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 Sanofi 2017 H7N9 With/Without AS03 in Adults/Elderly (NCT03312231), a randomized phase 2 study. The primary outcome is Geometric Mean Titers (GMTs) of Serum Hemagglutination Inhibition (HAI) Antibodies.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03312231 |
| Phase | Phase 2 |
| Condition | Avian Influenza, Influenza Immunisation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 720 |
| Arms in the primary outcome | 5 |
| Lead sponsor | National Institute of Allergy and Infectious Diseases (NIAID) |
| Results posted | Yes |
2. Clinical Question
Population
Healthy males and non-pregnant females aged 19 years and older. Enrollment was stratified by age, with groups for ages 19–64 years and 65 years and older.
Intervention
Participants received two intramuscular doses of 2017 inactivated H7N9 vaccine, on days 1 and 22. The study tested 3.75 mcg, 7.5 mcg, or 15 mcg vaccine with AS03 adjuvant, and 15 mcg or 45 mcg vaccine without adjuvant. The 3.75 mcg formulation also included PBS diluent.
Comparator
The five randomized groups provide comparisons among vaccine doses and adjuvant conditions. Group 1, which received 3.75 mcg vaccine with PBS diluent plus AS03, is the reference group for the posted secondary comparisons. The primary outcome is reported by group, without a posted two-arm comparison.
Primary question
What were the serum HAI antibody geometric mean titers at Day 43, 21 days after the second dose, in each study group? The study also set out to assess safety, reactogenicity, and HAI and neutralizing antibody responses by age.
The clinical question concerns immune responses and safety after vaccination, not prevention of influenza illness. HAI antibody titers are one laboratory measure of the immune response; the reported primary endpoint does not itself establish whether participants were protected from infection or disease. The registry record describes a healthy-adult population and a pre-pandemic 2017 H7N9 vaccine, so the results pertain to that study setting and those participants.
3. Trial Design
This was a Phase II, randomized, double-blinded, parallel-group study sponsored by the National Institute of Allergy and Infectious Diseases. The registry record lists 720 participants enrolled and the study as completed. The study began on 2018-02-14, with primary completion on 2019-09-26.
Participants were randomized to five groups, with randomization stratified by age. The intended group allocations described in the record were up to 420 people aged 19–64 years and up to 300 people aged 65 years and older. Three groups received vaccine with AS03: 3.75 mcg with PBS diluent, 7.5 mcg, or 15 mcg. Two groups received unadjuvanted vaccine: 15 mcg or 45 mcg. Each group was assigned two intramuscular doses on days 1 and 22.
The design therefore varies vaccine dose and adjuvant condition, but does not include a group described as receiving vaccine-free placebo alone. PBS is specified as diluent in the 3.75 mcg adjuvanted group. The registry record describes an approximately 16-month study and approximately 13 months of participation for each subject.
The primary objectives were to assess safety and reactogenicity after the two doses and to assess serum HAI and neutralizing antibody responses, stratified by age. The posted primary result concerns HAI geometric mean titers at Day 43. Actual analysis counts vary by endpoint; the primary endpoint uses the modified intent-to-treat population described in the record. A more detailed statistical analysis plan, including any planned primary between-group contrasts, 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.
Overall Study
| Stage | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 |
|---|---|---|---|---|---|
| STARTED | 184 | 176 | 181 | 89 | 90 |
| COMPLETED | 181 | 165 | 177 | 86 | 89 |
| NOT COMPLETED | 3 | 11 | 4 | 3 | 1 |
Reasons for not completing this period:
| Reason | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 |
|---|---|---|---|---|---|
| Lost to Follow-up | 2 | 6 | 1 | 3 | 1 |
| Withdrawal by Subject | 0 | 3 | 1 | 0 | 0 |
| Death | 0 | 1 | 1 | 0 | 0 |
| Study Vaccination not Received | 1 | 1 | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The modified intent-to-treat (mITT) population includes all participants who received at least one study vaccination and contributed both pre- and at least one post-study vaccination venous blood samples for HAI antibody assays for which valid results were reported.
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.
