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 Two Doses of a Tetravalent Influenza Vaccine in Adults Aged 18 Years and Above (NCT00620815), a randomized phase 2 study. The primary outcome is To Demonstrate the Equivalence of Antibody Response Against A/H5N1 Strain Elicited by the Three Different Immunization Schedules on Day 43..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00620815 |
| Phase | Phase 2 |
| Condition | Influenza |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 601 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Vaccines |
| Results posted | Yes |
2. Clinical Question
Population
Adults aged 18 years and above with influenza listed as the condition. The registry record reports an enrollment of 601. It does not report the number included in the primary per-protocol analysis.
Intervention
The study assessed schedules involving the tetravalent influenza vaccine, Aflunov, and, in one schedule, licensed seasonal vaccine. The schedules differed in which vaccine was given on day 1 and which was given on day 22.
Comparator
The primary objective was to assess equivalence of antibody response among three immunization schedules. The registry record also describes placebo given alongside a vaccine in some schedules, in a different arm.
Primary question
By day 43, were antibody responses against the A/H5N1 strain, measured by the SRH assay, equivalent across the three schedules according to geometric mean ratios?
This is an immunogenicity question: it concerns measured antibody response after vaccination, rather than a comparison of influenza illness or other clinical outcomes. The registry names the primary measure as geometric mean area in the SRH assay and says that geometric mean ratios were used for the equivalence analysis. The analysis population was the per-protocol set.
The posted registry information does not include the geometric mean areas, geometric mean ratios, confidence intervals, equivalence margins, or a conclusion about whether equivalence was established. Therefore, the objective can be described, but its result cannot be evaluated from the registry record. The outcome is specified up to day 43; the record does not provide enough result detail to determine the size or precision of the response in each schedule.
The study also listed outcomes for local and systemic reactions and several antibody and cellular-response measures. These provide additional kinds of information about response and tolerability, but they do not replace the primary equivalence comparison. Numerical results for those secondary outcomes are not reported in the registry record in the information available for this analysis.
3. Trial Design
The registry describes a randomized, placebo-controlled, observer-blind, multicenter phase II study with a parallel-group design. It lists an enrollment of 601 and a completed status. The study start is recorded as 2007-11, and primary completion as 2008-01. The sponsor is Novartis Vaccines.
The three main schedules were identified as T/P-A, A/P-T, and A/S-A. In T/P-A, participants received tetravalent influenza vaccine and placebo on day 1, followed by Aflunov on day 22. In A/P-T, they received Aflunov and placebo on day 1, followed by tetravalent influenza vaccine on day 22. In A/S-A, they received Aflunov and licensed seasonal vaccine on day 1, followed by Aflunov on day 22. The record also lists corresponding groups with an additional blood draw at visit 2 before the day 22 vaccination.
These schedules make the timing and combination of vaccinations central to the comparison. The registry's primary objective was to compare antibody response against A/H5N1 across the three schedules, rather than to compare only one vaccine with an untreated control. Placebo was included alongside vaccination in two of the main schedules, but the primary objective was the equivalence comparison among schedules.
The registry identifies the primary analysis population as the per-protocol set. It does not report the number analyzed in that set, the reasons for any exclusions, or the detailed criteria for inclusion in it. The number enrolled should therefore not be treated as the denominator for the primary endpoint.
Although the study is described as observer-blind, the registry does not report which roles were masked or how masking was maintained. Detailed allocation procedures, treatment adherence, and the handling of protocol deviations are not reported in the registry record. These details matter when interpreting a per-protocol analysis and evaluating the conduct of a randomized study.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: All subjects were included in the trial. The data entered is for the overall study.
