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 Safety and Immunogenicity of A/H1N1-SOIV (Swine Flu) Vaccine With and Without Adjuvant in Children (3 to < 9 Years) (NCT00972816), a randomized phase 2, phase 3 study. The primary outcome is Antibody Responses According to the Hemagglutinin Inhibition (HI) Assay After the First and Second Vaccinations.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00972816 |
| Phase | Phase 2, Phase 3 |
| Condition | Influenza |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 1357 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Vaccines |
| Results posted | Yes |
2. Clinical Question
Population
Healthy children aged 3 to under 9 years. The registry record reports enrollment of 1357 participants. The primary endpoint was analyzed in per-protocol populations, with analysis-set sizes reported for different follow-up periods.
Intervention
Two-dose A/H1N1-SOIV vaccine formulations administered on study day 1 and day 22. Formulations varied in antigen amount and MF59 adjuvant content. The listed antigen amounts were 3.75 μg, 7.5 μg, 15 μg, and 30 μg; listed MF59 levels were 0%, 50%, and 100%.
Comparator
The randomized groups received different vaccine formulations. Comparisons therefore concern dose and adjuvant combinations; no placebo group is listed in the registry record. The record does not report which pairwise comparisons were prespecified or how they were to be interpreted.
Primary question
Did each formulation meet the registry’s HI antibody response criteria after vaccination? For immunogenicity, the lower bound of the two-sided 95% confidence interval had to be at least 40% for seroconversion and at least 70% for an HI antibody titer of 1:40 or higher. Both criteria had to be fulfilled.
The study is registered as a randomized, single-blind, parallel-group Phase 2 and Phase 3 trial. Its stated focus is safety and immunogenicity in young children, rather than a direct comparison of clinical influenza illness. The primary endpoint concerns the proportion of participants attaining specified antibody responses, measured with the hemagglutinin inhibition assay. The outcome was assessed at Day 22, Day 29, Day 43, Day 202, and Day 387. The registry record does not report the response percentages or confidence intervals needed to determine whether any formulation met both criteria. It also does not report a single overall comparison that summarizes the different formulations and follow-up times.
3. Trial Design
This was a randomized, single-blind, parallel-group study registered in Phase 2 and Phase 3. The registry record lists 1357 participants and describes the population as healthy children aged 3 to under 9 years. The sponsor is Novartis Vaccines. The study started in 2009-09, had a primary completion date of 2009-11, and is recorded as completed.
Eight vaccine formulations varied by A/H1N1 antigen amount and MF59 adjuvant level. The listed combinations were 3.75 μg with 50% MF59; 7.5 μg with 0%, 50%, or 100% MF59; 15 μg with 0%, 50%, or 100% MF59; and 30 μg with 0% MF59. Each formulation was administered on study day 1 and day 22. Thus, the comparisons were between active vaccine formulations, not between vaccine and a listed placebo arm.
The word single-blind indicates that some aspect of treatment assignment was masked, but who was masked and how masking was maintained are not reported in the registry record. The randomization procedure, allocation ratio, concealment process, and operational details for delivering the formulations are also not reported. The registry record identifies eight groups but does not state a primary pairwise contrast or a hierarchy among them.
The primary outcome was HI antibody response after the first and second vaccinations, with measurements listed through Day 387. Secondary outcomes included geometric mean titers, antibody responses in relation to seasonal influenza vaccination in 2009 to 2010, responses by baseline seropositivity, solicited local and systemic symptoms, and unsolicited adverse events. The record lists 9 secondary outcome measures and 140 analyses. The exact statistical plan connecting those analyses to specific hypotheses is 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.
Only the first 6 of 8 groups are shown.
