What should you know about first hepatitis B vaccine?

Hepatitis B is caused by a virus that can spread through infected blood or body fluids and may affect the liver. Vaccination trains the immune system to recognise the virus before an exposure occurs. A first dose does not complete the vaccination course, so keep the follow-up plan provided by your clinician. Protection and the schedule can differ for babies, children, adults, and people with particular health risks.

Tell the vaccinator about a previous serious reaction to a vaccine, a current illness, pregnancy, immune problems, or medicines that affect immunity. Eat and drink normally unless you were given different instructions. After the injection, remain for the observation period recommended by the clinic. A sore arm, mild temperature, tiredness, or brief discomfort can occur. Keep the appointment record and ask when the next dose is due. If an exposure may already have happened, mention it promptly because vaccination alone may not be the whole response.

Seek urgent help for trouble breathing, swelling of the face or throat, widespread hives, fainting, or sudden severe weakness after vaccination. Contact a clinician about a persistent high fever, worsening illness, or a reaction that concerns you. Jaundice, dark urine, marked fatigue, vomiting, or pain under the right ribs need medical assessment; these symptoms do not by themselves show that a vaccine caused liver disease. Learn more about [Hepatitis B](/conditions/hepatitis-b/) and [Hepatitis B Vaccination](/treatments/preventive-care-and-vaccination/hepatitis-b-vaccination/).

Ask which schedule applies to you, whether any dose was recorded elsewhere, and what to do if an appointment is missed. You can also ask whether testing such as a [Liver Function Test](/treatments/diagnostics-and-screening/liver-function-test/) is relevant to your situation.