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 of Various Formulations of Live Attenuated Tetravalent Dengue Vaccine in Healthy US Adults (NCT00350337), a randomized phase 2 study. The primary outcome is N Antibody, Geometric Mean Titer(GMT) to Dengue Serotypes 1, 2, 3 and 4.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00350337 |
| Phase | Phase 2 |
| Condition | Dengue |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 86 |
| Arms in the primary outcome | n/a |
| Lead sponsor | U.S. Army Medical Research and Development Command |
| Results posted | Yes |
2. Clinical Question
Population
Healthy US adults enrolled in a Phase II study of candidate dengue vaccines. The registry record lists 86 participants and describes the primary immunogenicity population as unprimed subjects in the primary and booster ATP cohort. Further eligibility criteria and details defining that cohort are not reported in the registry record.
Intervention
Three WRAIR live attenuated tetravalent dengue vaccine formulations: Pre-transfection F17, Post-transfection F17, and Post-transfection F19. The official title describes two doses administered on a 0-6-month schedule. The registry also lists immunogenicity assessments after a third dose; how that assessment relates to the stated dose schedule is not reported in the registry record.
Comparator
Placebo, described as identical in appearance to the dengue vaccine. The study is listed as randomized, controlled, parallel-group, and quadruple-masked. The registry record does not specify which roles were masked or provide the allocation method.
Primary question
How do neutralizing-antibody geometric mean titers to dengue serotypes 1, 2, 3, and 4 change across the listed time points in the vaccine formulation groups? The primary outcome description refers to GMTs and a 95% confidence interval, but no group estimates or comparative analyses are reported in the registry record. Safety and other immunogenicity outcomes are also listed.
The study is titled as an evaluation of safety and immunogenicity, rather than a clinical disease-prevention trial. The registry lists dengue as the condition and describes healthy adults as the study population. Its primary endpoint focuses on antibody titers, a laboratory measure of the immune response. Secondary outcomes include solicited and unsolicited adverse events, serious adverse events, suspected or confirmed dengue during a defined post-vaccination period, seroresponse, physical-examination findings, and measurable viremia.
The practical statistical question is whether the recorded antibody measurements distinguish the formulations over time, and how precise those estimates are. The registry record does not give the titer results, uncertainty intervals, or analysis results needed to answer that question. It also does not report comparative evidence about clinical dengue outcomes. The study’s listed aims and endpoints should therefore be distinguished from findings: endpoints identify what investigators intended to measure, whereas estimates and their uncertainty would be needed to describe what the study observed.
3. Trial Design
This is a Phase II, randomized, controlled, parallel-group study at a single center, according to the official title and registry classifications. The title describes the study as observer-blind; the registry classification lists quadruple masking. The record does not explain which participants, investigators, assessors, or other roles were masked, nor how masking was maintained. Allocation is recorded as randomized, but the randomization sequence, allocation concealment, and group assignment procedure are not reported in the registry record.
The registry lists 86 enrolled participants and four groups: Pre-transfection F17, Post-transfection F17, Post-transfection F19, and placebo. The adverse-event summaries show 22 participants at risk in each F17 group and 21 in each F19 and placebo group. Those figures describe the populations used for the posted safety summaries; they do not establish how many participants contributed to every immunogenicity time point. Group-specific numbers analyzed for the primary outcome are not reported in the registry record.
The official title describes two doses given on a 0-6-month schedule. The primary-outcome timeframe separately lists measurements before dose 1, 1 month after dose 1, 7 months after dose 2, before dose 3, and 1 month after dose 3. These descriptions indicate repeated measurements over time, but the registry record does not explain the role of dose 3 relative to the two-dose schedule in the title. The listed study start is 2006-04-05, primary completion is 2007-06-20, and status is completed.
The interventions are described as three vaccine formulations and a placebo. The registry gives formulation details for the vaccine groups, including vaccine lots, but some arm descriptions are truncated in the record. The placebo is described as a sterile solution containing the same EMEM and virus stabilizer and as identical in appearance to the vaccine. The available record does not provide a full protocol, dose administration details beyond the stated schedule, or reasons for choosing the different formulations.