Overall Study
| Stage | 3.75_(50) MF59 | 7.5_(0) MF59 | 7.5_(50)MF59 | 7.5_(100)MF59 | 15_(0) MF59 | 15_(50) MF59 |
|---|---|---|---|---|---|---|
| STARTED | 173 | 169 | 169 | 169 | 169 | 169 |
| COMPLETED | 156 | 158 | 160 | 161 | 157 | 158 |
| NOT COMPLETED | 17 | 11 | 9 | 8 | 12 | 11 |
Reasons for not completing this period:
| Reason | 3.75_(50) MF59 | 7.5_(0) MF59 | 7.5_(50)MF59 | 7.5_(100)MF59 | 15_(0) MF59 | 15_(50) MF59 |
|---|---|---|---|---|---|---|
| Adverse Event | 0 | 0 | 1 | 0 | 0 | 0 |
| Withdrawal by Subject | 4 | 2 | 1 | 3 | 0 | 1 |
| Lost to Follow-up | 11 | 9 | 7 | 5 | 11 | 10 |
| Inappropriate enrolment | 0 | 0 | 0 | 0 | 0 | 0 |
| Unable to classify | 2 | 0 | 0 | 0 | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: The analysis was performed on per protocol set (PPS) population
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.
Only the first 6 of 9 groups are shown.
| Characteristic | Unit | 3.75_(50)MF59 | 7.5 Without MF59 | 7.5_(50)MF59 | 7.5_(100)MF59 | 15 Without MF59 | 15_(50)MF59 |
|---|---|---|---|---|---|---|---|
| Participants analysed | 173 | 169 | 169 | 169 | 169 | 169 | |
| Age, Continuous | years | 5.6 (SD 1.7) | 5.2 (SD 1.7) | 5.5 (SD 1.8) | 5.9 (SD 1.7) | 5.6 (SD 1.7) | 5.5 (SD 1.7) |
| Sex: Female, Male: Female | Participants | 81 | 88 | 83 | 83 | 79 | 80 |
| Sex: Female, Male: Male | Participants | 92 | 81 | 86 | 86 | 90 | 89 |
6. Primary Endpoint
The registry lists the primary outcome as Antibody Responses According to the Hemagglutinin Inhibition (HI) Assay After the First and Second Vaccinations, measured over Day 22, Day 29, Day 43, Day 202 and Day 387.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of subjects |
| Endpoint classification | Binary Endpoint |
The primary endpoint measures the percentage of participants who achieved specified HI antibody responses after vaccination. The hemagglutinin inhibition assay is described in the registry record as a method used to assess immune responses following vaccination. It reports antibody response categories, rather than a clinical outcome such as influenza illness.
The registry describes two criteria for participants younger than 65 years under Center for Biologics Evaluation and Research guidance. The lower bound of the two-sided 95% confidence interval for the percentage achieving seroconversion had to be at least 40%. The lower bound for the percentage with an HI antibody titer of 1:40 or higher had to be at least 70%. Both criteria had to be met to establish immunogenicity under the stated definition.
These criteria use confidence-interval bounds, not only the observed percentages. A confidence interval expresses uncertainty around an estimated response percentage; considering its lower bound makes the criterion depend on both the estimate and its precision. The endpoint was assessed at Day 22, Day 29, Day 43, Day 202, and Day 387. The registry record does not report the endpoint percentages, confidence intervals, or a result for whether either criterion was met in any group. The seroconversion definition and details of the assay implementation are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a threshold-based immunogenicity assessment. A formulation would satisfy the stated criterion only if the lower confidence bound for each of two response percentages met its respective threshold: at least 40% for seroconversion and at least 70% for an HI antibody titer of 1:40 or higher. The record explicitly requires both criteria. An observed percentage alone would not be enough to establish that the stated criterion was fulfilled; the confidence interval is part of the rule.
The registry entries do not include the group-specific antibody response percentages or their confidence intervals. They therefore do not show whether a particular formulation met either threshold, whether it met both, or how the formulations compared. No ranking of the dose and adjuvant combinations can be drawn from the endpoint description alone. The registry record also does not report a single summary contrast across the groups.
Timing matters to interpretation. The primary outcome lists assessments at Day 22, Day 29, Day 43, Day 202, and Day 387, while the stated primary endpoint title refers to responses after the first and second vaccinations. The registry record does not provide response values at those time points or explain how results across times were combined. A response at one assessment would not, by itself, describe the response at another assessment.
