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 This Study Will Describe the Burden of DENgue Fever Virus (DENV) Illness Among Household Members Aged 6 Months to 50 Years of Selected Communities in Latin America and Southeast Asia (NCT02766088), a na na study. The primary outcome is Incidence Percentage of Reverse Transcriptase Quantitative Polymerase Chain Reaction (RT-qPCR) Confirmed Symptomatic Dengue Infection During the Study Period by Study Site.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02766088 |
| Phase | NA |
| Condition | Dengue, Dengue Vaccines |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1750 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Household members aged 6 months to 50 years living in geographically defined communities in Latin America and Southeast Asia. The primary analysis population was the According-to-Protocol cohort: evaluable subjects who met eligibility criteria, followed protocol procedures, and had data from at least one follow-up contact.
Intervention
Blood sample collection was the registered study procedure. The study was observational in its stated purpose: to describe the burden of dengue virus illness, rather than to compare a dengue treatment or vaccine.
Comparator
There was no comparator group. The registry describes a single-group study and lists allocation as not applicable, so the record does not support a treatment-versus-control interpretation.
Primary question
What percentage of subjects had at least one symptomatic dengue infection confirmed by RT-qPCR during the study period, by study site, from Day 0 to Month 24?
The registry frames the question as one of disease burden in selected communities, not as a test of whether an intervention changes risk. Its primary endpoint concerns symptomatic cases that were suspected dengue cases and then confirmed by RT-qPCR. This definition focuses the outcome on illness with laboratory confirmation, rather than on all dengue virus infections or on antibody evidence of past infection.
The study also lists secondary measures concerning dengue-type-specific confirmed symptomatic infections, probable symptomatic infections, antibody positivity at the first visit, and suspected cases with symptoms or severity characteristics. These measures represent different aspects of dengue burden and should not be treated as interchangeable. In particular, antibody positivity at baseline is described as indicative of past infection, whereas the primary endpoint concerns symptomatic infection during follow-up.
The record identifies Mexico and the Philippines in secondary outcome descriptions, while the primary outcome is defined by study site. It does not report primary endpoint values by site, confidence intervals, or a numerical result for the burden question. The clinical question can therefore be described from the registered endpoint and population, but its answer is not reported in the registry record.
3. Trial Design
The record describes a single-group cohort study intended to assess dengue illness burden among household members in selected communities in Southeast Asia and Latin America. Allocation is listed as not applicable, masking as none, and the intervention as blood sample collection. These features fit a descriptive observational aim rather than a randomized comparison of treatment groups. No vaccine or therapeutic intervention is listed as being assigned to participants.
The registered age range was 6 months to 50 years at enrolment. The population description says that subjects lived in geographically defined communities and that the study population comprised household members. It also states that the population should include between 30% and 50% adults aged 18 years or above per site. This is a population-composition description; the record does not report whether that intended composition was achieved at each site.
The registry records enrollment of 1750. It gives a study start date of 2016-07-14 and a primary completion date of 2018-12-14. The status is terminated. The reason for termination and whether the planned follow-up was completed for all participants are not reported in the registry record. The primary endpoint timeframe is Day 0 to Month 24, described as the study end.
The primary analysis population was the According-to-Protocol cohort. It included evaluable subjects who met all eligibility criteria, complied with protocol procedures, and had data from at least one follow-up contact. This is narrower than simply referring to everyone enrolled, although the size of the analysis population is not reported in the registry record.
The study is not a like-for-like control comparison. Its descriptive estimates, if reported, would characterize the observed study population and period. Without a comparator group and a reported comparative analysis, the design cannot estimate a contrast between assigned strategies. The registry also does not report the recruitment methods, site count, follow-up schedule details, or reasons for participant exclusion beyond the analysis-population definition.
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 | Total Group |
|---|---|
| STARTED | 850 |
| COMPLETED | 344 |
| NOT COMPLETED | 506 |
Reasons for not completing this period:
| Reason | Total Group |
|---|---|
| Sponsor study termination | 498 |
| Migrated/moved from the study area | 1 |
| Lost to Follow-up | 5 |
| Other | 1 |
| Death | 1 |
Analysis population for the primary outcome, as defined in the registry: Analysis was performed on the According-to-Protocol cohort that included all evaluable subjects, i.e. subjects who met all eligibility criteria, complying with the procedures defined in the protocol and for whom data of at least one follow-up contact were available.