Enrollment describes the number entered into the study, not necessarily the number with complete measurements at every visit. Reasons for withdrawal, protocol deviations, and the numbers included in each analysis population are not reported in the registry record. Those details matter when interpreting repeated measurements because missing visits can change the participants contributing to estimates at different time points.
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.
Overall Study
| Stage | Pre-transfection F17 | Post-transfection F17 | Post-transfection F19 | Placebo |
|---|---|---|---|---|
| STARTED | 22 | 22 | 21 | 21 |
| COMPLETED | 17 | 19 | 18 | 21 |
| NOT COMPLETED | 5 | 3 | 3 | 0 |
Analysis population for the primary outcome, as defined in the registry: Number of subjects with titer within specified range
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.
| Characteristic | Unit | Pre-transfection F17 | Post-transfection F17 | Post-transfection F19 | Placebo | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 22 | 22 | 21 | 21 | 86 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 22 | 22 | 21 | 21 | 86 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 | 0 |
| Age, Continuous | years | 35.9 (SD 7.75) | 32.8 (SD 6.93) | 33 (SD 8.6) | 35.8 (SD 6.7) | 34.3 (SD 7.54) |
| Sex: Female, Male: Female | Participants | 6 | 11 | 8 | 10 | 35 |
| Sex: Female, Male: Male | Participants | 16 | 11 | 13 | 11 | 51 |
| Region of Enrollment: United States | participants | 22 | 22 | 21 | 21 | 86 |
6. Primary Endpoint
The registry lists the primary outcome as N Antibody, Geometric Mean Titer(GMT) to Dengue Serotypes 1, 2, 3 and 4, measured over Pre dose 1, 1 month post dose 1, 7 months post dose 2, Pre dose 3 and 1 month post dose 3.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | GMT value |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is titled as neutralizing-antibody geometric mean titer (GMT) to dengue serotypes 1, 2, 3, and 4. Measurements are listed before dose 1, 1 month after dose 1, 7 months after dose 2, before dose 3, and 1 month after dose 3. The record identifies the summary parameter as a mean and the dispersion as a 95% confidence interval. Its description refers to GMTs for dengue neutralizing antibodies among unprimed subjects in the primary and booster ATP cohort.
In general, a geometric mean summarizes measurements that are positive and often vary multiplicatively. It is typically calculated after transforming values to a logarithmic scale, averaging there, and transforming back. This can make a central summary more representative than an arithmetic mean when measurements are strongly skewed. The registry’s use of GMT signals that the endpoint is an antibody titer summary, but the precise assay, transformation, handling of values below detection limits, and calculation procedure are not reported in the registry record.
In general, neutralizing-antibody titers are used as an immunogenicity measure because they quantify an antibody response against a specified pathogen serotype in a laboratory assay. They are not, by themselves, a measure of clinical disease prevention. The registry record lists no primary-endpoint values or confidence intervals, so the magnitude and precision of any antibody response cannot be described from the posted results. The endpoint description also refers to the number of subjects with titer within a specified range, without defining those ranges or explaining how that description relates to the GMT outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the study’s intended primary outcome but does not post the primary immunogenicity estimates or results of statistical analyses. It therefore does not establish the observed GMT for any formulation, how antibody measurements changed across time points, or how the groups compared. The record lists zero analyses. Without the estimates and their uncertainty, the statistical size and precision of any observed difference cannot be assessed.
The primary outcome contains multiple serotypes and multiple time points. Each combination could describe a different part of the immune-response profile. A GMT at one visit does not, by itself, describe the pattern at another visit, and a result for one serotype does not automatically extend to the other serotypes. The registry record does not identify a single time point or serotype as the basis for a one-number comparison. Its stated reason for not reducing the primary outcome to one comparison is that it has several categories or time points.
The safety summaries report participants at risk and participants affected. For serious adverse events, the posted counts are 0 of 22 in Pre-transfection F17, 2 of 22 in Post-transfection F17, 1 of 21 in Post-transfection F19, and 1 of 21 in placebo. Deaths are listed as 0 in all four groups. These are descriptive counts. The registry record does not report a statistical comparison, confidence interval, event-level attribution, or an assessment of whether an event was caused by study intervention. The counts alone cannot establish whether group differences are more than chance variation, especially in groups of this size.
