ClinicalTrials.gg
Active, not recruitingNCT04270838Updated Nov 18, 2025

A Phase Ib/II Study of the Safety and Immunogenicity of the Candidate Rabies Vaccine ChAdOx2 RabG

A Phase 1/2 interventional study of ChAdOx2 RabG and Inactivated Rabies Vaccine in Rabies, sponsored by University of Oxford. Active, not recruiting at 1 site in Tanzania. Open to participants aged 2 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-11-18.

Sponsored by University of Oxford · Phase 1/2, Interventional, and Treatment

Phase
Phase 1/2
Study type
Interventional
Enrollment
174
Allocation
Randomized
Ages
2 Years to 45 Years
Sex
All
01

Study summary

This is a Phase Ib/II, open-label, head-to-head, age de-escalation dose-escalation, partially randomized trial to study the safety and immunogenicity of the candidate rabies vaccine ChAdOx2 RabG in healthy adults (age 18-45 years) and young children (age 2-6 years). ChAdOx2 RabG will be administered intramuscularly and licensed rabies vaccine will be given by intradermal injection.

Read the detailed description

A total of 120 participants will be recruited into 10 groups in Bagamoyo, Tanzania. The duration of the entire study will be up to 5.5 years per participant from the time of first vaccination. ChAdOx2 RabG will be administered intramuscularly and licensed rabies vaccine (Verorab) will be given by intradermal injection at two to four anatomical sites (deltoids, thighs or suprascapular areas).

All participants, regardless of which vaccine they receive at the start of the study, will receive a course of a licenced rabies vaccine (Verorab) during or at the end of the follow-up period.

02

Conditions studied

  • Rabies

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Keywords

  • Vaccine
03

In context

Rabies

114 studies on the registry are indexed under Rabies; 15 are open to participants now.

This study's enrollment of 174 is below the median of 201 across 104 interventional studies indexed under Rabies.

Browse Rabies studies →

Lead sponsor

University of Oxford is the lead sponsor of 812 studies on the registry; 119 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
2 Years to 45 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Adult groups: Healthy male or female adults aged 18-45 years at the time of enrolment with signed consent.
  • Adult groups (Female only participants): Must be non-pregnant (as demonstrated by a negative urine pregnancy test) and willing to use an effective form of . Or if they agree to an extended period of follow-up of up to 5.5 years, use an effective form of contraception during the first year of enrolment in the study).
  • Paediatric groups: Healthy male or female young children aged 2-6 years at the time of enrolment with signed consent obtained from parents or guardians.
  • Paediatric groups: completion of the Expanded Programme on Immunisation (EPI) at least 6 months prior to study enrolment.
  • Planned long-term (at least 61 months from the date of the first vaccination) or permanent residence in Bagamoyo town.
  • Adults with a (BMI) 18 to 35 Kg/m2; or young children with Z-score of weight-for-age within ±2SD.
  • Correctly answer all 10 questions on the protocol and study procedures understanding questionnaire within 2 attempts.

Exclusion criteria

Exclusion Criteria:

  • congenital abnormalities as judged by the PI or other delegated individual.
  • Clinically significant history of skin disorder, allergy, cardiovascular disease, respiratory disease, endocrine disorder, liver disease, renal disease, gastrointestinal disease and neurological illness which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data as judged by the PI or other delegated individual.
  • Any confirmed or suspected or immunodeficient state, including infection; asplenia; recurrent, severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months (inhaled and topical are allowed).
  • Any condition which would place the individual at elevated risk of serious COVID-19 infection, or any other factor which may make the individual eligible for priority COVID-19 vaccination (i.e. ahead of others in their age group).
  • History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
  • History of allergic disease or reactions likely to be exacerbated by any component of the vaccines, including IRVs e.g. amphotericin B, chlortetracycline, neomycin, polymyxin, streptomycin
  • Any history of anaphylaxis in relation to vaccination.
  • Clinically significant laboratory abnormality as judged by the PI or other delegated individual.
  • Receipt of any previous rabies vaccinations, including an incomplete course.
  • History of vaccination with previous adenoviral vectored vaccines in the 6 months prior to enrolment in the study, or of vaccination with any other vaccine (including non-adenovirus-vectored COVID-19 vaccines) in the 28 days prior to enrolment.
  • Planned / likely receipt of any other vaccine within 28 days after enrolment.
  • History of bleeding disorder (e.g., factor deficiency, coagulopathy or disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture, or continuous anticoagulation e.g., with warfarin
  • History of confirmed major thrombotic event, (including cerebral venous sinus thrombosis, deep vein thrombosis, pulmonary embolism) or,
  • History of antiphospholipid syndrome.
  • History of prior receipt of unfractionated heparin
  • History of heparin induced thrombocytopenia
  • Receipt of any blood products/ immunoglobulins within the three months preceding the planned administration of the vaccine candidate.
  • Participation in another research study involving receipt of an product in the 30 days preceding enrolment, or planned use during the study period.
  • Seropositive for surface antigen (HBsAg) or (HCV IgG).
  • Likelihood of travel away from the study area.
  • Female participant who is pregnant, lactating or planning pregnancy during the course of the trial.
  • Scheduled elective surgery or other procedures requiring general anaesthesia during the trial.
  • Any other significant disease, disorder or situation which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.
  • to use of paracetamol
Terms in these criteria, in plain language(11)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Sequential assignment
Masking
None (open label)
Enrollment
174 participants (actual)

