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Published on 2 September 2021

Yesterday (1 September 2021), the Joint Committee on Vaccination and Immunisation (JCVI) advised that a third COVID-19 vaccine primary dose be offered to individuals, aged 12 years and over, who were severely immunosuppressed at the time of either, or both, of their first two vaccine doses. This is because some individuals who are severely immunosuppressed due to underlying health conditions or certain medical treatments may not produce a full immune response to COVID-19 vaccination.  These individuals need additional protection and I welcome this advice. 

The JCVI advice details the groups who will be eligible and our NHS in Wales will work quickly to identify eligible individuals who will be contacted by their Health Boards. The decision on the timing of the third dose will be important for some patients, and will be determined by their specialist clinicians. Their appointment will be at an appropriate time during their treatment plan. There is no need for patients to contact their health board or clinicians to check eligibility. Work will begin immediately to identify and plan for patients to be vaccinated and communications from Health Boards will follow as soon as practicable.

We are working with specialist clinicians to identify and contact individuals who are eligible for a third dose under the latest guidance. Please do not contact your health board or GP practice about third doses. 

National guidance has not yet been published about booster vaccination.

JCVI Guidance on eligibility for third primary dose (source: Joint Committee on Vaccination and Immunisation (JCVI) advice on third primary dose vaccination - GOV.UK (

At the current time, JCVI advises that a third primary dose be offered to individuals aged 12 years and over with severe immunosuppression in proximity of their first or second COVID-19 vaccine doses in the primary schedule. Severe immunosuppression at the time of vaccination is defined using the guidance and timings stated below.

1. Individuals with primary or acquired immunodeficiency states at the time of vaccination due to conditions including:

  • acute and chronic leukaemias, and clinically aggressive lymphomas (including Hodgkin’s lymphoma) who were under treatment or within 12 months of achieving cure

  • individuals under follow up for chronic lymphoproliferative disorders including haematological malignancies such as indolent lymphoma, chronic lymphoid leukaemia, myeloma, Waldenstrom’s macroglobulinemia and other plasma cell dyscrasias (note: this list is not exhaustive)

  • immunosuppression due to HIV/AIDS with a current CD4 count of <200 cells/µl for adults or children

  • primary or acquired cellular and combined immune deficiencies – those with lymphopaenia (<1,000 lymphocytes/ul) or with a functional lymphocyte disorder

  • those who had received an allogeneic (cells from a donor) or an autologous (using their own cells) stem cell transplant in the previous 24 months

  • those who had received a stem cell transplant more than 24 months ago but had ongoing immunosuppression or graft versus host disease (GVHD)

  • persistent agammaglobulinaemia (IgG < 3g/L) due to primary immunodeficiency (for example, common variable immunodeficiency) or secondary to disease/therapy

2. Individuals on immunosuppressive or immunomodulating therapy at the time of vaccination including:

  • those who were receiving or had received immunosuppressive therapy for a solid organ transplant in the previous 6 months

  • those who were receiving or had received in the previous 3 months targeted therapy for autoimmune disease, such as JAK inhibitors or biologic immune modulators including B-cell targeted therapies (including rituximab but in this case the recipient would be considered immunosuppressed for a 6-month period), T-cell co-stimulation modulators, monoclonal tumour necrosis factor inhibitors (TNFi), soluble TNF receptors, interleukin (IL)-6 receptor inhibitors, IL-17 inhibitors, IL 12/23 inhibitors, IL 23 inhibitors (note: this list is not exhaustive)

  • those who were receiving or had received in the previous 6 months immunosuppressive chemotherapy or radiotherapy for any indication

3. Individuals with chronic immune-mediated inflammatory disease who were receiving or had received immunosuppressive therapy prior to vaccination including:

  • high-dose corticosteroids (equivalent to ≥ 20mg prednisolone per day) for more than 10 days in the previous month

  • long-term moderate dose corticosteroids (equivalent to ≥10mg prednisolone per day for more than 4 weeks) in the previous 3 months

  • non-biological oral immune modulating drugs, such as methotrexate >20mg per week (oral and subcutaneous), azathioprine >3.0mg/kg/day, 6-mercaptopurine >1.5mg/kg/day, mycophenolate >1g/day in the previous 3 months

  • certain combination therapies at individual doses lower than above, including those on ≥7.5mg prednisolone per day in combination with other immunosuppressants (other than hydroxychloroquine or sulfasalazine) and those receiving methotrexate (any dose) with leflunomide in the previous 3 months

4. Individuals who had received high-dose steroids (equivalent to >40mg prednisolone per day for more than a week) for any reason in the month before vaccination.

Individuals who had received brief immunosuppression (≤40mg prednisolone per day) for an acute episode (for example, asthma / COPD / COVID-19) and individuals on replacement corticosteroids for adrenal insufficiency are not considered severely immunosuppressed sufficient to have prevented response to the primary vaccination.

For the most up-to-date advice, see COVID-19: the green book, chapter 14a.

For those aged 18 years and over, JCVI advises a preference for mRNA vaccines for the third primary dose, with the option of the AstraZeneca Vaxzevria vaccine for individuals who have received this vaccine previously where this would facilitate delivery. In exceptional circumstances, persons who received a mRNA COVID-19 vaccine previously may be offered a third primary dose of AstraZeneca Vaxzevria vaccine following a decision by a health professional on a case-by-case, individualised basis. For those aged 12 to 17 years the Pfizer-BNT162b2 vaccine remains the preferred choice, as set out in JCVI advice of 4 August 2021.

The specialist involved should advise on whether the patient fulfils the eligibility criteria and on the timing of any third primary dose. In general, vaccines administered during periods of minimum immunosuppression (where possible) are more likely to generate better immune responses. The third primary dose should ideally be given at least 8 weeks after the second dose, with special attention paid to current or planned immunosuppressive therapies guided by the following principles:

  • where possible, the third primary dose should be delayed until 2 weeks after the period of immunosuppression, in addition to the time period for clearance of the therapeutic agent
  • if not possible, consideration should be given to vaccination during a treatment ‘holiday’ or at a nadir of immunosuppression between doses of treatment

As with current advice in the green book (chapter 14a) JCVI has advised that:

individuals who have received a bone marrow transplant after vaccination should be considered for a re-immunisation programme for all routine vaccinations and for COVID-19.

Re-vaccination with a 2-dose schedule should be considered 3 to 6 months post autologous and allogeneic human stem cell transplant or CAR-T therapy. A third primary dose of vaccine should be administered at least 8 weeks after the second dose (in line with the advice above).

Most individuals whose immunosuppression commenced at least 2 weeks after the second dose of vaccination do not require a third primary dose at this stage. Alongside those with lower levels of immunosuppression, they are likely to become eligible for a booster dose as part of a routine booster programme from around 6 months after the second dose, pending further advice.

It is expected that severely immunosuppressed individuals will become eligible for a booster dose as part of a routine booster programme from around 6 months after their third primary dose, pending further advice.