For other adverse events, the summaries list 19 of 22 participants affected in Pre-transfection F17, 19 of 22 in Post-transfection F17, 16 of 21 in Post-transfection F19, and 13 of 21 in placebo. The record lists solicited and unsolicited adverse-event outcomes with different observation windows, but the posted summary counts do not clarify which specific event categories or time windows contribute to the “other” totals. They should not be treated as counts of a single named event or as evidence of a causal effect.
The record lists secondary immunogenicity outcomes, suspected or confirmed dengue, viremia, physical-examination findings, and adverse events. It does not provide their outcome estimates or analysis results. Thus, the registry supports describing the planned measurement domains and the posted safety counts, but it does not support conclusions about the comparative immunogenicity results or the statistical uncertainty around them. Any broader interpretation would require results and analysis details that are not reported in the registry record.
9. Statistical Methods Explained
For this study, the registry identifies a continuous primary outcome summarized as a mean, with a 95% confidence interval, and calls the measure a geometric mean titer. The registry record does not report the actual estimates, confidence limits, statistical tests, or fitted models. The following explanations are general statistical context, not a description of analyses confirmed to have been performed in this trial.
What does a confidence interval express?
In general, a confidence interval describes uncertainty around an estimated quantity. A narrower interval indicates greater precision under the statistical procedure used; a wider interval indicates less precision. A 95% confidence interval does not mean there is a 95% probability that a fixed, already-calculated parameter lies inside that particular interval. Rather, the confidence level describes the long-run behavior of the procedure across repeated samples under its assumptions. The registry lists 95% confidence intervals for the primary outcome but does not report their limits or the method used to calculate them.
For a group-specific GMT, an interval would communicate uncertainty in the estimated average antibody level on the geometric scale. To assess a comparison between groups, readers would ordinarily need an estimate of the contrast and its uncertainty, or a clearly specified statistical test. Separate confidence intervals around two group estimates are not always an adequate substitute for an interval for their difference or ratio. The registry record does not report such contrasts or tests.
Why use a geometric mean?
In general, titers are positive measurements that can span a broad range and may be right-skewed. The geometric mean is useful when proportional changes are more meaningful than equal absolute changes, or when a logarithmic scale better describes the distribution. A common procedure is to transform titers to logarithms, calculate an arithmetic mean on that scale, and transform the result back. The resulting summary is expressed on the original titer scale, while its calculation reflects the transformed scale.
That approach requires decisions about values that are zero, below an assay’s detection limit, or otherwise not measurable. It also depends on the measurement scale and assumptions used for uncertainty estimates. The assay, detection limits, transformation details, and rules for handling such values are not reported in the registry record. Therefore, the endpoint label alone does not establish exactly how the GMTs or intervals were calculated.
How should repeated time points be understood?
In general, repeated measurements on the same participant are related: an individual’s antibody values over time are not independent observations. Analyses that model the full trajectory may account for within-participant correlation, whereas separate summaries at each visit may treat each time point as its own descriptive result. Both approaches can answer useful but different questions. The registry lists multiple measurement times, but does not report whether the planned analysis used repeated-measures methods, separate visit-specific summaries, or another method.
Participants may also have missing measurements at later visits. In general, a complete-case analysis uses only participants with the necessary observations, while other methods can use partial records under specified assumptions. These approaches can differ in their assumptions and in the participants contributing to estimates. The registry record does not report missing-data methods, visit-specific analysis counts, or reasons for missing observations.
What do the safety counts represent?
The safety record gives counts of participants at risk and affected for serious events and other adverse events. In general, an affected-participant count is different from an event count: one person may experience more than one event, while a participant-level summary may count that person once. The registry describes occurrences of serious adverse events and other adverse-event outcomes but does not provide enough detail in these summaries to determine all event-level counting conventions. Nor does it report comparative tests or uncertainty intervals for the safety counts.
