A Phase 2 interventional study of Ad26.ZEBOV vaccine in Ebola Virus Disease, sponsored by Universiteit Antwerpen. Completed at 1 site in Democratic Republic of the Congo. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-14.
Sponsored by Universiteit Antwerpen · Phase 2, Interventional, and Prevention
This Phase 2 study aims to improve preparedness for future Ebola outbreaks by vaccination of a well-known population at risk, ie, a cohort of health care providers (HCP) (such as primary, emergency, and community health care workers) who may be exposed to Ebola in the event of a future outbreak in the Democratic Republic of the Congo (DRC). This study will enhance the immunogenicity database by investigating the kinetics of the humoral immune response. The study will contribute to the safety database (serious adverse events) for VAC52150 following a heterologous vaccine regimen with Ad26.ZEBOV as first vaccine followed by second dose with MVA-BN-Filo administered 56 days later (Day 57). Additionally, after randomization (1:1), a booster vaccination with Ad26.ZEBOV will be executed at 1 year post first dose or 2 years post first dose.
This study is an open-label, monocentric (in Tshuapa province, DRC), phase 2 study to evaluate the immunogenicity and safety of Ad26.ZEBOV (5x1010 viral particles [vp]) as first dose and MVA-BN-Filo (1x108 50% infectious units [Inf U]) as second dose vaccination at a 56-day interval in health care providers (HCP) who may be exposed to Ebola in the event of a future Ebola outbreak in DRC. Additionally, after randomization (1:1) a booster of Ad26.ZEBOV (5x1010 vp) will be offered at respectively 1 year or 2 years after the first dose.
A planned total number of approximately 700 participants will be recruited from the Tshuapa province in DRC. At Day 1, interested participants will be assessed for their understanding of the study, will provide consent, their general health will be evaluated by the investigator, medical history (including vaccination history) will be collected, urine pregnancy testing for women of childbearing potential will be performed. Further during this first visit, vital signs will be measured and a blood sample for baseline immunogenicity assessment will be taken for testing of binding antibody level against EBOV GP using FANG ELISA, presence of pre-existing Human anti-EBOV GP IgG and anti-EBOV NP IgG using ELISA and on the first 100 subjects additionally testing for neutralizing antibody level against Ad26 and MVA vectors using respectively Ad26 VNA and MVA PRNT. Subsequently, a blood sample for baseline safety assessment will be performed to test hemoglobin, hematocrit, blood cell count (red and white), platelet count, urea, creatinine and transaminases. After these primary assessments, they will be vaccinated with first dose Ad26.ZEBOV vaccine. They will be given instructions to contact the study team for any serious adverse event that occurs up until 6 months after each vaccination, or in case of pregnancy of the participant during the study. Lastly on day 1, randomization will be performed (1:1) to determine timing of the booster vaccine at 1 year or 2 years after first dose. Contact information will be verified and an appointment for the second dose on Day 57 will be arranged.
At Day 57, participants will return to the study site for urine pregnancy testing for women of childbearing potential, vital signs measurement, assessment of safety (serious adverse events), for a blood sample for immunogenicity assessment (the binding antibody levels against EBOV GP using FANG ELISA) and afterwards administration of the MVA-BN-Filo vaccination, and they will be reminded to contact the study team for any serious adverse event that occurs, or in case of pregnancy of the participant during the study. Contact information will be verified and an appointment for the 21-day post-dose 2 (Day 78) visit will be arranged.
At 21 days post-dose 2 (Day 78), all participants will return to the study site for assessment of safety (serious adverse events) and collection of a blood sample for immunogenicity assessment. Contact information will be re-verified. They will be reminded to contact the study team for any serious adverse event that occurs, or in case of pregnancy of participant.
At approximately 6 months post-dose 2 vaccination, participants will be contacted by phone to inquire about any occurrence of serious adverse events, and to confirm contact information for additional follow up at 1 year post-first dose vaccination. At 1 year after first vaccine dose, a blood sample will be collected for immunogenicity assessment of all participants (where applicable, pre-administration of the booster dose).
