MonkeypoxM-BOOST-FRNCT06885853
Evaluation of Long-term Immunogenicity of a Boost Dose of MVA-BN Vaccine
An observational study of Monkeypox, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
This study is to evaluate the long-term immunogenicity of a boost dose of MVA-BN vaccine Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Monkeypox
- How many people
- 90 participants
- Where
- 1 siteFrance
- Study dates
- 7 May 2025to Nov 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will consist of Men who have Sex with Men (MSM), taking HIV pre-exposure prophylaxis (HIV PrEP), eligible for MVA-BN vaccination.
Who may be able to join
- Men aged over 18 years
- Have received two doses of MVA-BN vaccine as an initial schedule
- Eligible for a booster dose of MVA-BN (according to the HAS recommendation)
- Be eligible and wish to initiate PrEP-HIV treatment or be followed for PrEP-HIV treatment
- Covered by social security (excluding AME)
Who cannot join
- History of mpox (virologically confirmed)
- Be under guardianship or curatorship
- Be subject to a judicial protection measure
- Have a contraindication to vaccination against mpox
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site, 1 recruiting
- Recruiting
CIC 1417Cochin-Pasteur
Paris, Paris, 75679
Liem Binh Luong Nguyen, Degree medical doctor, 0033 1 58 41 28 58, liem.luong@aphp.fr
Odile LAUNAY, PUPH, 00 33 1 58 41 28 58, odile.launay@aphp.fr
About this study
This study is to evaluate the long-term immunogenicity of a boost dose of MVA-BN vaccine
Read the detailed description
Mpox is an endemic zoonosis in Africa, caused by the MPXV virus of which there are two clades: I (former Congo Basin) and II (former West Africa). Since 2022, clade II has emerged globally via sexual transmission, primarily among men who have sex with men (MSM), resulting in a declaration of public health emergency (PHEIC) by the WHO.
In 2023, a clade I epidemic emerged in East Africa with a high case fatality rate (3-5%). In August 2024, the WHO again declared a PHEIC after the spread of clade I to African countries with no previously reported cases and outside Africa, raising fears of higher mortality and transmission.
A 3rd generation vaccine, MVA-BN (Imvanex® /Jynneos®), initially developed against smallpox, was approved in 2022 to prevent mpox. In France, the HAS recommends post- and pre-exposure vaccination for populations at risk: MSM, trans people with multiple partners, sex workers and certain professionals. For people born before 1980 (history of smallpox vaccination), a single dose is recommended as primary vaccination, while immunocompromised subjects require 3 doses.
Data show vaccine effectiveness of 20-80% in post-exposure prophylaxis (PEP) and ~80% in pre-exposure but neutralizing antibodies become undetectable after one year. Since the summer of 2024, the HAS has recommended a booster dose 2 years after the primary vaccination, on the basis of immunogenicity studies showing an increase in seroconversion to 98.7% one month after administration, but underlines the need to have other data, in particular on the durability of this response.
A study is proposed in MSM on HIV PrEP (pre-exposure prophylaxis), a priority population for structured medical monitoring, to evaluate the immunogenicity and safety of the MVA-BN booster in this context.
- Conditions
- Monkeypox
- Keywords
- Monkeypox, MVA-BN booster vaccine, HIV pre-exposure prophylaxis
- Medical subject headings
- Mpox, Monkeypox
What is being measured
The primary outcome is the main question the study is designed to answer.
Immunogenicity a of a booster dose of MVA-BN vaccine
To evaluate the immunogenicity at 12 months of a booster dose of MVA-BN vaccine administered subcutaneously in HIV PrEP users.
Measured: 12 months
Secondary outcomes (3)
Persistence of humoral immunogenicity
Evaluate the persistence of humoral immunogenicity at 24 months of a booster dose, depending on the number of doses and the interval between doses
Measured: 24 months
Kinetics of the humoral response
Study the kinetics of the humoral response as a function of the number of doses and the interval between doses
Measured: 24 months
Description of cases of Mpox infection
Describe cases of Mpox infection based on number of doses and dose interval up to 24 month
Measured: 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Mar 2025
- Study start7 May 2025
- Primary completionNov 2026 (estimated)
- Study completionNov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MonkeypoxStudies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 90 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Liem Binh Luong Nguyen, Degree medical doctor, Principal investigator, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06885853
- Sponsor's protocol ID
- APHP250053
- Other IDs
- IDRCB:2025-A00095-44
- Acronym
- M-BOOST-FR
- Status last verified
- May 2025
- First submitted
- 13 Mar 2025
- Last updated
- 15 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Long-term Immunogenicity of a Boost Dose of MVA-BN Vaccine
- ClinicalTrials.gov ID
- NCT06885853
- Acronym / sponsor ID
- M-BOOST-FR / APHP250053
- Conditions
- Monkeypox
- Keywords
- Monkeypox, MVA-BN booster vaccine, HIV pre-exposure prophylaxis
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 90 participants (estimated)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Study start
- 7 May 2025 (actual)
- Primary completion
- Nov 2026 (estimated)
- Study completion
- Nov 2027 (estimated)
- First posted
- 20 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is to evaluate the long-term immunogenicity of a boost dose of MVA-BN vaccine
Detailed description
Mpox is an endemic zoonosis in Africa, caused by the MPXV virus of which there are two clades: I (former Congo Basin) and II (former West Africa). Since 2022, clade II has emerged globally via sexual transmission, primarily among men who have sex with men (MSM), resulting in a declaration of public health emergency (PHEIC) by the WHO.