Small group counts are especially important to interpret cautiously. A difference in counts can reflect random variation, differences in exposure or observation, or other factors; the counts alone do not distinguish among these explanations. A statistical comparison would need a defined estimand, the relevant observation period, and a specified method. The registry record does not report those comparison methods.
What does the planning illustration mean?
In general, a sample-size calculation estimates how many participants would be needed under specified assumptions to detect a chosen effect with a chosen significance level and power. The planning assumptions recorded for this analysis use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. Such calculations are planning illustrations, not evidence that a study had a particular probability of detecting an effect after it was completed. They are not observed power.
The record does not report a protocol-based sample-size justification, the target effect used in the original design, or a planned power calculation. The primary outcome is not reduced to one comparison because it spans several categories or time points. Accordingly, a single planning illustration cannot resolve the study’s multiple-endpoint interpretation or substitute for the missing outcome estimates and analysis results. The registry also does not report whether interim analyses were planned or conducted.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome covers four dengue serotypes and several measurement times. In general, testing multiple outcomes or time points creates a multiplicity issue: the more comparisons considered, the greater the chance that at least one appears statistically notable by chance if no adjustment or prespecified hierarchy is used. A study can address this by defining a primary comparison in advance, controlling the overall error rate, using a hierarchy, or treating results as exploratory. The registry record does not report a multiplicity strategy or specify a single primary time point and serotype for inference.
The registry lists 11 outcome measures and several secondary outcomes, including antibody seroresponse, dengue reports, viremia, physical-examination findings, and adverse events. It does not report which outcomes were prioritized in the analysis, whether any adjustment was used, or how the results were intended to be interpreted as confirmatory or exploratory. The number of listed measures alone does not establish how many statistical tests were performed; the registry lists zero analyses.
Missing-data information is also limited. The record gives enrollment and safety denominators, but does not report participant flow, withdrawals, visit-specific immunogenicity sample sizes, reasons for missing measurements, or imputation methods. In general, missing measurements can affect precision and can introduce bias if the likelihood of missingness relates to outcomes or group assignment. Whether that occurred in this study cannot be determined from the registry record.
The primary description names an unprimed primary and booster ATP cohort, but criteria for inclusion in that analysis population and its size are not reported. The registry does not explain how protocol deviations or incomplete dosing were handled. Without these details, the reported enrollment should not be assumed to be the analysis denominator for every endpoint.
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 |
|---|---|---|---|
| Pre-transfection F17 | 0 | 22 | 0.0% |
| Post-transfection F17 | 2 | 22 | 9.1% |
| Post-transfection F19 | 1 | 21 | 4.8% |
| Placebo | 1 | 21 | 4.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Pre-transfection F17 | 0 of 22 |
| Post-transfection F17 | 0 of 22 |
| Post-transfection F19 | 0 of 21 |
| Placebo | 0 of 21 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Pre-transfection F17 | 19 of 22 |
| Post-transfection F17 | 19 of 22 |
| Post-transfection F19 | 16 of 21 |
| Placebo | 13 of 21 |
Most frequent serious adverse event terms
| Event term | Organ system | Pre-transfection F17 | Post-transfection F17 | Post-transfection F19 | Placebo |
|---|---|---|---|---|---|
| axonal demyelinating polyneuropathy/bilateral upper and lower extremeties | Nervous system disorders | 0 of 22 | 0 of 22 | 1 of 21 | 0 of 21 |
| Rule out cerebral bleed secondary to assualt trauma (physical assault) | Social circumstances | 0 of 22 | 0 of 22 | 0 of 21 | 1 of 21 |
| Hodgkin's disease | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 22 | 1 of 22 | 0 of 21 | 0 of 21 |
| Procedural hypertension | Injury, poisoning and procedural complications | 0 of 22 | 1 of 22 | 0 of 21 | 0 of 21 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Pre-transfection F17 | Post-transfection F17 | Post-transfection F19 | Placebo |
