This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety and Immunogenicity Study of Traveler's Diarrhea Vaccine Patch (NCT01067781), a randomized phase 2 study. The primary outcome is Characterization and Comparison of the Safety of the TD Vaccine System: (1) Solicited and Unsolicited Adverse Events (AEs) (2) Clinical Laboratory Safety (3) Serious AEs.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01067781 |
| Phase | Phase 2 |
| Condition | Diarrhea |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 600 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Intercell USA, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Healthy adults enrolled in a phase 2 study of a traveler’s diarrhea vaccine system. The registry describes the study as gender-stratified. The record does not give further eligibility details or describe the characteristics of the participants included in each safety analysis.
Intervention
Two vaccinations with a patch containing heat-labile enterotoxin of E. coli (LT). The registry distinguishes LT patch groups by whether the skin was swabbed with alcohol before the patch was applied.
Comparator
Two vaccinations with a placebo patch, also with groups distinguished by whether alcohol swabbing was used. This provides placebo comparisons within the swabbing conditions, although the registry record does not report a statistical comparison for these groups.
Primary question
The primary outcome concerns safety: solicited and unsolicited adverse events, clinical laboratory safety, and serious adverse events from Day 0 to Day 180. The registry also describes immune-response outcomes, including geometric mean titers, geometric mean fold ratios, and seroconversion rates. The posted results summarized in the record are safety counts; a single combined primary-outcome comparison is not reported.
The study therefore addresses safety and immune-response questions across both patch contents and application conditions. Its four groups separate LT from placebo and no swabbing from swabbing. The record’s primary outcome description includes several event categories and observation windows rather than one clearly defined binary endpoint with a single reported comparison. For adverse events, the registry specifies which local and systemic events were solicited and when systemic events counted as solicited. It does not report results for the immune-response outcomes in the material summarized by the registry record.
3. Trial Design
This was a randomized, triple-masked, parallel-group phase 2 study with a placebo control. The official title describes it as gender-stratified. The registry lists enrollment of 600 and a completed status. The recorded study start is 2010-02, and primary completion is recorded as 2010-09. The sponsor is Intercell USA, Inc.
The four groups varied on two dimensions: whether the patch contained LT or placebo, and whether alcohol swabbing was used. Group 1 received two LT patch vaccinations without swabbing; Group 2 received two LT patch vaccinations with swabbing. Group 3 received two placebo patch vaccinations without swabbing; Group 4 received two placebo patch vaccinations with swabbing. The record gives the at-risk counts for each group in the safety summaries, but does not describe the allocation ratio or the randomization procedure.
Triple masking indicates that the registry classified the study as masked at three levels, but the record does not specify which roles were masked or how masking was maintained. It also does not report details of the swabbing procedure, the interval between vaccinations, or the basis for the gender stratification. These omissions limit what can be concluded about implementation from the registry record alone.
The study’s stated purpose was to evaluate and compare safety and immune responses following a two-vaccination regimen using LT patches or placebo, with or without alcohol swabbing. The primary outcome was safety-related and included solicited and unsolicited adverse events, clinical laboratory safety, and serious adverse events over Day 0 to Day 180. Secondary outcomes concerned LT-specific immune responses. The registry record does not report a statistical analysis plan or outcome-specific analysis results for those immune-response measures.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Up to Day 180
| Stage | Group 1: 37.5μg LT, No Swab | Group 2: 37.5μg LT, Swab | Group 3: 0μg LT, No Swab | Group 4: 0μg LT, Swab |
|---|---|---|---|---|
| STARTED | 203 | 199 | 97 | 101 |
| COMPLETED | 173 | 168 | 89 | 89 |
| NOT COMPLETED | 30 | 31 | 8 | 12 |
180 to Day 720
| Stage | Group 1: 37.5μg LT, No Swab | Group 2: 37.5μg LT, Swab | Group 3: 0μg LT, No Swab | Group 4: 0μg LT, Swab |
|---|---|---|---|---|
| STARTED | 173 | 168 | 89 | 89 |
| COMPLETED | 3 | 4 | 0 | 0 |
| NOT COMPLETED | 170 | 164 | 89 | 89 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: safety population: includes all study subjects that were consented and received investigational study material (i.e., at least one vaccination)
| Characteristic | Unit | Group 1: 37.5μg LT, No Swab | Group 2: 37.5μg LT, Swab | Group 3: 0μg LT, No Swab | Group 4: 0μg LT, Swab | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 203 | 199 | 97 | 101 | 600 | |