The analysis population is also relevant. The primary outcome specifies per-protocol set populations, with different reported analysis-set sizes for the Day 1-29, Day 1-202, and Day 1-387 periods. The record does not report why participants were excluded from those sets, how missing measurements were handled, or whether the analyzed participants differed systematically from those not included. Consequently, the endpoint description defines the intended measure, but it does not establish how representative each analysis set was.
Safety information is reported separately from antibody responses. Serious adverse event counts are given by group, and serious-event terms are listed with percentages. Those figures describe recorded events, not an explanation of their causes or a formal comparison of risk. The registry record does not report deaths as counts, so their absence cannot be inferred from the blank entries. Overall, the available information supports describing the design, endpoint criteria, and recorded safety counts, but not drawing a conclusion about comparative immunogenicity or clinical benefit.
9. Statistical Methods Explained
The primary endpoint is a binary response proportion: participants are classified according to whether they meet an antibody-response criterion, and the result is expressed as a percentage. In general, a proportion is useful when the question is how many participants reach a defined response state, rather than how large an individual measurement is on a continuous scale. The registry also lists geometric mean titers as secondary outcomes, which address antibody levels differently from the primary response percentages.
The registry’s stated decision rule combines a response threshold with a confidence interval. A confidence interval gives a range of values compatible with the observed data under the method used. Its width reflects precision: less precise estimates generally have wider intervals, while more precise estimates generally have narrower ones. The lower bound is the conservative edge used in the stated criterion. The registry says that the lower bound of a two-sided 95% confidence interval must reach at least 40% for seroconversion and at least 70% for an HI titer of 1:40 or higher. Both requirements must be fulfilled. This is not the same as checking whether the point estimate alone is above either threshold.
The record identifies the per-protocol set as the primary analysis population and gives separate set sizes for three follow-up periods. The Day 1-29 analysis set lists N=143, 149, 149, 146, 147, 147, 144, and 144 for Groups A through H. The Day 1-202 set lists N=82, 85, 84, 84, 86, 87, 82, and 79. The Day 1-387 set lists N=55, 63, 61, 58, 61, 65, 59, and 63. These are analysis-set sizes, not response counts. The registry record does not report the reasons for exclusion from a per-protocol set or how missing antibody measurements were treated.
In general, restricting analysis to participants who satisfy a per-protocol definition can make the analysis more closely reflect adherence to the study procedures. It can also reduce the number of observations and may affect how well the analyzed group represents everyone randomized. The specific per-protocol rules, including the handling of protocol deviations, are not reported in the registry record. It is therefore not possible to assess from the listed set sizes alone whether exclusions could have influenced the response estimates.
The trial has multiple formulations and several assessment times. In general, testing many outcomes or contrasts creates a multiplicity issue: the chance of at least one apparently notable result can increase when many statistical tests are considered. The record lists 140 analyses and 9 secondary outcome measures, but does not report whether a multiplicity adjustment was planned, which contrasts were primary among the formulation groups, or how the analysis hierarchy was organized. No specific correction or testing sequence should be assumed.
The registry describes confidence intervals for the primary response criteria but does not identify the interval construction method. It also does not provide the group-specific estimates, p-values, or detailed model specifications. The exact statistical procedures used to estimate the percentages and intervals are therefore not reported in the registry record. In general, interval methods for proportions can differ, especially when the number of responses is small or an estimate lies near the boundary of its possible range. The method matters because it can affect interval width and, in turn, whether a lower-bound criterion is met.
The secondary outcomes include geometric mean titers. In general, geometric means are used for measurements that are positive and may be skewed, by transforming values to a logarithmic scale, averaging on that scale, and transforming back. This can make a summary less dominated by very large values than an arithmetic mean. The registry lists GMT outcomes but does not report the transformation, treatment of values below assay limits, or the estimation procedure. Those details are not reported in the registry record.
The sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. These assumptions are not a report of the trial’s original design justification, and planning illustrations are not observed power. The registry record does not report the original sample-size justification or enough numerical output in the listed details to interpret a specific planning scenario. The design rationale and any interim analyses are not reported in the registry record.