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 | Total Group |
|---|---|---|
| Participants analysed | 850 | |
| Age, Continuous | years | 17.4 (SD 13.38) |
| Sex: Female, Male: Female | Participants | 456 |
| Sex: Female, Male: Male | Participants | 394 |
| Race and Ethnicity Not Collected | Participants | — |
6. Primary Endpoint
The registry lists the primary outcome as Incidence Percentage of Reverse Transcriptase Quantitative Polymerase Chain Reaction (RT-qPCR) Confirmed Symptomatic Dengue Infection During the Study Period by Study Site, measured over From Day 0 to Month 24 (study end).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | Percentage of subjects |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the incidence percentage of symptomatic dengue infection confirmed by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), reported by study site. It is defined as the percentage of subjects with at least one event reported during the study period, using the number of subjects in the population as the denominator. A confirmed case is a suspected dengue case confirmed by RT-qPCR. The timeframe is Day 0 to Month 24, described as the study end.
This measure is used to describe the proportion of the analysis population experiencing the specified illness during follow-up. Requiring symptoms and RT-qPCR confirmation makes the endpoint more specific than a measure based only on symptoms or antibody status. It does not represent all dengue virus infections: asymptomatic infections are outside the stated endpoint definition, and the record distinguishes this outcome from probable symptomatic infection and antibody positivity indicative of past infection.
The registry specifies a 95% Wald confidence interval for the percentage. A confidence interval expresses the statistical uncertainty around an estimate; its width depends on the observed information and the method used. The registry says a clustering effect was not retained because it was equal to or less than 1. The endpoint description does not provide site-level event counts, denominators, percentages, or confidence limits. Those results are not reported in the registry record, so the magnitude and precision of the observed endpoint cannot be assessed from the record's result information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary endpoint is clearly defined, but the registry record does not report its observed values. In particular, it gives no site-specific numerator, analysis denominator, incidence percentage, or 95% confidence interval. The trial's burden question therefore cannot be answered quantitatively from the registry record. The absence of a reported estimate is not evidence that no infections occurred, and it should not be read as a zero incidence result.
The endpoint is a percentage of subjects with at least one qualifying symptomatic, RT-qPCR-confirmed event during the stated follow-up period. It is not a count of all infections, a rate per unit of person-time, or a measure of disease severity. A subject with repeated qualifying events is represented under the definition as having at least one event; the registry does not report a separate recurrent-event analysis. Results would also depend on case identification, testing, follow-up, and the composition of the analysis population.
The primary analysis was planned for an According-to-Protocol cohort comprising evaluable subjects meeting eligibility criteria, complying with procedures, and having at least one follow-up contact. This definition matters for interpretation: it identifies who contributes to the stated analysis, but the registry does not report how many subjects met that definition or how their inclusion compared with those enrolled. If follow-up or protocol adherence differed across subjects or sites, the estimate could describe a selected subset. Whether that occurred is not reported in the registry record.
The endpoint description states that a 95% Wald confidence interval was calculated. In general, a confidence interval conveys uncertainty in an estimated percentage under its statistical assumptions; it does not address every source of uncertainty, such as selection into the cohort, incomplete ascertainment, or differences between sites. Since neither the estimate nor its interval is reported, neither the observed burden nor the precision of the estimate can be judged.
The record says a clustering effect was not retained because it was equal to or less than 1. This is the stated rationale for the interval calculation, but the record does not give details of the clustering assessment or the site-level data. In general, clustering matters when outcomes among people in the same household or community are more alike than outcomes among people sampled independently. It can affect uncertainty even when the outcome estimate itself is unchanged. The registry's statement should be reported as its analytic choice, rather than treated as evidence that clustering is impossible in this setting.
The study has no registered comparator and is described as single group. Any reported percentage would be descriptive for the analyzed cohort and period, not a causal estimate of an intervention effect. The listed secondary outcomes span laboratory-confirmed symptomatic illness, probable illness, antibody positivity, suspected cases, and severity characteristics. Each addresses a distinct question. Their presence does not fill the gap in the primary endpoint results, and their numerical findings are not reported in the registry record.