| Age, Continuous | years | 36.0 (SD 12.8) | 35.3 (SD 13.1) | 35.0 (SD 13.6) | 35.7 (SD 12.8) | 35.3 (SD 13.0) |
| Sex: Female, Male: Female | Participants | 102 | 99 | 48 | 51 | 300 |
| Sex: Female, Male: Male | Participants | 101 | 100 | 49 | 50 | 300 |
6. Primary Endpoint
The registry lists the primary outcome as Characterization and Comparison of the Safety of the TD Vaccine System: (1) Solicited and Unsolicited Adverse Events (AEs) (2) Clinical Laboratory Safety (3) Serious AEs, measured over Day 0 to Day 180.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is described as a characterization and comparison of safety across solicited and unsolicited adverse events, clinical laboratory safety, and serious adverse events. It is measured over Day 0 to Day 180, and the stated unit is participants. The record describes local events solicited for the duration of the study: erythema, rash, pain, pruritus, hyperpigmentation, hypopigmentation, and edema. Fever, malaise, headache, and diarrhea were solicited systemic events during the first seven days following each vaccination; events reported outside that window were considered non-solicited.
Safety endpoints are used to describe the occurrence and nature of unwanted events during and after an intervention. Counting participants with an event can show how many people in each group were affected, while event categories distinguish the kinds of safety observations being collected. Serious adverse events are important to describe separately because seriousness is a distinct classification from whether an event was solicited or unsolicited.
The endpoint description is broad: it includes several event types and clinical laboratory safety, rather than defining one event or one summary measure as the sole primary outcome. The registry record does not report the laboratory measures, a rule for combining event categories, or a single primary comparison. The available safety counts therefore describe selected participant-level event summaries; they do not represent a complete numerical account of every component named in the primary outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted safety summaries give participant counts by randomized group. For serious adverse events, the record lists 1 affected participant among 203 at risk in Group 1, 3 among 199 in Group 2, and 0 among 97 and 0 among 101 in the two placebo groups. For the other adverse-event count, it lists 197 among 203, 192 among 199, 90 among 97, and 92 among 101, respectively. These are descriptive counts. The registry record does not report confidence intervals, p-values, adjusted estimates, or a stated analysis comparing the groups.
Those counts should be read in the context of the four-group design. The LT groups differ from the placebo groups in patch content, while swabbing distinguishes groups within each patch-content category. The raw counts alone do not isolate an effect of LT, an effect of swabbing, or an interaction between them. Such interpretations require an explicit comparison and analysis, neither of which is reported in the registry record.
The primary safety outcome also includes clinical laboratory safety and solicited and unsolicited adverse events. The posted participant counts do not provide laboratory results or a full breakdown of all event categories, so they should not be treated as a complete account of that broad endpoint. The registry identifies solicited local events for the duration of the study and solicited systemic events during the first seven days following each vaccination. Events outside the specified systemic window were classified as non-solicited. That classification describes how events were categorized; it does not itself indicate whether an event was related to the patch.
The registry lists “Abortion spontaneous,” “Bipolar disorder,” “Accelerated hypertension,” and “Pancreatitis” among the top serious-event terms, each at 0.5%. The record does not connect these terms to a particular group in the information. A term-level percentage is not a substitute for an arm-specific comparative estimate, and the record does not provide a causal assessment for these events.
The study is marked completed, but completion status does not establish that every planned outcome was analyzed or reported. The record lists zero analyses, and its notes indicate that the primary outcome has several categories or time points and was not reduced to one comparison. As a result, the safety counts support a descriptive reading only. The registry record does not report enough statistical detail to determine the precision of between-group differences or whether any apparent differences could be attributed to the intervention rather than chance or other factors.
9. Statistical Methods Explained
The posted adverse-event figures are participant counts: the number of participants with an event and the number at risk in each group. This kind of outcome is binary at the participant level for a given event definition: a participant is counted as having experienced the event or not having experienced it. The record does not specify whether repeat occurrences of the same event in one participant are counted once or in another way, so the counts should not be interpreted as counts of total event episodes.
What do the counts describe?
