Contrast A A A Link to Twitter page

Third primary dose for people who are immunosupressed

Posted in Home

If you have a severely weakened immune system, you should have a third primary dose - this is not a booster, but a third dose to ensure that you get the same protection given by two doses for those with normal immune systems. 

The third primary doses are being offered to people aged 12 and over who are immunosuppressed. The third dose should be given at least 8 weeks after the second dose. 

You will still need to receive a booster dose six months (182 days) from the date of your third primary course dose.

Letters are being sent from specialist teams at the hospitals and/or General Practice to invite those eligible to receive their vaccine. 

If you believe you're eligible for a third dose, but have not been contacted yet, please contact your GP or hospital consultant to discuss eligibility and provision of an appropriate letter.


  • If you're eligible, you should have received a letter, text or email from a GP or hospital specialist, inviting you to book a 3rd dose.

  • You must take this to your appointment or you will not be able to receive a 3rd dose of the vaccine. 



Frequently Asked Questions on third doses

 What is a 3rd dose of the primary course?

The Joint Committee on Vaccinations and Immunisation (JCVI)  issued guidance on the 3rd September recommending a 3rd dose of the COVID-19 vaccine as part of the primary course of vaccination. This is being  offered as a routine part of vaccination to people who are severely immunosuppressed (as defined within the JCVI guidance) due to treatment for conditions such as cancer or for those with long-term chronic conditions where their immunity is affected by medication.

Why is it recommended?

People who have a severely weakened immune system as a result of treatment, may not have the same immune response to the vaccine, and therefore, the JCVI recommends that a 3rd dose will help reduce the risk of getting seriously ill or dying from COVID-19, and from spreading COVID-19 (Coronavirus (COVID-19) vaccines

Who is eligible for it?

JCVI guidance recommends that a 3rd dose is  offered to individuals aged 12 years and over with severe immunosuppression, including those who are being treated for conditions such as cancer or for those with long-term chronic conditions where their immunity is significantly affected by regular medication. Severe immunosuppression is defined within the advice section of the JCVI guidance.

Guidance for household contacts of those who are immunosuppressed has not changed. They are recommended to be vaccinated with their first and second doses, in line with current JCVI guidance.  Details are available here.

 Is there a list of conditions and treatments available which identifies people who are considered severely immunosuppressed?

The list has been published by the JCVI and is available here.

How will patients know if they are eligible?

Consultants and GPs have been asked to identify patients eligible for a 3rd dose. Patients will be contacted by their consultant / hospital doctor or GP team who will discuss the timing of the 3rd dose, in light of the current or planned immunosuppressive therapies the patient is undergoing. 

If the hospital consultant works at a hospital hub, with available vaccine supply, they should invite eligible individuals to be vaccinated on site.  If the patient cannot be vaccinated at the hospital site, the consultant will write to the patient’s GP with clear advice on timing of a 3rd dose and identifying any interaction with their current treatment. Patients should then be invited to be vaccinated at a PCN-led vaccination site.

GP teams should also identify patients on their list and liaise with hospital doctors to invite eligible individuals via their consultant. Patients will be given a clinical authorisation letter which they will need to take with them to receive their vaccination.

Can patients be vaccinated at a walk-in vaccination site?

A clinical authorisation letter will be given to eligible patients and this will act as authorisation to a COVID vaccination site that the patient requires a 3rd dose of the COVID-19 vaccine. Individuals can go to a centre which their clinician has highlighted or, if not specified, to any COVID vaccine centre offering walk-in vaccinations. Patients can find a walk-in COVID vaccine centre here: Search - Find a walk-in coronavirus (COVID-19) vaccination site ( They do not need to call their GP surgery or contact the hospital about this.

Can patients self-identify as severely immunosuppressed?

If individuals think they are eligible for a 3rd dose and have not been contacted as yet, they are advised to speak to their GP or Consultant.

Is the 3rd dose the same as the booster vaccine?

No.  The 3rd dose is not the booster vaccine.  It is recommended that the 3rd dose should be given at least 8 weeks after the 2nd dose and is part of the primary course of immunisation.  A booster jab is also expected be offered 6 months after the 3rd dose but we are currently awaiting JCVI guidance on this.

Which vaccine will be offered as a 3rd dose?

JCVI have advised a preference for mRNA vaccines (full dose Pfizer-BioNTech or Moderna) for the third dose, with the option of the AstraZeneca Vaxzevria vaccine for individuals who have received this vaccine previously where this would facilitate delivery. For those aged 12 to 17, the Pfizer-BioNTech vaccine is preferred.