The status is terminated, but the reason is not reported in the registry record. Termination alone does not establish that the study stopped early, that follow-up was incomplete, or that a particular result influenced the decision. Those possibilities cannot be resolved from the status field. Interpretation should remain limited to the documented design, endpoint definition, analysis population, and the lack of reported outcome estimates.
9. Statistical Methods Explained
What does the percentage measure? The registered primary measure is a percentage of subjects, not an incidence rate based on person-time. Its numerator is subjects with at least one qualifying event during the study period, and its denominator is subjects in the population. In general, a proportion answers how common an event was in a defined group over a specified observation period. Because the record does not give the numerator or denominator for the primary analysis, the percentage cannot be reconstructed from the enrollment figure. Enrollment and an endpoint-specific analysis denominator are not necessarily the same quantity.
The event definition combines clinical and laboratory criteria. A suspected dengue case must be confirmed by RT-qPCR to count toward the primary endpoint, and the outcome is limited to symptomatic infection. These criteria distinguish the primary endpoint from probable symptomatic infection, suspected cases without the stated confirmation, and dengue virus antibody IgG positivity at the first visit. The last measure is described as indicative of past infection. In general, these measures answer different questions: current symptomatic illness, suspected illness, and evidence consistent with previous exposure should not be conflated.
How should the confidence interval be understood? The registry specifies a 95% Wald confidence interval for the incidence percentage. In general, a confidence interval gives a range of values compatible with the estimate under the method's assumptions and summarizes sampling uncertainty. It is not a guarantee that the true value lies in the interval, nor does it capture every potential bias. A narrow interval can still accompany a systematically biased estimate, while a wider interval indicates less precision under the chosen model. No confidence limits are reported for the primary endpoint, so the statistical precision cannot be evaluated.
The Wald approach uses an approximation for uncertainty around a proportion. General considerations for proportion intervals include the amount of information in the denominator and how close the estimate is to the boundaries of the possible range. The registry does not report the observed proportion or denominator, so it is not possible to assess how those considerations apply to this analysis. No alternative interval method or sensitivity analysis is reported in the registry record.
What is the role of clustering? The registry says the clustering effect was not retained because it was equal to or less than 1. In general, clustering describes dependence among observations in shared settings, such as households or communities. When outcomes within a cluster tend to resemble one another, treating observations as independent can understate uncertainty. Accounting for clustering generally changes the estimated uncertainty, while the basic observed percentage may remain the same. The record does not describe the clustering calculation, specify the unit used to define clusters, or give site-level estimates. Its stated rationale can therefore be reported, but not independently assessed.
Who was analyzed? The primary analysis population is called the According-to-Protocol cohort. The record defines it as evaluable subjects who met all eligibility criteria, complied with protocol procedures, and had data from at least one follow-up contact. In general, an analysis restricted by protocol adherence can differ from an analysis of everyone enrolled. Such a restriction may affect representativeness if inclusion is related to health, exposure, site, or the chance of having an outcome recorded. The record does not report the cohort size, the number excluded, or reasons for exclusion beyond the stated definition.
What can be concluded from a single-group design? A single-group descriptive cohort can characterize observed outcomes in the population under study, if those outcomes are reported. It does not by itself provide a comparison against an alternative intervention or an unexposed control group. In general, causal claims require a suitable comparison and assumptions about how groups differ; this record identifies no comparator and no randomized allocation. The study's stated purpose is to describe burden, so its design should be read in that descriptive frame.
Are the sample-size illustrations observed power? No. The registry's sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. The assumptions say the effect to detect is a stated fraction of the observed effect. These are planning conventions, not evidence that the single-group study had those arms or that it achieved a particular power. The record does not provide a numerical sample-size illustration or report the trial's own sample-size justification. Such planning calculations should not be described as observed power.
