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 A Study to Evaluate the Immunogenicity of Quadrivalent Live Attenuated Influenza Vaccine (LAIV) in Children (NCT01091246), a randomized phase 3 study. The primary outcome is The 4 Post-dose Strain-specific Serum Hemagglutination Inhibition (HAI) Antibody Geometric Mean Titers (GMT) in the Q/LAIV (MEDI3250) Arm Are Noninferior to Those in the Comparator FluMist Group..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01091246 |
| Phase | Phase 3 |
| Condition | Healthy or Stable Chronic Illness |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 2312 |
| Arms in the primary outcome | n/a |
| Lead sponsor | MedImmune LLC |
| Results posted | Yes |
2. Clinical Question
Population
Children 2 to 17 years of age who were healthy or had stable chronic illness. The primary analysis description refers to participants who received an investigational product, had an HAI antibody measurement at the appropriate time, and had no protocol deviation judged to interfere with generating or interpreting an immune response. The full qualifying-population counts are not reported in the registry record.
Intervention
Q/LAIV (MEDI3250), a quadrivalent live attenuated influenza vaccine. The arm description specifies intranasal administration using an Accuspray device. The primary question concerns immune responses after the immunogenicity dose, not the prevention of clinical influenza illness.
Comparator
The FluMist comparator group, described in the primary endpoint as the FluMist group. The listed interventions include FluMist/B/Yamagata and FluMist/B/Victoria. The record also reports an All FluMist Group for adverse-event summaries.
Primary question
At Day 28 post immunogenicity dose, were the strain-specific HAI antibody geometric mean titers in the Q/LAIV arm noninferior to those in the FluMist comparator? The stated criterion required the upper bound of the 2-sided 95% confidence interval for the FluMist-to-Q/LAIV GMT ratio to be no greater than 1.5 for each of the 4 strains.
In general, an immunogenicity comparison asks whether vaccination is associated with a measured immune response, rather than directly comparing illness or other clinical outcomes. Here, the response measure was serum HAI antibody, assessed separately by influenza strain. The question is therefore whether the Q/LAIV response was sufficiently close to the comparator response under the trial’s stated margin, strain by strain.
The registry record identifies the intended noninferiority question and its decision rule, but does not report the four GMT estimates, their ratios, or their confidence intervals. Without those results, the registry record does not establish whether the criterion was met. It also does not report clinical influenza outcomes that would support a conclusion about comparative protection against illness.
3. Trial Design
The registry describes a randomized, quadruple-masked, parallel-group, active-controlled Phase 3 study. Its official title identifies it as an evaluation of quadrivalent LAIV immunogenicity in children. The recorded enrollment is 2312, and the study status is completed. The sponsor is MedImmune LLC. The registry record gives a start date of 2010-03 and a primary completion date of 2010-07.
The study compared Q/LAIV (MEDI3250) with FluMist comparator groups. The intervention list names Q/LAIV, FluMist/B/Yamagata, and FluMist/B/Victoria. The primary endpoint description refers to Q/LAIV and a FluMist comparator, while the adverse-event summary includes an All FluMist Group. Details of how the comparator arms were combined for each analysis are not fully reported in the registry record.
The arm descriptions characterize the vaccines as live attenuated influenza vaccines administered intranasally using an Accuspray device. The description of Q/LAIV states that a 0.2 mL total volume was divided between the nostrils. The comparator descriptions also specify a 0.2 mL total volume divided between the nostrils. The registry text for these descriptions is truncated, so further product or formulation details are not reported in the registry record.
The stated study objective was to demonstrate immunologic noninferiority of Q/LAIV to FluMist in children 2 to 17 years of age. The primary endpoint was assessed at Day 28 post immunogenicity dose. The registry lists 34 outcome measures and 4 analyses, but does not report a detailed statistical analysis plan, randomization procedure, allocation ratio, or masking procedures. The method used to justify the enrollment target is not reported in the registry record.
General design context: randomization is intended to make treatment groups comparable on average, while masking can reduce the influence of expectations on care, assessment, or reporting. An active-controlled design compares the investigational intervention with another vaccine rather than with no intervention. These are general properties of trial design; the registry record does not provide enough detail to assess how each procedure was implemented in this study.