Study arms

  • Experimental
    Group AC1 (Adult low dose)

    Volunteers aged 18-45 years. Volunteers will receive a standalone dose of 2.5×10\^10 vp ChAdOx2 RabG on D0. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    Group AC2 (Adult high dose)

    Volunteers aged 18-45 years. Volunteers will receive a standalone dose of 5×10\^10 vp ChAdOx2 RabG. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    Group AC3 (Adult preferred dose)

    Volunteers aged 18-45 years. Volunteers will receive a preferred dose of ChAdOx2 RabG on D0. The adult preferred dose will be 2.5×10\^10 vp OR 5×10\^10 vp. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    Group AV1 (Adult single-visit Verobab)

    Volunteers aged 18-45 years. Volunteers will receive Rabies IRV on D0. Volunteers will receive two further doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: Inactivated Rabies Vaccine

  • Experimental
    PC1a (Paediatric low dose)

    Volunteers aged 2-6 years. Volunteers will receive a standalone dose of 1×10\^10 vp ChAdOx2 RabG on D0. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    PC1b (Paediatric low dose)

    Volunteers aged 2-6 years. Volunteers will receive a half adult preferred dose of ChAdOx2 RabG on D0. The adult preferred dose will be 2.5×10\^10 vp OR 5×10\^10 vp. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    PC2 (Paediatric high dose)

    Volunteers aged 2-6 years. Volunteers will receive a full adult preferred dose of ChAdOx2 RabG on D0. The adult preferred dose will be 2.5×10\^10 vp OR 5×10\^10 vp. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    PC3 (Paediatric preferred dose)

    Volunteers aged 2-6 years. Volunteers will receive a paediatric preferred dose of ChAdOx2 RabG on D0. The paediatric preferred dose will be 50-100% of the adult preferred dose. Volunteers will receive two doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: ChAdOx2 RabG · Biological: Inactivated Rabies Vaccine

  • Experimental
    PV1 (Paediatric single-visit Verobab)

    Volunteers aged 2-6 years. Volunteers will receive Rabies IRV (Verorab) as a 2 site ID on D0. Volunteers will receive two further doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: Inactivated Rabies Vaccine

  • Experimental
    PV2 (Paediatric two-visit Verobab)

    Volunteers aged 2-6 years. Volunteers will receive Rabies IRV (Verorab) as a 2 site ID on D0. Volunteers will receive two further doses of Rabies IRV as simulated post-exposure prophylaxis (SPEP), 14 days apart during the follow-up period. All participants will receive Verorab as a 4 site ID on SPEP+0, and Verorab as a 2 site ID on SPEP+14. Participants who return a virus neutralising antibody (VNA) result below 0.5IU/mL will be randomised (1:1 ratio) for the SPEP+0 visit to happen at the next available visit or at the final annual visit. Any participants who do not return a VNA result below 0.5IU/mL will have their SPEP+0 visit take place at the final annual visit.

    Biological: Inactivated Rabies Vaccine

Interventions

  • BiologicalChAdOx2 RabG

    Single dose of ChAdOx2 RabG at different concentrations: 1x10\^10 and 5x10\^10

  • BiologicalInactivated Rabies Vaccine

    A complete pre-exposure prophylactic course of an existing rabies vaccine, ≥2.5 international units

    Also known as: Verorab

06

What researchers measure

Primary outcomes

  1. Safety profile of ChAdOx2 RabG in healthy adult volunteers (18-45 years) and young children (2-6 years) residing in a rabies-endemic country assessed by the occurrence of solicited adverse events.