In general, power is a design-stage probability of detecting a specified effect under stated assumptions. It does not indicate whether a result is true, nor can it be inferred from whether a result is statistically significant. Since the study has no registered comparator, and primary results are not reported in the registry record, a comparative power interpretation is not supported. The hypothetical equal-allocation assumptions do not change the documented single-group design.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies 10 outcome measures and lists secondary outcomes covering confirmed symptomatic infection by dengue type, study-period infection measures, probable symptomatic infection, antibody IgG positivity at the first visit, suspected cases with temperature and symptoms, and suspected cases with severity characteristics. These outcomes differ in case definition, timing, and meaning. A finding for one would not automatically establish the same pattern for another.
The number of analyses is recorded as 0. Outcome estimates and statistical test results are not reported in the registry record. A multiplicity-adjustment procedure, a hierarchy among secondary outcomes, and a prespecified approach to interpreting multiple comparisons are not reported in the registry record. In general, evaluating many outcomes or comparisons can increase the chance of at least one apparently unusual result, which is why a prespecified strategy can matter. Without reported analyses or a multiplicity plan, the extent to which this issue was addressed cannot be determined.
The primary analysis population is defined by eligibility, adherence to protocol procedures, and availability of at least one follow-up contact. The record does not report how much endpoint data were missing, how missing outcome status was handled, whether participants with incomplete follow-up were excluded, or whether any imputation or sensitivity analysis was used. These details are not reported in the registry record. A requirement for at least one follow-up contact does not, by itself, explain how incomplete follow-up affected the endpoint denominator.
In general, missingness can affect both the precision and the representativeness of an estimate, particularly if the chance of missing data is related to illness or exposure. No conclusion about the direction or size of any such effect is possible from the registry record. The absence of reported endpoint results must not be interpreted as missing events being counted as none.
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 |
|---|---|---|---|
| Total Group | 0 | 850 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Total Group | 1 of 850 |
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 |
|---|---|
| Total Group | 0 of 0 |
The registry's safety information for the Total Group lists 850 subjects at risk for serious adverse events and 0 affected. It also records 1 death. The record lists 0 at risk and 0 affected for other adverse events. No serious adverse event terms are listed.
These fields should be read as separate reported counts, not as an explanation of cause. In particular, the death count does not establish whether the death was related to dengue, the study procedure, or any other cause; that relationship is not reported in the registry record. The record also does not provide narrative details, timing, participant characteristics, or a causality assessment for the death.
A count of 0 affected for serious adverse events is not a substitute for the primary endpoint result. Serious adverse events and symptomatic dengue confirmed by RT-qPCR are distinct measures, with different definitions. The safety fields also do not establish how completely adverse events were ascertained or how the reported at-risk group relates to the primary analysis cohort. Those details are not reported in the registry record.
In general, adverse-event counts are interpreted in light of their definitions, observation period, completeness of reporting, and the population under surveillance. The registry entries support only the counts stated above; they do not establish a causal safety conclusion.
12. What the Result Does, and Does Not, Mean
The registered study addresses a descriptive question: the burden of dengue illness among household members in selected communities in Latin America and Southeast Asia. Its primary endpoint is a percentage of subjects with at least one symptomatic infection confirmed by RT-qPCR during the stated period, assessed by site. This provides a defined framework for describing laboratory-confirmed symptomatic illness in the analysis population.
The registry record does not report the primary endpoint estimate, its denominator, or its confidence interval. It therefore does not establish how frequent the endpoint was in the study population, how much estimates varied by site, or how precisely the burden was measured. The absence of a reported result should not be translated into evidence of no infections or no burden.
The study is single group, with allocation listed as not applicable and no comparator. It cannot support a treatment-effect comparison from the design described in the record. Blood sample collection is the listed procedure, not a therapeutic intervention. The study's results, if available elsewhere, would need to be interpreted according to their definitions, populations, follow-up, and analysis; no unreported results can be inferred from the study title, status, or outcome labels.
The endpoint also has boundaries. It concerns symptomatic cases confirmed by RT-qPCR, rather than every infection, all suspected illness, antibody evidence of prior infection, or disease severity in general. Secondary outcomes address some of these other dimensions, but their numerical findings are not reported in the registry record. The endpoint should therefore be understood as a specific measure of illness, not a comprehensive count of dengue burden.