Population: The baseline analysis population includes all participants who received at least one dose of study vaccine.
| Characteristic | Unit | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Total |
|---|---|---|---|---|---|---|---|
| Participants analysed | 183 | 175 | 180 | 89 | 90 | 717 | |
| Age, Continuous | years | 52.7 (SD 20.0) | 51.2 (SD 20.0) | 51.5 (SD 20.2) | 53.2 (SD 18.6) | 51.9 (SD 19.0) | 52.0 (SD 19.7) |
| Sex: Female, Male: Female | Participants | 94 | 99 | 81 | 47 | 50 | 371 |
| Sex: Female, Male: Male | Participants | 89 | 76 | 99 | 42 | 40 | 346 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 4 | 4 | 9 | 7 | 6 | 30 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 179 | 169 | 170 | 82 | 84 | 684 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 2 | 1 | 0 | 0 | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 1 | 1 | 2 |
| Race (NIH/OMB): Asian | Participants | 7 | 8 | 14 | 1 | 3 | 33 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 19 | 22 | 25 | 13 | 10 | 89 |
| Race (NIH/OMB): White | Participants | 149 | 137 | 130 | 69 | 73 | 558 |
| Race (NIH/OMB): More than one race | Participants | 6 | 5 | 7 | 4 | 2 | 24 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 | 3 | 4 | 1 | 1 | 11 |
| Region of Enrollment: United States | participants | 183 | 175 | 180 | 89 | 90 | 717 |
| Body Mass Index (BMI) | kg/m^2 | 27.5 (SD 5.3) | 28.2 (SD 6.5) | 26.8 (SD 5.4) | 27.2 (SD 5.8) | 27.5 (SD 4.3) | 27.5 (SD 5.6) |
6. Primary Endpoint
The registry lists the primary outcome as Geometric Mean Titers (GMTs) of Serum Hemagglutination Inhibition (HAI) Antibodies, measured over Day 43.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | titer |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the geometric mean titer (GMT) of serum hemagglutination inhibition (HAI) antibodies at Day 43. Blood samples were tested using the 2017 H7N9 vaccine virus as the antigen. Each sample was tested at least twice under the laboratory’s standard operating procedure, and the geometric mean of the replicate results was used as that participant’s result. The arm-level GMT was then calculated from available participant results.
HAI is a laboratory assay used to measure antibodies that inhibit hemagglutination by the tested virus. A GMT is used for titer data because titers are commonly analyzed on a logarithmic scale: the geometric mean summarizes the center of the measurements while respecting their multiplicative scale. It is not the same as an arithmetic average of the raw titers.
Day 43 is described as 21 days after the second dose. The reported 95% confidence intervals convey uncertainty around each arm’s estimated GMT. They do not describe the range of individual participants’ titers, and they do not by themselves establish the statistical significance of a difference between arms. The registry record reports the arm-specific estimates but does not report a primary two-arm comparison or an age-stratified primary result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
At Day 43, the posted HAI GMT estimates were 33.6 (95% CI 27.8 to 40.7) for Group 1, 33.5 (95% CI 27.9 to 40.2) for Group 2, and 39.2 (95% CI 32.6 to 47.0) for Group 3. The unadjuvanted groups had estimates of 5.5 (95% CI 5.3 to 5.7) for Group 4 and 6.3 (95% CI 5.7 to 6.9) for Group 5. These are arm-level antibody-titer summaries, not clinical outcomes.
The posted estimates describe different observed GMTs across the five vaccine groups. The three AS03-adjuvanted groups have estimates in a similar range to one another, while the two unadjuvanted groups have lower reported GMT estimates. This is a descriptive reading of the arm-level results. The registry record does not report a primary statistical comparison among these groups, so the posted estimates do not establish whether differences between groups meet a prespecified inferential criterion. Nor does an arm-level pattern identify the separate contribution of dose, adjuvant, or their combination.
The confidence intervals express the precision of each arm’s GMT estimate. For example, the interval for Group 3 spans 32.6 to 47.0, while Group 4’s interval spans 5.3 to 5.7. These intervals are not intervals for the difference between groups. A formal comparison would require an estimated contrast and its uncertainty under a specified analysis; the primary comparison is not reported in the registry record.
The endpoint population was modified intent-to-treat: participants had to receive at least one vaccination and contribute both a pre-vaccination and at least one post-vaccination venous blood sample with a valid HAI result. The arm-specific analysis counts were 179, 172, 180, 87, and 88, respectively. Those counts are not identical to the planned group allocations, and they describe the endpoint analysis population rather than all enrolled participants.
