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 Clinical Study to Evaluate the Safety, Immunogenicity and Efficacy of Investigational Flu Vaccine Compared to Approved Flu Vaccine in Children. (NCT01964989), a randomized phase 3 study. The primary outcome is Efficacy Endpoint: First-Occurrence Reverse Transcription-Polymerase Chain Reaction (RT-PCR) Confirmed Influenza A and/or B of Any Influenza Strain in Subjects ≥6 to <72 Months of Age.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01964989 |
| Phase | Phase 3 |
| Condition | Influenza Virus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 10644 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Seqirus |
| Results posted | Yes |
2. Clinical Question
Population
Children ≥6 to <72 months of age. The primary efficacy population was the Full Analysis Set for Efficacy: enrolled subjects who received a study vaccination and were evaluated for efficacy at least 21 days after the last vaccination.
Intervention
Adjuvanted Quadrivalent Subunit Influenza Virus Vaccine (aQIV), evaluated for safety, immunogenicity and efficacy.
Comparator
Non-adjuvanted influenza vaccine: Trivalent Influenza Vaccine (TIV) or Quadrivalent Influenza Vaccine (QIV), as applicable to the study period.
Primary question
How many children in the efficacy population had a first occurrence of RT-PCR-confirmed influenza A and/or B of any influenza strain after vaccination, comparing aQIV with the non-adjuvanted comparator? The primary endpoint counted cases during the specified post-vaccination follow-up period. A comparative estimate of this endpoint is not reported in the registry record.
The question is about a clinical outcome, rather than antibody response alone: whether laboratory-confirmed influenza occurred in the defined follow-up period. The registry describes efficacy as relative efficacy and specifies which influenza strains were considered common to the vaccines. It also lists secondary efficacy outcomes based on age groups, culture confirmation, risk status, vaccination history and timing. These are distinct questions and should not be treated as interchangeable with the primary endpoint.
General: a randomized comparison can estimate differences between assigned treatment groups while reducing the influence of baseline factors, especially when allocation and follow-up are handled as planned. Interpretation still depends on the endpoint definition, the population included in the analysis and the precision of the estimate. The registry record gives the primary endpoint definition and efficacy population, but does not report the primary comparison estimate or its precision.
3. Trial Design
This was a Phase III, randomized, stratified, observer-blind, controlled, multicenter study with a parallel-group model. The registry lists quadruple masking. The study evaluated an adjuvanted quadrivalent subunit influenza vaccine against a non-adjuvanted comparator, identified as TIV or QIV. The listed enrollment was 10644.
The study began in 2013-11, had primary completion in 2015-10 and is marked completed. The registry summary says it was conducted during the 2013/2014 and 2014/2015 northern hemisphere influenza season. The official title describes children ≥6 to <72 months of age, matching the age range in the primary endpoint.
Randomization assigns participants to study groups by chance. Stratification generally means allocation is organized within specified categories, but the categories and the details of the allocation procedure are not reported in the registry record. The record does not describe the masking procedures or specify which people were masked. It identifies the study as observer blind and lists quadruple masking; those labels alone do not establish precisely how masking was implemented.
General: a parallel-group design compares outcomes in separate groups assigned to different interventions. In a controlled trial, the comparator provides the reference for interpreting outcomes in the intervention group. The registry identifies the comparator as non-adjuvanted TIV/QIV, but does not report the specific allocation ratio or the number of enrolled participants in each arm.
The registry lists 23 outcome measures and 40 analyses. This indicates that the record covers multiple outcome definitions and analyses, not just the primary efficacy endpoint. The statistical plan, including any planned interim analyses, is not reported in the registry record. The sample-size justification is also not reported in the registry record.
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: All enrolled subjects were included in the trial. Non-naive participants received 1 dose of vaccine on Day 1 only. Naive participants received 2 doses of vaccine, the first dose on Day 1 and the second dose on Day 29.
