Innate Immunity and Respiratory Syncytial Virus (RSV) Infection in Children: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Innate Immunity and Respiratory Syncytial Virus (RSV) Infection in Children (NCT00593918), a registered phase not stated study. The primary outcome is Nasal Interferon (IFN)-a2.

2. Clinical Question

The scientific question concerns variation in an inflammatory response associated with a TLR4 genotype during RSV infection. The project description says it would study whether single nucleotide polymorphisms in the TLR4 gene induce varying levels of inflammatory chemokine and cytokine production. Nasal IFN-a2 is the specified primary outcome, measured from nasal lavage samples.

This is not a randomized treatment question. Genotype defines the groups, and the record does not state that participants were assigned to them. The comparison therefore concerns an association between genotype group and an immune measurement in the analyzed children; it cannot by itself establish that genotype caused a difference in the measurement. The registry record does not report the endpoint results needed to judge whether the groups' concentrations differed.

3. Trial Design

The registry identifies this completed study as “Innate Immunity and Respiratory Syncytial Virus (RSV) Infection in Children,” sponsored by the University of Wisconsin, Madison. The listed condition is RSV infection. The study start is recorded as 2003-11, primary completion as 2008-05, and status as COMPLETED. Enrollment is listed as 91.

The comparison divides children by TLR4 -2026 genotype: GG, and AG/AA. The GG genotype is described as the group of interest and hypothesized to be associated with less inflammation; AG/AA are described as control genotypes hypothesized to be associated with more inflammation. These are hypotheses in the arm descriptions, not findings. The record explicitly notes that this is not a randomized comparison, that allocation is not stated, and that the arms are not a like-for-like control comparison. The genotype-based grouping should therefore not be interpreted as an assigned intervention versus a randomized control.

The primary outcome is a continuous measurement: nasal IFN-a2, expressed in pg/ml. It was measured from nasal lavage samples by a Luminex multiplex assay during the timeframe “1-5 days during acute illness (not after day 5 of illness).” The analysis is described as per protocol, based on the number of children enrolled by genotype who completed nasal washes at the first visit.

The record lists 2 outcome measures and 2 analyses, but does not describe the other outcome or provide details of the analyses. It does not report the full protocol, allocation process, recruitment approach, or sample-size justification. These design details should not be inferred from the study title or the genotype hypotheses.

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.

Before assignment: Patients were enrolled if they met the enrollment criteria

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was per protocol based on the number of children enrolled by genotype and completed nasal washes at first visit.

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.

6. Primary Endpoint

The registry lists the primary outcome as Nasal Interferon (IFN)-a2, measured over 1-5 days during acute illness (not after day 5 of illness).

The primary endpoint is nasal interferon-a2 (IFN-a2), a continuous measurement reported in pg/ml. According to the registry, IFN-a2 was measured in nasal lavage samples using a Luminex multiplex assay. The specified collection window was 1-5 days during acute illness, excluding measurements after day 5 of illness.

As general context, a nasal immune marker can be used to describe part of the local inflammatory response during a respiratory infection. A continuous endpoint retains the measured concentration rather than reducing it to categories such as high or low. Comparing group means can therefore address whether the average measured concentration differs across the genotype groups. The meaning of any difference depends on the measurement method, timing, variability, and the characteristics of the analyzed participants.

The registry identifies the endpoint summary as a mean with standard deviation. A mean describes the average in the analyzed group, while a standard deviation describes variation among measurements around that average. Neither statistic is reported numerically in the registry record for this endpoint. The record also does not report a numerical effect estimate, confidence interval, or test result. Consequently, it is not possible to describe the size, direction, or precision of a group difference from the information recorded.

The endpoint is an immune measurement, not a direct measure of clinical recovery or disease severity. The registry’s hypothesis about inflammation does not establish how IFN-a2 relates to symptoms or other clinical outcomes in this study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is continuous: nasal IFN-a2 in pg/ml. The registry identifies the summary as a mean and standard deviation, and describes a per-protocol analysis. It does not report numerical endpoint summaries or a numerical comparison. The methods below explain how such statistics are generally read; they do not establish which unreported procedures were used in this study.

What does a mean describe?

In general, the mean is the arithmetic average of observed measurements in an analysis group. A comparison of group means describes the difference in average concentration between the groups as analyzed. It is important to distinguish this descriptive contrast from a causal effect. Here, the groups are defined by genotype, not by randomized treatment assignment, and the registry cautions that they are not a like-for-like control comparison. Any mean contrast would therefore describe an association in the analyzed participants unless stronger assumptions and supporting analyses were available.

What does the standard deviation add?

In general, the standard deviation describes how dispersed individual measurements are around their group mean. A larger standard deviation indicates more variability among measurements; it is not the uncertainty of the mean itself. The standard error and a confidence interval are commonly used to express uncertainty in an estimated mean or contrast, but the registry record does not report these statistics for IFN-a2. It also does not report the observed standard deviations.

How should a confidence interval be read?

