Please assess the completion status of the following clinical trial:

Trial Title: Heterologous Boost Immunization With Ad5-nCoV After Three-dose Priming With an Inactivated SARS-CoV-2 Vaccine

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: NONE
- Phase: PHASE4
- Number of Arms: 3.0

Eligibility Criteria:
Inclusion Criteria:~* Health subjects aged ≥18 years~* The subject can provide with informed consent and sign informed consent form (ICF).~* The subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study.~* Participants who have received three-dose of inactivated SARS-CoV-2 vaccine more than 6 months ago.~Exclusion Criteria:~* Have the medical history or family history of convulsion, epilepsy, encephalopathy and psychosis.~* Be allergic to any component of the research vaccines, or used to have a history of hypersensitivity or serious reactions to vaccination.~* Vaccine-related SAE occurred after previous vaccination with COVID-19 vaccine.~* Women with positive urine pregnancy test or in lactation.~* Have acute febrile diseases or infectious diseases or have a history of SARS.~* Axillary temperature\>37.0℃~* Have serious cardiovascular diseases, such as arrhythmia, conduction block, myocardial infarction, severe hypertension that cannot be controlled by medication (systolic blood pressure ≥180mmHg and/or diastolic blood pressure ≥110mmHg when measured in the field)~* Have severe chronic diseases or condition is not stable, such as asthma, diabetes, thyroid disease~* Congenital or acquired angioedema / neuroedema.~* Have the history of urticaria 1 year before.~* Have asplenia or functional asplenia.~* Patients with chronic obstructive pulmonary disease, pulmonary fibrosis and other pulmonary abnormalities.~* Have history of SARS-CoV-2 infection or COVID-19.~* Have symptoms of upper respiratory tract infection.~* Have traveled to medium or high risk areas or traveled abroad in the past 21 days, and epidemiologically contacted with SARS-CoV-2.~* Any medical, psychological, social, or other conditions that, in the investigator's judgment, are inconsistent with the protocol or affect the subject's informed consent.

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: t

Study Arms:
- Group A (Type: EXPERIMENTAL): Approximately 70 subjects recruited from the prior clinical trial and newly enrolled 50 subjects will receive a booster dose of aerosolized Ad5-nCoV after three-dose priming with ICV
- Group B (Type: EXPERIMENTAL): Approximately 70 subjects recruited from the prior clinical trial and newly enrolled 50 subjects will receive a booster dose of intramuscular Ad5-nCoV after three-dose priming with CoronaVac
- Group C (Type: EXPERIMENTAL): Approximately 70 subjects recruited from the prior clinical trial and newly enrolled 50 subjects will receive homologous fourth dose of CoronaVac.

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

Answer: outcome: complete