Depending on randomization performed at Day 1, the booster vaccination with Ad26.ZEBOV (5x1010 vp) will be given at 1 year after the first dose or 2 years post-first dose. Participants will be asked to collect solicited adverse events in a participant diary starting on the day of vaccination and continuing for the subsequent 7 days. At day 8 post booster (PB) the safety data including solicited adverse events will be reviewed and a blood sample for immunogenicity will be taken to document the immunity response. At 6 months PB, the participants will be contacted by phone and questioned about any serious adverse events that have occurred since the last vaccination. For all participants at 2 years after first dose, a sample will be collected for immunogenicity assessment (where applicable, pre-administration of the booster dose).
The total duration of the study is 2 years and 6 months post-first dose.
102 studies on the registry are indexed under Hemorrhagic Fever, Ebola; 13 are open to participants now.
This study's enrollment of 699 is above the median of 91 across 79 interventional studies indexed under Hemorrhagic Fever, Ebola.
Browse Hemorrhagic Fever, Ebola studies →Universiteit Antwerpen is the lead sponsor of 128 studies on the registry; 28 are open to participants now.
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Of childbearing potential and practicing (or intending to practice) a highly effective method of birth control consistent with local regulations and/or local culture regarding the use of birth control methods for participants in clinical studies, beginning at least 28 days prior to vaccination and during the study up to at least 3 months after the first (or only) vaccination (Ad26.ZEBOV) and 1 month after the MVA-BN-Filo vaccination (if applicable); and then starting again 14 days before the booster vaccination until 3 months after the booster vaccination.
OR Not of childbearing potential: postmenopausal (amenorrhea for at least 12 months without alternative medical cause); permanently sterilized (eg, bilateral tubal occlusion [which includes tubal ligation procedures as consistent with local regulations], hysterectomy, bilateral salpingectomy, bilateral oophorectomy); OR otherwise be incapable of pregnancy.
Exclusion Criteria:
Booster vaccine with AD26.ZEBOV after 1 year
Biological: Ad26.ZEBOV vaccine
Booster vaccine with AD26.ZEBOV after 2 years
Biological: Ad26.ZEBOV vaccine
The booster vaccination with Ad26.ZEBOV (5x10\^10 vp, same dosage as during the first dose) will be given at 1 year after the first dose or 2 years post-first dose.
Binding Antibody Responses Post-dose 2 Vaccination With MVA-BN-Filo
To assess binding antibody levels against the EBOV GP using FANG ELISA
Time frame: 21 days post-dose 2 vaccination on Day 78
Safety of a Heterologous Vaccine Regimen Utilizing Ad26.ZEBOV as Dose 1, MVA-BN-Filo as Dose 2 and Ad26.ZEBOV as Booster Dose 3
To assess serious adverse events (SAE) during the entire clinical study (up to 1.5 years for group 1, up to 2.5 years for group 2) and to assess solicited local and systemic adverse events until 7 days post booster/dose 3 vaccination with Ad26.ZEBOV
Time frame: Serious Adverse Events: 6 months post-booster (up to 1.5 years for group 1, up to 2.5 years for group 2); All other adverse events: 7 days post 1-year (group 1) or 2-year (group 2) booster
Binding Antibody Responses After Booster Vaccination With Ad26.ZEBOV
To assess binding antibody levels against the EBOV GP using FANG ELISA
Time frame: 7 days post-booster vaccination on Day 372 (Group 1) or Day 737 (Group 2)
On day 0, in maximum groups of 40 individuals, registered healthcare providers working in the Boende health district were invited to attend a workshop where the informed consent form was explained. If they were willing to participate in the study after attending the workshop, they were asked to return the next day for screening and consent (day 1).