Overall Study
| Stage | aQIV (≥6 to <72 Months) | TIV/QIV (≥6 to <72 Months) |
|---|---|---|
| STARTED | 5352 | 5292 |
| COMPLETED | 4568 | 4545 |
| NOT COMPLETED | 784 | 747 |
Reasons for not completing this period:
| Reason | aQIV (≥6 to <72 Months) | TIV/QIV (≥6 to <72 Months) |
|---|---|---|
| Protocol Violation | 3 | 4 |
| Administrative Reason | 103 | 95 |
| Adverse Event | 0 | 1 |
| Death | 1 | 3 |
| Withdrawal by Subject | 156 | 160 |
| Lost to Follow-up | 254 | 232 |
| Other | 267 | 252 |
Analysis population for the primary outcome, as defined in the registry: The Full Analysis Set for Efficacy consisting of all enrolled subjects who actually received a study vaccination and were evaluated for efficacy at least 21 days after the last vaccination was used for analysis.
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 | aQIV (≥6 to <72 Months) | TIV/QIV (≥6 to <72 Months) | Total |
|---|---|---|---|---|
| Participants analysed | 5352 | 5292 | 10644 | |
| Age, Continuous | months | 38.4 (SD 18.43) | 38 (SD 18.40) | 38.2 (SD 18.42) |
| Sex: Female, Male: Female | Participants | 2643 | 2590 | 5233 |
| Sex: Female, Male: Male | Participants | 2709 | 2702 | 5411 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 664 | 632 | 1296 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 4678 | 4647 | 9325 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 10 | 13 | 23 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 10 | 11 | 21 |
| Race (NIH/OMB): Asian | Participants | 2348 | 2361 | 4709 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 14 | 16 | 30 |
| Race (NIH/OMB): Black or African American | Participants | 711 | 692 | 1403 |
| Race (NIH/OMB): White | Participants | 2153 | 2091 | 4244 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 116 | 121 | 237 |
| Naivety Status: Vaccine Naive | Participants | 3611 | 3597 | 7208 |
| Naivety Status: Vaccine Non-Naive | Participants | 1741 | 1695 | 3436 |
6. Primary Endpoint
The registry lists the primary outcome as Efficacy Endpoint: First-Occurrence Reverse Transcription-Polymerase Chain Reaction (RT-PCR) Confirmed Influenza A and/or B of Any Influenza Strain in Subjects ≥6 to <72 Months of Age, measured over ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season (Northern Hemisphere: end of June; Southern Hemisphere: end of December; Philippines/Thailand: end of October), whichever was longer.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Number of cases |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint counts first occurrences of RT-PCR-confirmed influenza A and/or B of any influenza strain in children ≥6 to <72 months of age. The registry specifies assessment from ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer. The listed season endpoints differ by region: end of June in the Northern Hemisphere, end of December in the Southern Hemisphere, and end of October in the Philippines/Thailand.
The registry says efficacy was determined using cases caused by influenza strains related to the two A subtypes and B lineage or lineages common to the vaccines. For the first influenza season, these were A/H1N1, A/H3N2 and B/Yamagata. During the second season and through the end of the trial, the listed common strains were A/H1N1, A/H3N2 and both B lineages.
General: RT-PCR is a laboratory method used to detect viral genetic material. A confirmed-case endpoint makes the outcome depend on both the occurrence of illness and confirmation under the stated testing definition. Counting first occurrences gives a defined event for each participant, rather than counting repeated episodes as separate primary events. Such endpoints are useful for comparing clinical disease outcomes under a prespecified follow-up definition. The registry record does not report a comparative case count or effect estimate for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary efficacy question but does not report the primary comparative result. In particular, the record does not report the number of primary endpoint cases by group, a relative efficacy estimate, a confidence interval or a p-value. The outcome is therefore defined, but its estimated between-group contrast and statistical precision cannot be described from the registry record.
