New Methods to Measure the Immune Response to Hepatitis B Vaccine

Inclusion Criteria: All participants for both parts 1 and 2 must meet the following conditions in order to be enrolled: * Participant is willing and able to give informed consent for participation in the study * Healthy Male or Female, aged 18 - 60 years * No allergies to the vaccine or its excipients Participants enrolling in Part 1 must also meet the following conditions: * Participant has previously received a primary immunisation course of HepB vaccine (3 primary doses). The 4th booster dose recommended after 12 months is not a requirement. There are a variety of possible recommended schedules, and any may have been used as long as the final vaccine (or booster vaccine) was given at least 12 months prior to the participant enrolling in the study. * Participant is willing to allow their General Practitioner to be notified, if appropriate, of participation in the study Participants enrolling in Part 2 must also meet the following conditions Participant receiving HBvaxPro® (the usual vaccine given within the Occupational Health Department). Exclusion Criteria: The participant may not enter either study if ANY of the following apply: * Have any known or suspected impairment or alteration of immune function, resulting from, for example: * Congenital or acquired immunodeficiency (including IgA deficiency) * Human Immunodeficiency Virus infection or symptoms/signs suggestive of an HIV-associated condition * Autoimmune disease * Receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 12 months or long-term systemic corticosteroid therapy. * Chronic illness that could interfere with immunological function or donation of the required volumes of blood (e.g. cardiac or renal disease, diabetes, or auto-immune disorders). * Receipt of a HepB booster vaccine within the past 12 months. * Prior history of anaphylactic reaction to a previous dose of a Hepatitis B containing vaccine or known hypersensitivity to any vaccine component; * Receipt of blood, blood products, or plasma derivatives within the past 3 months. * Total blood donation greater than 50 ml within the past 3 months. * Thrombocytopenia or any bleeding disorder. * Pregnancy as confirmed by a positive pregnancy test, or currently breastfeeding. * Receipt of a live vaccine within 4 weeks prior to vaccination or a killed vaccine within 7 days prior to vaccination. * Plan to receive any vaccine other than the study vaccine within 4 weeks following vaccination. * Enrolled in another study, which, in the opinion of the investigator, could compromise the integrity of either study being conducted. * A member of staff on the delegation log * According to the TOPS database, have recently taken part in a significant number of other studies, which, in the opinion of the investigator, warrant exclusion from further studies. * Participant is a known non-responder to the HepB vaccine * Have any condition, which, in the opinion of the investigator, might interfere with the evaluation of the study objectives. * Unable to understand English, or what will be required from them during the study.