The at-risk count supplies the group context for each affected-participant count. Keeping both quantities visible is important: the same affected-participant count can have different meaning when the number assessed differs. The record reports the group-specific counts directly. It does not report comparative risk estimates, differences, ratios, or confidence intervals, and no such values can be inferred from the descriptive counts without recalculation. The group labels should be retained because LT versus placebo and swabbing versus no swabbing are separate design features.
Why distinguish event categories?
Solicited events are events the study specifically sought according to its stated definitions and observation windows. The registry lists local symptoms solicited for the duration of the study and systemic symptoms solicited for the first seven days following each vaccination. It says that systemic events outside that time frame were treated as non-solicited. This distinction affects event classification and collection; it does not establish that events outside the solicited window were absent. Serious adverse events are a separate safety category, and seriousness should not be conflated with whether an event was solicited.
General statistical context: participant-level event data are often summarized by group and compared using methods suitable for binary outcomes. A confidence interval expresses uncertainty around an estimated quantity; a wider interval indicates less precision. A formal comparison needs a defined estimand, such as a specific contrast between groups, and a method for estimating its uncertainty. The registry record does not report those elements for these safety summaries.
What does the design permit one to ask?
The parallel, randomized design includes LT and placebo patch groups, each with and without swabbing. General statistical context: a factorial structure can support separate questions about each design factor and whether the effect of one factor depends on the other, but these questions require planned contrasts and an appropriate analysis. The registry identifies the groups but does not report those contrasts, an interaction analysis, or the statistical model used. The fact that a comparison is possible in principle does not mean it was conducted or reported.
The trial is described as triple-masked, but masking procedures are not reported. General statistical context: masking can reduce the influence of expectations on participant reports, clinical assessments, or decisions, depending on which roles are masked and how outcomes are collected. Since the registry does not identify the masked roles or detail the procedures, the practical implications cannot be assessed from this record.
What can be said about the analysis?
The record lists four outcome measures and zero analyses. It does not report a statistical analysis plan, the analysis populations, handling of missing observations, adjustment for multiple outcomes, or methods for laboratory results. It also does not report inferential results for the primary safety outcome. Thus, there is no basis in the registry record to describe an adjusted or unadjusted treatment effect, a hypothesis test, or a finding of statistical significance.
A planning illustration is described using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of the observed effect. The record explicitly characterizes this as a planning illustration based on the observed effect, not the trial’s own design. Such illustrations concern sample sizes for a hypothetical future study under stated assumptions; they are not observed power and do not demonstrate that this trial had adequate power. No sample-size justification or design assumptions from the trial’s own protocol are reported in the registry record.
General statistical context: over-dispersion is relevant when observed variability exceeds what a simple statistical model assumes. It can make model-based uncertainty estimates too small if ignored. The posted safety results are participant counts, and the record does not identify a count model or report dispersion estimates, so over-dispersion is not an analysis feature that can be evaluated from the registry information.
10. Multiplicity, Missing Data and Analysis Populations
The study includes several safety components and secondary immune-response outcomes. The registry lists geometric mean titers, geometric mean fold ratios, and seroconversion rates among the secondary outcomes. The primary safety outcome itself covers solicited and unsolicited adverse events, clinical laboratory safety, and serious adverse events. When a study examines many outcomes or contrasts, the chance of at least one apparently unusual result can rise if each is assessed separately. General statistical practice may address this through prespecified outcome hierarchies or multiplicity adjustments, but the registry record does not report whether any such approach was planned or used.
The record lists four outcome measures and zero analyses. It does not report a complete outcome-by-group results set, inferential comparisons, or an analysis plan identifying a primary contrast among the four groups. Its note that the primary outcome has several categories or time points and was not reduced to one comparison reinforces that a single effect estimate is not available. This does not establish that no analyses were performed outside the registry; it means they are not reported in the registry record.
Missing-data handling and analysis populations are not reported in the registry record. In particular, the record does not state how participants with missing visits, unavailable laboratory measurements, or incomplete event information were treated, nor does it define an intention-to-treat, per-protocol, or safety population. The at-risk counts accompany the posted event counts, but do not by themselves explain participant flow, exclusions, or missingness. Without these details, the scope of the analyzed population and the potential influence of missing data cannot be assessed.
