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 was 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 was originally planned to include four substudies, i.e., substudy A (SSA), substudy B (SSB), substudy C (SSC), and substudy D (SSD). Sponsor decided not to conduct SSC, thus three substudies (SSA, SSB, and SSD) were conducted. In SSA and SSB, dosing started with an initial sentinel group, followed by the expansion cohort. In SSD, dosing was initiated after the interim analysis of SSA and SSB 1-month post-Dose 2 safety, reactogenicity, and immunogenicity data was received. 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 21, 2023 (Actual)
- Primary completion
- Aug 25, 2025 (Actual)
- Completion
- Mar 4, 2026 (Actual)
- Last update posted
- Sep 15, 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 Sep 15, 2026 · Synced Oct 23, 2026
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Open the official record
The complete public registry record, listed eligibility criteria, and available contact information for NCT05988203 live on ClinicalTrials.gov.