Safety - Moderna COVID-19 vaccine

All vaccines are tested for safety and effectiveness before they can be used. The HSE only uses a vaccine if it meets the required standards of safety and effectiveness.

The official name for Moderna's COVID-19 vaccine is 'Spikevax.' But most people call it the 'Moderna' vaccine.

It was the second COVID-19 vaccine to be approved for use in Ireland.

Who should not get the Moderna vaccine

Most people aged 30 and older can safely get the Moderna COVID-19 vaccine.

But this vaccine is not recommended if you have had a severe allergic reaction to:

  • any of the ingredients in this vaccine or the Pfizer/BioNTech vaccine - including polyethylene glycol or PEG
  • Trometamol - a contrast dye used in MRI radiological studies

You should also not get the vaccine if you:

  • have been told by a doctor that you should not get this vaccine or the Pfizer/BioNTech COVID-19 vaccine - they are both mRNA vaccines
  • had myocarditis after a previous dose of this vaccine or the Pfizer/BioNTech COVID-19 vaccine

Talk to your doctor before getting this vaccine if you:

  • have had a severe allergic reaction (anaphylaxis) in the past, including to any other vaccine or medication
  • had pericarditis after a previous dose of this vaccine or the Pfizer/BioNtech COVID-19 vaccine

How COVID-19 mRNA vaccines work

Moderna is an mRNA vaccine. mRNA vaccines teach your body how to make a protein that will trigger an immune response, without using the live virus that causes COVID-19.

Read about how COVID-19 mRNA vaccines work

How COVID-19 vaccines were developed quickly

The work to develop COVID-19 vaccines moved much faster than usual to make them available as soon as possible.

Read about COVID-19 vaccine development

Ingredients of Moderna COVID-19 vaccine

The Moderna COVID-19 vaccine does not contain eggs, preservatives or latex.

For a full list of ingredients, read the patient information leaflet for the COVID-19 Moderna vaccine.


This content was fact checked by vaccine experts working in Ireland.

Last updated: 23 November 2021 at 3.40pm

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