What should you know about mRNA in a COVID vaccine?

The vaccine delivers mRNA into some cells near the injection site. Those cells use the instructions briefly to make a harmless piece of a viral protein, which allows immune cells to practise recognising it. The mRNA is then broken down and cleared. It does not alter DNA and cannot cause COVID-19 because it does not contain a live coronavirus. Protection can change over time and vaccination does not prevent every infection, but it prepares immune defences for a later encounter.

Tell the vaccinator about a previous severe allergic reaction to a vaccine ingredient, a past reaction after a COVID vaccine, current illness, pregnancy, immune problems, and medicines. Remain for the observation period advised locally. A sore arm, tiredness, headache, chills, or fever can occur for a short time. Rest, drink fluids, and use only symptom medicine that is suitable for you. Keep following current infection-control advice when you are unwell.

Seek urgent help for trouble breathing, swelling of the face or throat, widespread hives, collapse, or severe dizziness after vaccination. Contact a clinician promptly for chest pain, shortness of breath, a fast or irregular heartbeat, or symptoms that are severe or worsening. Mild injection-site discomfort commonly settles, but persistent concerns deserve individual advice.

Ask which vaccine is recommended for you, whether your health conditions or medicines change the timing, how to manage a previous allergic reaction, and when another dose may be due. Ask how vaccination fits with recent COVID infection, other vaccines, pregnancy, breastfeeding, or immune-suppressing treatment.