For safety, the record gives serious adverse event counts and numbers at risk by group. In general, event counts and denominators should be read together: a count alone does not indicate the frequency without its corresponding population at risk. A formal comparison would also need to account for the study’s analysis plan and uncertainty. The registry does not report a statistical comparison of serious adverse events, or enough detail to infer a causal relationship between vaccination and a listed event.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 140 analyses across 9 secondary outcome measures, in addition to a primary outcome with several response categories and assessment times. The trial also has eight randomized formulation groups. In general, examining many outcomes, time points, or group contrasts creates multiplicity: even when there is no real difference, a larger collection of tests can increase the chance of seeing at least one result that appears unusual. The record does not report a multiplicity adjustment, a testing hierarchy, or which group contrasts were designated in advance.
Missing-data handling is not reported in the registry record. The primary outcome uses per-protocol populations, and the record gives analysis-set sizes for the Day 1-29, Day 1-202, and Day 1-387 periods. Those sizes differ across follow-up periods, but the reasons are not reported. The record does not describe whether missing measurements were excluded, imputed, or handled by another method, nor does it state how protocol deviations affected inclusion.
In general, estimates based on participants with available measurements can be affected if missingness is related to response or other participant characteristics. The analysis-set counts alone cannot show whether that occurred. The registry record also does not report a sensitivity analysis to assess how alternative assumptions about missing data might affect the antibody-response estimates. Consequently, the precision and representativeness of the reported per-protocol results cannot be assessed from the available analysis-set information alone.
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 | 0 | 171 | 0.0% |
| 7.5 Without MF59 | 5 | 168 | 3.0% |
| 7.5_(50)MF59 | 7 | 169 | 4.1% |
| 7.5_(100)MF59 | 4 | 168 | 2.4% |
| 15 Without MF59 | 3 | 168 | 1.8% |
| 15_(50)MF59 | 4 | 168 | 2.4% |
| 15_(100)MF59 | 1 | 167 | 0.6% |
| 30 Without MF59 | 0 | 169 | 0.0% |
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 | 171 of 171 |
| 7.5 Without MF59 | 168 of 168 |
| 7.5_(50)MF59 | 169 of 169 |
| 7.5_(100)MF59 | 168 of 168 |
| 15 Without MF59 | 168 of 168 |
| 15_(50)MF59 | 168 of 168 |
Most frequent serious adverse event terms
| Event term | Organ system | 3.75_(50)MF59 | 7.5 Without MF59 | 7.5_(50)MF59 | 7.5_(100)MF59 | 15 Without MF59 | 15_(50)MF59 |
|---|---|---|---|---|---|---|---|
| Pneumonia | Infections and infestations | 0 of 171 | 0 of 168 | 1 of 169 | 1 of 168 | 0 of 168 | 0 of 168 |
| Dehydration | Metabolism and nutrition disorders | 0 of 171 | 0 of 168 | 1 of 169 | 0 of 168 | 0 of 168 | 1 of 168 |
| Febrile Convulsion | Nervous system disorders | 0 of 171 | 0 of 168 | 1 of 169 | 0 of 168 | 0 of 168 | 0 of 168 |
| Hydrocele | Congenital, familial and genetic disorders | 0 of 171 | 0 of 168 | 1 of 169 | 0 of 168 | 0 of 168 | 0 of 168 |
| Cerumen Impaction | Ear and labyrinth disorders | 0 of 171 | 1 of 168 | 0 of 169 | 0 of 168 | 0 of 168 | 0 of 168 |
| Appendicitis Perforated | Infections and infestations | 0 of 171 | 0 of 168 | 1 of 169 | 0 of 168 | 0 of 168 | 0 of 168 |
| Chronic Tonsillitis | Infections and infestations | 0 of 171 | 0 of 168 | 0 of 169 | 0 of 168 | 1 of 168 | 0 of 168 |
| Otitis Media Chronic | Infections and infestations | 0 of 171 | 0 of 168 | 0 of 169 | 0 of 168 | 1 of 168 | 0 of 168 |
| Peritonsillar Abscess | Infections and infestations | 0 of 171 | 0 of 168 | 1 of 169 | 0 of 168 | 0 of 168 | 0 of 168 |
