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.

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

People with a weak immune system are recommended an mRNA vaccine (Pfizer or Moderna) for your first 2 doses. You should get an additional dose after this.

2 boosters are recommended for people aged 12 and older.

An example of recommended COVID-19 vaccination for someone aged 5 to 11 with a weak immune system is:

  • 2 doses of the Pfizer vaccine as your first round of COVID-19 vaccination
  • an additional dose at least 28 days after this

An example of recommended COVID-19 vaccination for someone over 12 with a weak immune system is:

  • 2 doses of the Pfizer vaccine as your first round of COVID-19 vaccination
  • an additional dose at least 2 months after this
  • a booster dose at least 3 months after your additional dose
  • a second booster at least 4 months after your first booster

Additional dose

If you had a weak immune system at the time of your first round of COVID-19 vaccination, you should have been offered an additional dose to give you better protection.

Talk to your hospital team or GP if you have not had your additional dose yet and you need one because of a weak immune system.

When you should get an additional dose

You should get an additional dose:

  • at least 2 months after finishing your first round of COVID-19 vaccination if you are 12 or older
  • at least 28 days after your second dose if you are aged 5 to 11

If you have had COVID-19 after your first round of vaccination, you need to wait:

  • 3 months after symptoms or from the date of your positive COVID-19 test before getting an additional dose

First booster dose

If you are over 12 with a weak immune system, you should get a first booster dose at least 3 months after your additional dose.

Second booster dose

If you had a weak immune system at the time of the first round of vaccination or your first booster dose, you should get a second booster dose.

You may not be due to get a second booster yet. Get your second booster dose at least 4 months after your first booster.

Your second booster should be your fifth dose of COVID-19 vaccine.

How to get vaccinated

Your GP or hospital consultant will confirm if you should get a second booster at this time.

COVID-19 vaccines will be given through a vaccination centre near you, or your hospital if you’re an inpatient. GPs may also vaccinate some people.

Weak immune system list

People with the following conditions or treatments should follow the recommended COVID-19 vaccination on this page. This is because COVID-19 vaccines may be less effective for you than other people.

Your GP or hospital consultant will confirm if you should get an additional dose or second booster at this time.

You will need your GP or hospital consultant to confirm you have a weak immune system before booking your vaccination appointment.

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

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

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

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)

Learn about the safety of a COVID-19 vaccine booster dose

Learn more about the safety and side effects of COVID-19 vaccines used in Ireland

Staying safe from COVID-19

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.

Learn more about how COVID-19 affects people with a weak immune system, including information on steroids