In 2023, a clade I epidemic emerged in East Africa with a high case fatality rate (3-5%). In August 2024, the WHO again declared a PHEIC after the spread of clade I to African countries with no previously reported cases and outside Africa, raising fears of higher mortality and transmission.
A 3rd generation vaccine, MVA-BN (Imvanex® /Jynneos®), initially developed against smallpox, was approved in 2022 to prevent mpox. In France, the HAS recommends post- and pre-exposure vaccination for populations at risk: MSM, trans people with multiple partners, sex workers and certain professionals. For people born before 1980 (history of smallpox vaccination), a single dose is recommended as primary vaccination, while immunocompromised subjects require 3 doses.
Data show vaccine effectiveness of 20-80% in post-exposure prophylaxis (PEP) and ~80% in pre-exposure but neutralizing antibodies become undetectable after one year. Since the summer of 2024, the HAS has recommended a booster dose 2 years after the primary vaccination, on the basis of immunogenicity studies showing an increase in seroconversion to 98.7% one month after administration, but underlines the need to have other data, in particular on the durability of this response.
A study is proposed in MSM on HIV PrEP (pre-exposure prophylaxis), a priority population for structured medical monitoring, to evaluate the immunogenicity and safety of the MVA-BN booster in this context.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will consist of Men who have Sex with Men (MSM), taking HIV pre-exposure prophylaxis (HIV PrEP), eligible for MVA-BN vaccination.
Key inclusion criteria (5 listed)
- Men aged over 18 years
- Have received two doses of MVA-BN vaccine as an initial schedule
- Eligible for a booster dose of MVA-BN (according to the HAS recommendation)
- Be eligible and wish to initiate PrEP-HIV treatment or be followed for PrEP-HIV treatment
- Covered by social security (excluding AME)
Key exclusion criteria (4 listed)
- History of mpox (virologically confirmed)
- Be under guardianship or curatorship
- Be subject to a judicial protection measure
- Have a contraindication to vaccination against mpox
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Immunogenicity a of a booster dose of MVA-BN vaccine
Time frame: 12 months
To evaluate the immunogenicity at 12 months of a booster dose of MVA-BN vaccine administered subcutaneously in HIV PrEP users.
3 secondary outcomes
Persistence of humoral immunogenicity
Time frame: 24 months
Kinetics of the humoral response
Time frame: 24 months
Description of cases of Mpox infection
Time frame: 24 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2025.
- Individual participant dataSharing planned: No
Related trials for Monkeypox
RecruitingObservational study
Evaluation of Effectiveness and Safety of LC16m8 Mpox Vaccine in the Democratic Republic of Congo (DRC)
Mpox (Monkeypox), Mpox
Enrolling by invitationObservational study
New York City Observational Study of Mpox Immunity
Monkeypox, Mpox
Enrolling by invitation
Smart Analysis and Decision-Making for Emerging Infectious Diseases
Emerging Infectious Diseases, COVID-19
Active, not recruitingPhase 4
Smallpox Vaccine for Mpox Post-Exposure Prophylaxis: A Cluster RCT
Monkeypox
RecruitingPhase 2
A Randomized Clinical Trial Investigating the Safety, Reactogenicity, and Immunogenicity After Immunization With an mRNA-based Mpox Vaccine Candidate in Africa
Mpox (Monkeypox), Smallpox
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Liem Binh Luong Nguyen, Degree medical doctor principal investigator
Assistance Publique - Hôpitaux de Paris
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Monkeypox, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Liem Binh Luong Nguyen, Degree medical doctor (0033 1 58 41 28 58, liem.luong@aphp.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Immunogenicity a of a booster dose of MVA-BN vaccine (time frame: 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2025; AzTrials last refreshed its copy on 7 Nov 2026.