What should you know about the hepatitis A vaccine injection site?

The injection site can feel tender or look mildly red or swollen as the immune system responds. The change should be observed for improvement rather than judged by appearance alone. An injection-site reaction is not the same as hepatitis A. Hepatitis A affects the liver and may be associated with dark urine, loss of appetite, nausea, or feeling generally unwell.

Keep the area clean and avoid rubbing or scratching it. A cool, clean cloth may ease discomfort. Wear clothing that does not press on the site, and follow medicine advice from a clinician or pharmacist, especially for a child. Note the size and progression of redness or swelling and tell the vaccination provider before any later dose. See Hepatitis A Vaccination for more information about the vaccine.

Call emergency services for trouble breathing, facial or throat swelling, collapse, or widespread hives after vaccination. Seek prompt review if the site becomes increasingly painful, hot, rapidly enlarges, develops drainage, or is accompanied by a high fever or marked illness. Contact a clinician if symptoms suggest hepatitis A; a liver function test may be considered after an examination.

Ask how the site should look as it settles, which comfort measures are suitable, how to describe a reaction before the next dose, and which changes require same-day advice. Tell the clinician about allergies and any earlier vaccine reactions.