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 Pivotal, Multicenter, Observer-Blind, Randomized Study of Influenza A (H1N1)2009 Monovalent Subunit Vaccine With and Without Adjuvant in Children Ages 6 to <36 Months (NCT00996307), a randomized phase 2, phase 3 study. The primary outcome is Antibody Responses After the First and Second Vaccinations.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00996307 |
| Phase | Phase 2, Phase 3 |
| Condition | Influenza |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 654 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Vaccines |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled healthy young children ages 6 to <36 months. The registry record reports enrollment of 654 participants and lists influenza as the condition. The primary analysis population was the per-protocol set, but its size and the criteria for inclusion in that set are not reported in the registry record.
Intervention
The study examined four A/H1N1 2009 vaccine regimens. They used 3.75 µg or 7.5 µg antigen with 50% MF59, 7.5 µg antigen without MF59, or 15 µg antigen without MF59. Each regimen was administered on study day 1 and day 22. These are the intervention descriptions in the registry record; additional administration details are not reported there.
Comparator
The four randomized groups allow comparisons among different antigen amounts and adjuvant combinations. The registry record does not identify a single primary pairwise comparison or state which regimen was the designated reference group. It also does not report a prespecified testing hierarchy for comparisons among all four groups.
Primary question
The primary endpoint concerns the percentages of subjects with specified antibody responses after the first and second vaccinations, with measurement at 21 days after each vaccination. The record cites CBER guidance: the lower bound of the two-sided 95% confidence interval for seroconversion should be ≥ 40%, and the lower bound for an HI antibody titer ≥ 1:40 should be ≥ 70%. Actual response percentages and confidence intervals are not reported in the registry record.
3. Trial Design
This was a randomized, parallel-group study described as pivotal, multicenter, observer-blind, and double-masked. The registry lists the study under both PHASE2 and PHASE3. It was sponsored by Novartis Vaccines and is marked completed. Enrollment was 654. The recorded start is 2009-10, and primary completion is listed as 2009-12.
Four groups received different A/H1N1 2009 vaccine formulations. The regimens were 3.75 µg antigen with 50% MF59, 7.5 µg without MF59, 7.5 µg with 50% MF59, and 15 µg without MF59. Each was administered on study day 1 and day 22. The registry describes the study objective as evaluating safety and immunogenicity in healthy young children.
Random assignment is intended, in general, to make treatment groups comparable with respect to factors that could affect measured outcomes. A parallel-group design means participants are assigned to a group and assessed within that group, rather than crossing between regimens. Masking is intended to limit the influence of knowledge about assignment on study conduct or outcome assessment. The record identifies the study as double-masked and observer-blind, but does not describe who was masked, how masking was maintained, or whether it was assessed.
The record lists nine outcome measures and sixteen analyses. It names secondary outcomes concerning geometric mean titers, seasonal influenza vaccination, baseline seropositivity, and antibody persistence. Allocation concealment, randomization procedures, site count, and detailed protocol methods are not reported in the registry record. No efficacy outcome results are included in the record; actual primary immunogenicity estimates are not reported.
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 subjects enrolled were included in the trial. The data entered is for the overall study.
Overall Study
| Stage | 3.75_(50)MF59 | 7.5_(0)MF59 | 7.5_(50)MF59 | 15_(0)MF59 |
|---|---|---|---|---|
| STARTED | 164 | 165 | 160 | 165 |
| COMPLETED | 144 | 148 | 146 | 144 |
| NOT COMPLETED | 20 | 17 | 14 | 21 |
Reasons for not completing this period:
| Reason | 3.75_(50)MF59 | 7.5_(0)MF59 | 7.5_(50)MF59 | 15_(0)MF59 |
|---|---|---|---|---|
| Adverse Event | 0 | 1 | 0 | 0 |
| Withdrawal by Subject | 3 | 2 | 5 | 5 |
| Lost to Follow-up | 13 | 13 | 7 | 15 |
| Administrative reason | 0 | 1 | 0 | 0 |
| Unable to classify | 4 | 0 | 2 | 1 |
Analysis population for the primary outcome, as defined in the registry: The analysis was done on the per-protocol set (PPS).
