Please assess the completion status of the following clinical trial:

Trial Title: Long-term Persistence of Immunity Against Hepatitis B in 7-8 Years Old Children After Hepatitis B Vaccination.

Study Design Characteristics:
- Allocation: NON_RANDOMIZED
- Intervention Model: SINGLE_GROUP
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: NONE
- Phase: PHASE4
- Number of Arms: 1.0

Eligibility Criteria:
Inclusion Criteria:~* Subjects who the investigator believes that their parents/guardians can and will comply with the requirements of the protocol.~* A male or female of 7 to 8 years of age (from and including the 7th birthday up to but excluding the 9th birthday) at the time of enrolment.~* With documented evidence of previous vaccination with three consecutive doses of Engerix™-B in Germany~* Written informed consent obtained from the parents or guardians of the subject at the time of enrolment.~* Healthy subjects as established by medical history and clinical examination before entering into the study.~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~* Evidence of previous hepatitis B booster vaccination since administration of the third dose of Engerix™-B vaccine.~* History of or intercurrent hepatitis B disease.~* Hepatitis B vaccination at birth.~* Planned administration/administration of a vaccine not foreseen by the study protocol during the period starting from 30 days before HBV vaccine challenge and ending 30 days after.~* Administration of immunoglobulins and/or any blood products within the three months preceding HBV vaccine challenge or planned administration during the study period.~* Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the HBV vaccine challenge.~* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination

- Gender: ALL
- Minimum Age: 7 Years
- Maximum Age: 8 Years
- Healthy Volunteers: t

Study Arms:
- Group Engerix (Type: EXPERIMENTAL): Subjects received a single challenge dose of Engerix™ (hepatitis-B \[HBV\] vaccine)

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