    Occurrence of solicited local and systemic adverse events (i.e: pain, redness, swelling and pruritus at injection site and temperature, feverishness, myalgia, arthralgia, malaise, headache, fatigue and nausea).

    Time frame: Assessment of solicited AEs in the first 7 days post vaccination

  2. Safety profile of ChAdOx2 RabG in healthy adult volunteers (18-45 years) and young children (2-6 years) residing in a rabies-endemic country assessed by the occurrence of solicited adverse events.

    Occurrence of unsolicited local and systemic adverse events

    Time frame: Unsolicited AEs to be assessed up to 28 days post vaccination

  3. Safety profile of ChAdOx2 RabG in healthy adult volunteers (18-45 years) and young children (2-6 years) residing in a rabies-endemic country assessed by the occurrence of solicited adverse events.

    Occurrence of serious adverse events

    Time frame: SAEs will be collected from enrolment until the end of the follow-up period (Day 1839)

  4. Safety profile of ChAdOx2 RabG in healthy adult volunteers (18-45 years) and young children (2-6 years) residing in a rabies-endemic country assessed by the occurrence of solicited adverse events.

    Occurrence of laboratory adverse events defined as clinically significant changes from baseline. Haematology (Full Blood Count) and Biochemistry (Kidney and Liver Function Tests) will be assessed.

    Time frame: Clinical Laboratory AEs to be assessed up to 28 days post vaccination

Secondary outcomes

  1. Immunogenicity of ChAdOx2 RabG administered to adults and young children residing in a rabies endemic country following primary vaccination, including the length of response maintenance, and secondary (recall) response.

    Rapid fluorescent focus inhibition test (RFFIT) of rabies virus neutralising antibody

    Time frame: At Days 0, 28, 56, 186, 365, 730, 1095, 1460, 1825

  2. Comparison of immunogenicity of ChAdOx2 RabG with a single visit two site intradermal IRV PrEP regimen

    Anamnestic rabies virus neutralising antibody response as assessed by rapid fluorescent focus inhibition test (RFFIT), at 7 days following simulated rabies virus exposure through IRV administration

    Time frame: At days SPEP+0 and SPEP+7

07

Study locations

1 site
  • IHI Clinical Trial Facility
    Bagamoyo, Tanzania
08

References and documents

Publications

  • Ritchie AJ, Hassan O, Urasa N, Apanga PA, Kimathi R, Kalinga WF, Mtaka IM, Lyimo RG, Shabani MM, Orliacq F, Berg A, Xiang Z, Ahmed S, Athuman T, Ertl HCJ, Olotu A, Douglas AD; RAB002 study team. Safety and immunogenicity of a single-dose adenovirus-vectored rabies vaccine over 1 year in adults and children in Tanzania: interim data from an ongoing, partly randomised, controlled, phase 1b/2 trial. Lancet Infect Dis. 2026 Apr 28:S1473-3099(26)00071-X. doi: 10.1016/S1473-3099(26)00071-X. Online ahead of print. PubMed 42066780 ↗

Individual participant data

Plan to share: Yes — Deidentified participant data will be made available on direct request to the Principal Investigator. Proposals will be reviewed by the sponsor, Principal Investigator, and collaborators on the basis of scientific merit. Data will be shared following approval of the proposal and signed data-access agreements.

Supporting information: Study protocol, Statistical analysis plan, Informed consent form

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Started Feb 2022 (actual). Primary completion is estimated for Sep 2028, 79 months after the start.

How these figures are worked out, and which studies are left out of them.

Registered
Feb 10, 2020
First posted
Feb 17, 2020
StartActual
Feb 17, 2022
Primary completionEst.
Sep 2028
CompletionEst.
Sep 2028
Last update
Nov 18, 2025
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Nov 18, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04270838
Collaborators
Ifakara Health Institute
Responsible party
Sponsor
First posted
Feb 17, 2020
Start date
Feb 17, 2022
Primary completion
Sep 2028 (estimated)
Completion
Sep 2028 (estimated)
Last update
Nov 18, 2025

Study contacts

Alexander D Douglas
principal investigator · Jenner Institute

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.

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