Secondary findings include small observed proportions for several antibody threshold and seroconversion outcomes, with uncertainty that is substantial relative to the observed proportions. Some unadjusted comparisons have p-values below 0.05, but these are secondary analyses among multiple outcomes and comparisons. The registry record does not report a multiplicity strategy, so those results should be treated as exploratory rather than as conclusive evidence of a difference.
9. Statistical Methods Explained
The posted results combine continuous antibody-titer summaries with secondary outcomes expressed as participant percentages. These measures answer related but distinct questions. A GMT summarizes the distribution of measured titers within an arm; a threshold percentage counts the share meeting a specified titer threshold; seroconversion is a separate response definition. None alone measures clinical protection.
What does a geometric mean represent?
In general, a geometric mean is appropriate for positive measurements that vary multiplicatively or are strongly skewed on their original scale. The measurements are transformed to a logarithmic scale, averaged there, and transformed back. This gives a central summary that is less dominated by very large raw values than an arithmetic mean can be. The registry record says the laboratory calculated each sample’s result as the geometric mean of replicate assay results, then calculated the GMT by study arm from available results.
The primary result is reported as a GMT with a 95% confidence interval for each group. In general, a confidence interval describes the statistical uncertainty in an estimate under the assumptions of the analysis. It is not a range expected to contain a fixed share of individual titers. Confidence intervals around separate arm estimates also are not the same as a confidence interval for a between-arm difference. Without a reported primary contrast, the arm estimates should be read descriptively.
What is the analysis population?
The modified intent-to-treat population included participants who received at least one study vaccination and contributed a pre-vaccination and at least one post-vaccination blood sample with a valid HAI result. This definition requires both vaccination and usable assay data. It differs from a population that includes every randomized participant regardless of whether endpoint data were available. The reason for each participant’s absence from an endpoint analysis is not reported in the registry record.
The primary endpoint arm counts were 179 for Group 1, 172 for Group 2, 180 for Group 3, 87 for Group 4, and 88 for Group 5. Secondary endpoint counts vary by outcome. Such variation can arise when different assays, timepoints, or response definitions have different available observations; the specific reasons for variation are not reported in the registry record.
How should percentage outcomes be read?
For a binary outcome, the reported percentage is the proportion of participants meeting the stated criterion in an arm. Its confidence interval reflects uncertainty in that proportion. When events or qualifying responses are uncommon, estimates can be imprecise, and intervals can extend from near zero to appreciably higher values. The confidence interval is especially important when interpreting small observed percentages.
The secondary comparisons include risk differences, which express the difference between two observed proportions on an absolute scale. In general, a risk difference near zero indicates similar observed proportions, while its confidence interval describes uncertainty about the contrast. A confidence interval that includes zero does not provide clear evidence of a nonzero difference under that analysis. The comparison estimates and p-values posted for secondary endpoints are unadjusted calculations; the registry record lists no reported analyses for those outcomes.
A p-value describes how compatible the observed data are with a specified null hypothesis under the model used. It is not the probability that the null hypothesis is true, and it does not measure clinical importance. Unadjusted p-values also do not account for the number of outcomes and comparisons examined. Because several secondary outcomes and contrasts are listed, an isolated small p-value requires cautious interpretation.
What do the planning illustrations mean?
Planning illustrations are based on the observed effect, not on the original trial design. Their assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect equal to the stated fraction of the observed effect. The illustrations describe participants per arm for 80% or 90% power under those assumptions. They are not observed power, do not show the power of this completed trial, and do not establish that the original design used those assumptions. The trial’s own sample-size justification is not reported in the registry record.
The registry record does not report whether interim analyses were conducted, what statistical model was used for the primary endpoint, or whether the primary comparison was adjusted for age or other factors. These details should not be inferred from the arm estimates or the secondary calculations.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists many outcome measures, including several HAI and neutralizing antibody outcomes, multiple timepoints, and results across five randomized groups. It does not report a multiplicity plan describing how the chance of false-positive findings across these outcomes and comparisons was controlled. A testing hierarchy, adjustment procedure, or designation of confirmatory versus exploratory secondary outcomes is not reported in the registry record.