| Milestone | Group 1 | Group 2 |
|---|---|---|
| Started | 350 | 348 |
| Vaccinated dose 1 (ad26.zebov) | 350 | 348 |
| Vaccinated dose 2 per protocol (mva-bn-filo) | 343 | 342 |
| Boosted per protocol (ad26.zebov) | 314 | 310 |
| Completed | 321 | 322 |
| Not completed | 29 | 26 |
| Withdrew: Lost to follow-up | 10 | 12 |
| Withdrew: Physician decision | 0 | 4 |
| Withdrew: Death | 2 | 1 |
| Withdrew: Withdrawal by subject | 4 | 1 |
| Withdrew: Pregnancy | 1 | 2 |
| Withdrew: Moved out of study area | 12 | 6 |
To assess binding antibody levels against the EBOV GP using FANG ELISA
| ELISA Units/mL | Group 1 | Group 2 |
|---|---|---|
| Binding Antibody Responses Post-dose 2 Vaccination With MVA-BN-Filo | 3854.6 (3340.7 to 4447.5) | 4505.2 (3903.8 to 5199.3) |
To assess serious adverse events (SAE) during the entire clinical study (up to 1.5 years for group 1, up to 2.5 years for group 2) and to assess solicited local and systemic adverse events until 7 days post booster/dose 3 vaccination with Ad26.ZEBOV
| Participants | Group 1 (SAE) | Group 2 (SAE) |
|---|---|---|
| Safety of a Heterologous Vaccine Regimen Utilizing Ad26.ZEBOV as Dose 1, MVA-BN-Filo as Dose 2 and Ad26.ZEBOV as Booster Dose 3 | 15 | 32 |
To assess binding antibody levels against the EBOV GP using FANG ELISA
| ELISA Units/mL | Group 1 | Group 2 |
|---|---|---|
| Binding Antibody Responses After Booster Vaccination With Ad26.ZEBOV | 10781.6 (9354.4 to 12426.4) | 10746.9 (9208.7 to 12542.0) |
Collected over Serious adverse events were collected from enrollment until 6 months after the last received dose (ie, group 1: 1 year and 6 months follow-up period & group 2: 2 years and 6 months follow-up period). Adverse events were collected using a participant diary for 7 days after booster vaccination only.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Group 1 | 2/350 (0.6%) | 15/350 (4.3%) | 174/314 (55.4%) |
| Group 2 | 2/348 (0.6%) | 32/348 (9.2%) | 166/310 (53.5%) |
| Event | Group 1 | Group 2 |
|---|---|---|
| Inguinal herniaGastrointestinal disorders | 0/350 | 7/348 |
| AppendicitisGastrointestinal disorders | 1/350 | 4/348 |
| Typhoid feverInfections and infestations | 1/350 | 4/348 |
| MalariaInfections and infestations | 4/350 | 3/348 |
| PyrexiaGeneral disorders | 0/350 | 2/348 |
| Calculus bladderRenal and urinary disorders | 1/350 | 2/348 |
| Cerebrovascular accidentNervous system disorders | 0/350 | 2/348 |
| DehydrationMetabolism and nutrition disorders | 1/350 | 2/348 |
| Foetal distress syndromePregnancy, puerperium and perinatal conditions | 2/350 | 0/348 |
| HydroceleCongenital, familial and genetic disorders | 0/350 | 1/348 |
| Event | Group 1 | Group 2 |
|---|---|---|
| Systemic adverse eventGeneral disorders | 133/314 | 127/310 |
| Local solicited adverse eventGeneral disorders | 95/314 | 95/310 |
| Unsolicited adverse eventsGeneral disorders | 64/314 | 79/310 |
| Age, Continuous(years) | Group 1 | Group 2 | Total |
|---|---|---|---|
| Mean | 45.4 ± 11.5 | 44.6 ± 12.5 | 45.0 ± 12.0 |
| Sex: Female, Male(Participants) | Group 1 | Group 2 | Total |
|---|---|---|---|
| Female | 90 | 74 | 164 |
| Male | 260 | 274 | 534 |
| Race (NIH/OMB)(Participants) | Group 1 | Group 2 | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 350 | 348 | 698 |
| White | 0 | 0 | 0 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Region of Enrollment(participants) | Group 1 | Group 2 | Total |
|---|---|---|---|
| Congo, The Democratic Republic of the | 350 | 348 | 698 |
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