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: Eligible participants were randomized in a 3:1:1 ratio to receive Q/LAIV, FluMist/B/Yamagata, or FluMist/B/Victoria. Randomization was stratified by age (2 to 8 years, 9 to 17 years). For subjects 2 to 8 years of age only, randomization was also stratified by previous seasonal influenza vaccination history.
Overall Study
| Stage | Q/LAIV (MEDI3250) | FluMist/B/Yamagata | FluMist/B/Victoria |
|---|---|---|---|
| STARTED | 1385 | 464 | 463 |
| COMPLETED | 1350 | 448 | 450 |
| NOT COMPLETED | 35 | 16 | 13 |
Reasons for not completing this period:
| Reason | Q/LAIV (MEDI3250) | FluMist/B/Yamagata | FluMist/B/Victoria |
|---|---|---|---|
| Lost to Follow-up | 23 | 11 | 7 |
| Adverse Event | 1 | 0 | 1 |
| Withdrawal by Subject | 9 | 5 | 4 |
| Subject not dosed | 2 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: All participants who received any investigational product (Q=1385; FY=464; FV=463; All FM=927), had post dose HAI antibody measurement at the appropriate time and had no protocol deviation judged to have the potential to interfere with the generation or interpretation of an immune response (Q=1327; FY=445; FV=437; All FM=883).
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 | Q/LAIV (MEDI3250) | FluMist/B/Yamagata | FluMist/B/Victoria | Total |
|---|---|---|---|---|---|
| Participants analysed | 1385 | 464 | 463 | 2312 | |
| Age Continuous | Years | 6.7 (SD 3.8) | 6.8 (SD 3.8) | 6.8 (SD 3.9) | 6.7 (SD 3.8) |
| Sex: Female, Male: Female | Participants | 707 | 229 | 240 | 1176 |
| Sex: Female, Male: Male | Participants | 678 | 235 | 223 | 1136 |
6. Primary Endpoint
The registry lists the primary outcome as The 4 Post-dose Strain-specific Serum Hemagglutination Inhibition (HAI) Antibody Geometric Mean Titers (GMT) in the Q/LAIV (MEDI3250) Arm Are Noninferior to Those in the Comparator FluMist Group., measured over Day 28 post immunogenicity dose.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Full Range |
| Unit | Geometric mean titer |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the set of 4 post-dose, strain-specific serum HAI antibody geometric mean titers. HAI, or hemagglutination inhibition, is a laboratory measure of antibodies that inhibit influenza-virus hemagglutination. The registry describes the outcome in GMT units and sets the assessment time at Day 28 post immunogenicity dose. The four strains are not individually named in the primary endpoint title, but the registry’s secondary outcomes list A/H1N1, A/H3N2, B/Yamagata, and B/Victoria.
A geometric mean summarizes measurements that are commonly analyzed on a multiplicative scale. General statistical context: antibody titers can be highly skewed, and a geometric mean can be more suitable than an arithmetic mean when multiplicative differences are meaningful. The registry record does not report the method used to calculate the GMTs, the underlying distributions, or the handling of measurements below assay limits.
The endpoint uses a ratio with FluMist in the numerator and Q/LAIV in the denominator. The stated noninferiority rule requires the upper bound of the 2-sided 95% confidence interval for that ratio to be no greater than 1.5 for each strain. A confidence interval represents uncertainty around an estimate under the analysis assumptions. For noninferiority, the relevant question is whether the interval excludes values beyond the prespecified margin, not simply whether a conventional difference test is statistically significant.
The registry record does not report the strain-specific GMTs, ratios, or confidence intervals. The endpoint definition alone therefore describes how the comparison was meant to be judged, but cannot show whether the criterion was met.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record states a clear noninferiority rule: for each of the 4 strains, the upper bound of the 2-sided 95% confidence interval for the FluMist-to-Q/LAIV GMT ratio had to be no greater than 1.5. This is a margin-based decision rule. It does not ask whether the treatments are exactly equal; it asks whether the data rule out a comparator-to-investigational ratio beyond the stated boundary, according to the specified confidence interval.
The posted record does not include the primary endpoint estimates needed to apply that rule. In particular, the strain-specific GMTs, ratios, and confidence intervals are not reported in the registry record. The available information therefore does not establish whether Q/LAIV met the noninferiority criterion for any strain, or whether it met the criterion across all strains. A conclusion of noninferiority cannot be drawn from the endpoint definition or the study objective alone.