This matters because each statistical test addresses a particular contrast or outcome. When many tests are considered, the chance of at least one apparently unusual result can increase, even if no real differences exist. A nominal p-value such as the unadjusted 0.043 for one secondary comparison therefore has less evidential weight when considered among a wider collection of outcomes and comparisons. The registry record lists no reported secondary analyses that would clarify whether this finding was planned or how it was interpreted by the study investigators.
The primary GMT estimates are reported by arm, but no primary between-group test, adjusted contrast, or age-stratified analysis is reported in the registry record. The trial’s detailed statistical plan and any interim-analysis procedures are also not reported. It is not possible to determine from the posted results whether additional analyses were prespecified or conducted outside the registry record.
The primary population is modified intent-to-treat and requires valid pre- and post-vaccination HAI results. This is a defined endpoint population, but the registry record does not explain why participants were excluded from each endpoint analysis or how missing assay results were handled. It also does not report a missing-data sensitivity analysis. Since analyzed counts vary among groups and outcomes, readers should distinguish the endpoint-specific analysis population from the total enrollment and avoid assuming that all randomized participants contributed to every measure.
These reporting gaps limit how confidently the secondary findings can be treated as confirmatory and how fully the primary analysis can be reconstructed. They do not change the descriptive values posted for the groups, but they constrain interpretation of statistical evidence beyond those arm-level summaries.
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 |
|---|---|---|---|
| Group 1 | 4 | 183 | 2.2% |
| Group 2 | 9 | 175 | 5.1% |
| Group 3 | 4 | 180 | 2.2% |
| Group 4 | 3 | 89 | 3.4% |
| Group 5 | 1 | 90 | 1.1% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Group 1 | 1 of 183 |
| Group 2 | 1 of 175 |
| Group 3 | 1 of 180 |
| Group 4 | 0 of 89 |
| Group 5 | 0 of 90 |
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 |
|---|---|
| Group 1 | 172 of 183 |
| Group 2 | 170 of 175 |
| Group 3 | 167 of 180 |
| Group 4 | 70 of 89 |
| Group 5 | 73 of 90 |
Most frequent serious adverse event terms
| Event term | Organ system | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 |
|---|---|---|---|---|---|---|
| Urinary retention | Renal and urinary disorders | 1 of 183 | 2 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
| Acute coronary syndrome | Cardiac disorders | 0 of 183 | 1 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
| Angina unstable | Cardiac disorders | 1 of 183 | 0 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
| Stress cardiomyopathy | Cardiac disorders | 0 of 183 | 0 of 175 | 0 of 180 | 0 of 89 | 1 of 90 |
| Small intestinal obstruction | Gastrointestinal disorders | 0 of 183 | 1 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
| Chest pain | General disorders | 1 of 183 | 0 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
| Cholelithiasis | Hepatobiliary disorders | 0 of 183 | 0 of 175 | 1 of 180 | 0 of 89 | 0 of 90 |
| Bacteraemia | Infections and infestations | 0 of 183 | 0 of 175 | 0 of 180 | 1 of 89 | 0 of 90 |
| Epididymitis | Infections and infestations | 0 of 183 | 0 of 175 | 0 of 180 | 1 of 89 | 0 of 90 |
| Contusion | Injury, poisoning and procedural complications | 0 of 183 | 1 of 175 | 0 of 180 | 0 of 89 | 0 of 90 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 |
|---|---|---|---|---|---|---|
| Injection site tenderness | General disorders | 142 of 183 | 146 of 175 | 150 of 180 | 28 of 89 | 37 of 90 |
| Injection site pain | General disorders | 87 of 183 | 99 of 175 | 110 of 180 | 12 of 89 | 15 of 90 |
| Fatigue | General disorders | 65 of 183 | 67 of 175 | 67 of 180 | 21 of 89 | 21 of 90 |
| Injection site erythema | General disorders | 51 of 183 | 47 of 175 | 58 of 180 | 23 of 89 | 25 of 90 |
| Myalgia | Musculoskeletal and connective tissue disorders | 57 of 183 | 57 of 175 | 57 of 180 | 10 of 89 | 16 of 90 |
| Headache | Nervous system disorders | 55 of 183 | 51 of 175 | 52 of 180 | 19 of 89 | 18 of 90 |
| Injection site induration | General disorders | 46 of 183 | 41 of 175 | 62 of 180 | 11 of 89 | 14 of 90 |
| Malaise | General disorders | 45 of 183 | 44 of 175 | 44 of 180 | 5 of 89 | 8 of 90 |
| Feverishness | General disorders | 28 of 183 | 31 of 175 | 35 of 180 | 1 of 89 | 6 of 90 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 28 of 183 | 21 of 175 | 35 of 180 | 7 of 89 | 7 of 90 |
Serious events with the highest arm-level rate: urinary retention (1.1%), bacteraemia (1.1%), epididymitis (1.1%), diffuse large b-cell lymphoma (1.1%), stress cardiomyopathy (1.1%).
