.

Booster vaccine programme for those who are not immunocompromised

If you are not considered immunocompromised, you will have had 2 doses of the vaccine 12 weeks apart. This will likely be applicable to you if you were diagnosed with an acute leukaemia and have been in remission or not been treated for a long period of time. You will now also be offered a booster dose of the COVID-19 vaccine.

If you are a chronic leukaemia, MPN or MDS patient and/or still in treatment/have been treated recently, you are more likely to need 3 primary doses as well as a booster. Please go back to the advice at the top of this blog for the correct advice. You can contact us or speak to your haematology team if you are not sure which group you fall into.

What is the evidence for this?
Recent studies have indicated that, even in those who have responded well to the vaccine, immunity has declined over time slightly. This is fairly normal and happens with other vaccines too (e.g. tetanus). Therefore, to try to avoid another spike of infection, the governments have decided that the most vulnerable to COVID-19 should have a boost of their immunity at 6 months after vaccination, to try to restore their immunity to its original level.

Who is eligible for the booster dose?
 The JCVI has now confirmed that all adults aged 18 to 39 years should be offered a booster dose. Booster doses should be given no sooner than three months after the primary course. However, the JCVI continues to say that booster doses should be prioritised by age wherever possible, as the biggest risk factor for severe COVID-19 is increasing age. Booster doses will therefore be offered to the public in descending age order.

When and where will I receive my booster dose?
As of 29th November 2021 booster doses have been approved for all adults. You will be contacted by the NHS when it is your turn to receive your booster jab. If it has been over three months since your 2nd dose and you haven’t had an invitation, you can either book a vaccination appointment online or go to a walk-in vaccination site to get vaccinated. Precise arrangements may depend on where you live, check the links at the bottom of this blog.

The vaccine given will most likely be a full dose of Pfizer or a half dose Moderna.

If you have questions, you can contact the Advocacy team by calling 08088 010 444, or emailing

Further information links: 

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