The record states that the primary outcome was the number of children with first-occurrence RT-PCR-confirmed influenza A and/or B during the specified follow-up period. The efficacy population included enrolled participants who received a study vaccination and were evaluated for efficacy at least 21 days after the last vaccination. These criteria matter because a result from that population would not automatically describe all enrolled participants or all children in the age range.
Several secondary outcomes are listed, including RT-PCR-confirmed and culture-confirmed influenza, age subgroups, participants at high risk of influenza complications, vaccine-naive and non-naive participants, and analyses using different post-vaccination windows. The registry also lists immunogenicity outcomes based on hemagglutination inhibition antibody responses. These outcomes address different aspects of efficacy or immune response. Without reported estimates, they cannot establish the direction or size of any comparison.
General: an effect estimate describes the observed contrast between groups, while a confidence interval conveys the range of values compatible with the data under the analysis assumptions. A narrow interval indicates greater precision than a wide interval; neither interval width nor a p-value alone establishes clinical importance. No confidence interval or hypothesis-test result for the primary endpoint is reported in the registry record, so precision and statistical compatibility with possible effects cannot be assessed.
The registry reports 10644 enrolled participants, but enrollment alone does not reveal how many participants contributed to the primary efficacy analysis. The registry-defined efficacy population requires vaccination and evaluation after a specified interval. The numbers in that analysis population, the group-specific case counts and missing outcome counts are not reported in the registry record.
The safety entries provide group counts for participants at risk and affected, as well as deaths and selected serious adverse-event terms. Those descriptive entries are not a substitute for the missing efficacy comparison. They also do not, by themselves, establish that an event was caused by a study vaccine. The registry record does not report an interpretation of the safety comparisons.
Accordingly, the record supports a description of the trial question, design and endpoint definitions, but not a conclusion about the magnitude, direction or precision of the primary efficacy contrast. That limitation is about what is reported in the registry record, not evidence for or against an effect.
9. Statistical Methods Explained
What does the primary endpoint count?
The primary measure is the number of participants with a first occurrence of RT-PCR-confirmed influenza A and/or B of any influenza strain. The stated follow-up begins at least 21 days after the last vaccination and continues through no more than 180 days after that vaccination or until the end of the influenza season, whichever was longer. The region-specific season endpoints are also specified in the registry record. This definition identifies the event, the confirmation method, the population age range and the time window that would govern an efficacy analysis.
General: a case definition improves consistency by specifying what qualifies as an outcome. A result using a different test, time window or influenza strain definition would address a different outcome and might not be directly comparable. The registry lists several secondary endpoints that change one or more of these features, including culture confirmation, age range and timing after vaccination.
What does randomization contribute?
The registry describes a randomized, stratified, controlled, parallel-group study. General: randomization uses chance to assign participants, helping balance measured and unmeasured participant characteristics across groups on average. It does not guarantee exact balance in any particular trial. Stratification generally organizes randomization within categories, but the categories and implementation details are not reported in the registry record.
A parallel-group comparison follows separate groups assigned to aQIV or the non-adjuvanted TIV/QIV comparator. The record labels the study observer blind and lists quadruple masking. General: masking can reduce bias when expectations might influence participant behavior, clinical assessment, testing or outcome reporting. The registry record does not describe who was masked or how masking was maintained.
Why does the analysis population matter?
The Full Analysis Set for Efficacy is defined as enrolled subjects who actually received a study vaccination and were evaluated for efficacy at least 21 days after the last vaccination. This is the population the registry says was used for the primary efficacy analysis. The record does not report the number in this population or how participants who lacked evaluation were handled.
General: analysis populations define which participants contribute to an estimate. Excluding participants can affect interpretation, particularly if inclusion depends on events after randomization or if missing outcomes differ between groups. The registry’s population definition is available, but the handling of missing data, protocol deviations and participants who did not meet the analysis criteria is not reported in the registry record.
How should the primary comparison be understood?
The registry says relative efficacy was determined using the number of participants with the defined influenza outcome in the vaccine groups. However, no comparative estimate, case counts, confidence interval or p-value for the primary endpoint is reported in the registry record. Without those results, the observed contrast and its uncertainty cannot be characterized.
