What to know about an FDA-authorised mRNA vaccine

An mRNA vaccine delivers temporary genetic instructions to some cells. Those cells make a harmless target protein or part of one, allowing the immune system to practise recognising it. The mRNA is then broken down and does not enter the cell nucleus or alter your DNA. The vaccine cannot give you the infection it is designed to help prevent.

Common short-lived reactions can include soreness, tiredness, headache, muscle aches, chills, or fever. The product, your age, health conditions, previous reactions, and current recommendations all affect whether a particular vaccine is suitable.

Before vaccination, tell the clinician about severe allergies, a previous reaction to a vaccine, pregnancy, immune problems, recent illness, and medicines you take. Follow the current schedule provided by your healthcare service. Afterward, remain for the observation period advised at the vaccination site and drink fluids as tolerated.

For a sore arm, gentle movement and a cool cloth may help. Use a fever or pain medicine only if it is appropriate for you and according to its label or a clinician's advice. Keep a note of the product and date so future doses can be discussed accurately.

Call emergency services for trouble breathing, swelling of the face or throat, widespread hives, collapse, or severe weakness soon after vaccination. Seek medical advice for chest pain, shortness of breath, a racing or irregular heartbeat, or symptoms that are severe, unusual, or not settling.

Ask which product and schedule apply to you, whether a previous allergy changes the plan, how to manage expected reactions, and which symptoms require urgent review. Ask when another dose or a delayed dose should be considered.