A Phase 2 interventional study of Mpox vaccination with MVA-BN in Mpox (Monkeypox), sponsored by Institute of Tropical Medicine, Belgium. Active, not recruiting at 1 site in Democratic Republic of the Congo. Open to participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-05-19.
Sponsored by Institute of Tropical Medicine, Belgium · Phase 2, Interventional, and Prevention
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.
72 studies on the registry are indexed under Mpox, Monkeypox; 30 are open to participants now.
This study's planned enrollment of 600 is above the median of 305 across 36 interventional studies indexed under Mpox, Monkeypox.
Browse Mpox, Monkeypox studies →Institute of Tropical Medicine, Belgium is the lead sponsor of 104 studies on the registry; 21 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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.
Exclusion Criteria:
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
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.
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.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm are stratified in the group with participants with a CD4 level below 200cells/µL.
Biological: Mpox vaccination with MVA-BN
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
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.
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
Time frame: 2 weeks after the last vaccine dose
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
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: day 0 (prior to first dose), Day14, Day 28, Day 28+14 days, Day 28+6Months
Plan to share: Yes
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
No publications or documents are linked to this record.
Started Aug 2025 (actual). Primary completion is estimated for May 2026, 9 months after the start.
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This study is active, not recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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Institute of Tropical Medicine, Belgium →