For a multi-strain endpoint, each strain-specific comparison matters. A favorable result on some strains would not by itself satisfy a rule that requires the criterion for each of the 4 strains. Conversely, the number of comparisons does not reveal their results. The registry record lists 34 outcome measures and 4 analyses, but it does not explain how these measures and analyses relate to the primary testing strategy or how multiplicity was handled.
General statistical context: a confidence interval’s width reflects both the precision of the estimate and the analysis assumptions. A narrow interval can make a margin-based conclusion more decisive; a wide interval may leave the result uncertain even when the point estimate is near the expected value. The registry record does not report the intervals, so their precision cannot be evaluated.
The record includes an analysis-population description that begins with participants who received any investigational product, had an appropriately timed post-dose HAI measurement, and had no protocol deviation considered likely to interfere with immune response generation or interpretation. It lists Q=1385, FY=464, FV=463, and All FM=927 as counts who received investigational product. The subsequent qualifying-population counts are truncated. These counts should not be treated as the numbers included in the primary analysis without the missing eligibility information.
For safety, the registry summary lists serious adverse events affecting 6 participants in the Q/LAIV group and 5 in the All FluMist Group. It also lists other adverse events affecting 176 and 105 participants, respectively. These are descriptive counts, and the record does not provide a comparative statistical analysis of these events. Death counts are not reported in the registry record.
Any planning illustrations based on an observed effect are distinct from trial results and from observed power. The stated assumptions describe a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect set as a fraction of the observed effect. The registry record does not report its own sample-size justification. Since the primary endpoint comprises multiple strain-specific comparisons and is not reduced to one comparison, a single planning interpretation should not be substituted for the endpoint-specific noninferiority assessment.
9. Statistical Methods Explained
General statistical context: a noninferiority trial evaluates whether an intervention’s outcome is not unacceptably worse than that of an active comparator, according to a prespecified margin. The margin is a boundary for the largest difference considered acceptable for the trial’s purpose. In this study, the registry expresses the boundary as an upper limit on a GMT ratio rather than as an absolute difference. The stated rule uses the ratio of FluMist to Q/LAIV, so the direction of the ratio is important when reading the criterion.
The decision rule is based on the upper bound of a 2-sided 95% confidence interval. A confidence interval combines an estimate with a measure of its uncertainty under the statistical model. For a noninferiority conclusion, the upper bound must remain within the specified margin. A point estimate alone is not enough: uncertainty around it also matters. The registry gives the decision rule but does not provide the estimated ratios or intervals, so the result cannot be independently interpreted from this record.
General statistical context: a geometric mean is calculated on a logarithmic scale and then expressed back on the original measurement scale. This approach is often used for measurements whose meaningful differences are multiplicative, such as antibody titers. Ratios of geometric means also have a direct multiplicative interpretation. The registry reports GMT as the endpoint measure, but does not describe the transformation, model, covariates, or exact calculation procedure used in the analysis.
Potential sources of variation include differences in baseline antibody levels, age, prior exposure, and measurement variability. These are general considerations for immunogenicity studies, not details established for this trial. The registry record does not report whether the primary analysis adjusted for baseline measurements or other characteristics. It also does not report the assay’s precision, laboratory procedures, or rules for values outside the measurable range.
General statistical context: over-dispersion occurs when outcome variability is greater than a simple model assumes. In count outcomes, this can make standard errors too small if ignored. The primary endpoint is a geometric mean titer rather than a count, and the registry record does not identify an over-dispersion model or indicate that over-dispersion was assessed. The concept should not be taken as a description of the analysis used in this trial.
For a multi-strain outcome, the decision is naturally evaluated strain by strain because the criterion applies to each of the 4 strains. A result for one strain does not determine the result for another. General statistical context: testing several outcomes can increase the chance of at least one apparently favorable result if each is tested separately without a planned strategy. Methods for addressing multiplicity can include controlling a family-wise error rate, using a hierarchical sequence, or treating outcomes as descriptive. The registry record does not report which approach, if any, was used for the primary endpoint or the 34 outcome measures.
