Mpox Biology, Outcome, Transmission and Epidemiology - Tracking the Immune Response After mpoX vaCcination (MBOTE-TRAXX): Clinical Study to Monitor the Immunological Response Following Mpox Vaccination in the City of Kinshasa, Democratic Republic of the Congo

NCT07499739 | Active Not Recruiting Phase 4

• 1 other identifier: 1998/26
• Study Type: interventional
• Target: 300
• Locations: 1 country
• Sites: 3

Brief Summary

The study Mbote-TRAXX evaluates humoral and cellular immune responses in individuals vaccinated against mpox with the MVA-BN or LC16m8 vaccine administered as part of a routine mpox vaccination campaign in Kinshasa, Democratic Republic of the Congo (DRC). Participants will be followed up at multiple time points after vaccination in order to assess the kinetics and durability of the immune response by collection of blood samples. It is planned to include approximately 150 participants vaccinated with MVA-BN and 150 participants vaccinated with LC16m8.

Conditions

Mpox

Keywords

mpox vaccines

Outcome Measures

Primary Outcomes (1)

• To estimate the seroconversion rate for neutralising antibodies against the mpox virus (MPXV) 28 days after administration of an mpox vaccine (MVA-BN or LC16m8)

  Seroconversion 28 days after administration of an mpox vaccine, defined as the appearance of an MPXV neutralizing antibody titer (NT50) greater than or equal to the limit of detection in participants who were seronegative at baseline, or at least a two-fold increase in the antibody titer compared to baseline (Day 0) in participants who were seropositive at inclusion

  Day 28 after inclusion

Secondary Outcomes (8)

• To estimate the positivity rate for neutralizing antibodies against MPXV 59 days and 8 months after administration of an mpox vaccine (MVA-BN or LC16m8).

  Day 59 and Month 8

• To analyze the longitudinal evolution of neutralizing antibody titers against MPXV between Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8).

  Day 0, Day 28, Day 59 and Month 8

• To estimate the positivity rate for binding antibodies (IgG) against MPXV at all sampling time points: Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8).

  Day 0, Day 28, Day 59, Month 8, Month 16 and Month 24

• To analyze the longitudinal evolution of binding antibody (IgG) titers against MPXV between Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8).

  Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

• To identify factors associated with weak immune responses, measured by the seroconversion rate of neutralizing antibodies at Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8).

  Day 0, Day 28, Day 59, and Month 8

Other Outcomes (3)

• To determine, in a subgroup, the T-cell response induced by the MVA-BN or LC16m8 vaccine at Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24.

  Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

• To compare the seroconversion rates of neutralizing antibodies and binding antibodies (IgG) against MPXV, and of vaccine-induced T lymphocytes, between participants vaccinated with MVA-BN versus LC16m8.

  Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

• To compare the seroconversion rates of neutralizing antibodies and binding antibodies (IgG) against MPXV, and of vaccine-induced T lymphocytes, between naïve participants and those with a history of smallpox/mpox vaccination or prior mpox infection.

  Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

Study Arms (1)

MVA-BN or LC16m8 vaccinated

OTHER

Participants vaccinated with MVA-BN or LC16m8 vaccine during the national vaccination campaign

Procedure: blood sample collection

Interventions

blood sample collection PROCEDURE

10 mL of blood will be collected at every visit and additional 20 mL blood samples will be taken from a subgroup of participants at every visit.

MVA-BN or LC16m8 vaccinated

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Any person aged 18 years old or over at the time of giving informed consent, of any gender
• Participant received the MVA-BN or LC16m8 mpox vaccine as part of the national vaccination campaign
• Participant has the capacity and willingness to give informed written consent
• Participant agrees to adhere to the study's follow-up schedule

Sponsors & Collaborators

• Institute of Tropical Medicine, Belgium: lead
• Programme Elargi de Vaccination de République Démocratique du Congo: collaborator
• National Institute of Public Health of the Democratic Republic of the Congo: collaborator
• Institut National de Recherche Biomédicale (INRB). Kinshasa, Democratic Republic of Congo: collaborator

Study Sites (3)

Centre Convivial Kasa-Vubu

Kinshasa, Democratic Republic of the Congo

Location

Kinoise

Kinshasa, Democratic Republic of the Congo

Location

Kokolo

Kinshasa, Democratic Republic of the Congo

Location

MeSH Terms

Conditions

Mpox, Monkeypox

Condition Hierarchy (Ancestors)

Poxviridae Infections; DNA Virus Infections; Virus Diseases; Infections; Primate Diseases; Animal Diseases; Rodent Diseases

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 24, 2026
• First Posted: March 30, 2026
• Study Start: May 15, 2026
• Primary Completion (Estimated): December 15, 2026
• Study Completion (Estimated): December 15, 2028
• Last Updated: June 11, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

DE (3)