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 | 3.75_(50)MF59 | 7.5_(0)MF59 | 7.5_(50)MF59 | 15_(0)MF59 | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 164 | 165 | 160 | 165 | 654 | |
| Age, Continuous: 6 to <36 Months age | Months | 21.2 (SD 7.9) | 21.6 (SD 8.8) | 21.1 (SD 8.4) | 21.3 (SD 8.9) | 21.3 (SD 8.5) |
| Sex: Female, Male: Female | Participants | 75 | 79 | 80 | 78 | 312 |
| Sex: Female, Male: Male | Participants | 89 | 86 | 80 | 87 | 342 |
6. Primary Endpoint
The registry lists the primary outcome as Antibody Responses After the First and Second Vaccinations, measured over 21 days after each vaccination.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | Percentages of Subjects |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint measures antibody responses after vaccination. The registry describes percentages of subjects and specifies assessment 21 days after each vaccination. It refers to seroconversion for HI antibody and to the proportion with an HI antibody titer ≥ 1:40. The analysis population is the per-protocol set (PPS).
The record cites CBER guidance for people younger than 65 years. Under the stated criteria, the lower bound of the two-sided 95% confidence interval for the percentage achieving seroconversion should be ≥ 40%, and the lower bound for the percentage achieving an HI antibody titer ≥ 1:40 should be ≥ 70%. These are criteria named in the endpoint description; they are not, by themselves, evidence that either criterion was met.
In general, antibody measures are used to describe an immune response, while a confidence interval communicates uncertainty around an estimated response percentage. Assessing the lower bound against a threshold makes the uncertainty relevant to the stated criterion, rather than relying only on the point estimate. The registry record does not report the observed percentages, confidence intervals, or whether the criteria were met. It also does not provide a single aggregated endpoint result that can stand in for the several response categories and assessment times.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study question and design, but it does not report the primary antibody-response estimates. There are no posted response percentages or corresponding 95% confidence intervals for the first or second vaccination in the information summarized in the record. Consequently, the stated CBER thresholds cannot be evaluated from these details alone. The criteria are benchmarks in the endpoint description, not observed findings.
The primary endpoint includes more than one response category and more than one assessment time. The record notes that the primary outcome has several categories or time points and is not reduced to one comparison. That matters for interpretation: an estimate for one antibody category at one assessment cannot automatically represent the other category or assessment. Nor does the record identify a single primary comparison among the four randomized regimens. The posted information therefore does not support a ranking of the regimens on the primary endpoint.
In general, the width of a confidence interval indicates how precisely an estimate is measured. A lower confidence bound can be compared with a prespecified criterion only when the corresponding estimate and interval are available, and when the analysis definition is clear. Here, the endpoint description provides the intended confidence level and thresholds, but the outcome values are not reported in the registry record. No conclusion about precision or threshold attainment can be drawn from the endpoint description alone.
The record identifies the PPS as the analysis population. This tells the reader which general population was named for the analysis, but not how many participants contributed to each estimate or what exclusions were applied. Those details are important because estimates based on a selected analysis population may differ from estimates based on all randomized participants. The PPS definition and the numbers analyzed are not reported in the registry record.
Safety information is available as counts of participants affected by serious adverse events and other adverse events in the four groups, along with a list of serious-event terms and percentages. Those counts describe what the registry lists; without fuller outcome definitions, follow-up details, and comparative analyses, they do not establish whether rates differed between regimens. The listed percentages for serious-event terms also lack accompanying denominator and uncertainty details in the registry record.
Overall, the posted information supports a description of the randomized study, its four vaccine regimens, its planned antibody criteria, and selected safety counts. It does not report the primary immunogenicity results needed to assess the antibody criteria or compare regimens. The statistical interpretation should remain bounded by that distinction between a stated analysis objective and a reported result.