| Pharyngitis Streptococcal | Infections and infestations | 0 of 171 | 0 of 168 | 0 of 169 | 1 of 168 | 0 of 168 | 0 of 168 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 3.75_(50)MF59 | 7.5 Without MF59 | 7.5_(50)MF59 | 7.5_(100)MF59 | 15 Without MF59 | 15_(50)MF59 |
|---|---|---|---|---|---|---|---|
| Injection site pain | General disorders | 98 of 171 | 70 of 168 | 85 of 169 | 117 of 168 | 85 of 168 | 99 of 168 |
| Pyrexia | General disorders | 41 of 171 | 34 of 168 | 38 of 169 | 34 of 168 | 44 of 168 | 34 of 168 |
| Headache | Nervous system disorders | 37 of 171 | 31 of 168 | 39 of 169 | 44 of 168 | 28 of 168 | 37 of 168 |
| Cough | Respiratory, thoracic and mediastinal disorders | 34 of 171 | 36 of 168 | 30 of 169 | 27 of 168 | 34 of 168 | 35 of 168 |
| Fatigue | General disorders | 33 of 171 | 22 of 168 | 31 of 169 | 32 of 168 | 30 of 168 | 29 of 168 |
| Upper respiratory track infection | Infections and infestations | 29 of 171 | 36 of 168 | 23 of 169 | 26 of 168 | 25 of 168 | 21 of 168 |
| Injection site erythema | General disorders | 29 of 171 | 16 of 168 | 26 of 169 | 38 of 168 | 25 of 168 | 26 of 168 |
| Vomiting | Gastrointestinal disorders | 22 of 171 | 14 of 168 | 27 of 169 | 20 of 168 | 19 of 168 | 18 of 168 |
| Myalgia | Musculoskeletal and connective tissue disorders | 24 of 171 | 10 of 168 | 17 of 169 | 36 of 168 | 13 of 168 | 18 of 168 |
| Otitis Media | Infections and infestations | 17 of 171 | 14 of 168 | 28 of 169 | 18 of 168 | 21 of 168 | 18 of 168 |
Serious events with the highest arm-level rate: bipolar disorder (0.6%), intermittent explosive disorder (0.6%), cerumen impaction (0.6%), chronic tonsillitis (0.6%), otitis media chronic (0.6%).
The registry reports serious adverse event counts by vaccine group, with the number at risk alongside each count. The recorded counts are 0 of 171 for 3.75_(50)MF59; 5 of 168 for 7.5 Without MF59; 7 of 169 for 7.5_(50)MF59; 4 of 168 for 7.5_(100)MF59; 3 of 168 for 15 Without MF59; 4 of 168 for 15_(50)MF59; 1 of 167 for 15_(100)MF59; and 0 of 169 for 30 Without MF59. These are descriptive counts, not a statistical comparison between formulations.
The listed serious-event terms are Bipolar Disorder, Intermittent Explosive Disorder, Cerumen Impaction, Chronic Tonsillitis, Otitis Media Chronic, and Pharyngitis Streptococcal; each is reported as 0.6%. The registry record does not give enough information to attribute those events to a particular formulation or to vaccination. It also does not report the observation window or a comparative safety analysis. Death counts are not reported in the registry record; blank death entries should not be interpreted as evidence that no deaths occurred.
12. What the Result Does, and Does Not, Mean
The registry record establishes what the trial set out to measure: HI antibody responses after two administrations of different A/H1N1 vaccine formulations, together with safety outcomes. It specifies response thresholds and a confidence-interval rule for classifying immunogenicity. It also reports analysis-set sizes for several follow-up periods and serious adverse event counts by group.
Those details do not, by themselves, establish which formulation met the immunogenicity criteria. The primary response percentages and their confidence intervals are not reported in the registry record. Without those values, it is not possible to determine whether a group met the seroconversion criterion, the HI titer criterion, or both. Nor can the formulations be ranked by response on the basis of the endpoint description.
Antibody response is an immunologic outcome, not a direct measure of prevention of influenza illness. The listed primary endpoint is based on an HI assay; the listed secondary outcomes include antibody titers and adverse events. A clinical outcome such as influenza illness is not included among the listed outcome measures. The registry record therefore does not establish a clinical effect on illness from the information.
