Skip to main content

Coronavirus (COVID-19) vaccine for people with a severely weakened immune system

If you had a severely weakened immune system when you had your first 2 doses of the coronavirus (COVID-19) vaccine, you will be offered an additional primary dose (3rd dose) before your booster.

The first 2 doses may not have given you as much protection as they can for people who do not have a severely weakened immune system. An additional primary dose may help give you better protection.

A booster helps improve the protection you have from your previous doses of the vaccine. It helps give you longer-term protection against getting seriously ill from COVID-19.

Severely weakened immune system list

People with a severely weakened immune system include those who had or have:

  • a blood cancer (such as leukaemia or lymphoma)
  • a weakened immune system due to a treatment (such as steroid medicine, biological therapy, chemotherapy or radiotherapy)
  • an organ or bone marrow transplant
  • a condition that means you have a very high risk of getting infections
  • a condition or treatment your specialist advises makes you eligible for an additional primary dose

When to get your COVID-19 vaccine

You'll usually be offered an additional primary dose at least 8 weeks after you had your 2nd dose.

Your GP or hospital specialist may suggest a different time depending on if you have any ongoing or planned treatment that affects your immune system.

If you think you're eligible for an additional primary dose but have not been contacted, speak to a GP or your hospital specialist.

You can get a booster dose from 3 months after your additional primary dose.

If it has been at least 3 months since you had your booster dose, you can also get a spring booster.

If you have not yet had a booster dose, you can get a spring booster from 3 months after your additional primary dose.

How to get your COVID-19 vaccine

If you're eligible, the NHS will usually invite you to get your additional primary dose or booster.

You may get a letter advising that you may be eligible and to discuss this with your doctor.

Your doctor will discuss with you how you can get your vaccine.

You'll usually get vaccinated at your local hospital or a local NHS service such as a GP surgery.

Book your appointments online

If you're aged 12 or over, you can also book your additional primary dose or booster appointments online.

You'll need to bring with you either:

  • a letter from your GP or hospital specialist inviting you for an additional primary dose or booster
  • a hospital letter that describes the condition or treatment that caused you to have a severely weakened immune system at the time of your 1st or 2nd dose
  • a prescription or a medicine box with your name and the date showing when the medicine was prescribed – this must show that you had a severely weakened immune system at the time of your 1st or 2nd dose

If you think you’re eligible for an additional primary dose or booster but you do not have a suitable letter, prescription or medicine box, you may still be able to get your vaccination.

Go to a walk-in vaccination site

If you're aged 12 or over, you can go to a walk-in vaccination site to get your additional primary dose or booster without needing an appointment.

You will need to bring with you either:

  • a letter from your GP or hospital specialist inviting you for an additional primary dose or booster
  • a hospital letter that describes the condition or treatment that caused you to have a severely weakened immune system at the time of your 1st or 2nd dose
  • a prescription or a medicine box with your name and the date showing when the medicine was prescribed – this must show that you had a severely weakened immune system at the time of your 1st or 2nd dose

If you think you’re eligible for an additional primary dose or booster but you do not have a suitable letter, prescription or medicine box, you may still be able to get your vaccination.

Page last reviewed: 28 April 2022
Next review due: 28 October 2022