Overall Study
| Stage | T/P-A | A/P-T | A/S-A |
|---|---|---|---|
| STARTED | 199 | 203 | 199 |
| COMPLETED | 195 | 192 | 192 |
| NOT COMPLETED | 4 | 11 | 7 |
Reasons for not completing this period:
| Reason | T/P-A | A/P-T | A/S-A |
|---|---|---|---|
| Adverse Event | 1 | 1 | 2 |
| Withdrawal by Subject | 1 | 2 | 0 |
| Lost to Follow-up | 1 | 6 | 3 |
| Inappropriate enrolment | 0 | 0 | 1 |
| Protocol Violation | 1 | 2 | 1 |
Analysis population for the primary outcome, as defined in the registry: The analysis was done on 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 | T/P-A | A/P-T | A/S-A | Total |
|---|---|---|---|---|---|
| Participants analysed | 199 | 203 | 199 | 601 | |
| Age, Customized: ≤60 years | participants | 196 | 202 | 198 | 596 |
| Age, Customized: ≥ 61 Years | participants | 3 | 1 | 0 | 4 |
| Sex/Gender, Customized: Female (≤60 years of age) | participants | 126 | 129 | 114 | 369 |
| Sex/Gender, Customized: Male (≤60 years of age) | participants | 70 | 73 | 84 | 227 |
| Sex/Gender, Customized: Female (≥61 years of age) | participants | 1 | 1 | 0 | 2 |
| Sex/Gender, Customized: Male (≥61 years of age) | participants | 2 | 0 | 0 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as To Demonstrate the Equivalence of Antibody Response Against A/H5N1 Strain Elicited by the Three Different Immunization Schedules on Day 43., measured over up to day 43.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Area (mm^2) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint measures antibody response against the A/H5N1 strain using the single radial haemolysis assay, or SRH. The response is expressed as geometric mean area, with area measured in mm². The registry describes the timeframe as up to day 43 and identifies geometric mean ratios as the basis for assessing equivalence across the three immunization schedules.
Geometric means are used for measurements that are commonly analyzed on a multiplicative scale. A geometric mean ratio expresses the relative response between groups rather than the absolute difference between their arithmetic averages. For an equivalence question, the comparison asks whether the group responses are sufficiently similar under a prespecified range of acceptable differences. The registry record does not report that range, so the criterion for declaring equivalence cannot be checked.
Antibody assays provide a laboratory measure of immune response. They can help characterize how the immune system responds to the schedules, but the endpoint is not itself a measure of clinical influenza cases or protection from illness. The registry's listed primary objective is specifically an antibody-response equivalence objective.
The analysis was conducted on the per-protocol set, according to the registry. This population generally includes participants meeting specified protocol requirements, but the exact requirements and analyzed group size are not reported in the registry record. Nor are the group-level SRH results or the geometric mean ratios reported. Thus, the endpoint and intended comparison are identifiable, while the magnitude, precision, and conclusion of the primary analysis are not.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical question is whether antibody responses measured by SRH were equivalent among the three schedules at the day 43 assessment. The registry states that geometric mean ratios were used for this purpose and that the analysis used the per-protocol set. However, it does not report the estimates, their confidence intervals, an equivalence margin, or a stated conclusion. The primary result therefore cannot be independently interpreted from the posted registry information.
Equivalence is not established merely because a conventional test fails to find a statistically significant difference. In general, an equivalence analysis evaluates whether the uncertainty around the between-group comparison lies within prespecified limits that represent acceptable similarity. This requires both an estimate and a confidence interval, along with the equivalence limits. Those details are not reported in the registry record. Without them, it is not possible to tell whether the data were sufficiently precise to support equivalence, whether the result was inconclusive, or how the observed responses compared.
The registry lists several secondary outcomes, including local and systemic reactions after vaccination, antibody measures using SRH, HI and MN assays, B-cell antibodies, and T-cell responses. The listed outcomes describe a broad set of immune-response and reaction measures. Numerical results for these outcomes are not reported in the registry record here, so no direction, magnitude, or precision can be stated for them.
The safety fields give counts for participants at risk and participants affected in serious-event and other-event categories. For T/P-A, the record lists 2 serious-event participants among 199 at risk and 190 affected in the other-event field among 199 at risk. For A/P-T, the corresponding entries are 3 among 203 and 185 among 203. For A/S-A, they are 4 among 198 and 183 among 198. These are registry counts, not adjusted comparisons. The record does not give a causal assessment for the events, and the other-event category is not further defined in the available information.