General: an effect estimate is the numerical summary of a comparison. A confidence interval expresses uncertainty around that estimate under the method’s assumptions; a p-value summarizes how compatible the observed data are with a specified null hypothesis, also under assumptions. These statistics answer related but different questions. Neither should be interpreted without the endpoint definition, analysis population and study design.
What do multiple outcomes imply?
The registry lists 23 outcome measures and 40 analyses. The secondary outcomes span efficacy, age subgroups, risk categories, vaccination history, timing and immunogenicity. General: examining many outcomes or subgroups can increase the chance of finding an apparently notable result by chance if each is tested separately. Methods to address multiplicity may include prespecifying a hierarchy or adjusting inference, but the registry record does not report whether such methods were planned or used. It also does not report the complete statistical analysis plan.
How should planning calculations be read?
General: sample-size planning illustrations ask how many participants might be needed under assumed design conditions and a target effect. They are not observed trial results, and they do not show the probability that a completed study has established an effect. A planning illustration based on a fraction of an observed effect is conditional on that assumption. The registry record does not report the trial’s own sample-size justification, and no primary effect estimate is reported in the registry record from which to assess such planning assumptions.
General: over-dispersion matters when outcome variability exceeds what a statistical model assumes; standard errors and confidence intervals can then be misleading if the extra variability is ignored. The primary outcome is a case count, but the registry record does not report a dispersion parameter or the model used to analyze it. No claim about over-dispersion or a particular modeling approach can therefore be made for this trial.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 23 outcome measures and 40 analyses. The outcomes include several efficacy definitions and subgroups as well as immunogenicity outcomes. Because multiple comparisons can complicate interpretation, it is important to know which analyses were primary, which were secondary or exploratory, and whether any adjustment or testing hierarchy was prespecified. The registry record defines a primary efficacy endpoint but does not report the complete statistical analysis plan, the multiplicity strategy or whether interim analyses were planned or conducted.
The primary efficacy analysis population is described as enrolled subjects who received a study vaccination and were evaluated for efficacy at least 21 days after the last vaccination. The number of participants meeting those criteria is not reported in the registry record. The record also does not report group-specific analysis denominators, missing outcome counts, reasons for missingness, or methods used to handle missing data.
General: missing outcomes can affect an estimate if the chance of missingness is related to treatment assignment or outcome status. An analysis population definition does not, by itself, explain how incomplete observations were treated. Likewise, the presence of many analyses does not establish that multiplicity was ignored; the methods used are simply not reported in the registry record.
These gaps limit appraisal of how the listed outcomes were analyzed and how much confidence to place in any reported comparison. Here, no primary comparative estimate is reported in the registry record, so multiplicity adjustment and missing-data handling cannot be evaluated against an observed primary result.
