New RNA mpox vaccine shows promise in early trial

NCT ID NCT05988203

Completed ⭐️ VACCINE ⭐️ Sponsor: BioNTech SE Source: ClinicalTrials.gov ↗

First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This early-stage trial tested an RNA-based vaccine called BNT166a against mpox (monkeypox) in 96 healthy volunteers. The goal was to check safety and see if the vaccine triggers an immune response. Researchers looked for side effects like pain, fever, and fatigue, and monitored serious reactions over several months.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: RNA-based mpox vaccine (BNT166a)
What this could lead to: If successful, this could lead to a new vaccine to protect against mpox (monkeypox).
What could go wrong: This is an early-phase trial with only 96 participants, so results may not apply to larger populations. The vaccine may cause side effects or fail to provide strong immunity.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

monkeypox prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

MONKEYPOX

Contacts and locations

Locations

Addenbrooke's Hospital - Cambridge University Hospitals NHS Foundation Trust

Cambridge, CB2 0QQ, United Kingdom
Alliance for Multispecialty Research, LLC

Kansas City, Missouri, 64114, United States
Alliance for Multispecialty Research, LLC

Knoxville, Tennessee, 37909, United States
California Research Foundation

San Diego, California, 92123, United States
Guy's and St Thomas' NHS Foundation Trust of St Thomas' Hospital

London, SE1 7EH, United Kingdom
Medicine Evaluation Unit Ltd, The Langley Building, Wythenshawe Hospital

Manchester, M239QZ, United Kingdom
Royal Surrey County Hospital Foundation Trust, NIHR Royal Surrey Clinical Research Facility

Guildford, GU2 7XP, United Kingdom
University Hospital Southampton

Southampton, SO16 6YD, United Kingdom
University of Washington Virology Research Clinic

Seattle, Washington, 98104, United States

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