The serious-event terms listed individually each have a reported frequency of 0.5%: Bile Duct Stenosis, Endoscopic Retrograde Cholangiopancreatography, Ovarian Cancer, Cerebral Haemorrhage, Intracranial Aneurysm, and Bulimia Nervosa. The registry information does not establish that any event was caused by vaccination. Death values are not reported in the registry record.
Overall, the record provides the study objective, design, and some safety counts, but not the primary efficacy-style immunogenicity estimates needed to judge the equivalence objective. No conclusion about the comparative antibody response should be inferred from the design alone.
9. Statistical Methods Explained
The registry identifies the primary measure as geometric mean area from the SRH assay and the primary comparison as geometric mean ratios across three immunization schedules. The analysis population is described as the per-protocol set. The registry does not report the detailed statistical analysis plan, equivalence limits, model specification, confidence intervals for the primary comparison, or numerical primary results. The concepts below are general explanations of the methods named in the record, not claims about additional procedures used in this study.
Why use a geometric mean?
General: Biological measurements such as antibody responses can have a skewed distribution, with some values much larger than others. A geometric mean is calculated on a logarithmic scale and then expressed back on the original scale. It can provide a useful summary when differences are naturally interpreted as proportional changes. The registry reports geometric mean areas, but does not report the underlying distribution or whether any transformation checks were performed.
General: A geometric mean ratio compares the typical response in one group with the typical response in another on a multiplicative scale. For an equivalence objective, the ratio is interpreted against limits set in advance. A confidence interval conveys the range of values reasonably compatible with the data under the model. To support equivalence, the full interval would ordinarily need to fall within the accepted equivalence limits. The limits and interval are not reported in the registry record, so the equivalence decision cannot be reconstructed.
What does equivalence mean?
General: Equivalence is a specific statistical claim that the difference between treatments is small enough, in either direction, to be considered practically unimportant under a prespecified margin. It is distinct from showing superiority and distinct from simply failing to detect a difference. A wide interval can include no difference while also allowing meaningful differences, and therefore may not support equivalence. In this study, the registry states an equivalence objective but does not report the margin or result needed to determine whether that objective was met.
Why does the analysis population matter?
The registry says the primary analysis was performed in the per-protocol set. General: A per-protocol analysis focuses on participants who meet protocol requirements relevant to the analysis. Its interpretation depends on how those requirements are defined and how exclusions are handled. In an equivalence study, exclusions or deviations can affect the observed similarity between groups, so both the analysis population and its rationale are important. The exact per-protocol criteria, the number analyzed, and any sensitivity analyses are not reported in the registry record.
General: Randomization aims to make comparison groups similar in expectation with respect to measured and unmeasured characteristics. It supports a fair comparison when allocation is implemented as intended and participants are analyzed appropriately. Randomization does not, on its own, ensure that all groups remain comparable after exclusions, missing measurements, or deviations. The registry identifies randomized allocation, but detailed allocation methods and post-randomization handling are not reported.
How should confidence intervals be read?
The primary measure is described with a 95% confidence interval. General: A confidence interval indicates the statistical uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. It does not guarantee that the true value lies within the particular interval. For an equivalence claim, the position of the interval relative to the prespecified equivalence limits is essential. The registry record does not provide the primary interval or the limits, so precision cannot be assessed.
General: Precision depends on factors such as the amount of usable outcome information, variability in the measurement, and the analysis model. Enrollment alone is not enough to determine precision. The registry reports enrollment of 601 but does not report the primary analysis sample size or the variability of the SRH measurements. It is therefore not possible to infer how precise the primary comparison was from enrollment alone.
What do the planning illustrations mean?
The accompanying planning material is described as an 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 describes planning for a stated fraction of the observed effect. General: Such calculations can illustrate how a hypothetical future study's size might vary with the effect it aims to detect and the assumptions chosen. They are not evidence that the current trial had a particular probability of finding a result, and they are not observed power.
