The hepatitis B vaccines used in the UK are inactivated vaccines. They do not contain live hepatitis B virus. The vaccine trains your immune system to recognise hepatitis B, so it can reduce your chance of infection if you are exposed later. For travel, many people have a course over several months. Common schedules include doses at 0, 1 and 6 months, or an accelerated course at 0, 1, 2 and 12 months when protection is needed sooner. Some adults may be suitable for a very rapid schedule, with early doses over three weeks and a later dose at 12 months, but that needs proper assessment rather than a guess from the calendar. Children can be vaccinated too, and many UK children now receive hepatitis B as part of routine childhood immunisation. Product choice and timing vary by age, previous vaccines and medical history. Side effects are usually mild and short-lived, such as a sore or red arm. Fever, rash or flu-like symptoms can occur. The vaccine does not protect against hepatitis A, hepatitis C or HIV, so safer sex, avoiding shared needles and being careful with tattoos, piercings and medical treatment still matter.