What to know about COVID-19 mRNA vaccines

The vaccine delivers mRNA, a short-lived instruction that helps some cells make a harmless piece of the virus. The immune system recognises that piece and develops a response. The mRNA is then broken down; it does not enter the cell nucleus or alter your DNA. Vaccine products and recommendations can change, so the product offered locally may depend on current guidance, age, health conditions and previous doses.

Tell the vaccination team about previous vaccine reactions, severe allergies, pregnancy, immune-suppressing treatment and recent illness. Bring your vaccination record if available and ask which product is being offered and why. Common short-lived effects include a sore arm, tiredness, headache, muscle aches or fever. Rest, drink fluids and use a medicine only if a healthcare professional says it is suitable for you.

Seek emergency help for breathing difficulty, facial or throat swelling, collapse, or widespread hives after vaccination. Get prompt medical advice for chest pain, shortness of breath, a racing or irregular heartbeat, or severe symptoms that are worsening. A clinician can distinguish an expected immune response from an illness needing assessment.

Ask which mRNA vaccine is suitable, whether your medical history changes the timing, how to manage expected reactions, and what to do if you have missed or cannot verify a previous dose.