Why is mRNA vaccine used in COVID-19 vaccination?

The mRNA is delivered into cells and provides instructions for making a protein that resembles part of the virus. The immune system notices that protein and builds a response against it. The mRNA does not need to enter the cell nucleus, and the body breaks down the instructions after they have been used.

If the immune system later meets the virus, its earlier training can help it respond. Vaccination reduces the chance of severe outcomes for many people, but it does not replace assessment or treatment when someone is unwell.

Tell the vaccinating clinician about serious allergies, a previous reaction to a vaccine dose, current illness, pregnancy, breastfeeding, immune conditions, and regular medicines. Remain for the recommended observation period after the injection. Soreness at the injection site, tiredness, headache, chills, or a mild fever can occur as the immune system responds.

Use the information supplied with your vaccine and follow local clinical advice about doses. For a fuller explanation of the technology, see mRNA Vaccine.

Get emergency help for breathing difficulty, swelling of the lips, tongue, face, or throat, fainting, or widespread itchy welts after vaccination. Seek prompt medical advice for chest pain, shortness of breath, a fast or irregular heartbeat, or symptoms that are severe, worsening, or do not settle as expected.

Ask which COVID-19 vaccine is appropriate for you, whether a previous reaction changes the plan, and how your medicines or health conditions affect timing. If you are currently ill, ask whether vaccination should be delayed until you recover.