The record's status is terminated. The reason for termination and its implications for data collection are not reported in the registry record. It cannot be assumed that the study ended as planned or that termination altered the results. Overall, the registry describes a cohort and a measurable endpoint, but it does not provide the numerical outcome needed to quantify the study's finding.
13. Why This Trial Matters Statistically
Statistically, the study is a useful example of why the design and the estimand must be read together. The stated aim is descriptive, the design is single group, and the primary endpoint is a site-specific percentage of subjects with at least one qualifying symptomatic infection during follow-up. That framework differs from a randomized efficacy trial, where the central quantity is often a contrast between assigned groups. Applying a comparative interpretation to this cohort would exceed what the registered design supports.
The endpoint definition also illustrates how case criteria shape an estimand. Requiring symptomatic illness and RT-qPCR confirmation yields a more specific target than counting all suspected cases or antibody positivity. Those other outcomes can be valuable, but they represent distinct states and should be analyzed and interpreted separately. A clear event definition is essential for understanding what a percentage actually describes.
Household members in geographically defined communities also make dependence and population composition relevant statistical considerations. Outcomes may be related among people sharing settings, and the registry explicitly records a decision about retaining a clustering effect. The available record gives the decision but not the calculations or cluster-level details, illustrating why methodological rationale and numerical results are both important for assessing precision.
Finally, a detailed endpoint definition does not replace reporting its estimate. Without event counts, denominators, and confidence intervals, readers cannot evaluate observed burden, uncertainty, or differences by site. The study record shows the distinction between a protocol-level statistical question and a reported statistical answer: the former is documented, while the latter is not reported in the registry record.
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 primary limitation for interpreting this trial record is the absence of numerical outcome results. The registry defines the primary endpoint and confidence-interval method but does not report event counts, denominators, percentages, or confidence limits. The primary question about observed burden therefore remains unanswered by the record.
The status is terminated, but the reason and the effect, if any, on follow-up or data availability are not reported in the registry record. The record gives enrollment of 1750, but not the size of the According-to-Protocol cohort or the number with complete endpoint assessment. It is therefore not possible to assess attrition or determine how the analysis population relates to enrollment.
The study is limited to selected communities and a stated age range of 6 months to 50 years. The record does not report enough site-level information to assess how the enrolled population represents other communities or populations. It states an intended adult composition of between 30% and 50% per site, but whether that composition was achieved is not reported in the registry record.
The primary endpoint captures symptomatic RT-qPCR-confirmed cases, not all infections or all measures of dengue illness. Test availability, case detection, follow-up contact, and protocol adherence may affect which events enter the analysis; the registry does not report detailed procedures or sensitivity analyses for these issues. It also states that a clustering effect was not retained because it was equal to or less than 1, without reporting the assessment details needed to evaluate that decision.
Finally, there is no comparator group, and the registry does not report a multiplicity strategy, missing-data method, or numerical analysis results. These omissions limit both descriptive evaluation and any attempt to draw broader conclusions. The record does not permit conclusions about treatment effects, causal relationships, or the reason the study was terminated.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: This Study Will Describe the Burden of DENgue Fever Virus (DENV) Illness Among Household Members Aged 6 Months to 50 Years of Selected Communities in Latin America and Southeast Asia — NCT02766088.
- Registry record last updated 2024-03-15; status last verified 2024-02.
- Results first posted 2020-04-27.
- 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
NCT02766088 is a terminated, single-group cohort study sponsored by GlaxoSmithKline. Its purpose was to describe dengue virus illness burden among household members aged 6 months to 50 years in selected communities in Latin America and Southeast Asia. Blood sample collection was the listed procedure; allocation was not applicable and masking was none.
The record lists enrollment of 1750, a start date of 2016-07-14, and a primary completion date of 2018-12-14. The primary endpoint was the percentage of subjects with at least one symptomatic RT-qPCR-confirmed dengue infection, by study site, from Day 0 to Month 24. The specified analysis population was the According-to-Protocol cohort, and the planned interval method was a 95% Wald confidence interval.
Primary endpoint results, confidence limits, the reason for termination, and details of missing-data handling are not reported in the registry record. The design supports a descriptive question, not a comparison between treatment groups.