Vaccines are the safest way to prevent infectious diseases. They teach your immune system (your body's natural defences) how to protect you from a specific virus.
Protection from a COVID-19 vaccine, COVID-19 infection, or both, weakens over time. Protection can be increased by getting a booster dose. Some people at higher risk should get seasonal booster doses to extend the protection of COVID-19 vaccines.
The European Medicines Agency (EMA) and National Immunisation Advisory Committee (NIAC) have recommended adapted mRNA COVID-19 vaccines as booster doses.
While all previous vaccines offer protection against COVID-19, the adapted vaccines are expected to give wider protection against COVID-19 variants. This includes Omicron variants.
Doses and immunity
The doses needed for COVID-19 vaccines used in Ireland are listed below.
If you have a weak immune system, you should have been offered an ‘additional dose’ to give you better protection. This is because your immune system may not respond as well to vaccination. You will still need booster doses after this additional dose.
Pfizer/BioNTech COVID-19 vaccine
For your first round of vaccination, you will need 2 doses of the Pfizer/BioNTech vaccine.
It takes 7 days after the second dose for the Pfizer/BioNTech COVID-19 vaccine to work.
If you recently had COVID-19, wait at least 4 weeks before getting your dose 1 or dose 2.
A booster dose is recommended to extend vaccine protection for people age 18 and older. Booster doses are available to children age 5 and older. Some people at higher risk of serious COVID-19 illness will be offered seasonal booster doses.
Novavax COVID-19 vaccine (Non-mRNA)
The Novavax COVID-19 vaccine is called Nuvaxovid.
We do not know yet how long immunity will last after getting this vaccine. Clinical trials are happening now to find this out.
How to get the Novavax vaccine
The Pfizer/BioNTech vaccine is the recommended COVID-19 vaccine for most people.
Some people may not be able to get this vaccine or have chosen not to get one. For example, because of an allergy to one of the vaccine's ingredients. In this case, you may be offered the Novavax vaccine.
Phone HSELive on 1800 700 700 to find out where you can get the Novavax vaccine.
The number of doses you need will depend on if you have been vaccinated against COVID-19 yet.
If you have never had a COVID-19 vaccine, you will need 2 doses of the Novavax vaccine, 21 days apart.
Not completed your first round of vaccination
This means you only had the first dose of either the Pfizer, Moderna or AstraZeneca vaccine.
You can get the Novavax vaccine as your second dose, 28 days after your first COVID-19 vaccine dose.
If you had your first round of vaccination with Pfizer, Moderna or AstraZeneca, you may be offered the Novavax vaccine as a booster dose if you are 12 or older. This is only for people who cannot get or have chosen not to get an mRNA vaccine as your booster dose.
If you are getting Novavax for a booster dose, you should get this 4 to 9 months after your last COVID-19 vaccine.
If you had the Novavax vaccine as your first round of COVID-19 vaccination, further doses of Novavax may be considered as boosters after a risk-benefit discussion with your vaccinator.
People with a weak immune system are offered an additional dose for better protection. The Pfizer/BioNTech vaccine is the recommended COVID-19 vaccine for an additional dose.
In cases where you cannot get or choose not to get an mRNA vaccine, you may be offered the Novavax vaccine as your additional dose if you are 12 or older.
VidPrevtyn Beta COVID-19 vaccine (Non-mRNA)
VidPrevtyn Beta can be used as a booster in those aged 18 years and older who have previously had:
- an mRNA vaccine (Pfizer/BioNTech or Moderna)
- a viral vector vaccine (AstraZeneca or Janssen)
It is not available as a booster to people who have previously had the Novavax COVID-19 vaccine.
If you are pregnant, you will be offered an mRNA vaccine as a booster dose. If an mRNA vaccine is not suitable for you, VidPrevtyn Beta may be considered. Talk to your GP, specialist, or vaccinator for advice.
Moderna COVID-19 vaccine (not currently available)
The official name of this COVID-19 vaccine is 'Spikevax.' This vaccine is not available in Ireland at this time.
If you got the Moderna vaccine before, you will be offered the Pfizer/BioNTech vaccine for a booster dose.
Janssen/Jcovden COVID-19 vaccine (not currently available)
The official name of the Janssen COVID-19 vaccine is 'Jcovden'. This vaccine is not available in Ireland at this time.
Even if you got the Janssen vaccine as your first dose, you will be offered the Pfizer/BioNTech vaccine for a booster dose.
Some people may not be able to get an mRNA vaccine, or may not want to. For example, if you are allergic to polyethylene glycol (PEG), an ingredient in the mRNA vaccines. In this case, you may be offered the Novavax or Vidprevtyn Beta vaccine as your booster dose.
AstraZeneca COVID-19 vaccine (not currently available)
The official name of AstraZeneca's COVID-19 vaccine is 'Vaxzevria'.
This vaccine is not available in Ireland at this time.
If you got the AstraZeneca vaccine before, you will be offered the Pfizer/BioNTech vaccine for a booster dose.
Getting different vaccines
You may be offered a different vaccine for your second dose or booster dose to the one you originally had. For example, you may get a booster dose of the Pfizer/BioNTech after getting the AstraZeneca vaccine for your first 2 doses.
So far, there have been no concerns about serious side effects with this option. Some side effects may be more common if you get a different vaccine from the one you got previously. For example, pain, fever, headache and fatigue. These are short-lived side effects and will not last long.
Studies have found that the immune response after getting different vaccines may be as good as getting the same vaccine. In some cases, it can be better.
The different types of COVID-19 vaccines that have been used in Ireland are:
- mRNA - Pfizer/BioNTech and Moderna
- viral vector - AstraZeneca and Janssen
- protein subunit - Novavax and Vidprevtyn Beta
Side effects and safety
Like all medicines, COVID-19 vaccines can cause side effects. Most of these are mild to moderate and do not last long.
Protection from COVID-19
Anyone who gets COVID-19 can become seriously ill or have complications. Getting vaccinated is the best way to protect yourself and others.
You can still get COVID-19 after vaccination. But being vaccinated can reduce how serious your symptoms will be.
Continue to follow public health advice on how to stop the spread of COVID-19. For example, washing your hands properly and often.
This content was fact checked by vaccine experts working in Ireland.