Completed

Safety and Immunogenicity Study of an Intranasal Shigella Flexneri 2a Invaplex 50 Vaccine

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What is being tested

Data Collection

Who is being recruted

Diarrhea

+ Signs and Symptoms, Digestive
From 18 to 40 Years
See all eligibility criteria
How is the trial designed

Prevention Study

Phase 1
Interventional
Study Start: April 2004
See protocol details

Summary

Principal SponsorU.S. Army Medical Research and Development Command
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner
Study start date: April 1, 2004Actual date on which the first participant was enrolled.

This is an open-labeled dose escalating trial in which a total of 32 subjects (minimum of 24 allowable) will receive one of four intranasal Invaplex 50 vaccine doses according to the following chart: Test articles/dose Group / N\* / Invaplex 50 A / 8 / 10 micrograms B / 8 / 50 micrograms C / 8 / 240 micrograms D / 8 / 480 micrograms \*minimum of 6 volunteers/group An interval no less than 7 days following the third (and final) dose (total of 35 days between initial dose at the lower dose level and the next initial dose at the next higher dose level) will separate volunteer groups receiving different doses. All volunteers will receive three immunizations. The first dosing time point is Day 0, the second is Day 14 (+- one day), and the third is Day 28 (+- 2 days). Blood and stool specimens will be collected at intervals to examine systemic and mucosal vaccine antigen-specific immune responses. Vaccine safety will be actively monitored during vaccination and for 28 days following the third vaccination dose.

Official TitleSafety and Immunogenicity Study of an Intranasal Shigella Flexneri 2a Invaplex 50 Vaccine 
NCT00082069
Principal SponsorU.S. Army Medical Research and Development Command
Last updated: January 14, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
32 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Prevention Study
Prevention studies aim to stop a disease from developing. They often involve people at risk and test things like vaccines, lifestyle changes, or preventive medications.

How participants are assigned to different groups/arms
In this clinical study, participants are assigned to groups based on specific criteria, such as their medical history or a doctor's recommendation. This approach ensures that treatments are given to those who may benefit the most, based on known factors.

Other Ways to Assign Participants
Randomized allocation: Participants are assigned randomly, like flipping a coin, to ensure fairness and reduce bias.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
In this study, all participants receive the same treatment. This approach is often used to evaluate the effects of a single intervention without comparing it to another.

Other Ways to Assign Treatments
Parallel assignment: Participants are split into separate groups, each receiving a different treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Sequential assignment: Participants receive treatments one after another in a specific order, possibly based on individual responses.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the interventions assigned to participants is kept confidential
Everyone involved in the study knows which treatment is being given. This is typically used when it's not possible or necessary to hide the treatment details from participants or researchers.

Other Ways to Mask Information
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.
Quadruple-blind: Participants, researchers, outcome assessors, and care providers all do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 40 YearsRange of ages for which participants are eligible to join.
Healthy volunteers allowedIf individuals who are healthy and do not have the condition being studied can participate.
Conditions
Pathology
Diarrhea
Signs and Symptoms, Digestive
Criteria

Inclusion Criteria: * Be in very good health. Exclusion Criteria: * Smoker, or have stopped smoking less than one year ago * Pregnant * History of chronic illnesses, such as: asthma, chronic sinusitis, or chronic seasonal allergies (such as hay fever) * Received a vaccination for Shigella or exposure to Shigella bacteria in a research study or through work in a laboratory * Positive for HIV, hepatitis B, and hepatitis C by blood test * Using anti-diarrheal, anti-constipation, or antacid medications on a regular basis

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Study Objectives
Study Objectives
Primary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
Suspended
Walter Reed Army Institute of ResearchSilver Spring, United StatesSee the location
CompletedOne Study Center
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