Monkeypox
Conditions
Keywords
Monkeypox, MVA-BN booster vaccine, HIV pre-exposure prophylaxis
Brief summary
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.
Interventions
None listed
Sponsors
Assistance Publique - Hôpitaux de Paris
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* 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)
Exclusion criteria
* History of mpox (virologically confirmed) * Be under guardianship or curatorship * Be subject to a judicial protection measure * Have a contraindication to vaccination against mpox
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Immunogenicity a of a booster dose of MVA-BN vaccine | 12 months | To evaluate the immunogenicity at 12 months of a booster dose of MVA-BN vaccine administered subcutaneously in HIV PrEP users. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Persistence of humoral immunogenicity | 24 months | Evaluate the persistence of humoral immunogenicity at 24 months of a booster dose, depending on the number of doses and the interval between doses |
| Kinetics of the humoral response | 24 months | Study the kinetics of the humoral response as a function of the number of doses and the interval between doses |
| Description of cases of Mpox infection | 24 months | Describe cases of Mpox infection based on number of doses and dose interval up to 24 month |
Countries
France
Contacts
Primary ContactLiem Binh Luong Nguyen, Degree medical doctor
Backup ContactOdile LAUNAY, PUPH
Outcome results
None listed