Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Weak immune system and COVID-19 vaccines

It is important that you are vaccinated against COVID-19 if you have a weak immune system (immunosuppressed or immunocompromised).

Having a weak immune system puts you at higher risk of serious illness if you get COVID-19. Getting vaccinated will give you some protection against this.

See the weak immune system conditions list

Recommended vaccination

People with a weak immune system aged 6 months and older should follow the recommended vaccination below:

  • 2 doses, 4 weeks apart, as your first round of COVID-19 vaccination
  • an additional dose 8 weeks after this - only if advised by a specialist

Booster doses

People with a weak immune system aged 5 and older should also get:

How to get your vaccine

Vaccines will be given in hospital if you're an inpatient.

If you are 12 or older, you can also:

Children under 12

Children under 12 must go to a walk-in clinic. They cannot be vaccinated at a GP or pharmacy.

Find a walk-in vaccination clinic for children

Additional dose

COVID-19 vaccines may be less effective for you than other people.

If you have a weak immune system at the time of your first round of COVID-19 vaccination, you need 2 doses for your first round to give you better protection.

Your doctor may also recommend an additional (third) dose to give you better protection. Talk to your hospital team or GP if you have a weak immune system and may need an additional dose.

When you should get an additional dose

You should get an additional dose 8 weeks after your second dose. But you can get it 4 weeks after your second dose if you need to be protected urgently.

If you had COVID-19 after your second dose

If you had COVID-19 after your second dose, you may not need an additional dose. This depends on the timing of the infection.

More than 7 days

If your COVID-19 infection was more than 7 days after the second dose, you do not need to get an additional dose. You should still get your booster dose when they are being offered.

Within 7 days

If you get COVID-19 within 7 days of your second dose, you should get an additional dose 4 to 8 weeks after your COVID-19 infection. You only need this if an additional dose is recommended by your doctor or hospital team.

Weak immune system list

People with the following conditions or treatments should follow the recommended COVID-19 vaccination on this page.

Your GP or hospital consultant will confirm if you should get an additional dose or booster. If you are newly diagnosed, they will need to refer you for COVID-19 vaccination.

Cancer patients

Cancer patients affected include:

  • receiving or within 6 weeks of receiving systemic cytotoxic chemotherapy, targeted therapy, monoclonal antibodies or immunotherapies
  • receiving treatment or pending treatment for a haematological cancer
  • haematological cancer - within 5 years of treatment
  • undergoing or within 6 weeks of surgery or radiotherapy for lung or head and neck cancer
  • advanced metastatic cancer

Haematological cancer includes:

  • leukaemia
  • lymphomas
  • blood dyscrasias
  • other malignant neoplasms affecting the bone marrow or lymphatic systems
Chronic kidney disease

People who have chronic kidney disease:

  • on dialysis, or eGFR less than 15ml/min
  • eGFR less than 30ml/min

People who have:

  • been listed for solid organ or haematopoietic stem cell transplant (HSCT)
  • had a solid organ transplant at any time
  • had a HSCT in the past 12 months
Genetic diseases

People who have:

  • autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED)
  • inborn errors in the interferon pathway
  • some B and T cell deficiencies

People using any of the following for treatment:

  • Cyclophosphamide
  • Rituximab
  • Alemtuzumab
  • Cladribine
  • Ocrelizumab
High dose systemic steroids

The following doses of prednisolone (or equivalent dose of other glucocorticoid) are likely to be immunosuppressive:

  • adults and children over 10kg: ≥40mg/day for more than 1 week, or ≥20mg/day for 2 weeks or longer
  • children under 10kg: 2mg/kg/day for 2 weeks or longer

People living with HIV not on treatment, or who have CD4 count less than 200/10-6L for adults

Safety and side effects of COVID-19 vaccines

All COVID-19 vaccines used in Ireland are approved by the European Medicines Agency (EMA)

Safety and side effects of COVID-19 vaccines used in Ireland

Staying safe from COVID-19

Because your immune system may not respond as well to vaccination, you could still be at risk of becoming severely ill from COVID-19. You are also at risk of COVID-19 infection lasting for longer.

Avoid situations where you could pick up the virus, such as crowded areas.

Everyone you live with who can get vaccinated should get vaccinated against COVID-19. This will help to protect both you and them from COVID-19.

How COVID-19 affects people with a weak immune system, including information on steroids

Page last reviewed: 18 April 2024