New mRNA vaccine against mpox enters key trial in africa
NCT ID NCT07379580
First seen Jun 24, 2026 · Last updated Aug 12, 2026 · Updated 7 times
Summary
This study tests an experimental mRNA vaccine called BNT166a to see if it is safe and can protect against mpox (monkeypox). About 310 healthy adults in Africa will receive either the vaccine or a placebo. The trial is double-blind, meaning neither participants nor doctors know who gets what. Researchers will monitor side effects and measure immune responses.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- BNT166a (mRNA vaccine)
- What this could lead to
- If successful, this could lead to a safe and effective vaccine to prevent mpox (monkeypox) and related orthopoxvirus infections.
- What could go wrong
- This is a Phase 2 trial with only 310 participants, so it is still early. The vaccine may cause side effects like pain or fever, and it may not provide strong enough immunity to prevent infection.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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About 310 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Feb 2026
- Expected to finish
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Jun 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 64 years
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Key Inclusion Criteria (applicable to all participants unless otherwise specified): * Are male or female individuals ≥18 years of age at the time of giving informed consent: * Cohort 1: ≥18 to ≤45 years of age * Cohort 2: ≥18 to ≤64 years of age * Cohort 1: Participants must be Orthopoxvirus-naïve (have no history of smallpox or mpox vaccination or mpox infection). * Cohort 2: Participants must be Orthopoxvirus-experienced (have evidence of mpox or smallpox vaccination or mpox infection at least 2 years prior to consent). Key Exclusion Criteria (applicable to all participants unless otherwise specified): * Have had recent exposure to mpox (defined as close contact with a probable or confirmed case of mpox within the past 28 days, or have evidence of mpox infection or mpox vaccination within 2 years prior to consent). * Have a contraindication, warning and/or precaution to vaccination with a messenger ribonucleic acid (mRNA) Coronavirus disease 2019 (COVID-19) vaccine as specified in the Summary of Product Characteristics for BNT162b2 (COMIRNATY United States Prescribing Information/European Union Summary of Product Characteristics) and BNT166 Investigator Brochure. * Have a history of allergies, hypersensitivities, or intolerance to the study treatments including any excipients thereof. * Have a current or history of cardiovascular diseases, e.g., myocarditis, pericarditis, myocardial infarction, congestive heart failure, cardiomyopathy, or clinically significant arrhythmias. * Have any known bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. * Have a body mass index ≤18.5 kg/m\^2 or ≥35 kg/m\^2. NOTE: Other protocol defined Inclusion/Exclusion criteria apply.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
6 sites in 2 countries. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Desmond Tutu Health Foundation Masiphumelele Clinic
RECRUITINGCape Town, 7975, South Africa
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Institute National de Recherche Biomedicale
RECRUITINGKinshasa, 5345, Democratic Republic of the Congo
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Perinatal HIV Research Unit
RECRUITINGJohannesburg, 1864, South Africa
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TASK Applied Science
RECRUITINGCape Town, 7405, South Africa
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TREAD Research Pty Ltd
RECRUITINGCape Town, 7530, South Africa
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University of Kinshasa UNIKIN
RECRUITINGKinshasa, 01306, Democratic Republic of the Congo
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Smallpox drug put to the test in healthy volunteers
- Smallpox drug put to the test: can TPOXX be taken safely for a month?
- Can common kidney drugs weaken the smallpox antiviral TPOXX?
- Smallpox drug put to the test in heavier adults
- Can an antiviral drug stop smallpox? researchers track survival
- Experimental drug targets smallpox and monkeypox after exposure