What should you know about hepatitis B shots for adults?

Adults may be offered vaccination if they are unvaccinated, have a partner or household contact with hepatitis B, work around blood or body fluids, or have a medical condition that raises concern about liver infection. The vaccine trains the immune system to recognise hepatitis B before exposure. It cannot clear an infection that is already present, so testing may be discussed when past exposure is possible. Protection may require a series of doses rather than one visit, depending on the product and clinical situation.

Bring any vaccine records and tell the clinician about allergies, pregnancy, immune-system problems, and previous reactions. Follow the appointment schedule given for your vaccine; if a dose is late, ask how to continue rather than restarting on your own. Mild soreness or tiredness can occur after a shot. Keep the injection site clean and use simple comfort measures recommended by your clinician. Read the dedicated [Hepatitis B Vaccination](/treatments/preventive-care-and-vaccination/hepatitis-b-vaccination/) guide and learn about [Hepatitis B](/conditions/hepatitis-b/).

Seek urgent help for trouble breathing, swelling of the face or throat, widespread hives, fainting, or severe weakness after vaccination. These reactions are uncommon but need immediate assessment. Contact a clinician for persistent fever, worsening pain, or symptoms such as yellow eyes, [Dark Urine](/symptoms/dark-urine/), or unusual [Fatigue](/symptoms/fatigue/), which may need a separate evaluation. A [Liver Function Test](/treatments/diagnostics-and-screening/liver-function-test/) may be considered when liver symptoms are present.

Ask whether you need testing before vaccination, which schedule applies, what to do after a missed appointment, and whether a blood test is useful after the series. Mention medicines or conditions that affect immunity.