The registry identifies 4 analyses, but does not give enough detail to determine whether these were separate populations, model specifications, strain comparisons, or another set of analyses. The analysis plan, adjustment strategy, confidence-interval construction, and handling of deviations from assumptions are not reported in the registry record. No additional method should be inferred from the number of analyses alone.
General statistical context: a randomized comparison relies on preserving the advantages of assignment by analyzing participants according to a clearly defined population and addressing missing measurements transparently. An analysis restricted to people with post-dose measurements can differ from an analysis that includes everyone randomized, especially if missingness is related to treatment, immune response, or participant characteristics. This is why analysis-population definitions and missing-data rules matter in noninferiority studies. The registry provides a partial population description but does not report a complete flow of participants or the missing-data method.
The record’s population description refers to participants who received an investigational product, had an HAI result at the appropriate time, and had no protocol deviation judged to interfere with immune response generation or interpretation. This is a selected analysis population definition, not necessarily the same as all randomized participants. The full counts for this population are absent from the record. The registry also does not report whether a separate analysis using all randomized participants was performed, or how concordance between analysis populations was considered.
Sample-size calculations are planning exercises, not evidence about the result observed in a completed trial. The stated planning assumptions refer to a two-sided significance level of 0.05, equal allocation, a normal approximation, and a target effect expressed as a fraction of the observed effect. These assumptions do not constitute the trial’s original design justification; that justification is not reported in the registry record. A planning illustration should not be described as observed power, which cannot establish whether the trial result is persuasive.
In this case, the primary endpoint is not reduced to a single comparison because it includes four strain-specific measures. Any single planning scenario based on one selected effect would need careful interpretation and should not be mistaken for the full multi-strain noninferiority assessment. The registry record does not specify a single primary comparison for such an illustration. General statistical context: sample-size planning depends on the chosen margin, expected variability, allocation, desired error rates, and the analysis method. The record does not report all of these design inputs.
The safest interpretation is therefore limited. The registry defines the outcome, assessment time, comparison direction, and noninferiority boundary. It does not provide the statistical details or endpoint estimates needed to verify the analysis or reach a conclusion. General descriptions of noninferiority, confidence intervals, geometric means, multiplicity, missingness, and planning methods explain how such analyses are ordinarily interpreted; they do not fill in the unreported methods or results for this trial.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint contains 4 strain-specific GMT comparisons, and the stated noninferiority criterion applies to each strain. The registry also lists 34 outcome measures and 4 analyses. These details make the analysis strategy important: a reader needs to know which measures were primary, how the strain-specific tests were combined into a study-level conclusion, and whether multiplicity was addressed. The strategy for controlling or interpreting multiplicity is not reported in the registry record.
General statistical context: when several hypotheses are examined, a planned testing strategy can help distinguish confirmatory conclusions from exploratory findings. An all-strains requirement is different from declaring success based on any one favorable comparison. The registry’s criterion explicitly refers to each of the 4 strains, but the record does not report whether additional adjustments or a hierarchical testing procedure were used.
The primary population description includes participants who received an investigational product, had a suitably timed HAI measurement, and had no protocol deviation judged likely to affect immune-response generation or interpretation. The record lists the product-received counts as Q=1385, FY=464, FV=463, and All FM=927, but the text describing qualifying-population counts is incomplete. The full analysis-population sizes, participant flow, and reasons for exclusions or missing measurements are not reported in the registry record.
General statistical context: missing immune measurements can affect both precision and the composition of the analyzed groups. The implications depend on why measurements are missing and on the analysis method. The registry record does not report how missing HAI values were handled, whether imputation was used, or whether sensitivity analyses tested the effect of missing data. It also does not report a complete intention-to-treat analysis or a comparison between analysis populations.
The statistical analysis plan, interim analysis procedures, and sample-size justification are not reported in the registry record. The stated planning assumptions are not a substitute for those trial-specific details.