The record also does not report interim analyses, stopping rules, or a plan for controlling type I error. These details should not be inferred from the randomized and masked design or from the study’s completed status.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Group 1: 37.5μg LT, No Swab | 1 | 203 | 0.5% |
| Group 2: 37.5μg LT, Swab | 3 | 199 | 1.5% |
| Group 3: 0μg LT, No Swab | 0 | 97 | 0.0% |
| Group 4: 0μg LT, Swab | 0 | 101 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Group 1: 37.5μg LT, No Swab | 197 of 203 |
| Group 2: 37.5μg LT, Swab | 192 of 199 |
| Group 3: 0μg LT, No Swab | 90 of 97 |
| Group 4: 0μg LT, Swab | 92 of 101 |
Most frequent serious adverse event terms
| Event term | Organ system | Group 1: 37.5μg LT, No Swab | Group 2: 37.5μg LT, Swab | Group 3: 0μg LT, No Swab | Group 4: 0μg LT, Swab |
|---|---|---|---|---|---|
| Pancreatitis | Gastrointestinal disorders | 1 of 203 | 0 of 199 | 0 of 97 | 0 of 101 |
| Abortion spontaneous | Pregnancy, puerperium and perinatal conditions | 0 of 203 | 1 of 199 | 0 of 97 | 0 of 101 |
| Bipolar disorder | Psychiatric disorders | 0 of 203 | 1 of 199 | 0 of 97 | 0 of 101 |
| Accelerated hypertension | Vascular disorders | 0 of 203 | 1 of 199 | 0 of 97 | 0 of 101 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Group 1: 37.5μg LT, No Swab | Group 2: 37.5μg LT, Swab | Group 3: 0μg LT, No Swab | Group 4: 0μg LT, Swab |
|---|---|---|---|---|---|
| Vaccination site erythema | General disorders | 164 of 203 | 157 of 199 | 44 of 97 | 32 of 101 |
| Vaccination site rash | General disorders | 173 of 203 | 168 of 199 | 9 of 97 | 10 of 101 |
| Vaccination site pruritis | General disorders | 163 of 203 | 156 of 199 | 22 of 97 | 15 of 101 |
| Vaccination site hyperpigmentation | General disorders | 139 of 203 | 138 of 199 | 6 of 97 | 6 of 101 |
| Vaccination site edema | General disorders | 56 of 203 | 73 of 199 | 2 of 97 | 1 of 101 |
| Vaccination site pain | General disorders | 40 of 203 | 47 of 199 | 10 of 97 | 13 of 101 |
| Headache | Nervous system disorders | 33 of 203 | 36 of 199 | 19 of 97 | 18 of 101 |
| Diarrhea | Gastrointestinal disorders | 33 of 203 | 40 of 199 | 14 of 97 | 14 of 101 |
| Malaise | General disorders | 18 of 203 | 25 of 199 | 9 of 97 | 6 of 101 |
Serious events with the highest arm-level rate: abortion spontaneous (0.5%), bipolar disorder (0.5%), accelerated hypertension (0.5%), pancreatitis (0.5%).
The serious adverse-event figures are participant counts by group, paired with the number at risk. The record lists 1 of 203 for Group 1, 3 of 199 for Group 2, and 0 of 97 and 0 of 101 for Groups 3 and 4. These figures describe the posted summaries; they are not comparative estimates and do not establish whether a difference between groups is statistically meaningful.
The registry also lists four serious-event terms with a reported value of 0.5% for each: “Abortion spontaneous,” “Bipolar disorder,” “Accelerated hypertension,” and “Pancreatitis.” The record does not specify the group assignment or further context for these term-level entries in the information. They should not be combined with the group counts or interpreted as evidence of a relationship to treatment.
Seriousness is a safety classification, not a judgment about causation. The registry record does not report investigators’ assessments of whether events were related to LT, placebo, or the application procedure. It also does not provide confidence intervals, adjusted comparisons, or a complete narrative of each serious event. The counts therefore support a descriptive account of reported serious adverse events, not a conclusion about comparative risk or cause.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized, placebo-controlled study designed to examine safety and immune responses to a two-vaccination patch regimen. Its safety summaries show participant counts with serious and other adverse events in four groups defined by patch content and swabbing. Those counts are useful for describing what was recorded in each group, but the record does not provide inferential comparisons or uncertainty estimates.
