Please assess the completion status of the following clinical trial:

Trial Title: Evaluation of Full Versus Fractional Dose of COVID-19 Vaccine Given as a Booster for the Prevention of COVID-19 in Adults in Mongolia.

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: QUADRUPLE
- Phase: PHASE3
- Number of Arms: 6.0

Eligibility Criteria:
Inclusion Criteria:~1. Have completed two doses of Sinopharm, AstraZeneca or Sputnik vaccines with the recommended schedule 6 months prior to the date of enrolment~2. Willing and able to give written informed consent~3. Aged 18 years or above~4. Willing to complete the follow-up requirements of the study~Exclusion Criteria:~1. Received 3 doses of COVID-19 vaccine~2. Received 2 doses of COVID-19 less than 6 months prior to the start of the trial~3. Currently on immunosuppressive medication or anti-cancer chemotherapy~4. HIV infection~5. Congenital immune deficiency syndrome~6. Has received immunoglobulin or other blood products in the 3 months prior to vaccination~7. Study staff and their relatives~8. Have a history of a severe allergic reaction to any COVID-19 vaccines or have a medical exception to receiving further COVID-19 vaccines

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

Study Arms:
- AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech booster group (Type: ACTIVE_COMPARATOR): Previously received two doses of AstraZeneca as primary COVID-19 vaccine
- AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech booster group (Type: EXPERIMENTAL): Previously received two doses of AstraZeneca as primary COVID-19 vaccine~.
- Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech booster group (Type: ACTIVE_COMPARATOR): Previously received two doses of Sinopharm as primary COVID-19 vaccine
- Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech booster group (Type: EXPERIMENTAL): Previously received two doses of Sinopharm as primary COVID-19 vaccine
- Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech booster group (Type: ACTIVE_COMPARATOR): Previously received two doses of Sputnik as primary COVID-19 vaccine
- Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech booster group (Type: EXPERIMENTAL): Previously received two doses of Sputnik as primary COVID-19 vaccine

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