The registry describes the primary objective as a comparison among three schedules, while the planning assumptions refer to two arms. A two-arm planning illustration should not be mistaken for the full design or for the primary three-schedule analysis. Numerical planning estimates are not reported in the registry information used for this explanation. The registry also does not report that those illustrations were the sponsor's original design justification.
Why does over-dispersion matter?
General: Over-dispersion occurs when outcome variability is greater than a statistical model assumes. If a model understates variability, standard errors may be too small and confidence intervals may be too narrow; if it accounts for excess variability, uncertainty can be represented more realistically. This concept is relevant to some count outcomes, but the registry does not report a model for the reaction counts or state whether over-dispersion was assessed. It should not be assumed to have been part of the analysis.
The registry lists multiple assays and reaction outcomes in addition to the primary endpoint. Those outcomes can involve different measurement scales and may require different statistical approaches. The analysis methods for those secondary outcomes, including any adjustment for multiple comparisons, are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary equivalence objective and several secondary outcomes covering local reactions, systemic reactions, antibody measures, B-cell antibodies, and T-cell responses. These outcomes involve different assays, response definitions, and assessment times. When many outcomes are examined, the chance of at least one apparently notable result can increase. General: Multiplicity procedures can control or describe that risk, but they depend on a prespecified testing strategy.
The registry record does not report whether a multiplicity adjustment was planned or applied, how secondary outcomes were prioritized, or whether any analyses were exploratory. It also does not report a detailed statistical analysis plan. No claim about control of false-positive findings can therefore be made from the information available.
Missing-data handling is also not reported. The registry does not state how missing SRH measurements, incomplete follow-up, or participants without an evaluable day 43 result were handled. It does not provide the number analyzed for the primary endpoint or reasons participants may have been excluded from the per-protocol set. These omissions limit assessment of how the reported analysis population relates to enrollment and whether missing measurements could affect the comparison.
The primary analysis population is identified as per protocol, but the criteria defining that set and any complementary analysis population are not reported. For an equivalence objective, the choice and implementation of analysis populations can be important because different exclusions may influence apparent similarity. The registry does not describe sensitivity analyses addressing that issue.
The record also does not report interim analyses, stopping rules, or a sample-size justification. These should not be inferred from the planning illustrations, which are described as calculations based on the observed effect rather than the trial's original design. Without the analysis plan and missing-data details, the primary objective and intended method are known, but the robustness of the analysis 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 |
|---|---|---|---|
| T/P-A | 2 | 199 | 1.0% |
| A/P-T | 3 | 203 | 1.5% |
| A/S-A | 4 | 198 | 2.0% |
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 |
|---|---|
| T/P-A | 190 of 199 |
| A/P-T | 185 of 203 |
| A/S-A | 183 of 198 |
Most frequent serious adverse event terms
| Event term | Organ system | T/P-A | A/P-T | A/S-A |
|---|---|---|---|---|
| Retinal Detachment | Eye disorders | 0 of 199 | 1 of 203 | 0 of 198 |
| Diarrhoea | Gastrointestinal disorders | 0 of 199 | 1 of 203 | 0 of 198 |
| Intestinal Polyp | Gastrointestinal disorders | 1 of 199 | 0 of 203 | 0 of 198 |
| Bile Duct Stenosis | Hepatobiliary disorders | 0 of 199 | 0 of 203 | 1 of 198 |
| Pyelonephritis | Infections and infestations | 0 of 199 | 1 of 203 | 0 of 198 |
| Endoscopic Retrograde Cholangiopancreatography | Investigations | 0 of 199 | 0 of 203 | 1 of 198 |
| Ovarian Cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 199 | 0 of 203 | 1 of 198 |
