An observational study in Monkeypox (Mpox), sponsored by Osaka Metropolitan University. Enrolling by invitation at 1 site in Democratic Republic of the Congo. Per ClinicalTrials.gov, last updated 2025-07-16.
Sponsored by Osaka Metropolitan University · Observational
The goal of this observational study is
Mpox is caused by the monkeypox virus (MPXV), a member of the genus Orthopoxvirus (family Poxviridae). This virus is closely related to the variola virus, which causes smallpox. MPXV was first identified in 1958, and the first human case was reported in the Democratic Republic of the Congo (DRC) in 1970. It was presumed that the smallpox (vaccinia) vaccine would confer cross-protection against mpox. Following the global eradication of smallpox in 1980, mpox remained largely confined to limited regions in Central Africa-where zoonotic spillover from wild animal reservoirs constituted the primary route of transmission. Equateur Province is among the areas in the DRC with a notably high burden of reported mpox cases.
Over the past five decades, routine smallpox vaccination ceased worldwide, resulting in waning herd immunity against orthopoxviruses. During this period, mpox incidence rose markedly, with an estimated tenfold increase in global cases. Two principal genetic clades of MPXV have been identified: clade I (historically referred to as the Congo Basin clade) and clade II (the West African clade). In 2018, Nigeria experienced a resurgence of mpox, highlighting the virus's potential to emerge in previously controlled areas. Starting in 2022, clade II mpox circulated globally, especially among men who have sex with men (MSM), peaking in mid-2022 before declining to persistently lower levels by early 2023. Although clade II mpox typically exhibits a low case-fatality ratio (\<1%), clade I has historically been associated with more severe disease and higher mortality. In 2023, the number of reported mpox cases continued to climb in the DRC, prompting the World Health Organization (WHO) to declare a Public Health Emergency of International Concern (PHEIC) in August 2024.
Recent surveillance indicates that sub-clade Ia MPXV is spreading in western DRC through multiple transmission modes, including contact with infected wild animals, household exposure, or sexual contact. By contrast, sub-clade Ib mpox in the eastern part of the country appears initially to spread via intimate or sexual contact between adults, followed by household transmission. Numerous environmental and social risk factors-including the consumption of rodent species, deforestation, climate change, civil unrest, population displacement, emerging MPXV variants, and weakened immunity-may be driving mpox incidence. Clade Ia mpox is currently affecting western parts of the DRC, yet the epidemiology remains poorly understood due to the limited number of laboratory-confirmed cases.
This study aims to better understand the dominant modes of transmission of Mpox in Equateur Province in DRC and to estimate the extent of transmission among contacts by determining the secondary infection rate for human-to-human transmission at an indicidual level and identifying factors associated with secondary infections. The findings will advance understanding of mpox transmission dynamics, ultimately informing more effective prevention and control strategies in endemic settings.
72 studies on the registry are indexed under Mpox, Monkeypox; 30 are open to participants now.
This study's planned enrollment of 122 is below the median of 224 across 34 observational studies indexed under Mpox, Monkeypox.
Browse Mpox, Monkeypox studies →Osaka Metropolitan University is the lead sponsor of 6 studies on the registry; 5 are open to participants now.
Counted across the registry records on this site, refreshed daily.
This study targets laboratory-confirmed cases of mpox and their contacts, defined based on exposure to the primary case within the household or in external settings (e.g., workplaces, social interactions).
This study targets patients reported as suspected mpox cases (all ages, both sexes) to the Health District Central Office in the selected sites. The study population is designed to minimize selection bias related to health-seeking behavior.
Cases are defined as Individuals who reported to local health agents with symptoms consistent with mpox and subsequently tested positive for mpox through a molecular-based diagnostic test.
Contacts are defined as individuals identified as having close contact with a laboratory-confirmed mpox case. Close contact includes but is not limited to the following type of contact.
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.
Proxy-assisted informed consent is allowed under safety considerations. Following oral consent, the investigator will document this on the informed consent form as a witness.
Fulfillment of the current mpox clinical case definition in the DRC, which includes:
Presence of a vesicular or pustular eruption with deep-seated, firm pustules.
At least one of the following symptoms:
Fever preceding the eruption. Lymphadenopathy (inguinal, axillary, or cervical). Presence of pustules or crusts on the palms of the hands or soles of the feet.
Laboratory confirmation:
At least one molecular-based mpox diagnostic test confirming the diagnosis.
Exclusion Criteria:
Refusal to participate in the study:
Individuals who decline to provide consent for study participation will be excluded
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.
Transmission chain
Definition: The sequence and structure of mpox transmission events within households and beyond, including identification of primary and secondary cases. To map transmission dynamics and determine how mpox spreads within close-contact settings. Detailed epidemiological tracing and genetic sequencing to confirm transmission links.
Time frame: through study completion, average 4 weeks
Incubation Period
Definition: The time between exposure to the mpox virus and the onset of symptoms. To estimate the range and median incubation period of mpox based on detailed exposure history and symptom onset data. Exposure dates and symptom onset dates from confirmed cases and their contacts.
Time frame: through study completion, an average 4 weeks
Serial Interval
Definition: The time between the onset of symptoms in a primary case and the onset of symptoms in a secondary case they infect. To estimate the serial interval of mpox, which is critical for understanding transmission timelines and epidemic control. Symptom onset dates for linked cases within households and other close-contact settings.
Time frame: through study completion, an average 4 weeks
Secondary Attack Rate (SAR)
Definition: The proportion of susceptible household contacts who develop mpox after exposure to a confirmed case. To quantify transmission efficiency within households and identify risk factors influencing SAR.
Time frame: through study completion, an average 4 weeks
Effective Reproduction Number (Re)
Definition: The average number of secondary cases generated by a single infectious individual in the current population. To estimate Re during the study period, which reflects real-time transmission potential under existing control measures. Based on observed transmission chains and SAR data.
Time frame: through study completion, an average of 2 years
Started Aug 2024 (actual). Primary completion is estimated for Dec 2025, 16 months after the start.
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 16 months is below that.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
No contact was published for this record. The registry link below has the sponsor’s details.
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.
Osaka Metropolitan University