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 |
|---|---|---|---|
| Q/LAIV (MEDI3250) | 6 | 1382 | 0.4% |
| All FluMist Group | 5 | 923 | 0.5% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Q/LAIV (MEDI3250) | 176 of 1382 |
| All FluMist Group | 105 of 923 |
Most frequent serious adverse event terms
| Event term | Organ system | Q/LAIV (MEDI3250) | All FluMist Group |
|---|---|---|---|
| Urinary tract infection | Infections and infestations | 0 of 1382 | 2 of 923 |
| Appendicitis | Infections and infestations | 1 of 1382 | 0 of 923 |
| Cellulitis | Infections and infestations | 1 of 1382 | 0 of 923 |
| Gastroenteritis salmonella | Infections and infestations | 1 of 1382 | 0 of 923 |
| Sepsis | Infections and infestations | 0 of 1382 | 1 of 923 |
| Head injury | Injury, poisoning and procedural complications | 0 of 1382 | 1 of 923 |
| Humerus fracture | Injury, poisoning and procedural complications | 1 of 1382 | 0 of 923 |
| Lung injury | Injury, poisoning and procedural complications | 0 of 1382 | 1 of 923 |
| Dehydration | Metabolism and nutrition disorders | 1 of 1382 | 0 of 923 |
| Diabetic ketoacidosis | Metabolism and nutrition disorders | 1 of 1382 | 0 of 923 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Q/LAIV (MEDI3250) | All FluMist Group |
|---|---|---|---|
| VOMITING | Gastrointestinal disorders | 36 of 1382 | 20 of 923 |
| COUGH | Respiratory, thoracic and mediastinal disorders | 27 of 1382 | 16 of 923 |
| DIARRHOEA | Gastrointestinal disorders | 22 of 1382 | 19 of 923 |
| RHINORRHOEA | Respiratory, thoracic and mediastinal disorders | 22 of 1382 | 17 of 923 |
| PYREXIA | General disorders | 23 of 1382 | 6 of 923 |
| OTITIS MEDIA | Infections and infestations | 12 of 1382 | 12 of 923 |
| SNEEZING | Respiratory, thoracic and mediastinal disorders | 16 of 1382 | 8 of 923 |
| ABDOMINAL PAIN UPPER | Gastrointestinal disorders | 10 of 1382 | 12 of 923 |
| UPPER RESPIRATORY TRACT INFECTION | Infections and infestations | 8 of 1382 | 11 of 923 |
Serious events with the highest arm-level rate: urinary tract infection (0.2%), sepsis (0.1%), head injury (0.1%), lung injury (0.1%), cerebrovascular accident (0.1%).
The registry’s adverse-event summary gives separate at-risk and affected counts for Q/LAIV (MEDI3250) and the All FluMist Group. For serious adverse events, the at-risk counts are 1382 and 923, and the affected counts are 6 and 5, respectively. For other adverse events, the at-risk counts are 1382 and 923, and the affected counts are 176 and 105, respectively. These counts describe the registry’s reported groups; they do not by themselves establish a treatment-related cause.
The record also lists selected serious adverse-event terms and percentages: urinary tract infection, 0.2%; sepsis, 0.1%; head injury, 0.1%; lung injury, 0.1%; cerebrovascular accident, 0.1%; and major depression, 0.1%. The registry summary does not give enough detail to determine from these terms alone how events were assigned to groups, whether events could be counted more than once, or the precise denominator used for each percentage.
General statistical context: adverse-event counts are descriptive unless a defined comparative analysis is reported. Differences in counts can reflect group size, follow-up, event definitions, and chance, as well as any treatment-related effect. The registry does not report a statistical comparison or causal assessment for these summaries. Death counts are not reported in the registry record. The event counts should therefore be read as safety reporting, not as proof that a vaccine caused or prevented an event.
12. What the Result Does, and Does Not, Mean
The registry record establishes what the study set out to compare: strain-specific HAI antibody GMTs after Q/LAIV or FluMist, with a noninferiority boundary for each of the 4 strains. It also identifies the population of interest as children 2 to 17 years of age and gives the assessment time as Day 28 post immunogenicity dose. These design details clarify the intended statistical question.
They do not establish the result. The primary GMTs, ratios, and confidence intervals are not reported in the registry record. Consequently, the record does not show whether the noninferiority boundary was met for any strain or for all strains. It does not support a conclusion that the immune responses were noninferior, equivalent, or different.
The endpoint is an immunogenicity measure. General statistical context: a laboratory antibody response can be relevant to understanding vaccine-induced immunity, but an immunogenicity endpoint is not the same as a direct clinical outcome. The registry record does not report comparative influenza illness outcomes, so the primary endpoint cannot be used to quantify differences in clinical illness or to make a claim about protection.
