An observational study in Mpox (Monkeypox) and Monkeypox, sponsored by London School of Hygiene and Tropical Medicine. Not yet recruiting at 1 site in Guinea. Per ClinicalTrials.gov, last updated 2026-04-16.
Sponsored by London School of Hygiene and Tropical Medicine · Observational
This study has three primary objectives to address the public health challenges of the Mpox outbreak in Guinea, West Africa. Objective 1 (MOVIE-West Africa) focuses on understanding the kinetics of Monkeypox virus (MPXV) elimination from the human body in Mpox cases. Objective 2 (TRACE-West Africa) aims to determine the MPXV transmission dynamics between Mpox cases and their contacts. Objective 3 (VE-West Africa) examines the vaccine effectiveness of the MVA-BN vaccine in protection against MPXV infection and Mpox disease.
A new outbreak of clade 2b Monkeypox virus (MPXV) was first documented in Guinea in September 2024. This outbreak has a great potential to spread through intimate contact and sexual activity. The public health response to date has focused on reporting and isolation of confirmed cases, contact tracing and testing. In 2025, a donation of the JYNNEOS (modified vaccinia Ankara-Bavaria Nordic; MVA-BN) vaccine was provided to Guinea. It is a live attenuated vaccine licensed as a two-dose vaccine for prevention of Mpox infection. Due to limited vaccine supplies, many governments in West Africa have focused on giving out one dose of the vaccine to individuals at risk.
There is a dearth of information regarding transmission dynamics for clade 2b and vaccine effectiveness in endemic settings in West Africa, in populations with a high prevalence of other comorbidities and infections such as malaria. Given the current mpox outbreak's public health significance for Guinea, there is a need for comprehensive research in this endemic setting to better understand disease pathogenesis, transmission dynamics and effective control and prevention measures for clade 2b outbreaks. We have an opportunity to conduct this key research now to inform the public health measures for the current Guinea Mpox outbreak.
This study has three linked objectives to address the public health challenge of Mpox in Guinea. Objective 1 (MOVIE-West Africa) focuses on understanding the kinetics of viral elimination, shedding light on how MPXV interacts with host tissues and immune defense, and informing endpoint selection for therapeutic trials. This is important because currently there are significant data gaps in MPXV viral dynamics and transmission patterns to inform control measures for clade 1a and clade 2b in endemic settings. There are no data regarding the dynamics of viral clearance in clade 2b cases from endemic countries in West Africa. Understanding the kinetics of viral clearance is crucial for advising the Guinea government and other countries on clinical management practice and the duration of isolation protocols.
Objective 2 (TRACE-West Africa) aims to determine the secondary attack rate (SAR), assessing host susceptibility and offering vital data to target interventions towards vulnerable groups and informing vaccine efforts by contributing to the assessment of vaccine efficacy endpoints. Understanding the SAR has important implications for controlling the outbreak. By quantifying the risk of secondary transmission, SAR data can guide decisions on the prioritization of contact tracing efforts, deployment of healthcare personnel, distribution of medical supplies to mitigate further infections and inform development and adjustment of isolation and quarantine policies. High SAR values suggest a greater likelihood of secondary transmission, prompting stricter isolation measures and longer quarantine periods for contacts of mpox cases. Conversely, low SAR values may indicate that existing control measures are effective, allowing for more targeted interventions.
Objective 3 (VE-West Africa) examines the vaccine effectiveness of the MVA-BN vaccine in protection against MPXV infection and Mpox disease. The JYNNEOS vaccine is recommended as a prophylactic two-dose regimen for maximum protection against MPXV infection. Given the limited global vaccine supply, the country has taken a decision to proceed with an alternative one-dose schedule for at-risk individuals. This study will use the opportunity to measure MVA-BN vaccine effectiveness against clade 2b, the first time that this is being conducted in a clade 2b Mpox endemic country in sub-Saharan Africa. Importantly, our SAR data will be instrumental for this third objective and for future vaccine efficacy trials and vaccination campaigns and will help guide decisions on the deployment and prioritization of vaccines in Mpox outbreaks.
The MOVIE-TRACE-West Africa study will generate comprehensive evidence on clade 2b MPXV viral clearance, transmission pattern and vaccine effectiveness to guide rapid response and control policies in Guinea and other Mpox affected countries.
72 studies on the registry are indexed under Mpox, Monkeypox; 30 are open to participants now.
This study's planned enrollment of 992 is above the median of 224 across 34 observational studies indexed under Mpox, Monkeypox.
Browse Mpox, Monkeypox studies →London School of Hygiene and Tropical Medicine is the lead sponsor of 298 studies on the registry; 15 are open to participants now.
Counted across the registry records on this site, refreshed daily.
All individuals regardless of age or sex, who either have confirmed MPXV infection or have close contacts with a confirmed Mpox case.
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.
MOVIE-West Africa
TRACE-West Africa
VE-West Africa
Exclusion Criteria:
(1) MOVIE-West Africa
Individuals with a confirmed alternative diagnosis explaining their illness.
(3) VE-West Africa
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.
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.
Confirmed Mpox cases
Contacts of a MOVIE case
Confirmed Mpox cases and their contacts
Viral clearance in oropharyngeal swabs
Time to viral clearance in oropharyngeal swabs (number of days from onset of symptoms to first negative PCR result).
Time frame: From day 1 to day 56
Secondary attack rate of infection
Estimation of Secondary Attack Rate of infection (SAR-i), the proportion of contacts who become infected (PCR positive), regardless of exhibiting symptoms.
Time frame: From day 1 to day 14
Secondary attack rate of disease
Estimation of Secondary attack rate of disease (SAR-d), the proportion of contacts who become infected (PCR positive) and develop symptoms.
Time frame: From day 1 to day 28
Viral clearance in skin lesions
Time to viral clearance in skin lesions (number of days from onset of symptoms to first negative PCR result).
Time frame: From day 1 to day 56
Viral clearance in urine
Time to viral clearance in urine (number of days from onset of symptoms to first negative PCR result).
Time frame: From day 1 to day 56
Risk factors of transmission
Identification of factors that influence the risk of transmission
Time frame: From day 1 to day 14
Immunological assessments
Measurement of MPXV-specific antibodies by immunoassays
Time frame: From day 1 to day 56
Plan to share: Undecided — Individual participant data (IPD) will be shared under reasonable request
Start is estimated for Apr 2026; primary completion for Feb 2027, 10 months later.
Of 23 observational studies under Mpox, Monkeypox, half reached primary completion within 18 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 45. This study's planned 10 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
London School of Hygiene and Tropical Medicine →