Please assess the completion status of the following clinical trial:

Trial Title: A Study of Ad26.COV2.S Administered as Booster Vaccination in Adults Who Have Previously Received Primary Vaccination With Ad26.COV2.S or BNT162b2

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE2
- Number of Arms: 6.0

Eligibility Criteria:
Inclusion Criteria:~* Cohort 1: Participant received Ad26.COV2.S in VAC31518COV3001. The interval between the Ad26.COV2.S primary vaccination should preferably be greater than or equal to (\>=) 6 months prior to study vaccination on VAC31518COV2008, however a window of maximum -20 days is allowed; Cohort 2: Participant completed primary vaccination with a 2-dose regimen of BNT162b2 vaccine. The last dose of BTN162b2 should preferably be \>=6 months prior to study vaccination on COV2008, however a window of a maximum of -20 days is allowed~* Participant must provide consent indicating that he or she understands the purpose, procedures and potential risks and benefits of the study, and is willing to participate in the study~* Participant agrees to not donate bone marrow, blood, and blood products from the study vaccine administration until 3 months after receiving the study vaccine~* Participant must be willing to provide verifiable identification, has means to be contacted and to contact the investigator during the study~* Participant must be able to read, understand, and complete questionnaires in the electronic clinical outcome assessment (eCOA) (that is, the Coronavirus disease (COVID-19) signs and symptoms surveillance question, the e-Diary, and the electronic patient-reported outcomes (ePROs). Participants with visual impairment are eligible for study participation and may have caregiver assistance in completing the eCOA questionnaires~Exclusion Criteria:~* Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature \>= 38.0 degree Celsius (C) (100.4 degree Fahrenheit \[F\]) within 24 hours prior to the planned study vaccination; randomization at a later date is permitted at the discretion of the investigator. Please notify the sponsor (or medical monitor) of this decision~* Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine~* Participant received treatment with immunoglobulins (Ig) in the 3 months or exogenous blood products (autologous blood transfusions are not exclusionary) in the 4 months before the planned administration of the study vaccine or has any plans to receive such treatment during the study~* Participant has a known history of confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection~* Participant has a history of heparin-induced thrombocytopenia or thrombosis in combination with thrombocytopenia~* Participant has a history of acute polyneuropathy (example. Guillain-Barre syndrome)~* History of capillary leak syndrome

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

Study Arms:
- Cohort 1: Group 1: Ad26.COV2.S (Dose Level 1) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with Ad26.COV2.S will receive single intramuscular (IM) injection of Ad26.COV2.S booster vaccination at dose level 1 on Day 1.
- Cohort 1: Group 2: Ad26.COV2.S (Dose Level 2) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with Ad26.COV2.S will receive single IM injection of Ad26.COV2.S booster vaccination at dose level 2 on Day 1.
- Cohort 1: Group 3: Ad26.COV2.S (Dose Level 3) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with Ad26.COV2.S will receive single IM injection of Ad26.COV2.S booster vaccination at dose level 3 on Day 1.
- Cohort 2: Group 4: Ad26.COV2.S (Dose Level 1) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with BNT162b2 will receive single IM injection of Ad26.COV2.S booster vaccination at dose level 1 on Day 1.
- Cohort 2: Group 5: Ad26.COV2.S (Dose Level 2) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with BNT162b2 will receive single IM injection of Ad26.COV2.S booster vaccination at dose level 2 on Day 1.
- Cohort 2: Group 6: Ad26.COV2.S (Dose Level 3) (Type: EXPERIMENTAL): Participants who have previously received primary vaccination with BNT162b2 will receive single IM injection of Ad26.COV2.S booster vaccination at dose level 3 on Day 1.

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