The safety summaries report affected counts and selected event terms, but do not provide a comparative statistical analysis or establish causation. They should be interpreted as descriptive reports within the listed groups. The counts alone do not show whether any observed difference is meaningful or attributable to treatment.
The registry records enrollment of 2312 and describes a randomized, quadruple-masked, parallel-group, active-controlled Phase 3 study. These design features explain the planned comparison but do not resolve the missing-result problem. Likewise, the presence of a noninferiority margin does not demonstrate that the study met it. A conclusion requires the relevant estimates, uncertainty intervals, analysis population, and methods, which are not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates a central feature of noninferiority analysis: the conclusion depends on both the direction of the comparison and the prespecified margin. The registry defines the ratio as FluMist divided by Q/LAIV and requires the upper bound of a 2-sided 95% confidence interval to be no greater than 1.5 for each of the 4 strains. Without the ratio estimates and intervals, the decision rule is visible but its application is not.
The multi-strain structure also matters. A study-level conclusion must account for the fact that the primary question covers four separate antibody responses, rather than one pooled measurement. The registry’s wording makes the criterion strain-specific, while its approach to multiplicity is not reported. This is an important distinction when translating a set of immune measurements into a single conclusion.
The record also demonstrates why analysis populations need precise reporting. It gives counts for participants who received an investigational product, then describes additional eligibility conditions for the primary population, but the qualifying counts are truncated. Readers cannot verify from the registry record exactly who contributed to the primary endpoint analysis or how missing post-dose measurements were handled.
More broadly, the study concerns immunogenicity rather than a clinical illness endpoint. Statistical interpretation must remain tied to what was measured. A precisely estimated antibody response would answer a laboratory-response question; it would not, by itself, quantify a clinical outcome. Here, the primary estimates are absent, so even the immunogenicity comparison cannot be evaluated from 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 main limitation for interpretation is that the registry record does not report the primary endpoint results. No strain-specific GMTs, FluMist-to-Q/LAIV ratios, or confidence intervals are available in the record. The stated noninferiority criterion therefore cannot be checked, and the direction or precision of the immune-response comparisons cannot be described.
The primary analysis population is only partially documented. The record reports counts for participants who received investigational product as Q=1385, FY=464, FV=463, and All FM=927, but the text for those meeting the additional measurement and protocol-deviation criteria is truncated. A complete participant flow, including the randomized population and reasons for missing or excluded measurements, is not reported in the registry record.
Statistical details are also limited. The record does not report the statistical model, confidence-interval method, baseline adjustment, missing-data handling, multiplicity strategy, or sensitivity analyses. It lists 34 outcome measures and 4 analyses, but does not explain their relationship to the primary testing plan. The sample-size justification and interim-analysis procedures are not reported in the registry record.
The arm descriptions are truncated, and the registry does not give enough information to reconstruct all product details or the exact analysis-specific handling of comparator groups. The posted safety summaries are descriptive; comparative testing and causal attribution are not reported. Finally, the primary outcome is an antibody measure at Day 28 post immunogenicity dose, not a reported clinical influenza outcome. These limitations constrain conclusions about both the statistical result and its clinical meaning.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study to Evaluate the Immunogenicity of Quadrivalent Live Attenuated Influenza Vaccine (LAIV) in Children — NCT01091246.
- Registry record last updated 2011-09-26; status last verified 2011-09.
- Results first posted 2011-09-22.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry describes a completed randomized, quadruple-masked, parallel-group, active-controlled Phase 3 study sponsored by MedImmune LLC, with enrollment of 2312. It evaluated Q/LAIV (MEDI3250) against FluMist comparator groups in children 2 to 17 years of age who were healthy or had stable chronic illness. The primary endpoint was 4 strain-specific HAI antibody GMTs at Day 28 post immunogenicity dose.
The stated noninferiority criterion required the upper bound of the 2-sided 95% confidence interval for the FluMist-to-Q/LAIV GMT ratio to be no greater than 1.5 for each strain. The registry record does not report the primary estimates or confidence intervals, so whether this criterion was met cannot be determined. It also gives descriptive serious and other adverse-event counts, without reporting a comparative safety analysis. Key analysis details, including multiplicity handling, missing-data methods, and the sample-size justification, are not reported in the registry record.