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 |
|---|---|---|---|
| aQIV (≥6 to <72 Months) | 234 | 5243 | 4.5% |
| TIV/QIV (≥6 to <72 Months) | 230 | 5161 | 4.5% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| aQIV (≥6 to <72 Months) | 1 of 5339 |
| TIV/QIV (≥6 to <72 Months) | 3 of 5272 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| aQIV (≥6 to <72 Months) | 4627 of 5339 |
| TIV/QIV (≥6 to <72 Months) | 4430 of 5272 |
Most frequent serious adverse event terms
| Event term | Organ system | aQIV (≥6 to <72 Months) | TIV/QIV (≥6 to <72 Months) |
|---|---|---|---|
| Pneumonia | Infections and infestations | 38 of 5243 | 28 of 5161 |
| Gastroenteritis | Infections and infestations | 23 of 5243 | 23 of 5161 |
| Animal bite | Injury, poisoning and procedural complications | 24 of 5243 | 19 of 5161 |
| Dehydration | Metabolism and nutrition disorders | 15 of 5243 | 11 of 5161 |
| Bronchitis | Infections and infestations | 12 of 5243 | 13 of 5161 |
| Asthma | Respiratory, thoracic and mediastinal disorders | 9 of 5243 | 11 of 5161 |
| Febrile convulsion | Nervous system disorders | 13 of 5243 | 7 of 5161 |
| Dengue fever | Infections and infestations | 9 of 5243 | 9 of 5161 |
| Influenza like illness | General disorders | 7 of 5243 | 8 of 5161 |
| Pharyngitis | Infections and infestations | 4 of 5243 | 7 of 5161 |
Most frequent non-serious adverse event terms
| Event term | Organ system | aQIV (≥6 to <72 Months) | TIV/QIV (≥6 to <72 Months) |
|---|---|---|---|
| Influenza like illness | General disorders | 2690 of 5339 | 2664 of 5272 |
| Injection site pain | General disorders | 2360 of 5339 | 1861 of 5272 |
| Irritability | Psychiatric disorders | 1441 of 5339 | 1204 of 5272 |
| Somnolence | Nervous system disorders | 1366 of 5339 | 1107 of 5272 |
| Injection site erythema | General disorders | 1226 of 5339 | 1031 of 5272 |
| Eating disorder | Psychiatric disorders | 1163 of 5339 | 898 of 5272 |
| Pyrexia | General disorders | 1178 of 5339 | 778 of 5272 |
| Upper respiratory tract infection | Infections and infestations | 722 of 5339 | 724 of 5272 |
| Injection site induration | General disorders | 804 of 5339 | 576 of 5272 |
| Diarrhoea | Gastrointestinal disorders | 701 of 5339 | 677 of 5272 |
Serious events with the highest arm-level rate: pneumonia (0.7%), animal bite (0.5%), gastroenteritis (0.4%), dehydration (0.3%), bronchitis (0.3%).
The registry lists serious adverse-event entries for aQIV and TIV/QIV. In the aQIV group, 5243 participants were at risk and 234 were affected; in the TIV/QIV group, 5161 were at risk and 230 were affected. The registry also lists other adverse-event entries: 5339 at risk and 4627 affected for aQIV, and 5272 at risk and 4430 affected for TIV/QIV. Death counts are 1 and 3, respectively.
The listed serious adverse-event terms and percentages are Pneumonia, 0.7%; Animal bite, 0.5%; Gastroenteritis, 0.4%; Dehydration, 0.3%; Bronchitis, 0.3%; and Febrile convulsion, 0.2%. The registry record does not specify in these entries the denominator underlying each listed percentage or provide a comparative statistical analysis.
General: counts of participants affected are descriptive. They do not establish that an event was caused by vaccination, and counts alone do not account for differences in follow-up or participant characteristics. The registry entries should be read as reported safety data, not as proof of causation or as a complete assessment of the balance of benefits and harms. A safety analysis plan and further details about event ascertainment are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record identifies a randomized Phase III study comparing aQIV with non-adjuvanted TIV/QIV in children ≥6 to <72 months of age. It defines a primary efficacy endpoint based on first-occurrence RT-PCR-confirmed influenza A and/or B and specifies the follow-up period and efficacy analysis population. These details make the intended question identifiable.
However, a primary comparison result is not reported in the registry record. There is no reported primary case count by group, relative efficacy estimate, confidence interval or p-value. Consequently, the record does not establish the direction, size or precision of the primary efficacy contrast. The absence of a reported estimate is not evidence that the groups were equivalent, nor does it show that either group had a particular outcome.
The registry also lists outcomes for culture-confirmed influenza, age groups, risk categories, vaccination history, timing and antibody responses. A list of planned or registered outcomes does not provide their results. In the absence of reported comparisons for these outcomes, their findings cannot be characterized.
General: statistical evidence and clinical interpretation depend on the estimate, its uncertainty, the study population and the outcome definition. A result with substantial uncertainty may be compatible with a range of effects, while a precise estimate still requires consideration of clinical relevance and study conduct. The registry record does not provide the efficacy estimates needed for that assessment.