9. Statistical Methods Explained
Statistical methods are useful only when the outcome definition, analysis population, and comparison are clear. The registry record identifies a primary antibody-response endpoint, the PPS, and a two-sided 95% confidence interval. It does not report the estimated response percentages or intervals. The following concepts explain how such an endpoint is generally interpreted, without implying that a particular result was observed in this study.
What does a response percentage describe?
A response percentage describes the share of analyzed participants who meet a specified antibody-response definition. In this study, the endpoint description refers to seroconversion for HI antibody and an HI antibody titer ≥ 1:40. Those are separate response criteria. A participant may or may not meet each definition, and the resulting percentages answer different questions. The registry record does not provide the operational definition of seroconversion, such as how baseline and post-vaccination values were used.
When the outcome is a percentage, its estimate depends on both the number of participants meeting the definition and the number included in the analysis. A percentage alone does not show how much uncertainty surrounds the estimate. The registry gives the number enrolled, but not the number in the PPS or the number contributing to each endpoint assessment. Those denominators cannot be inferred from total enrollment.
Why does the confidence interval matter?
In general, a confidence interval expresses statistical uncertainty around an estimated quantity. A two-sided interval has a lower and an upper bound. The primary endpoint description focuses on the lower bound and specifies separate threshold criteria: ≥ 40% for seroconversion and ≥ 70% for the proportion with an HI antibody titer ≥ 1:40. A point estimate above a threshold would not alone establish that the lower-bound criterion was met. The interval itself must be available to assess that rule.
The confidence interval is not a range containing a known fixed share of individual responses, and it is not a guarantee about future participants. It describes uncertainty in the estimate under the assumptions of the statistical procedure. The registry identifies a 95% confidence interval but does not report how it was calculated, whether any adjustment was used, or the resulting bounds. The stated guidance should therefore be understood as the intended evaluation criterion, not a result.
How do the four groups shape comparisons?
The parallel design has four formulations: 3.75 µg with 50% MF59, 7.5 µg without MF59, 7.5 µg with 50% MF59, and 15 µg without MF59. This structure makes several kinds of comparisons possible, including comparisons that differ in antigen amount, adjuvant status, or both. A comparison that changes more than one formulation feature does not isolate the effect of one feature. The registry record does not name a single primary pairwise contrast or give a testing hierarchy.
In general, a comparison should be interpreted according to the question it was designed to answer. A difference between groups can reflect the combined changes represented by those groups unless the design and analysis isolate a specific component. The posted endpoint description gives thresholds for antibody response, but it does not report a single contrast or group-level estimates. It is therefore not possible to use the record to quantify or rank differences among the four regimens.
What do geometric mean titers add?
The listed secondary outcomes include geometric mean titers (GMTs), antibody responses with and without seasonal influenza vaccination for year 2009 to 2010, responses by baseline seropositivity, and antibody persistence. In general, a geometric mean summarizes measurements that are positive and often vary multiplicatively. It is commonly interpreted on a transformed scale or through ratios, depending on the analysis. The registry record names these outcome types but does not provide their values, confidence intervals, transformations, or comparison methods. No conclusion about the magnitude or persistence of antibody levels can be drawn from the outcome names alone.
Baseline seropositivity and seasonal influenza vaccination are listed as factors for secondary analyses. These classifications can be relevant because initial antibody status or vaccination history may be associated with subsequent measured responses. However, the record does not report group-specific results for these categories or state whether they were prespecified strata, covariates, or descriptive subgroups. Their role in the statistical analysis is not reported in the registry record.
How should planning illustrations be read?
In general, a sample-size calculation is a planning exercise that links a target effect, variability assumptions, significance level, allocation, and desired power. The registry record describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also says that the effect to detect is a stated fraction of the observed effect. Such an illustration is not the trial’s original design justification and is not observed power.
The planning assumptions do not establish what effect the study was designed to detect before enrollment, or whether the study had adequate power for its actual primary questions. A calculation based on an observed effect is retrospective as a planning illustration; it should not be treated as proof that the trial was adequately sized. The trial’s own sample-size justification and design assumptions are not reported in the registry record.
Why can over-dispersion matter?
