Evaluation of Effectiveness and Safety of LC16m8 Mpox Vaccine in the Democratic Republic of Congo (DRC)
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age1+
SponsorInternational Vaccine Institute
About this trial
This is a health facility-based prospective test-negative (TND) case-control study to evaluate vaccine effectiveness and active safety monitoring (cohort event monitoring), and passive surveillance for evaluation of the safety of the LC16m8 mpox vaccine in individuals aged one year and older in the DRC.
This study aims to assess the LC16m8 vaccine effectiveness and safety. The following activities will be carried out:
* Community engagement * Enhanced health facility-based mpox disease surveillance * Vaccination using the LC16m8 vaccine * Safety monitoring following immunization * LC16m8 Vaccine effectiveness evaluation using a TND
Study Hypothesis: The LC16m8 vaccine, administered as pre-exposure prophylaxis, confers greater than 70% protection against symptomatic mpox disease among adults and children in the DRC.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Individuals aged 12 months and above
Living in the study catchment area
Written informed consent/assent (if applicable)
Disqualifiers
Prior receipt of any mpox vaccine dose
Women known to be pregnant or breast feeding
Individuals suffering from any spreading skin disease
Immunocompromised individuals with known severe immuno-deficiency conditions (example, HIVAIDS, individuals being on chronic use of systemic steroids (>2 mg/kg/day or >20 mg/day prednisolone equivalent for periods exceeding 10 days, cytotoxic or other immunosuppressive drugs)
Trial population
The vaccination will be conducted in 2 to 3 selected health zones/areas which meet the criteria for a hotspot as defined by the DRC vaccination strategy for targeted vaccine delivery. As of February 2025, the DRC government has updated their comprehensive mpox vaccination plan which targets both high-risk groups (e.g., healthcare workers, contacts of confirmed cases, etc.) as well as population residing in 57 health zones considered mpox hotspots based on recent epidemiologic data. Selection of health zones/area for the study, where LC16m8 is expected to be offered to everyone one year or older, will be determined based on the latest mpox epidemiological data, operational feasibility, and existing research infrastructure in close consultation with DRC MoH, Institut National de Santé Publique (INSP), and local stakeholders.
Trial design
Design model
Other
Time perspective
Prospective
Treatments tested in this trial
LC16m8
Biological/VaccineLC16m8 vaccine will be offered to all individuals aged \>1 year and meet the inclusion criteria within the catchment population. This will be done in line with the DRC government's LC16m8 vaccine roll out plan.
Treatment groups
11,990 Participants
are divided into 2 treatment groupsGroup A: Cohort Event Monitoring (CEM) - Safety cohort1 intervention
Group B: Vaccine Effectiveness (VE) Assessment0 interventions
Trial outcomes
Primary outcomes
1
Proportion of participants with complete mpox vaccination among those with symptomatic, RT-PCR confirmed mpox infection compared to those who test negative for mpox RT-PCR.
This outcome measures the percentage of participants who had complete vaccination among those who tested positive for mpox by RT-PCR in comparison to the percentage of participants who had complete vaccination who tested negative for mpox by RT-PCR. Unit of Measure: Odds ratio Measurement tool: The odds of complete Vaccination status determined through vaccination record or participant self-report (complete vaccination is defined as symptom onset ≥14 days after receiving mpox vaccine) among mpox positive cases (RT-PCR positive) compared to the odds of complete Vaccination status among controls (mpox RT-PCR negative).
Time frame
At baseline (Day 0)Secondary outcomes
1
The percentage of participants with complete vaccination in different age strata of participants with RT-PCR-confirmed mpox disease compared with the percentage of participants with complete vaccination in those without mpox disease.
This outcome will assess the correlation between mpox disease status and vaccination status at the time of enrollment. Specifically, the investigators will compare the odds of having received a complete mpox vaccination among participants with RT-PCR-confirmed mpox disease to the odds among those who test negative for mpox. Analyses will be stratified by age group to explore potential age-related differences in vaccine coverage and effectiveness. Complete vaccination is defined as onset of first mpox symptoms 14 days or more after receipt of mpox vaccine. Unit of measure: Odds ratio Measurement tool: The odds of complete vaccination status (complete vaccination is defined as symptom onset ≥14 days after receiving mpox vaccine) in among mpox positive cases (RT-PCR positive) compared to the odds of complete Vaccination status among controls (mpox RT-PCR negative).
Time frame
At baseline (Day 0)2
The percentage of participants with incomplete vaccination among participants with RT-PCR-confirmed mpox disease compared to the percentage of participants with incomplete vaccination among participants with negative mpox RT-PCR(overall&stratified by age
This outcome measures the odds of having an incomplete mpox vaccination status among participants with RT-PCR-confirmed mpox at the time of enrollment compared to participants who test negative to mpox. Incomplete vaccination is defined as onset of first mpox symptoms within 14 days of receipt of mpox vaccine. The analysis will be conducted both overall and stratified by age to examine potential differences across age groups. Unit of measurement: Odds ratio Measurement tool: The odds of incomplete vaccination status (incomplete vaccination is defined as symptom onset within 14 days of receiving mpox vaccine) among mpox positive cases (RT-PCR positive) compared to the odds of incomplete Vaccination status among controls (mpox RT-PCR negative).
Time frame
At baseline (Day 0)3
The percentage of participants with complete vaccination in those with RT-PCR-confirmed severe mpox disease compared to the percentage of participants with complete vaccination in those without mpox (overall & stratified by age).
This outcome assesses whether complete vaccination is associated with reduced odds of developing severe mpox disease. Odds of complete vaccination will be compared between participants with RT-PCR-confirmed severe mpox and those without mpox, both overall and stratified by age. Complete vaccination is defined as onset of first mpox symptoms 14 days or more after receipt of mpox vaccine. Unit of measurement: Odds ratio Measurement tool: The odds of complete Vaccination status (complete vaccination is defined as symptom onset ≥14 days after receiving mpox vaccine) among mpox positive cases (RT-PCR positive) compared to the odds of complete Vaccination status among controls (mpox RT-PCR negative).
Time frame
From baseline (Day 0) to severe outcome (death or hospitalization, assessed up to Day 42)4
The percentage of participants with incomplete vaccination in those with RT-PCR-confirmed severe mpox disease compared to the percentage of incomplete vaccination among those without mpox disease (overall & stratified by age).
Comparison of the odds of incomplete vaccination status between participants diagnosed with RT-PCR-confirmed severe mpox disease and those without mpox disease, overall and stratified by age groups. Incomplete vaccination is defined as onset of first mpox symptoms within 14 days of receipt of mpox vaccine. Unit of measurement: Odds ratio Measurement tool: The odds of incomplete vaccination status (incomplete vaccination is defined as symptom onset within14 days of receiving mpox vaccine) among mpox positive cases (RT-PCR positive) compared to the odds of incomplete vaccination status among controls (mpox RT-PCR negative).
Time frame
From enrollment (Day 0) to severe outcome (death or hospitalization, assessed up to Day 42)Sponsors and contacts
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International Vaccine Institute
Lead sponsor
Japan Institute for Health Secutiry
Collaborator
Institut National de Recherche Biomédicale. Kinshasa, République Démocratique du Congo
Collaborator
Source ClinicalTrials.gov
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