Safety Study of Inactivated Shigella Whole Cell Vaccine in Adults

August 10, 2021 updated by: PATH

A Phase 1 Study to Evaluate the Safety, Tolerability, and Immunogenicity of an Oral Inactivated Whole Cell Shigella Flexneri 2a Vaccine in Healthy Adult Subjects

This is a research study about an experimental (investigational) oral inactivated whole cell Shigella flexneri 2a killed vaccine (Sf2aWC). Sf2aWC is a killed vaccine that is being made to prevent disease from Shigella., which causes bloody, watery diarrhea. Infants and children living in developing countries experience the greatest consequences of this disease. The purpose of this study is to find a dose of the vaccine that is safe, tolerable, and develops an immune response. About 82 healthy adults, ages 18-45, will participate in this study. This study will require volunteers to stay in the research facility for several nights for the first dose. Participants in Cohorts 2, 3, and 4 will not be required to stay overnight for the second and third doses. Participants will be assigned to receive 1 of 4 vaccine doses by mouth. Study procedures include: stool samples, blood samples and documenting side effects. Participants will be involved in study related procedures for about 8 months.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Despite the public health burden of Shigella spp. on travelers, deployed soldiers and, most significantly, young children in the developing world, there is no licensed vaccine against Shigella. The rationale for using Shigella flexneri 2a whole cell killed vaccine (Sf2aWC), is that it is expected to be especially well tolerated by subjects. If Sf2aWC is safe and immunogenic, it may be combined with S. sonnei and S. flexneri 3a as the basis of a multivalent vaccine, because these three components should cover up to 80% of shigella infections in developing countries and over 90% in developed countries. This is a single site, Phase 1, double-blind, randomized, placebo-controlled, dose-escalation study in healthy adult subjects. Approximately 82 subjects will be enrolled into four separate cohorts and will be randomized to receive Sf2aWC or placebo. The placebo preparation will be bicarbonate buffer. Cohort 1 subjects will receive a single oral dose of Sf2aWC (2.6±0.8 x 10^8 vp/mL) or placebo. Dosing and 72 hours of supervised post-vaccination safety follow-up will be conducted in the Center for Immunization Research, Johns Hopkins School of Public Health (CIR) Inpatient Unit. Before enrolling subjects in subsequent cohorts, safety data from the previous Cohort(s) through Study Day 7 will be evaluated and reviewed by the Safety Review Committee (SRC). Cohorts 2, 3, and 4 participants will receive three doses of Sf2aWC vaccine or placebo at 0, 1 and 2 months. The first immunization will be administered in the CIR inpatient unit, followed by 72 hours of direct post-immunization observation. If after review by the SRC the first dose appears safe and well tolerated, subsequent doses will be administered on an outpatient basis. Safety will be assessed by solicited symptoms/subject memory aid and laboratory evaluations. Adverse events (AE)s will be graded according to standardized criteria. The immunogenicity outcome measures of interest include serum immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies by ELISA against S. flexneri 2a Lipopolysaccharide (LPS) and S. flexneri 2a invasive protein antigens (Ipa), cytokine assays, B and T cell memory responses, and vaccine-specific IgA responses. The proposed sample size of twenty per group in Cohorts 2, 3, and 4 would be sufficient to select the appropriate dose to move into the next study phase, providing that a difference in the immunogenicity between the two arms is 20% or greater. Participants will include 82 healthy adult male and female subjects, ages 18 to 45 inclusive. The primary objective of this study is to assess the safety and tolerability of Sf2aWC vaccine when administered in three oral doses over a range of dose levels in healthy adult subjects. The secondary objective is to assess the immunogenicity of the Sf2aWC vaccine over a range of doses in healthy adult subjects.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
82

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Baltimore, Maryland, United States, 21224
        • Center for Immunization Research (CIR) at Johns Hopkins School of Public Health (JHSPH)
      • Baltimore, Maryland, United States, 21224
        • Johns Hopkins University CIR Isolation Unit

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy adults, male or female, age 18 to 45 years (inclusive) at the time of enrollment.
  • Completion and review of comprehension test (achieved >70% accuracy).
  • Signed informed consent form.
  • Available for the required follow-up period and scheduled clinic visits.
  • Negative urine pregnancy test before each vaccination for female subjects of childbearing potential. Females of childbearing potential must agree to use an efficacious hormonal or barrier method of birth control during the study. Abstinence is also acceptable.