Safety entries describe affected participants, selected serious adverse-event terms and deaths in both groups. They can be read as descriptive counts, but the registry record does not report an analysis establishing causation or a full interpretation of between-group safety differences. The enrollment total and safety counts should not be used to infer an unreported efficacy result.
13. Why This Trial Matters Statistically
Statistically, this trial illustrates why an endpoint definition is essential for interpreting a clinical comparison. The primary question specifies a laboratory-confirmed outcome, an age range, a first-occurrence event and a follow-up window tied to vaccination and influenza-season timing. Without those details, the meaning of an efficacy estimate would be less clear.
The design also makes the distinction between a study’s registered question and its reported result important. The registry identifies randomization, stratification, masking, a parallel-group model and a named efficacy population. Yet the comparative result for the primary endpoint is not reported in the registry record. A detailed design description cannot substitute for an effect estimate and its precision.
The broad outcome set is another statistical consideration. The registry lists 23 outcome measures and 40 analyses across disease endpoints, subgroup definitions and immunogenicity. General: multiple analyses can produce a complex evidence picture, so prespecification, multiplicity handling and clear separation of primary from exploratory results help readers assess how strongly findings support a claim. Those details are not reported in the registry record.
The entry also demonstrates why enrollment and analysis populations should not be conflated. Enrollment was 10644, while the efficacy definition required vaccination and evaluation after a specified interval. The number analyzed for the primary endpoint is not reported in the registry record.
These features make the record useful for understanding the intended comparison and the information needed to interpret it, while leaving the primary efficacy result and its uncertainty unavailable 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 principal limitation for interpreting efficacy is that the registry record does not report the primary comparative result. Primary endpoint case counts, a relative efficacy estimate, a confidence interval and a p-value are not reported. Without these, the magnitude, direction and precision of the primary comparison cannot be assessed.
The registry defines the efficacy population but does not report how many participants were included in it or how missing outcome assessments were handled. Group-specific efficacy denominators, participant flow and reasons for exclusion from the analysis are not reported in the registry record. The posted enrollment total does not resolve those questions.
Although the record identifies a stratified randomized design and lists quadruple masking and observer blinding, it does not report the stratification categories, allocation details or masking procedures. The complete statistical analysis plan, the multiplicity strategy, interim analysis details and the trial’s sample-size justification are not reported in the registry record.
The registry lists numerous secondary outcomes and analyses, but does not report results for them in the registry record in this record. The listed safety counts and selected serious-event terms are descriptive; details of the safety analysis and causal assessment are not reported in the registry record. The record therefore supports description of study structure and outcome definitions, but not a complete assessment of efficacy, precision, missingness or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clinical Study to Evaluate the Safety, Immunogenicity and Efficacy of Investigational Flu Vaccine Compared to Approved Flu Vaccine in Children. — NCT01964989.
- Registry record last updated 2023-03-27; status last verified 2023-03.
- Results first posted 2023-03-27.
- 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
NCT01964989 is a completed Phase III randomized, stratified, observer-blind, controlled, multicenter, parallel-group study with listed quadruple masking. It enrolled 10644 participants and compared adjuvanted quadrivalent subunit influenza vaccine (aQIV) with non-adjuvanted TIV/QIV in children ≥6 to <72 months of age. The study began in 2013-11 and had primary completion in 2015-10; the registry summary places it across the 2013/2014 and 2014/2015 northern hemisphere influenza seasons.
The primary efficacy endpoint counted first occurrences of RT-PCR-confirmed influenza A and/or B during the specified post-vaccination follow-up period. The efficacy population required vaccination and evaluation at least 21 days after the last vaccination. A comparative result for this primary endpoint, including its estimate and precision, is not reported in the registry record. The record lists 23 outcome measures and 40 analyses, along with descriptive safety entries, but does not provide the complete statistical analysis plan, missing-data methods or multiplicity approach.