In general, a confidence interval gives an uncertainty range for an estimate under a specified method and its assumptions. For a group contrast, the interval helps show which effect sizes are compatible with the observed data and the analysis approach. An interval spanning values on both sides of no difference would indicate uncertainty about the direction of the contrast; an interval excluding no difference would still need to be interpreted in light of design limitations, measurement, and multiplicity. No confidence interval is reported in the registry record, so none of these interpretations can be applied to this endpoint’s result.

What can a p-value say?

In general, a p-value measures how unusual data at least as discrepant as those observed would be under a specified null hypothesis and statistical model. It is not the probability that the null hypothesis is true, nor does it quantify effect size or clinical importance. The registry record does not report a p-value for the primary endpoint. The sample-size assumptions mention a two-sided significance level of 0.05 for a planning illustration; that planning assumption is not a reported endpoint test result and does not establish that this threshold was the trial’s analysis plan.

Why does the analysis population matter?

The registry describes the primary analysis as per protocol, based on children enrolled by genotype who completed nasal washes at the first visit. In general, an analysis limited to participants with the required measurement can differ from an analysis of everyone enrolled if measurement availability relates to participant characteristics or outcome values. The record does not report the number analyzed by genotype for this endpoint, reasons for unavailable nasal washes, or a missing-data method. The impact of incomplete measurement therefore cannot be assessed.

What is the role of the planning assumptions?

The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is a stated fraction of the observed effect. The record also distinguishes planning illustrations from observed power. These are planning concepts, not evidence that the study had a particular power or that its design used those assumptions. No numerical planning results are reported in the available record. Sample-size illustrations should be read as hypothetical planning quantities rather than as observed findings or as a substitute for an estimate and its uncertainty.

For a continuous outcome, a normal approximation is a general method that can be used for some planning or inference calculations. Whether it is appropriate depends on the data and model assumptions. The registry record does not provide diagnostics, distributional summaries, or a detailed statistical plan for the endpoint. No specific model, transformation, variance assumption, or adjustment procedure should therefore be attributed to this analysis beyond the endpoint description and per-protocol population recorded.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Toll-like Receptor 4 GG Genotype", "Toll-like Receptor 4 AG/AA Genotypes")
n   <- c(17, 74)
m   <- c(10, 26)
sp  <- c(3, 31)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Toll-like Receptor 4 GG Genotype  17  10.000  3.000  8.458  11.542
CARM  Toll-like Receptor 4 AG/AA Genotypes  74  26.000  31.000  18.818  33.182

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and 2 analyses. It does not identify the other outcome, describe the analysis corresponding to each outcome, or state whether the primary endpoint was part of a wider family of statistical tests. A multiplicity adjustment, if any, is not reported in the registry record. Without that information, the handling of multiple outcomes or analyses cannot be evaluated, and no adjustment should be assumed.

The primary outcome analysis is described as per protocol, based on children enrolled by genotype who completed nasal washes at the first visit. The record does not state the endpoint-specific number analyzed in either genotype group, the number without a completed wash, or reasons measurements may have been missing. It does not describe imputation, exclusion rules beyond the stated analysis population, or sensitivity analyses for missing data. The consequences of missing measurements therefore cannot be determined from the record.

As general context, missingness can affect an estimate when the chance of a measurement being unavailable is related to the participant or the unobserved value. An analysis of completed measurements is most straightforward to interpret when the reasons for non-completion are understood. The per-protocol description clarifies that completion of nasal washes at the first visit was part of the analysis basis, but does not explain whether included and non-included children differed.

The record does not report an intention-to-treat analysis, and the comparison is not described as randomized. No statistical analysis plan, prespecified hierarchy, multiplicity procedure, or sensitivity-analysis strategy is reported in the registry record. These absences limit assessment of how robust or confirmatory the reported analysis would be, even if numerical results were available.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists serious and other adverse-event counts by genotype group. For the TLR4 GG group, 17 were listed as at risk and 0 as affected for serious events; 17 were listed as at risk and 0 as affected for other events. For the TLR4 AG/AA group, 74 were listed as at risk and 0 as affected for serious events; 74 were listed as at risk and 0 as affected for other events.

These entries mean that the registry reports zero affected participants in the listed categories for these groups. They should not be read as proof that no adverse experiences occurred in any broader sense, or as evidence that the genotypes differ in safety. The registry record does not provide serious-event terms, and it does not report death counts; the death entries are not available in the record. The adverse-event data also do not change the fact that genotype groups are not randomized treatment arms.

As general context, zero reported events in a registry entry does not establish that the underlying risk is zero. Interpretation depends on how events were collected, defined, monitored, and reported. Those details are not reported in the registry record. These safety figures should therefore be read narrowly as the posted counts, not as a comprehensive safety assessment.

13. What the Result Does, and Does Not, Mean

The study record establishes a focused biological question: whether nasal IFN-a2 during acute RSV illness differs across TLR4 -2026 genotype groups. It identifies the assay, measurement units, collection window, summary type, and per-protocol analysis population. It also records the investigators’ hypotheses about the expected inflammatory direction in the genotype groups. These details define what the primary comparison was intended to address.