The safety counts should likewise be interpreted descriptively. They show how many serious adverse events were recorded in each group among those at risk, but do not establish causation or demonstrate a difference between formulations. The record does not report a formal safety comparison, and death counts are not reported in the registry record. The results summarized in the record should be read within those limits, without extending them to unreported clinical outcomes or explanations.
13. Why This Trial Matters Statistically
This trial illustrates why an immunogenicity result is not just a response percentage. The registry defines success using the lower bounds of two-sided 95% confidence intervals for two separate antibody-response measures, and requires both bounds to meet their specified criteria. That approach makes precision part of the stated decision rule. A high point estimate would not alone answer the question if its confidence interval were too wide to satisfy the lower-bound requirement.
The design also presents a common challenge in dose-finding studies: several formulations differ in both antigen amount and adjuvant level. The eight groups create multiple possible contrasts, while antibody responses are assessed at several times. Interpreting such a design requires clarity about which comparisons were primary and how multiplicity was handled. Those details are not reported in the registry record, despite the record listing 140 analyses.
Follow-up adds another statistical consideration. The analysis-set sizes are reported for periods extending to Day 387, and the numbers included differ by period. Longer-term interpretation depends not only on the observed response but also on who contributes measurements at each time and how missing observations are addressed. The record does not report the reasons for exclusions or missing-data methods.
The study is also a useful example of the distinction between immunologic and clinical endpoints. An assay-based antibody response can characterize immune response, but it is not the same outcome as illness prevention. Keeping the endpoint and its limits explicit helps readers avoid treating an unreported clinical outcome as if it were measured. Here, the endpoint criteria and safety counts are documented, while the primary response estimates and several analysis details are not reported in the registry record.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most important limitation for interpreting the primary endpoint is that the registry record does not report the group-specific response percentages or their 95% confidence intervals. Since the stated immunogenicity rule depends on both lower confidence bounds, the endpoint’s result cannot be assessed from its description alone. The record also does not report a single summary comparison among the eight formulations.
Some statistical details needed to evaluate the results are not reported in the registry record. These include the seroconversion definition, interval estimation method, criteria for the per-protocol sets, handling of missing measurements, and any multiplicity adjustment. The record lists 140 analyses but does not identify the prespecified hierarchy of comparisons. The rationale for the original sample size and any interim analyses are also not reported.
The reported per-protocol analysis-set sizes vary across follow-up periods. The record does not explain the differences, so they cannot be attributed to withdrawal, protocol exclusions, missing measurements, or another cause. The population is limited to healthy children aged 3 to under 9 years; the findings should not be generalized from this trial description to populations not represented in the stated eligibility description.
The study is single-blind, but the identity of the masked parties and the masking procedures are not reported. Safety information includes serious-event counts and listed terms, but the observation window and comparative safety methods are not reported. Death counts are not reported in the registry record. These gaps limit assessment of both the immunogenicity estimates and the safety comparisons.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity of A/H1N1-SOIV (Swine Flu) Vaccine With and Without Adjuvant in Children (3 to < 9 Years) — NCT00972816.
- Registry record last updated 2016-04-14; status last verified 2016-03.
- Results first posted 2011-01-27.
- 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
NCT00972816 is a completed randomized, single-blind, parallel-group Phase 2 and Phase 3 study sponsored by Novartis Vaccines. It enrolled 1357 healthy children aged 3 to under 9 years and compared eight A/H1N1 vaccine formulations differing in antigen amount and MF59 adjuvant level. Each formulation was administered on study day 1 and day 22.
The primary outcome was the percentage meeting HI antibody response criteria, with assessments listed at Day 22, Day 29, Day 43, Day 202, and Day 387. The stated immunogenicity definition required both specified lower confidence-bound criteria to be met. Secondary outcomes covered antibody titers, response subgroups, and adverse events. The registry record reports per-protocol analysis-set sizes and serious adverse event counts, but the primary response percentages and confidence intervals are not reported in the registry record.