People in the UK with severely weakened immune systems will be offered a third dose of a coronavirus vaccine.

Around half a million people with conditions such as leukaemia, advanced HIV and recent organ transplants who are over the age of 12 will be given a third jab following a recommendation from the Joint Committee on Vaccination and Immunisation (JCVI).

Ministers have put the mass booster programme on hold to prioritise those with serious illnesses, although a separate announcement on this is expected soon.

The announcement is separate to any decision on a booster programme, but it is understood news on that is expected soon.

Who is eligible for a third jab?

People considered to have had severe immunosuppression at the time of vaccination will be offered a third dose.

This includes the following groups:

People with primary or acquired immunodeficiency states at the time of vaccination due to condition. This includes:

  • acute and chronic leukaemias, and clinically aggressive lymphomas (including Hodgkin’s lymphoma) who were under treatment or within 12 months of achieving cure
    people under follow up for a chronic lymphoproliferative disorders, including haematological malignancies
  • immunosuppression due to HIV/AIDS with a current CD4 count of <200 cells/µl for adults Primary or acquired cellular and combined immune deficiencies – those with lymphopenia (<1,000 lymphocytes/ul) or with a functional lymphocyte disorder
  • people who have received an allogeneic or an autologous stem cell transplant in the previous 24 months
  • people who received a stem cell transplant more than 24 months ago but have ongoing immunosuppression or graft versus host disease (GVHD)
  • persistent agammaglobulinemia (IgG < 3g/L) due to primary immunodeficiency or secondary to disease / therapy

People on immunosuppressive or immunomodulatory therapy at the time of vaccination. This includes:

  • people who were receiving or had received immunosuppressive therapy for a solid organ transplant in the previous six months
  • people who were receiving or have received in the previous three months targeted therapy for autoimmune disease
  • people who were receiving or have received in the previous six months immunosuppressive chemotherapy or radiotherapy for any indication

People with chronic immune-mediated inflammatory disease who were receiving or have received immunosuppressive therapy before vaccination. This includes:

  • high dose corticosteroids (equivalent ≥ 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 three 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 three months
  • certain combination therapies at individual doses lower than above, including those on ≥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 three months

Individuals who have received high dose steroids (equivalent to >40mg prednisolone per day for more than a week) for any reason in the month before vaccination. Those who received brief immunosuppression (≤40mg prednisolone per day) for an acute episode, and individuals on replacement corticosteroids for adrenal insufficiency, are not considered severely immunosuppressed sufficient to have prevented response to the primary vaccination.

When will the mass rollout start?

Health Secretary Sajid Javid said the Government was continuing to plan for a booster programme to begin this month and said people most at-risk from Covid-19 would be prioritised for that.

However, the JCVI is still deliberating on the potential benefits of booster vaccines for the wider population and is awaiting further evidence to inform its decision.

It is also yet to decide on any extension of the vaccine programme to include all healthy 12 to 15-year-olds.

Giving its recommendation on Wednesday, the JCVI said people who were severely immunosuppressed at the time of their first or second dose of a coronavirus vaccine may not have been able to mount a full response to vaccination, meaning they could be less protected than the wider population.

The committee said studies are ongoing to see how effective a third dose is for this group of people, and as it is considered unlikely to cause any harm, the JCVI has decided that a third jab can be safely offered and might boost protection.

The preference for children in this category who are aged between 12 and 17 is the Pfizer vaccine, while those aged 18 and over will be given either Pfizer or Moderna.

Both of these jabs are mRNA vaccines and almost all of the data so far on third doses is based on this kind of vaccine.

The timing of a third dose will be made by a patient’s specialist doctor, but the jab will usually be given at least eight weeks after the second dose, with some flexibility on that.

The recommendation does not apply to all those considered clinically extremely vulnerable, but is estimated to include between 400,000 and 500,000 people, or less than one per cent of the population.

Mr Javid said he has accepted the JCVI’s recommendation, stating: “We know people with specific conditions that make them particularly vulnerable to Covid-19 may have received less protection against the virus from two vaccine doses.

“I am determined to ensure we are doing all we can to protect people in this group and a third dose will help deliver that.

“The NHS will contact people as soon as possible to discuss their needs and arrange an appointment for a third dose where clinically appropriate.

“This is not the start of the booster programme – we are continuing to plan for this to begin in September to ensure the protection people have built from vaccines is maintained over time and ahead of the winter.

“We will prioritise those most at risk to Covid-19, including those who are eligible for a third primary vaccine, for boosters based on the final advice of the JCVI.”

GPs and consultants will be involved in identifying eligible patients and delivering jabs, with more details to be set out.