In general, over-dispersion occurs when outcome variability exceeds what a statistical model assumes. If it is not accounted for, uncertainty can be understated and confidence intervals may be too narrow. The endpoint information available for this study does not identify an over-dispersion model or indicate that over-dispersion was assessed. No claim can be made about whether it was relevant to the actual analysis.
More broadly, the methods needed to reproduce or fully evaluate an analysis include the outcome definitions, analysis denominators, missing-data rules, model specification, and comparison plan. Several of those details are not reported in the registry record. Statistical concepts can explain how the listed endpoint would ordinarily be read, but they cannot replace the missing estimates and analysis details.
10. Multiplicity, Missing Data and Analysis Populations
The record lists nine outcome measures and sixteen analyses. The primary endpoint includes multiple antibody-response categories and assessment times, and the secondary outcomes cover GMTs, seasonal influenza vaccination, baseline seropositivity, and persistence. With multiple outcomes, time points, groups, and possible contrasts, the chance of obtaining at least one seemingly notable result can increase if many tests are conducted. In general, multiplicity procedures can address that issue, but the registry record does not report whether adjustment, a testing hierarchy, or another strategy was used.
The primary analysis population is identified as the per-protocol set (PPS). The criteria defining that set, the number included, and how participants with incomplete observations were handled are not reported in the registry record. The record also does not state whether an intention-to-treat or other analysis population was used for the primary endpoint.
Missing-data methods are not reported in the registry record. It is therefore unknown how unavailable antibody measurements, withdrawals, protocol deviations, or incomplete vaccination were treated in the endpoint analyses. Those choices can affect both the denominator and the interpretation of an estimated response percentage.
The record’s mention of multiple analyses does not establish that all listed comparisons were prespecified or that all were confirmatory. Interim analyses, stopping rules, and any method for controlling false-positive findings are not reported in the registry record. Without these details, the multiplicity implications and the exact analysis populations cannot be assessed.
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 |
|---|---|---|---|
| 3.75_(50)MF59 | 5 | 162 | 3.1% |
| 7.5_(0)MF59 | 6 | 164 | 3.7% |
| 7.5_(50)MF59 | 1 | 162 | 0.6% |
| 15_(0)MF59 | 10 | 166 | 6.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| 3.75_(50)MF59 | 144 of 162 |
| 7.5_(0)MF59 | 152 of 164 |
| 7.5_(50)MF59 | 141 of 162 |
| 15_(0)MF59 | 142 of 166 |
Most frequent serious adverse event terms
| Event term | Organ system | 3.75_(50)MF59 | 7.5_(0)MF59 | 7.5_(50)MF59 | 15_(0)MF59 |
|---|---|---|---|---|---|
| Respiratory syncytial virus bronchiolitis | Infections and infestations | 0 of 162 | 0 of 164 | 0 of 162 | 3 of 166 |
| Staphylococcal abscess | Infections and infestations | 1 of 162 | 0 of 164 | 1 of 162 | 0 of 166 |
| Subcutaneous abscess | Infections and infestations | 0 of 162 | 0 of 164 | 0 of 162 | 2 of 166 |
| Dehydration | Metabolism and nutrition disorders | 0 of 162 | 2 of 164 | 0 of 162 | 0 of 166 |
| Accidental exposure to product | Injury, poisoning and procedural complications | 2 of 162 | 0 of 164 | 0 of 162 | 0 of 166 |
| Subdural haematoma | Injury, poisoning and procedural complications | 1 of 162 | 0 of 164 | 0 of 162 | 1 of 166 |
| Hypoxia | Respiratory, thoracic and mediastinal disorders | 0 of 162 | 0 of 164 | 0 of 162 | 2 of 166 |
| Intussusception | Gastrointestinal disorders | 0 of 162 | 1 of 164 | 0 of 162 | 0 of 166 |
| Vomiting | Gastrointestinal disorders | 0 of 162 | 1 of 164 | 0 of 162 | 0 of 166 |
| Pyrexia | General disorders | 0 of 162 | 1 of 164 | 0 of 162 | 0 of 166 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 3.75_(50)MF59 | 7.5_(0)MF59 | 7.5_(50)MF59 | 15_(0)MF59 |
