Please assess the completion status of the following clinical trial:

Trial Title: Evaluation of Antibody Persistence and Immune Memory Against the Hepatitis B Antigen in Previously Vaccinated Children

Study Design Characteristics:
- Allocation: NON_RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: NONE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Subjects who the investigator believes that their parents/Legally acceptable representative) can and will comply with the requirements of the protocol should be enrolled in the study.~* A male or female aged 11-12 years at the time of study entry (from and including the 11th birthday until and excluding the 13th birthday).~* Written informed consent obtained from the parent or Legally Acceptable Representative of the subject.~* Study procedures will be explained to subjects and depending on their understanding, optional informed assent will be sought at the discretion of the investigator.~* Written informed assent obtained from the subject in addition to the informed consent signed by the parent(s)/ Legally Acceptable Representative (s).~* Healthy subjects as established by medical history and clinical examination before entering into the study.~* Subjects who have received all three doses of Infanrix hexa or Engerix-B in the primary study 217744/031 (NCT01457495).~* Female subjects of non-childbearing potential may be enrolled in the study.~* Female subjects of childbearing potential may be enrolled in the study, if the subject:~  * has practiced adequate contraception for 30 days prior to vaccination, and~ * has a negative pregnancy test on the day of vaccination, and~ * has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series.~Exclusion Criteria:~* Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product.~* Child in care.~* Use of any investigational or non-registered product drug or vaccine) other than the study vaccine within 30 days preceding the challenge dose of HBV vaccine, or planned use during the study period.~* Receipt of hepatitis B (containing) vaccine after vaccination in the primary study 217744/031 (NCT01457495).~* History of hepatitis B disease.~* Planned administration/administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before and ending 30 days after the HBV vaccine challenge dose.~* Administration of immunoglobulins and/or any blood products within the three months preceding the challenge dose of HBV vaccine or planned administration during the study period.~* Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the challenge dose of HBV vaccine.~* Pregnant or lactating female.~* Female planning to become pregnant or planning to discontinue contraceptive precautions.~* Known hypersensitivity to any component of the HBV vaccine or evidence of hypersensitivity after previous immunisation with a vaccine containing the hepatitis B component.~* Acute disease and/or fever at the time of enrolment.~* Fever is defined as temperature ≥ 37.5°C (99.5°F) on oral, axillary or tympanic setting~* Subjects with a minor illness without fever may be enrolled at the discretion of the investigator.

- Gender: ALL
- Minimum Age: 11 Years
- Maximum Age: 12 Years
- Healthy Volunteers: t

Study Arms:
- Infanrix-hexa/Engerix-B Group (Type: EXPERIMENTAL): Subjects aged 11-12 year old received 3 doses of Infanrix-hexa vaccine in the primary study (217744/031 (NCT01457495)) and a challenge dose of Engerix-B vaccine in this study. Engerix-B was administered as a single dose intramuscularly into the deltoid region of the non-dominant arm.
- Infanrix-IPV+Hib/Engerix-B Group (Type: ACTIVE_COMPARATOR): Subjects aged 11-12 year old received 3 doses of Infanrix-IPV+Hib and Engerix-B vaccines in the primary study (217744/031 (NCT01457495)) and a challenge dose of Engerix-B vaccine in this study. Engerix-B was administered as a single dose intramuscularly into the deltoid region of the non-dominant arm.

Based on this trial design, predict the completion outcome and termination type (if applicable).

Answer: outcome: complete