| Cerebral Haemorrhage | Nervous system disorders | 0 of 199 | 0 of 203 | 1 of 198 |
| Intracranial Aneurysm | Nervous system disorders | 0 of 199 | 0 of 203 | 1 of 198 |
| Abortion Spontaneous | Pregnancy, puerperium and perinatal conditions | 1 of 199 | 0 of 203 | 0 of 198 |
Most frequent non-serious adverse event terms
| Event term | Organ system | T/P-A | A/P-T | A/S-A |
|---|---|---|---|---|
| Injection Site Pain | General disorders | 172 of 199 | 164 of 203 | 155 of 198 |
| Fatigue | General disorders | 88 of 199 | 92 of 203 | 71 of 198 |
| Headache | Nervous system disorders | 90 of 199 | 86 of 203 | 60 of 198 |
| Myalgia | Musculoskeletal and connective tissue disorders | 75 of 199 | 77 of 203 | 57 of 198 |
| Malaise | General disorders | 66 of 199 | 55 of 203 | 38 of 198 |
| Nasopharyngitis | Infections and infestations | 39 of 199 | 38 of 203 | 26 of 198 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 37 of 199 | 29 of 203 | 19 of 198 |
| Cough | Respiratory, thoracic and mediastinal disorders | 30 of 199 | 28 of 203 | 26 of 198 |
| Nausea | Gastrointestinal disorders | 30 of 199 | 29 of 203 | 14 of 198 |
| Chills | General disorders | 30 of 199 | 19 of 203 | 11 of 198 |
Serious events with the highest arm-level rate: bile duct stenosis (0.5%), endoscopic retrograde cholangiopancreatography (0.5%), ovarian cancer (0.5%), cerebral haemorrhage (0.5%), intracranial aneurysm (0.5%).
The registry lists participants at risk and participants affected in serious-event and other-event fields for the three main schedules. In T/P-A, the serious-event field lists 2 affected among 199 at risk, and the other-event field lists 190 among 199. In A/P-T, the corresponding counts are 3 among 203 and 185 among 203. In A/S-A, they are 4 among 198 and 183 among 198. These counts should be read within their recorded categories and denominators, rather than as a direct comparison of treatment effects.
The registry also lists six serious-event terms, each with a reported frequency of 0.5%: Bile Duct Stenosis, Endoscopic Retrograde Cholangiopancreatography, Ovarian Cancer, Cerebral Haemorrhage, Intracranial Aneurysm, and Bulimia Nervosa. The listing does not establish that these events were caused by vaccination, nor does it provide enough detail to assess timing, clinical context, or relatedness. Deaths are not reported in the registry record.
The other-event field is not defined further in the information available. Its counts should not be relabeled as a specific type of reaction or treated as equivalent to the listed serious events. The registry lists local and systemic reactions as secondary outcomes, but their numerical results are not reported. Descriptive safety counts alone do not establish a causal relationship or a comparative safety conclusion.
12. What the Result Does, and Does Not, Mean
The record establishes that this randomized phase II study was designed to compare antibody responses against A/H5N1 across three immunization schedules. It identifies the SRH geometric mean area as the primary measure, geometric mean ratios as the basis for the equivalence assessment, and the per-protocol set as the analysis population. These details clarify what the primary question was and how the registry says it was approached.
The record does not report the numerical primary estimates, confidence intervals, equivalence margins, or a conclusion. It therefore cannot establish from the posted information whether the schedules met the study's equivalence criterion, how large the responses were, or how precisely they were estimated. The absence of a numerical result in this record is not evidence that the responses were equal, different, or clinically meaningful.
The primary outcome is a laboratory measure of antibody response, not a direct measure of influenza illness or clinical protection. The registry also lists reaction outcomes and other immune-response measures, but does not report numerical results for them in the information. The study's listed outcomes should not be treated as interchangeable: different assays capture different aspects of immune response, and reaction outcomes address a different question from antibody measurements.
The serious-event and other-event counts are descriptive entries. They do not, by themselves, determine whether an event was caused by a vaccine or whether one schedule has a different risk from another. The event listing does not include a causal assessment, and deaths are not reported in the registry record.