|---|---|---|---|---|---|
| Irritability | Psychiatric disorders | 58 of 162 | 62 of 164 | 60 of 162 | 52 of 166 |
| Upper respiratory tract infection | Infections and infestations | 62 of 162 | 54 of 164 | 51 of 162 | 64 of 166 |
| Injection site pain | Nervous system disorders | 60 of 162 | 51 of 164 | 60 of 162 | 50 of 166 |
| Diarrhoea | Gastrointestinal disorders | 57 of 162 | 52 of 164 | 63 of 162 | 45 of 166 |
| Pyrexia | General disorders | 53 of 162 | 52 of 164 | 54 of 162 | 53 of 166 |
| Cough | Respiratory, thoracic and mediastinal disorders | 45 of 162 | 54 of 164 | 46 of 162 | 54 of 166 |
| Crying | General disorders | 47 of 162 | 46 of 164 | 48 of 162 | 42 of 166 |
| Somnolence | Nervous system disorders | 51 of 162 | 41 of 164 | 48 of 162 | 39 of 166 |
| Otitis media | Infections and infestations | 56 of 162 | 38 of 164 | 37 of 162 | 45 of 166 |
| vomiting | Gastrointestinal disorders | 33 of 162 | 37 of 164 | 33 of 162 | 24 of 166 |
Serious events with the highest arm-level rate: respiratory syncytial virus bronchiolitis (1.8%), accidental exposure to product (1.2%), dehydration (1.2%), subcutaneous abscess (1.2%), hypoxia (1.2%).
The registry lists serious adverse events by randomized group. The group receiving 3.75 µg with 50% MF59 had 5 affected participants among 162 at risk; the 7.5 µg without MF59 group had 6 among 164; the 7.5 µg with 50% MF59 group had 1 among 162; and the 15 µg without MF59 group had 10 among 166. These are reported counts, not adjusted comparisons. No statistical comparison or confidence interval for these counts is reported in the registry record.
The record also lists serious-event terms with percentages: respiratory syncytial virus bronchiolitis, 1.8%; accidental exposure to product, dehydration, subcutaneous abscess, and hypoxia, each 1.2%; and staphylococcal abscess, 0.6%. The registry information does not provide the denominator or uncertainty for these term-specific percentages, nor does it establish a causal relationship to a vaccine regimen.
For the separate other-adverse-event listing, affected counts were 144 of 162, 152 of 164, 141 of 162, and 142 of 166 across the four groups in the same order. The registry record does not provide further details about event definitions or comparative analyses. Deaths are not reported in the registry record; an unreported value should not be interpreted as a reported count of zero.
12. What the Result Does, and Does Not, Mean
The study was designed to assess antibody responses after two vaccinations in healthy children ages 6 to <36 months. It used four vaccine formulations that varied in antigen amount and MF59 adjuvant status. The primary endpoint description specifies response definitions, assessment timing, confidence intervals, and benchmark lower bounds. Those details explain what the study intended to evaluate, but they do not reveal whether the observed responses met the benchmarks.
The primary antibody-response percentages and confidence intervals are not reported in the registry record. The record therefore cannot establish whether the lower-bound criteria were reached, how responses differed between groups, or how precisely any group-specific response was estimated. A study’s objective and its outcome results are distinct: a stated threshold is not an observed result.
In general, an antibody measurement is an immunogenicity outcome. It describes a measured immune response and is not itself a direct measure of clinical illness or protection. The registry record does not report clinical influenza outcomes or demonstrate a relationship between the listed antibody outcomes and clinical outcomes in these participants. No claim about clinical benefit or lack of benefit follows from the information recorded.
The serious adverse-event counts and listed terms provide a limited account of reported safety data. They do not, by themselves, show that an event was caused by vaccination or that groups differed statistically. Interpretation would require the event definitions, follow-up period, completeness of reporting, and an appropriate comparative analysis. Those details are not reported in the registry record.
