Like all medicines, COVID-19 vaccines can cause side effects. Most of these are mild to moderate and short-term. Not everyone gets side effects.
If you are concerned about side effects, phone your GP for advice.
Serious side effects, like a severe allergic reaction, are extremely rare. Your vaccinator is trained to treat allergic reactions.
Fever after COVID-19 vaccines
It’s common to develop a fever (temperature of 38 degrees Celsius or above) after COVID-19 vaccination. This usually happens within 48 hours of getting a vaccine.
If you feel uncomfortable, take paracetamol or ibuprofen following the instructions on the box or leaflet.
Side effects of COVID-19 vaccines
The side effects of the COVID-19 vaccines used in Ireland are listed below.
Pfizer/BioNTech COVID-19 vaccine side effects
The Pfizer/BioNTech COVID-19 vaccine is called Comirnaty.
Who should not get this vaccine
Most people can safely get the Pfizer/BioNTech COVID-19 vaccine. You will be offered a different vaccine if this vaccine is not suitable.
Novavax COVID-19 vaccine side effects
The Novavax COVID-19 vaccine is called Nuvaxovid.
Who should not get this vaccine
Most people aged 12 or older can safely get the Novavax COVID-19 vaccine Nuvaxovid. It is usually offered if the Pfizer/BioNTech COVID-19 vaccine is not suitable.
Vaccines previously offered
Side effects of COVID-19 vaccines previously offered in Ireland.
Find a:
- list of side effects of the Vidprevtyn Beta COVID-19 vaccine on the European Medicines Agency website - ema.europa.eu
- list of side effects of the Moderna vaccine Spikevax on the European Medicines Agency website - ema.europa.eu
- list of side effects of the Janssen vaccine Jcovden on the European Medicines Agency website - ema.europa.eu
- list of side effects of the AstraZeneca vaccine Vaxzevria on the European Medicines Agency website - ema.europa.eu
Reporting side effects
As with all vaccines, you can report suspected side effects to the Health Products Regulatory Authority (HPRA).
If you are reporting a side effect to the HPRA
Give as much information as possible. Include the vaccine batch number if you have it. You'll find this on your vaccine record card. You can also ask your doctor or a family member to report side effects for you.
The HPRA cannot provide clinical advice on individual cases. Talk to your doctor or pharmacist about any medical concerns you may have.
Safety of COVID-19 vaccines
All vaccines are tested to make sure they are safe and work before they can be used. The HSE only uses a vaccine if it meets the required standards of safety and effectiveness.
You will be offered the vaccine that is most suitable for you.
It is expected that the safety of the adapted vaccines will be similar to the previous vaccines. The safety of COVID-19 vaccines will continue to be monitored by the EMA.
Mpox vaccine
If you recently had the Mpox vaccine, wait 4 weeks before you get vaccinated with any COVID-19 vaccine. This is a precaution because of the unknown risk of myocarditis.
This content was fact checked by vaccine experts working in Ireland.