Accordingly, the most supportable interpretation is limited: the registry documents an equivalence-focused immunogenicity trial and some safety counts, while leaving the primary result and key analysis details unavailable. No conclusion about vaccine effectiveness, clinical benefit, or comparative safety follows from the registry information.
13. Why This Trial Matters Statistically
This trial is statistically notable because its primary objective is equivalence rather than superiority. That distinction changes what evidence is needed. A superiority analysis commonly asks whether one group differs from another; an equivalence analysis asks whether the uncertainty around a comparison is confined within acceptable limits set in advance. A non-significant difference alone cannot demonstrate equivalence.
The design also compares three immunization schedules, with differences in which vaccines are given on day 1 and day 22. This makes the timing and combination of vaccination part of the scientific question. The primary endpoint focuses on the antibody response against A/H5N1, measured by SRH, and uses geometric mean ratios to compare schedules. The analysis is specified for the per-protocol set, making the definition and handling of that population relevant to interpretation.
The registry record illustrates why knowing the objective and method is not enough to evaluate a result. The estimates, confidence intervals, equivalence margin, and conclusion are not reported. Without those elements, readers cannot judge whether the comparison was precise enough to support equivalence or whether uncertainty remained substantial. Missing details about the analysis population, missing data, and multiplicity also limit assessment of robustness.
More broadly, the trial highlights the distinction between an immune-response endpoint and a clinical endpoint. A laboratory response can be useful for studying immunogenicity, but it does not, on its own, describe clinical illness outcomes. The registry's several secondary immune measures and reaction outcomes address additional questions, yet their numerical results are not reported in the information available.
The statistical lesson is that a clearly stated equivalence objective needs its prespecified margin and interval-based result to be interpretable. The design and endpoint are documented, but the registry information does not provide those decisive pieces of evidence.
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 interpretation is that the registry record does not report numerical results for the primary endpoint. Geometric mean areas, geometric mean ratios, confidence intervals, equivalence limits, and the conclusion of the equivalence analysis are not reported. As a result, the primary objective cannot be judged from the available record.
The record identifies the per-protocol set but does not give its size or define the criteria used to form it. It also does not report the number with an evaluable day 43 SRH measurement, exclusions, protocol deviations, or methods for handling missing data. These details are important for understanding who contributed to the primary analysis and how representative that analysis was of enrollment.
Although the study is described as randomized and observer-blind, the allocation procedure and the roles included in masking are not reported. The registry does not provide the detailed statistical analysis plan, multiplicity approach, interim-analysis information, or a sample-size justification. These features should not be inferred from the design description or planning illustrations.
The safety record gives counts in serious-event and other-event fields and lists serious-event terms, but it does not report causal assessments or enough context to interpret those terms clinically. Deaths are not reported in the registry record. The other-event category is not defined further in the available information.
Finally, the registry lists numerous secondary immune and reaction outcomes without numerical results in the information available for this analysis. Their direction, size, precision, and relationship to the primary result cannot be assessed. The trial's laboratory antibody endpoint also does not directly report clinical influenza outcomes.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity of Two Doses of a Tetravalent Influenza Vaccine in Adults Aged 18 Years and Above — NCT00620815.
- Registry record last updated 2016-03-28; status last verified 2016-03.
- Results first posted 2012-09-19.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
This completed, randomized, placebo-controlled, observer-blind, multicenter phase II study had a parallel-group design and enrolled 601 adults aged 18 years and above. It compared three schedules involving tetravalent influenza vaccine, Aflunov, placebo, and licensed seasonal vaccine, with vaccination on day 1 and day 22.
The primary objective was equivalence of antibody response against A/H5N1 by day 43. The endpoint used SRH geometric mean area, with geometric mean ratios as the basis of the comparison, analyzed in the per-protocol set. The registry record does not report the primary estimates, confidence intervals, equivalence margin, or conclusion.
Secondary outcomes included local and systemic reactions and several antibody and cellular-response measures. The safety fields list serious-event and other-event counts by schedule, as well as six serious-event terms at 0.5% each. Causal assessments and deaths are not reported in the registry record.