Third dose of COVID-19 vaccines for people with severely lowered immunity

The UK is offering a programme of third COVID-19 vaccine doses for people with severely weakened immune systems. This includes many people affected by lymphoma.

Update 29th November: The government has recommended a fourth (booster) vaccine dose for people who are immunosuppressed. This means immunosuppressed individuals are eligible for three primary doses and a booster dose. The main booster programme is also being expanded to include all adults and people over 16 who are at higher risk of serious illness. We will update our information as soon as more detail is available on how to access these doses.

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Who can have a third dose?

How do I get a third dose?

When can I have a third dose?

Which vaccine will I get?

Am I likely to respond to a third dose if I didn't respond to the first two?

Is this the same as a booster dose?

What if I'm offered a booster instead of a third dose?

What if I'm not eligible for a third dose?


We’re pleased that the Joint Committee on Vaccination and Immunisation (JCVI) has recommended a programme of third COVID-19 vaccine doses for people with severely lowered immunity. These people are at higher risk of becoming seriously ill from COVID-19, and might not have responded well to their initial course of vaccination. The government has produced a vaccination guide for people with a weakened immune system.

Many people with lymphoma are eligible for third doses.


Who can have a third dose?

A third dose is recommended for people who had severely weakened immune systems at the time they had their initial vaccine doses. This is because they may not have responded to vaccination as well as healthy people.

You do not need to have an antibody test to find out whether or not you responded in order to have a third dose.

Those eligible for a third dose include:

  • People with Hodgkin lymphoma or high-grade non-Hodgkin lymphoma who were on treatment or within 12 months of achieving cure at the time they had their initial COVID-19 vaccinations.
  • People with low-grade non-Hodgkin lymphoma or chronic lymphocytic leukaemia (CLL) who were under follow-up at the time they had their initial COVID-19 vaccinations. This might include some people on active monitoring (watch and wait), if their immune systems are severely weakened. Specialists will consider the individual circumstances to decide whether or not people on active monitoring are likely to need a third dose.
  • People who had a self (autologous) or donor (allogeneic) stem cell transplant in the 2 years before they had their initial COVID-19 vaccinations (or more than 2 years for people who are still immunosuppressed or have graft-versus-host disease). Note that people who had a stem cell transplant or CAR T-cell therapy after their initial COVID-19 vaccinations should be completely revaccinated 3 to 6 months after treatment.
  • People who were on immunosuppressive chemotherapy or radiotherapy at the time of their initial COVID-19 vaccinations or within the previous 6 months.
  • People who had high-dose steroids in the month before their initial COVID-19 vaccinations.

This list does not include all eligible people – we have focused on those that are relevant to people affected by lymphoma. The full JCVI guidance includes a more detailed list of people who are eligible.

As announced earlier in the year, people aged 12 and over who live with someone who has a severely weakened immune system are also eligible for vaccination. They will receive the usual course of two doses.

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How do I get a third dose?

GPs and hospital specialists have been asked to check their lists to identify people who are eligible for a third dose. If you are eligible, you should have received a letter or text telling you how to get your vaccination. The letter might come from your hospital specialist or from your GP. If you think you are eligible for a third dose and you have not been contacted yet, get in touch with your GP for advice.

In England, people aged 18 or over who have a letter from their GP or hospital consultant confirming that they are eligible for a third dose can book a third dose online or go to a walk-in vaccination site.

You might find it helpful to read the government and NHS guidance on the third dose for England, Northern Ireland, Scotland or Wales.

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When can I have a third dose?

If you are eligible for a third dose, your specialist will consider the best time for you to have it. It should be at least 8 weeks after your second dose.

  • If possible, you should have your third dose at least 2 weeks after your immune system recovers.
  • If this isn’t possible, you should have your third dose during a period when your immune system is least weakened (for example, in between cycles of treatment or during a treatment holiday).
  • If your immune system is always severely weakened, you should still have a third dose. You can have this at any time from 8 weeks after your second dose.

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Which vaccine will I get?

Whichever vaccine you had for your first two doses, the JCVI recommends that most eligible adults should have either the Pfizer or Moderna vaccines for their third dose.  The Astra Zeneca vaccine might be used in some cases.

The Pfizer vaccine is recommended for eligible 12-to-17 year olds.

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Am I likely to respond to a third dose if I didn’t respond to the first two?

Clinical trials are looking into this at the moment. Early evidence suggests that many people with blood cancer who had no or low response to their initial course of vaccination have an improved immune response after a third dose. However, some people still may not respond, particularly people who have had recent treatment that target B cells (for example, rituximab or obinutuzumab). It is important to keep taking precautions to reduce your risk of developing COVID-19.

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Is this the same as a booster dose?

Not quite. Booster doses aim to help your immune response to vaccination last as long as possible. This programme is called a ‘third primary dose’. It aims to improve the initial response to vaccination in people who may not have responded well to their first two doses.

The government is rolling out a booster programme for all adults and over 16s who are at higher risk of becoming seriously ill from COVID-19. This is not limited to people with lowered immunity. If you are not eligible for a third primary dose, you are likely to be eligible for a booster dose.

The government has announced that people who have a third primary dose are also eligible for a booster (a fourth dose) no sooner than 3 months after their third dose. We are waiting for confirmation of how to access this.

For more detail, you might like to read our article on the difference between a booster and a third primary dose.

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What if I’m offered a booster instead of a third dose?

Many people are having difficulty accessing a third primary dose of COVID-19 vaccine. If you are eligible for a third dose but you are invited for a booster instead, a consensus of UK lymphoma specialists recommends that you have the booster dose. This helps you get additional protection against COVID-19 as soon as possible.

If you book a booster dose, try to find out which vaccine you are having.

  • Most boosters will be the Pfizer/BioNTech vaccine (Comirnaty®). The booster dose for this vaccine is exactly the same as the third primary dose.
  • Some centres might be offering the Moderna vaccine (Spikevax®). The booster for this vaccine is a half dose but the third primary dose is a full dose. If possible, try to arrange your appointment at a clinic that is offering the Pfizer/BioNTech vaccine instead.
  • The Oxford/AstraZeneca vaccine (Vaxzevria®) is not routinely being offered as a booster dose. When it is used, it is exactly the same as the third primary dose.

Your dose will be recorded as a booster dose initially, while the NHS system is being updated. Your record should be updated at a later date to show that you had a third primary dose. This is important so you can be invited for your booster (fourth dose) when you become eligible.

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What if I’m not eligible for a third dose?

If you developed a weakened immune system 2 weeks or more after your initial course of COVID-19 vaccination, you are unlikely to be eligible for a third dose at this stage. However, you are likely to be eligible for a booster dose. The NHS will contact you when it is your turn to have a booster.

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