An Immunogenicity and Safety Trial of MVA-BN in Adults Living With HIV for the Prevention of Mpox Infection, in Kinshasa, DRC (Mbote-HIVAX)

The Mpox Biology, Outcome, Transmission and Epidemiology Project - HIV Immunization and Vaccination Against Mpox eXposure Trial

This is an open-label, phase 2, immunogenicity and safety trial of the MVA-BN vaccine for the prevention of mpox in adults living with HIV with different level of CD4 counts in Kinshasa, DRC.

The study team aims to investigate whether the administration of 2 standard subcutaneous doses of the Modified Vaccinia Ankara of Bavarian Nordic (MVA-BN) vaccine given 28 days apart, is immunogenic and safe when administered to People Living with HIV (PLHIV) with different levels of CD4 counts in the Democratic Republic of the Congo (DRC).

Enrollment will be stratified according to three different subgroups based on CD4 counts assessed during visit 1A: <200 cells/µL; 200 to 499 cells/µL; ≥ 500 cells/µL. A total of 600 participants will be included in the trial, with 200 participants per subgroup.

All participants will be invited to 6 trial visits over a period of 7 months.

This study will take place in cooperation with the National Programme for the Fight against AIDS (PNLS), the 'Programme Elargi de Vaccination (PEV)' and the 'Institut National de Santé Publique (INSP)'. As part of the response to the current mpox epidemic in DRC, a large cohort of about 10,000 individuals living in Kinshasa will be vaccinated in this program. Vaccination will take place in the Centre Hospitalier Kabinda (CHK) and the Pakadjuma Health Centre. All people living with HIV (PLHIV) with the intention to be vaccinated in the CHK, will be asked for their willingness to participate in the MBOTE-HIVAX clinical trial until the sample size of 600 participants needed for this clinical trial is reached.

Study Overview

• Status: Active, not recruiting
• Conditions: Mpox (Monkeypox)
• Intervention / Treatment: Biological: Mpox vaccination with MVA-BN

• Study Type: Interventional
• Enrollment (Estimated): 600
• Phase: Phase 2

Contacts and Locations

Study Locations

• Democratic Republic of the Congo
  • Kinshasa, Democratic Republic of the Congo
    • Centre Hospitalier Kabinda

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥ 18 years and ≤ 45 years at time of informed consent
• Able and willing to provide written informed consent
• Infected with HIV and receiving combination antiretroviral therapy (ART) for ≥ 8 weeks prior to study entry and vaccination
• Preparedness to follow the study schedule
• Willingness to use contraception for 1 month after each vaccination (only for women of childbearing potential)

Exclusion Criteria:

• A known history of mpox and/or smallpox
• A known history of vaccination with 1st, 2nd or 3rd generation smallpox vaccines, or vaccine platforms that contain MVA as a vector
• Planned MVA-based vaccination (other than study vaccination) during the trial
• Close contact to a confirmed mpox case in the 3 weeks prior to study enrollment
• Uncontrolled severe infection or other condition requiring hospitalization
• Pregnancy
• History of anaphylaxis or severe allergic reaction to any vaccine or known allergy to one of the components of the study vaccine

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: CD4 <200; Participants in this arm are stratified in the group with participants with a CD4 level below 200cells/µL.	Biological: Mpox vaccination with MVA-BN; All participants will be vaccinated on day 0 with the MVA-BN vaccine followed by a second injection on day 28.
Experimental: CD4 200-499; Participants in this arm are stratified in the group with participants with a CD4 level between 200 and 499 cells/µL.	Biological: Mpox vaccination with MVA-BN; All participants will be vaccinated on day 0 with the MVA-BN vaccine followed by a second injection on day 28.
Experimental: CD4 >= 500; Participants in this arm are stratified in the group with participants with a CD4 level of 500cells/µL or more.	Biological: Mpox vaccination with MVA-BN; All participants will be vaccinated on day 0 with the MVA-BN vaccine followed by a second injection on day 28.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Seroconversion rates for monkeypox virus (MPXV) neutralizing antibodies	Seroconversion two weeks after administration of two standard doses of MVA-BN, defined as either the appearance of an MPXV neutralizing antibody titre (NT50) greater than or equal to the detection limit for initially seronegative participants or more than doubling of the antibody titre compared to baseline for participants seropositive at baseline	2 weeks after the last vaccine dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety and reactogenicity of the MVA-BN vaccine in PLHIV	Solicited local AEs (pain, redness, swelling, induration, and itch at the injection site) and systemic AEs (generalized myalgia, headache, fatigue, nausea and/or vomiting, chills and/or fever (≥ 38.0°C)) up to day 14 post vaccination Unsolicited AEs up to day 14 post vaccination SAEs until the end of participation	Up to day 14 and until end of participation
Seroconversion rates for vaccinia virus (VACV) neutralizing antibodies	Seroconversion two weeks after administration of two standard doses of MVA-BN, defined as either the appearance of an VACV neutralizing antibody titre (NT50) greater than or equal to the detection limit for initially seronegative participants or more than doubling of the antibody titre compared to baseline for participants seropositive at baseline.	2 weeks after last vaccine dose
Waning of MPXV neutralizing antibodies in PLHIV	The ratio between neutralizing antibody titre against MPXV at 6 months (D28 + 6M) versus 14 days (D28 + 14 days) after administration of two standard doses of MVA-BN.	On day 14 and month 6
Waning of VACV neutralizing antibodies in PLHIV	The ratio between neutralizing antibody titre against VACV at 6 months (D28 + 6M) versus 14 days (D28 + 14 days) after administration of two standard doses of MVA-BN.	On day 14 and month 6
Seroconversion rates and IgG antibody titre dynamics against MPXV and VACV antigens in serum	The absolute IgG antibody titre against the following antigens: A35R, H3L, B2R, A5L, A27L, B6R, E8L and A29L from mpox, and A33R and B5 from vaccinia virus at D14, D28 (second dose), D28+14d, D28+6M after administration of two standard doses of MVA-BN, be defined as either the appearance of Median Fluorescent Values (MFI) greater than the detection limit for initially seronegative participants or more than doubling of the antibody titre compared to baseline for participants seropositive at baseline.	day 0 (prior to first dose), Day14, Day 28, Day 28+14 days, Day 28+6Months

Collaborators and Investigators

• Sponsor: Institute of Tropical Medicine, Belgium
• Collaborators: Institut National pour la Recherche Biomedicale (INRB); MSF Médecins Sans Frontières Belgium
• Investigators: Principal Investigator: Laurens Liesenborghs, MD, Institute of Tropical Medicine

Study record dates

Study Major Dates

• Study Start (Actual): August 4, 2025
• Primary Completion (Estimated): May 20, 2026
• Study Completion (Estimated): November 30, 2026

Study Registration Dates

• First Submitted: February 17, 2025
• First Submitted That Met QC Criteria: February 17, 2025
• First Posted (Actual): February 21, 2025

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Vaccination; MVA-BN; Mpox
• Additional Relevant MeSH Terms: Infections; Virus Diseases; Poxviridae Infections; DNA Virus Infections; Animal Diseases; Primate Diseases; Rodent Diseases; Mpox, Monkeypox; Anti-Infective Agents; Antiviral Agents; smallpox and monkeypox vaccine modified vaccinia ankara-bavarian nordic
• Other Study ID Numbers: Mbote-HIVAX

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No