|---|---|---|---|---|---|
| Headache | Nervous system disorders | 14 of 22 | 11 of 22 | 10 of 21 | 9 of 21 |
| Fatigue | General disorders | 10 of 22 | 9 of 22 | 6 of 21 | 7 of 21 |
| Pain | General disorders | 9 of 22 | 3 of 22 | 5 of 21 | 5 of 21 |
| Redness | Injury, poisoning and procedural complications | 8 of 22 | 3 of 22 | 5 of 21 | 5 of 21 |
| Fever >37.5ºC | General disorders | 5 of 22 | 7 of 22 | 3 of 21 | 5 of 21 |
| Swelling | Injury, poisoning and procedural complications | 7 of 22 | 4 of 22 | 5 of 21 | 3 of 21 |
| Muscle aches | Musculoskeletal and connective tissue disorders | 6 of 22 | 5 of 22 | 4 of 21 | 4 of 21 |
| Pain behind the eyes | Eye disorders | 4 of 22 | 7 of 22 | 5 of 21 | 3 of 21 |
| Pruritus | Skin and subcutaneous tissue disorders | 9 of 22 | 3 of 22 | 3 of 21 | 4 of 21 |
| Nausea | Gastrointestinal disorders | 6 of 22 | 5 of 22 | 4 of 21 | 2 of 21 |
Serious events with the highest arm-level rate: axonal demyelinating polyneuropathy/bilateral upper and lower extremeties (4.8%), rule out cerebral bleed secondary to assualt trauma (physical assault) (4.8%), hodgkin's disease (4.5%), procedural hypertension (4.5%).
The posted serious adverse-event summaries list participants affected relative to participants at risk. They report 0 of 22 in Pre-transfection F17, 2 of 22 in Post-transfection F17, 1 of 21 in Post-transfection F19, and 1 of 21 in placebo. The death count is 0 in each group. These figures are descriptive counts, not estimates of a causal effect and not results of a reported statistical comparison.
The record also lists four serious-event terms with percentages: axonal demyelinating polyneuropathy/bilateral upper and lower extremeties, 4.8%; Rule out cerebral bleed secondary to assualt trauma (physical assault), 4.8%; Hodgkin's disease, 4.5%; and Procedural hypertension, 4.5%. The registry record does not explain the denominator or counting method for these percentages, or how the terms relate to the participant-level counts. The terms therefore should not be interpreted as evidence that an event was caused by a vaccine formulation.
In general, serious adverse events are distinct from common or non-serious adverse events, and a participant-level count may not equal the total number of events. The record’s safety counts do not provide event timing, duration, outcome, relatedness assessment, or exposure-adjusted rates. With small groups, descriptive counts have substantial uncertainty, and the absence of a reported statistical comparison means that the counts do not establish a difference between groups.
12. What the Result Does, and Does Not, Mean
The registry record documents a randomized Phase II study comparing three vaccine formulations with placebo and describes immunogenicity and safety outcomes. It identifies antibody GMTs to four dengue serotypes as the primary outcome and provides measurement time points. It also posts descriptive serious-event and other adverse-event counts. These registry entries describe the study’s design and the safety summaries available in the record.
The record does not report primary GMT estimates, confidence-interval limits, group comparisons, or statistical analysis results. Consequently, it is not possible to describe the direction, magnitude, or precision of the antibody findings from the registry record. The absence of posted primary results is not evidence that antibody responses were absent or equivalent across groups; it means the record does not provide the estimates needed to assess them.
In general, an antibody titer is a laboratory measure of immunogenicity. It does not automatically establish prevention of infection or disease. The record lists suspected and confirmed dengue reports and viremia as secondary outcomes, but does not post their results. It therefore does not support a conclusion about clinical dengue outcomes or the relationship between antibody titers and protection in this study.
The safety figures show that serious adverse events were recorded in the vaccine and placebo groups, with the participant counts listed in the registry. They do not, on their own, identify causes or establish comparative risk. The record does not provide detailed event descriptions, attribution, timing, or statistical uncertainty for the group counts. The counts should be read as descriptive observations rather than as proof that any formulation caused, prevented, or changed an adverse event.
More generally, a trial’s title, aims, endpoints, and completed status are not substitutes for outcome estimates. Interpretation of immunogenicity and safety would require the results, analysis populations, missing-data information, and statistical methods. Those details are not reported in the registry record, so conclusions should remain limited to the design and descriptive counts that are posted.