When will a 3rd dose be offered? What interval will there be between 2nd and 3rd dose?

The JCVI recommends that the 3rd dose should be offered at least 8 weeks after the 2nd dose.

Research shows that, as with the interval between the 1st and 2nd dose, 8 weeks has been observed as providing the individual with the most benefits in terms of an immune response. If, however, the patient’s GP or Consultant believes that an alternative interval should be offered, because of ongoing treatment or starting treatment which will suppress the individual’s immune system, then this timing may be altered. Intervals will be considered, in light of the individual’s specific health circumstances and an assessment made by their clinician.

Where possible, JCVI recommends that the 3rd primary dose should be delayed until two weeks after the period of immunosuppression, in addition to the time period for clearance of the therapeutic agent.

Will a booster vaccine also be given?

It is expected that, in line with interim JCVI guidance, individuals will be eligible for a booster vaccine, as part of the routine booster programme, from around 6 months after their 3rd dose. We are currently awaiting final advice from the JCVI.

If a severely immunosuppressed individual has had a good immune response to the first two doses, will they still be offered a third dose?

Some people who are immunosuppressed may not generate a good immune response regardless of the number of vaccine doses administrated. However, data is not currently available to reliably identify who might, or might not, benefit from a third primary dose of a COVID-19 vaccine.

The JCVI guidance highlights published studies describing the effect of a third dose of mRNA vaccine in persons who are immunosuppressed reporting increased immune responses in varying proportions.

JCVI guidance recommends that a 3rd dose will be offered to individuals aged 12 years and over with severe immunosuppression (as defined within the JCVI guidance).

 What are the side-effects of a third dose?

Find out more about COVID-19 vaccines side effects and safety.

 When can people expect to be invited for, and to receive, these 3rd doses?

Hospital doctors and GP teams are already identifying and consulting with severely immunosuppressed patients.  The precise timing of an individual’s 3rd dose vaccination will be determined following consultation with their consultant / GP in line with JCVI advice.

Are people in this group also eligible for the flu vaccine?

Some patients who are immunosuppressed are also eligible for the flu vaccine and we would strongly encourage them to get vaccinated to protect themselves against flu, which can have very serious complications for some immunosuppressed patients. Local GP teams and pharmacy services are offering flu vaccines in line with local available supply.

Close contacts of immunocompromised individuals are also eligible for the national influenza vaccination programme, specifically individuals who expect to share living accommodation on most days over the winter and, therefore, for whom continuing close contact is unavoidable.

Will the 3rd dose be given alongside the flu vaccine?

Flu vaccine is not currently included in this advice. Advice on co-administration within this context will be issued in due course.

What do I do if I am contacted to have my third dose, after I've received my booster?

If a patient, who is immunosuppressed has already received their booster dose, this dose will be re-categorised on NHS systems as their third primary dose through a nationally coordinated process in due course. The patient can therefore ignore this letter if they have already received their booster dose as this will count as their third dose. As with other eligible patients, you will be able to access your booster dose after at least 182 days have passed since your last dose.


Reference documents

On 1 September 2021 the JCVI issued advice on third dose COVID-19 vaccinations as part of primary course vaccination schedule for those severely immunosuppressed.

JCVI issues advice on third dose vaccination for severely immunosuppressed - GOV.UK (

Third primary COVID-19 vaccine dose for people who are immunosuppressed: JCVI advice - GOV.UK (

The JCVI stated that the specialist involved should advise on whether the patient fulfils the eligibility criteria and on the timing of any third primary dose.

On 2 September 2021 NHSE/I wrote to all GP practices, NHS trust chief executives, CCGs and ICS/STP leads, among others, setting out actions for all systems to take to vaccinate immunosuppressed group identified by JCVI as requiring a third primary course dose.

C1399-Updated-JCVI-guidance-for-vaccinating-immunosuppressed-individuals-with-third-primary-dose.pdf (

On 30 September 2021 NHSE/I outlined the assurance process for GPs and Trusts .

NHS England and NHS Improvement continue to emphasise the roles of clinicians and are working alongside patient charities and clinician networks to ensure eligible patients are identified and advised on the criteria of the third primary dose in line with JCVI guidance. Information for patients is available on the NHS website:

This information is correct as at: 29/11/2021