Exclusion Criteria:

  • Presence of a significant medical or psychiatric condition that in the opinion of the investigator precludes participation in the study. Some medical conditions, that are adequately treated and stable, would not preclude entry into the study. These conditions might include stable asthma, hypertension or depression controlled with medication.
  • Clinically significant abnormalities on physical examination.
  • Clinically significant abnormalities in screening hematology, serum chemistry, or urinalysis as determined by PI or PI in consultation with Medical Monitor.
  • History of febrile illness within 48 hours prior to vaccination.
  • BMI <19 or >34.
  • Positive blood test for HBsAG, hepatitis C virus (HCV), HIV-1, Human leukocyte antigen (HLA)-B27.
  • Women currently nursing.
  • History of reactive arthritis.
  • Evidence of current excessive alcohol consumption
  • Evidence of current drug use or drug dependence.
  • Regular use of anti-diarrheal, anti-constipation, or antacid therapy (excluding use associated with spicy meals).
  • Abnormal stool pattern (fewer than 3 stools per week or more than 3 stools per day) on a regular basis; loose or liquid stools on other than an occasional basis.
  • Personal or family history of an inflammatory arthritis.
  • History of allergy to soy products.
  • History of microbiologically confirmed Shigella infection within 3 years.
  • Prior receipt of experimental Shigella vaccine or live Shigella challenge within 3 years.
  • Symptoms of travelers' diarrhea associated with travel to countries where Shigella or other enteric infections are endemic (most of the developing world) within 1 year prior to dosing.
  • Occupation involving handling of Shigella bacteria currently, or in the past 3 years.
  • History of diarrhea during the 7 days before vaccination.
  • Use of antibiotics during the 7 days before vaccination.
  • Use of proton pump inhibitors, H2 blockers, or antacids within 48 hours prior to dosing.
  • Inability to comply with inpatient rules and regulations.
  • Use of immunosuppressive and/or immunomodulative drugs such as corticosteroids or chemotherapeutics that may influence antibody development.
  • Participation in research involving another investigational product (defined as receipt of investigational product or exposure to invasive investigational device) 30 days before planned date of first vaccination.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Cohort 1
Received one oral dose of 2.6±0.8 x 10^8 vp/mL Shigella flexneri 2a whole cell killed vaccine (Sf2aWC)
Biological: Vaccine: 2.6±0.8 x 10^8 vp/mL, 1 dose
Shigella flexneri 2a whole cell killed vaccine (Sf2aWC): 2.6±0.8 x 10^8 vp/mL administered on Day 0
Experimental: Cohort 2
Received three oral doses of 2.6±0.8 x 10^9 vp/mL Shigella flexneri 2a whole cell killed vaccine (Sf2aWC)
Biological: Vaccine: 2.6±0.8 x 10^9 vp/mL, 3 doses
Shigella flexneri 2a whole cell killed vaccine (Sf2aWC): 2.6±0.8 x 10^9 vp/mL administered on Days 0, 28, and 56
Experimental: Cohort 3
Received three oral doses of 2.6±0.8 x 10^10 vp/mL Shigella flexneri 2a whole cell killed vaccine (Sf2aWC)
Biological: Vaccine: 2.6±0.8 x 10^10 vp/mL, 3 doses
Shigella flexneri 2a whole cell killed vaccine (Sf2aWC): 2.6±0.8 x 10^10 vp/mL administered on Days 0, 28, and 56
Experimental: Cohort 4
Received three oral doses of 2.6±0.8 x 10^11 vp/mL Shigella flexneri 2a whole cell killed vaccine (Sf2aWC)
Biological: Vaccine: 2.6±0.8 x 10^11 vp/mL, 3 doses
Shigella flexneri 2a whole cell killed vaccine (Sf2aWC): 2.6±0.8 x 10^11 vp/mL administered on Days 0, 28, and 56
Placebo Comparator: Placebo
Received oral dose of placebo concurrent with Cohort 1 (one dose), 2, 3, or 4 (3 doses).
Biological: Placebo: 1-3 doses
Placebo administered on Day 0 (if 1 dose) or Day 0, 28, and 56 (3 doses)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Maximum Reactogenicity Per Subject and Treatment Group
Time Frame: 7 days after each vaccination (Day 0, Day 35, Day 63)
Local and systemic reactogenicity was assessed post-vaccination using targeted physical examinations, vital signs and clinical laboratory tests, and diary cards (completed following discharge daily through Day 7). Reactogenicity included: nausea, vomiting, fever, abdominal pain, abdominal cramping, bloating, malaise, headache, decreased appetite, generalized myalgias, chills, light-headedness, constipation, excessive flatulence, reactive arthritis, dysentery, loose stool, diarrhea, hypovolemia, joint pain, defecation urgency, and oral temperature.
7 days after each vaccination (Day 0, Day 35, Day 63)
Frequency of Unsolicited Adverse Events With a Reasonable Possibility That the Study Product Caused the Event
Time Frame: 6 months after final vaccination (Day 168 or Day 224)
6 months after final vaccination (Day 168 or Day 224)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number and Percentage of Subjects in Cohort 3 With Positive Immunologic Response in Serum Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 35 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
35 days
Number and Percentage of Subjects in Cohort 4 With Positive Immunologic Response in Serum Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Serum Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response in Cohort 3
Time Frame: 35 days
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
35 days
Geometric Mean Titer (GMT) of Serum Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response in Cohort 4
Time Frame: 63 days
