A Clinical Study Investigating the Safety and Immune Responses After Immunization With Investigational Monkeypox Vaccines
Public ClinicalTrials.gov record NCT05988203. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
A Randomized, Partially Observer-blind, Dose-escalation, Phase I/II Trial Evaluating the Safety and Immunogenicity of Investigational RNA-based Mpox Vaccine Candidates
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
This is a dose-escalation, Phase I/II study evaluating the safety, tolerability, reactogenicity and immunogenicity of the investigational RNA-based multivalent vaccine candidate BNT166a for active immunization against monkeypox (mpox). This study started with substudy A (SSA) and substudy B (SSB) for which recruitment has been completed. A Substudy C (SSC) was planned, but the sponsor decided not to conduct it. This study will therefore continue with substudy D (SSD). In SSA and SSB, dosing started with an initial sentinel group, followed by the expansion cohort. This study was initially planned to investigate two vaccine candidates (the quadrivalent BNT166a and the trivalent BNT166c). The sponsor decided to not activate the groups with BNT166c.
Study identification
- NCT ID
- NCT05988203
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Phase 1, Phase 2
- Enrollment
- 96 participants
Conditions and interventions
Eligibility (public fields only)
- Age range
- 18 Years to 65 Years
- Sex
- All
- Healthy volunteers
- Accepts healthy volunteers
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Sep 20, 2023
- Primary completion
- Aug 24, 2025
- Completion
- Mar 3, 2026
- Last update posted
- Mar 26, 2026
2023 – 2026
United States locations
- U.S. sites
- 4
- U.S. states
- 4
- U.S. cities
- 4
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| California Research Foundation | San Diego | California | 92123 | — |
| Alliance for Multispecialty Research, LLC | Kansas City | Missouri | 64114 | — |
| Alliance for Multispecialty Research, LLC | Knoxville | Tennessee | 37909 | — |
| University of Washington Virology Research Clinic | Seattle | Washington | 98104 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
Non-U.S. locations
This page focuses on the U.S. directory. The official record also lists 5 non-U.S. sites.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT05988203, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Mar 26, 2026 · Synced Sep 7, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT05988203 live on ClinicalTrials.gov.