13. Why This Trial Matters Statistically
This study illustrates a common statistical challenge in early clinical research: outcomes can be biologically informative while still requiring careful distinction from clinical outcomes. Here, the primary measure is an antibody GMT across four serotypes and multiple visits. Those repeated, multidimensional outcomes do not naturally reduce to one estimate without a clearly defined comparison and analysis plan.
It also shows why endpoint definitions and reported results must be considered together. The registry names GMT and a 95% confidence interval, while the endpoint description additionally refers to the number of subjects with titers in a specified range. It does not define the ranges or clarify how that description connects to the GMT. Such details matter for interpreting what is being summarized and for reproducing an analysis.
The design includes three formulation groups and placebo, while the posted serious-event counts are small and descriptive. In general, this makes transparent reporting of denominators, event definitions, follow-up, and uncertainty especially important. A raw count can be informative about what was recorded, but it cannot resolve whether a difference between groups is statistically distinguishable or attributable to an intervention.
The record also lists several primary measurement times and secondary outcome domains without reporting analyses. This highlights the importance of prespecifying how multiple outcomes will be handled, which analysis populations will be used, and how incomplete follow-up will be addressed. Without those elements and the resulting estimates, readers can identify the questions the study set out to examine but cannot assess the precision or comparative findings.
Statistically, the key lesson is to separate the trial’s design, its intended endpoints, and its posted results. The registry contains useful design and safety information, but does not report the primary outcome estimates or analysis methods needed for a full assessment of immunogenicity.
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.
Several trial-specific details needed to interpret the results are not reported in the registry record. Most importantly, the primary GMT estimates and their confidence intervals are absent, as are comparative analyses. The record lists several serotypes and measurement times but does not identify a single primary comparison among them. It also does not report a multiplicity strategy.
The outcome description includes both GMTs and the number of subjects with titers within a specified range. The ranges, assay details, and relationship between those descriptions are not reported. The record does not state how values below detection limits were handled, how the GMTs or intervals were calculated, or whether the primary analysis used repeated-measures methods.
Although 86 participants were enrolled, the registry does not provide a participant-flow account or visit-specific denominators for the immunogenicity analyses. The size and inclusion rules for the named ATP cohort are not reported. Missing-data methods, withdrawal reasons, and the handling of protocol deviations are also not reported, limiting assessment of potential selection and missing-data effects.
The title describes two doses on a 0-6-month schedule, while the endpoint timeframe includes a pre-dose 3 measurement and a post-dose 3 measurement. The registry record does not explain this relationship. It also does not provide the randomization procedure, allocation concealment, masking roles, or details sufficient to assess how the single-center design may affect generalizability.
Safety summaries provide counts but not event timing, duration, participant-level narratives, attribution, or uncertainty intervals. The serious-event term percentages are listed without a stated denominator or counting convention. The record does not report a protocol-based sample-size justification, interim-analysis plan, or statistical analysis plan. These gaps limit interpretation of both safety and immunogenicity beyond the descriptive details recorded.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity of Various Formulations of Live Attenuated Tetravalent Dengue Vaccine in Healthy US Adults — NCT00350337.
- Registry record last updated 2021-02-12; status last verified 2021-02.
- Results first posted 2018-10-26.
- 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
NCT00350337 is a completed Phase II, randomized, parallel-group, controlled, single-center study of three WRAIR live attenuated tetravalent dengue vaccine formulations and placebo in healthy US adults. The official title describes an observer-blind study with two doses on a 0-6-month schedule; the registry classification lists quadruple masking. Enrollment was 86. The listed study start is 2006-04-05, and primary completion is 2007-06-20.
The primary outcome concerns neutralizing-antibody GMTs to dengue serotypes 1, 2, 3, and 4 at multiple time points, with a stated 95% confidence interval. Secondary outcomes include adverse events, serious adverse events, dengue reports, antibody seroresponse, physical-examination findings, and viremia. The record posts descriptive safety counts but lists no analyses and does not report primary immunogenicity estimates or analysis methods.