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects in Cohort 3 With Positive Immunologic Response in Serum Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response From Baseline
Time Frame: 16 weeks
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
16 weeks
Number and Percentage of Subjects in Cohort 4 With Positive Immunologic Response in Serum Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response From Baseline
Time Frame: 16 weeks
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
16 weeks
Geometric Mean Titer (GMT) of Serum Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response in Cohort 3
Time Frame: 35 days
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
35 days
Geometric Mean Titer (GMT) of Serum Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response in Cohort 4
Time Frame: 16 weeks
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
16 weeks
Number and Percentage of Subjects With Positive Immunologic Response in Serum Antibody From Lymphocytes Supernatant (ALS) Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Serum Antibody From Lymphocytes Supernatant (ALS) Lipopolysaccharide (LPS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects With Positive Immunologic Response in Serum Antibody From Lymphocytes Supernatant (ALS) Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Serum Antibody From Lymphocytes Supernatant (ALS) Lipopolysaccharide (LPS) Immunoglobulin G (IgG) Response
Time Frame: 63 days
S. flexneri 2a LPS were used as the ELISA antigens. Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects With Positive Immunologic Response in Invasion Plasmid Antigens B (IpaB) Lymphocytes Supernatant (ALS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Invasion Plasmid Antigens B (IpaB) Lymphocytes Supernatant (ALS) Immunoglobulin A (IgA) Response
Time Frame: 63 days
Whole blood samples were collected for determination of ALS (antibody from lymphocytes supernatant). Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects With Positive Immunologic Response in Invasion Plasmid Antigen D (IpaD) Lymphocytes Supernatant (ALS) Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Invasion Plasmid Antigen D (IpaD) Lymphocytes Supernatant (ALS) Immunoglobulin A (IgA) Response
Time Frame: 63 days
Whole blood samples were collected for determination of ALS (antibody from lymphocytes supernatant). Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects in Cohort 3 With Positive Immunologic Response in Fecal Immunoglobulin A (IgA) Response From Baseline
Time Frame: 16 weeks
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
16 weeks
Geometric Mean Titer (GMT) of Fecal Immunoglobulin A (IgA) Response in Cohort 3
Time Frame: 16 weeks
Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
16 weeks
Number and Percentage of Subjects in Cohort 3 With Positive Immunologic Response in Total Immunoglobulin A (IgA) Response From Baseline
Time Frame: 16 weeks
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
16 weeks
Geometric Mean Titer (GMT) of Total Immunoglobulin A (IgA) Response in Cohort 3
Time Frame: 16 weeks
Whole blood samples were collected for determination of ALS (antibody from lymphocytes supernatant). Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
16 weeks
Number and Percentage of Subjects in Cohort 4 With Positive Immunologic Response in Total Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Total Immunoglobulin A (IgA) Response in Cohort 4
Time Frame: 63 days
Whole blood samples were collected for determination of ALS (antibody from lymphocytes supernatant). Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days
Number and Percentage of Subjects in Cohort 4 With Positive Immunologic Response in Fecal Immunoglobulin A (IgA) Response From Baseline
Time Frame: 63 days
A positive immunological response is defined as an increase of 4-fold or more over the appropriate baseline value for ALS or an increase of more than 2-fold for serological responses (fold increases will be calculated to 1 decimal place). For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14. The fold-change in response was then calculated as the ratio of each value to the baseline value (so the minimum baseline value was 0.14). Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected.
63 days
Geometric Mean Titer (GMT) of Fecal Immunoglobulin A (IgA) Response in Cohort 4
Time Frame: 63 days
Immunogenicity responses are presented for Cohorts 3 and 4 only. Specimens from vaccine recipients in Cohorts 1 and 2 were not tested for immunogenicity data and no data were collected. For all immunology variables, the raw values were first adjusted to the geometric mean of positive controls, and any values <0.15 were changed to 0.14.
63 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
PATH

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Clayton D Harro, MD, ScM, Johns Hopkins Bloomberg School of Public Health

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2011

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2012

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2012

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 5, 2012

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 10, 2012

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 13, 2012

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 11, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 10, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • VAC 001

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Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

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