Evaluation of Immune Memory to Twinrix or Comparator by Challenge Dose Administration 4 Years After Primary Vaccination

Number of Subjects Reporting Unsolicited Symptoms

Unsolicited symptoms = any adverse event (AE) reported in addition to those solicited during the clinical study. Also any "solicited" symptom with onset outside the specified period of follow-up for solicited symptoms was reported as an unsolicited adverse event.

Time frame: During the 31-day follow-up period after the challenge dose.

Number of Subjects With Serious Adverse Events (SAEs) Since the Last Study Visit of the HAB-160 (NCT00603252) Long-term Follow-up Study Considered by the Investigator to Have a Causal Relationship to Primary Vaccination

A serious adverse event (SAE) is any untoward medical occurrence that results in death, is life-threatening, requires hospitalisation or prolongation of existing hospitalisation, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study subject, or is a sign of suspected or confirmed hepatitis A or hepatitis B.

Time frame: Since the last study visit of the primary study long-term follow-up study up to challenge dose administration (1 year)

Number of Subjects Reporting Serious Adverse Events (SAEs)

A serious adverse event (SAE) is any untoward medical occurrence that results in death, is life-threatening, requires hospitalisation or prolongation of existing hospitalisation, results in disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study subject, or is a sign of suspected or confirmed hepatitis A or hepatitis B.

Time frame: During one month following the administration of the challenge dose