The available information does not establish that LT, placebo, or swabbing caused any event, nor does it quantify the size or precision of a between-group difference. A zero count in a group is a description of the posted observations, not proof that an event cannot occur. Conversely, an event recorded during a study does not by itself demonstrate that the intervention caused it. Causal interpretation would require fuller clinical context and analyses that are not reported in the registry record.
The primary endpoint is broader than the adverse-event counts alone: it includes clinical laboratory safety and multiple solicited and unsolicited event categories. The record gives definitions and windows for selected solicited symptoms, but does not report all endpoint components or a single primary comparison. Secondary immune-response outcomes are listed, but their results are not included in the record.
Accordingly, the posted results should be understood as a limited descriptive account of selected safety counts, not as a complete statistical evaluation of the trial’s stated objectives. The registry record does not report the analysis populations, missing-data methods, multiplicity handling, or a statistical analysis plan. These gaps make it impossible to assess the precision and robustness of any group contrast from the registry information alone. The completed status indicates the study is recorded as completed; it does not fill those reporting gaps.
13. Why This Trial Matters Statistically
This study is statistically notable for separating two features of the intervention process: patch content and alcohol swabbing. There are LT and placebo groups under both swabbing conditions, so the design presents more than one possible comparison. Interpreting the design well requires distinguishing those questions rather than treating the groups as a single vaccine-versus-placebo contrast. The registry record identifies the four groups but does not report the planned contrasts or analysis used to compare them.
The safety outcome also illustrates a reporting challenge. It spans different kinds of events, a laboratory-safety component, and multiple observation windows. Local symptoms were solicited for the duration of the study, whereas specified systemic symptoms were solicited during the first seven days following each vaccination. Combining such categories into one result can obscure differences in event definition and timing; reporting each component clearly is important for interpretation. The registry record does not reduce the broad endpoint to one comparison.
Finally, the record illustrates the distinction between descriptive results and inferential evidence. Counts by group can show what was recorded, but without an analysis plan, comparative estimates, and uncertainty measures, they cannot establish the precision or statistical significance of group differences. The posted record marks the study completed and gives safety counts, while listing immune-response outcomes without their results. That difference between a stated objective and the results available in the registry is important when assessing how much statistical evidence the record can support.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record does not report a statistical analysis plan, outcome-specific hypothesis tests, confidence intervals, p-values, or adjusted effect estimates. It lists zero analyses and notes that the primary outcome contains several categories or time points rather than one comparison. This prevents assessment of the precision of group differences or the methods used to draw inferential conclusions.
The primary endpoint includes clinical laboratory safety and multiple adverse-event categories, but the record does not provide laboratory results or a complete category-by-group breakdown. It gives definitions for selected solicited events and their observation windows, yet does not report a full account of event ascertainment or repeated events. Serious-event terms are listed without group-specific context in the information recorded.
Analysis populations, participant flow, missing-data methods, and multiplicity handling are not reported in the registry record. The at-risk counts do not explain whether or why participants were excluded from particular summaries. The record also lacks details of the randomization procedure, allocation ratio, masking roles, and swabbing implementation. These omissions constrain assessment of bias and of how closely the reported summaries represent the study’s randomized groups.
The registry lists secondary immune-response outcomes but does not include their results in the reported information. It also does not state how clinical laboratory safety was assessed, or how the different safety components were intended to be summarized. Consequently, the available counts cannot be treated as a complete evaluation of the study’s stated safety and immunogenicity objectives.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity Study of Traveler's Diarrhea Vaccine Patch — NCT01067781.
- Registry record last updated 2020-02-10; status last verified 2020-02.
- Results first posted 2014-03-13.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01067781 is recorded as a completed, randomized, triple-masked, parallel-group phase 2 study sponsored by Intercell USA, Inc. It enrolled 600 healthy adults and compared two LT patch vaccinations with placebo patch vaccinations, with and without alcohol swabbing. The registry describes the study as gender-stratified.
The primary outcome concerns solicited and unsolicited adverse events, clinical laboratory safety, and serious adverse events from Day 0 to Day 180. Group-level safety counts are reported for serious and other adverse events. Secondary outcomes concern LT-specific geometric mean titers, geometric mean fold ratios, and seroconversion rates. The registry record does not report analyses for these outcomes, a statistical analysis plan, or inferential comparisons of the safety groups.