Evaluate the Safety and Immunogenicity of the MVA-SIBP Vaccine in the Democratic Republic of the Congo

Phase 2 Double-Blind, Randomized, Controlled Study of MVA-SIBP Vaccine for Mpox in Age De-escalation in the Democratic Republic of the Congo

To evaluate the safety and immunogenicity of the MVA-SIBP vaccine using a double-blind, randomized, controlled, age de-escalation design conducted in Kinshasa, Democratic Republic of the Congo (DRC).

Study Overview

• Status: Not yet recruiting
• Conditions: Monkeypox (Mpox)
• Intervention / Treatment: Biological: MVA-SIBP low dose; Biological: MVA-SIBP high dose; Biological: MVA-BN

Detailed Description

Given the urgent need for pediatric data and the high burden of mpox in the DRC, this trial will evaluate the safety and immunogenicity of the MVA-SIBP vaccine using a double-blind, randomized, controlled, age de-escalation design conducted in Kinshasa, DRC. The trial is designed to generate critical data to support regulatory approval and broader access to affordable, stable, and scalable mpox vaccines for Africa.

• Study Type: Interventional
• Enrollment (Estimated): 180
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Dandan Chen; Phone Number: +862162800991; Email: ddchen.sh@sinopharm.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults: 18 to 45 years inclusive at the time of informed consent. Adolescents: 12 to 17 years inclusive at the time of consent/assent. Children: 2 to 11 years inclusive at the time of consent/assent.
• Participant is in good general health as determined by medical history, targeted physical examination, and clinical judgment of the investigator.
• Adults: Able to read and understand the written informed consent, and willing to comply with all study procedures and availability for the entire study duration. Adolescents: Parent(s) or legally acceptable representative(s) able and willing to provide written informed consent; participant able and willing to provide appropriate assent per local regulations and IRB requirements. Children: Parent(s) or legally acceptable representative(s), with the relationship to the child similarly verified and documented on the consent form, and able and willing to provide written informed consent.
• Willing and able to comply with all study procedures, visit schedule, and follow-up requirements as judged by the investigator.
• No history of smallpox or mpox vaccination. No history of confirmed or suspected infection with monkeypox, cowpox, or vaccinia virus.
• Negative serum or urine pregnancy test at screening and prior to each vaccination. Willing to use highly effective contraception from 30 days prior to first vaccination through 60 days after the last dose. Breastfeeding.
• Resides in the study catchment area and has no plans to relocate for the duration of the study. Has reliable access to a telephone and/or other means of contact.
• Adults must have been born in 1980 or later. Able to provide direct written informed consent.
• Adolescents: Able to provide written or written assent as appropriate. Children: Parent(s)/guardian(s) able to provide written informed consent; child able to provide assent if developmentally appropriate.

Exclusion Criteria:

• Any prior smallpox or mpox vaccination. History of confirmed or suspected infection with monkeypox, cowpox, or vaccinia virus.
• Close contact, as defined by WHO.
• Known or suspected immunocompromised state as specified in the protocol.
• Acute febrile illness (≥38.0°C) or clinically significant infection within 72 hours prior to vaccination. Any acute illness requiring systemic therapy or hospitalization within 14 days prior to enrollment.
• History of severe allergy or anaphylaxis to any vaccine or vaccine component. History of severe allergic asthma or asthmatic reactions.
• Pregnant or breastfeeding at screening or planning to become pregnant during the study period.
• Participation in another clinical trial with an investigational product or vaccine within 6 months prior to enrollment or planned during the study.
• Receipt of any live vaccine within 28 days or inactivated vaccine within 14 days prior to enrollment or planned within 28 days after any study vaccination.
• Any medical disease or condition that, in the opinion of the investigator, would place the participant at unacceptable risk, interfere with study objectives, or compromise protocol compliance.
• Blood transfusion within three months before inclusion. Significant laboratory test result abnormalities should be added as exclusion criteria. Any condition that, in the opinion of the investigator, would preclude safe participation or successful completion of the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group 1; MVA-SIBP low dose: low dose monkeypox vaccine produced by Shanghai Institute of Biological Products Co., Ltd. (SIBP)	Biological: MVA-SIBP low dose; Participants received one subcutaneous dose of 0.5ml MVA-SIBP low dose on days 0 and 28, respectively, for a total of two doses.
Experimental: Experimental group 2; MVA-SIBP high dose: high dose monkeypox vaccine produced by Shanghai Institute of Biological Products Co., Ltd. (SIBP)	Biological: MVA-SIBP high dose; Participants received one subcutaneous dose of 0.5ml MVA-SIBP high dose on days 0 and 28, respectively, for a total of two doses.
Active Comparator: Control group; MVA-BN: monkeypox vaccine produced by Bavarian Nordic(BN)	Biological: MVA-BN; Participants received one subcutaneous dose of 0.5ml MVA-BN low dose on days 0 and 28, respectively, for a total of two doses.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Unsolicited adverse events	An unsolicited AE is any AE reported in addition to those solicited during the clinical study.	Day 28 after each dose
Solicited local adverse events	That is frequency of occurrence of events pain, erythema, swelling, induration, pruritus at injection site and recorded by memory aid.	Day 8 after each dose
Solicited systemic adverse events	That is frequency of occurrence of events headache, fatigue, myalgia, fever, chills, nausea and recorded by memory aid.	Day 8 after each dose
Serious Adverse Events(SAEs)	To evaluate the incidence of SAE after vaccination.	Day 365 after the first dose
Adverse Events of Special Interest(AESIs)	To evaluate the incidence of AESI after vaccination.	Day 365 after the first dose
Medically Attended Adverse Events(MAAEs)	To evaluate the incidence of MAAE after vaccination.	Day 365 after the first dose
Grade 3+ related adverse events	Grade 3+ incidence of adverse events related to vaccination.	Day 28 after each dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plaque Reduction Neutralization Test(PRNT) Geometric Mean Titers(GMT) of vaccinia	Neutralizing antibody titer by PRNT against vaccinia virus.	Day 0, 28, 56, 181, 365
PRNTest GMTof mpox	Neutralizing antibody titer by PRNT against mpox virus.	Day 0, 28, 56, 181, 365
Seroconversion rate of vaccinia	Seroconversion rate is ≥4-fold rise in PRNT titer vs. baseline.	Day 28, 56, 181, 365
Seroconversion rate of mpox	Seroconversion rate is ≥4-fold rise in PRNT titer vs. baseline.	Day 28, 56, 181, 365

Collaborators and Investigators

• Sponsor: Shanghai Institute Of Biological Products
• Investigators: Principal Investigator: Hypolite Muhindo Mavoko, University of Kinshasa

Study record dates

Study Major Dates

• Study Start (Estimated): December 31, 2025
• Primary Completion (Estimated): February 28, 2027
• Study Completion (Estimated): February 28, 2027

Study Registration Dates

• First Submitted: November 19, 2025
• First Submitted That Met QC Criteria: November 19, 2025
• First Posted (Actual): November 28, 2025

Study Record Updates

• Last Update Posted (Actual): November 28, 2025
• Last Update Submitted That Met QC Criteria: November 19, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: safety; vaccine; immunogenicity; Monkeypox
• Additional Relevant MeSH Terms: Infections; Virus Diseases; Poxviridae Infections; DNA Virus Infections; Animal Diseases; Primate Diseases; Rodent Diseases; Mpox, Monkeypox; smallpox and monkeypox vaccine modified vaccinia ankara-bavarian nordic
• Other Study ID Numbers: SIBP-V08-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No