The record does not include the primary endpoint results. Group means, standard deviations, an effect estimate, a confidence interval, and a p-value are not reported in the registry record. As a result, the available information does not show whether IFN-a2 concentrations were higher, lower, or similar across groups, nor how precisely any contrast was estimated. The stated hypotheses cannot be substituted for observed findings.

Even with a reported contrast, this design would address an association between genotype and an immune marker, rather than a randomized treatment effect. The registry explicitly cautions that the arms are not a like-for-like control comparison, and allocation is not stated. The record does not report adjustment for other factors that might relate to the measurement. Causal interpretation would therefore require evidence and assumptions beyond the endpoint description.

The measurement is specific to nasal IFN-a2 obtained during the recorded acute-illness window. It does not by itself describe every inflammatory pathway, all stages of RSV illness, or broader clinical outcomes. The study description gives a rationale involving chemokine and cytokine production, but the registry record does not report results for those broader biological questions. The endpoint should be understood as one measured marker, not a complete account of immune function.

The appropriate conclusion is limited: the registry records a completed genotype-based study and its primary measurement, but does not report enough outcome statistics to judge the observed association. It neither confirms nor refutes the stated hypothesis on the basis of the available endpoint record.

14. Why This Trial Matters Statistically

This trial is statistically instructive because its group labels can easily be mistaken for treatment and control arms. The registry identifies a genotype of interest and a comparison genotype group, but explicitly says the comparison is not randomized and the arms are not a like-for-like control comparison. Keeping the distinction between a biological grouping and an assigned intervention is essential when interpreting contrasts and avoiding causal claims unsupported by the design.

The endpoint also illustrates why a study question and a result are different things. The registry describes a continuous biomarker, the assay, the measurement window, and the intended summary as a mean with standard deviation. Yet it does not report the numerical endpoint results. A well-defined outcome does not reveal the direction, magnitude, or precision of a difference without the corresponding data summaries and uncertainty estimates.

The per-protocol population makes analysis membership relevant. Children needed to be enrolled by genotype and to have completed nasal washes at the first visit. The record does not report endpoint-specific analyzed counts or explain unavailable measurements. This highlights the importance of distinguishing overall enrollment from the population contributing to a particular outcome and of understanding how measurement completion may affect interpretation.

Finally, the record lists multiple outcomes and analyses without detailing their identities or how multiplicity was handled. This limits the ability to assess whether a result, if available, was exploratory or part of a prespecified confirmatory strategy. Together, these features make transparent reporting of analysis populations, estimates, uncertainty, missingness, and multiplicity particularly important for interpreting genotype-associated biomarker studies.

15. 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 central limitation of the registry record for interpreting the primary endpoint is that it does not report numerical results. No group means, standard deviations, between-group contrast, confidence interval, or p-value are recorded. The direction, size, and precision of the endpoint association therefore cannot be evaluated.

The study is not described as randomized, allocation is not stated, and the registry cautions that the arms are not a like-for-like control comparison. The group contrast is consequently not equivalent to a randomized treatment comparison. The record does not describe participant characteristics by genotype or covariate adjustment, so potential differences between groups and their handling cannot be assessed.

The endpoint analysis was per protocol and depended on completion of nasal washes at the first visit. The record does not report the number contributing to the primary analysis by genotype, the extent or reasons for missing measurements, or methods used to address missing data. Overall enrollment does not resolve those endpoint-specific uncertainties.

The outcome is limited to nasal IFN-a2 measured by Luminex from nasal lavage during 1-5 days of acute illness, not after day 5. Results for other illness windows or other inflammatory measures are not reported in the record. Although 2 outcome measures and 2 analyses are listed, their full descriptions and any multiplicity strategy are not reported. The statistical plan, sample-size justification, model details, and sensitivity analyses are also not reported in the registry record.

The adverse-event entries list zero affected participants in the recorded categories, but event-collection and reporting procedures are not described, and death counts are not reported. These registry entries cannot establish absence of all adverse experiences. Collectively, these limitations constrain conclusions about both the endpoint association and the broader biological or clinical meaning of the study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Innate Immunity and Respiratory Syncytial Virus (RSV) Infection in Children — NCT00593918.
• Registry record last updated 2015-10-20; status last verified 2015-09.
• Results first posted 2010-05-13.
• 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.

19. Record Summary

The registry record describes a completed study of innate immunity and RSV infection in children, sponsored by the University of Wisconsin, Madison. It lists enrollment of 91, a study start of 2003-11, and primary completion of 2008-05.

The primary endpoint is nasal IFN-a2 in pg/ml, measured by Luminex from nasal lavage during 1-5 days of acute illness, not after day 5. The analysis is described as per protocol and based on children enrolled by genotype who completed nasal washes at the first visit. The comparison is between TLR4 -2026/GG and AG/AA genotypes, with no randomized allocation stated.

The registry record does not report the primary endpoint’s numerical results, analysis details beyond the population description, or a multiplicity strategy. It lists 2 outcomes and 2 analyses. Serious and other adverse-event entries list zero affected participants in the genotype groups; death counts are not reported. The record supports describing the study question and its limitations, but not drawing a conclusion about the observed IFN-a2 difference.