The appropriate reading is therefore narrow: the record describes a randomized four-group immunogenicity and safety study, reports selected design details and safety counts, and states antibody-response criteria. It does not include the primary results needed to evaluate those criteria. Absence of those results in the registry record is not evidence that a criterion was met or not met.
13. Why This Trial Matters Statistically
This study illustrates why endpoint definitions and outcome reporting need to be read separately. The primary endpoint is not just a general measure of antibody response: it specifies seroconversion and a titer threshold, uses a two-sided 95% confidence interval, and evaluates lower bounds against stated criteria. Each part matters. A threshold is interpretable only with the associated estimate, its uncertainty, and a clear analysis population.
The four-group design also shows why a trial’s comparison structure is important. The formulations vary in antigen amount and adjuvant status, so a group comparison may reflect more than one formulation difference. Without a designated primary contrast or testing hierarchy, the reader cannot tell which comparison was intended to carry the main inferential claim. The record does not report such a hierarchy.
The record identifies a PPS analysis but does not give its definition or size. This is a useful reminder that randomized enrollment and endpoint analysis are not automatically the same population. Eligibility for a per-protocol analysis can shape the denominator and the interpretation of response estimates, particularly when assessments or protocol adherence are incomplete.
Finally, the record lists multiple outcome measures and analyses, while the primary result values are not reported. Statistical interpretation depends not only on the design, but on transparent estimates, uncertainty, analysis populations, and handling of multiple questions. Without those results and methods, the registry supports description of the intended evaluation, not a conclusion about comparative antibody responses.
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 central limitation for interpretation is that primary antibody-response estimates are not reported in the registry record. The record does not include response percentages or 95% confidence intervals for either vaccination assessment, so the stated lower-bound criteria cannot be evaluated. It also does not report group-level results that would support comparisons among the four regimens.
The endpoint description does not provide the full operational definition of seroconversion or detailed laboratory methods. It names an HI antibody titer threshold and assessment timing, but does not report assay characteristics, handling of values outside measurable ranges, or the precise calculation procedure for confidence intervals. These details are not reported in the registry record.
The record names the PPS but does not define its eligibility rules or give the number analyzed. Missing-data procedures, participant flow by group, deviations from the planned regimen, and denominators at each assessment are not reported in the registry record. These omissions limit assessment of who contributed to the endpoint estimates and whether incomplete follow-up could affect them.
The study includes several formulations, outcomes, and analyses, but the record does not report a primary contrast hierarchy or multiplicity approach. The trial’s sample-size justification, interim analyses, and detailed statistical plan are also not reported in the registry record. The retrospective planning illustration described in the record should not be taken as the original design rationale.
Safety interpretation is similarly limited by the available detail. The registry provides group counts and selected serious-event terms, but does not report event-specific denominators, uncertainty, comparative tests, or detailed follow-up information. Deaths are not reported in the registry record. These limitations prevent stronger interpretation of the safety counts or attribution of events to a particular regimen.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pivotal, Multicenter, Observer-Blind, Randomized Study of Influenza A (H1N1)2009 Monovalent Subunit Vaccine With and Without Adjuvant in Children Ages 6 to <36 Months — NCT00996307.
- Registry record last updated 2017-05-30; status last verified 2017-04.
- Results first posted 2011-05-25.
- 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
The registry record describes a completed randomized, double-masked, parallel study of four A/H1N1 2009 vaccine formulations in healthy children ages 6 to <36 months. Enrollment was 654. The regimens differed by antigen amount and use of 50% MF59, and each was administered on study day 1 and day 22. The study is listed under PHASE2 and PHASE3, with Novartis Vaccines as sponsor.
The primary endpoint concerns antibody responses 21 days after each vaccination, analyzed in the PPS. The record cites lower-bound criteria for seroconversion and HI antibody titer response, but does not report the response estimates or confidence intervals. It lists secondary immunogenicity outcomes and selected adverse-event counts. Detailed analysis methods, missing-data handling, multiplicity strategy, and the primary results are not reported in the registry record.