The registry record reports serious adverse events and deaths by study group, with a denominator of participants at risk for each group. Serious adverse events were recorded for 4 of 183 participants in Group 1, 9 of 175 in Group 2, 4 of 180 in Group 3, 3 of 89 in Group 4, and 1 of 90 in Group 5. The record also lists deaths by group: 1 in Group 1, 1 in Group 2, 1 in Group 3, 0 in Group 4, and 0 in Group 5.
These counts describe what was reported during the study; they do not establish that an event was caused by vaccination. The registry record does not provide event-level timing, adjudication, or a causal assessment for these counts. The listed serious adverse-event terms include urinary retention, bacteraemia, epididymitis, diffuse large B-cell lymphoma, and stress cardiomyopathy, each reported as 1.1%, and acute coronary syndrome at 0.6%. The record does not link those terms to particular groups in the displayed term list.
Other adverse events are also recorded by group, but the registry description does not define that category in the results. Counts should not be treated as a complete account of event severity, duration, or relatedness. Between-group safety comparisons are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The results describe measured antibody responses after two doses of a particular 2017 inactivated H7N9 vaccine in healthy adults aged 19 years and older. The primary endpoint is a laboratory antibody titer at Day 43. It is not a measure of infection, influenza illness, hospitalization, or prevention of disease. The study’s immunogenicity findings therefore should not be translated directly into a claim about clinical protection.
The arm-specific GMTs show the observed antibody levels in the endpoint analysis population. The estimates are accompanied by confidence intervals that indicate statistical uncertainty, but the registry record does not report a primary comparison between groups. The descriptive pattern alone cannot establish that one group differs from another under a prespecified statistical test, nor can it identify whether observed differences are due to vaccine dose, adjuvant, or both.
The secondary antibody outcomes provide additional laboratory summaries, but their results are not clinical outcomes either. Some unadjusted comparisons have small p-values, yet the number of outcomes and the absence of a reported multiplicity strategy make isolated secondary findings less conclusive. The record does not report an analysis relating antibody measurements to subsequent clinical outcomes.
Safety counts should also be read within their limits. The registry reports serious adverse events and deaths by group, but the counts do not establish causation, and the record does not provide a comparative safety analysis. The listed data do not determine an individual’s risk or guide a personal health decision.
Overall, the posted results support a description of group-level HAI antibody titers, secondary laboratory response measures, and recorded adverse-event counts in this trial. They do not establish clinical effectiveness, a definitive ranking of vaccine formulations, or a causal interpretation of reported adverse events.
13. Why This Trial Matters Statistically
This trial raises several statistical issues that commonly arise in vaccine immunogenicity studies. First, the primary outcome is a titer summarized by a geometric mean, while many secondary outcomes are percentages meeting a threshold or response definition. These summaries answer different questions and should not be collapsed into a single judgment about the immune response.
Second, the design includes five groups that differ in dose and adjuvant condition. That structure permits descriptive examination of several formulations, but it also creates multiple possible contrasts. Statistical interpretation depends on which comparisons were planned and how multiplicity was handled. Neither a primary contrast plan nor a multiplicity strategy is reported in the registry record, so the arm-level estimates carry more interpretive weight than isolated unadjusted secondary tests.
Third, antibody outcomes are measured in an endpoint-specific analysis population. The primary mITT definition requires vaccination and valid blood-sample results, and the analyzed group counts differ from one another. A trial’s enrollment total and an outcome’s analysis population are therefore not interchangeable. Understanding which participants contributed data is important when judging precision and possible selection effects.
Finally, statistical evidence about laboratory responses is not equivalent to evidence about clinical benefit. The trial measures HAI and neutralizing antibodies, alongside safety and reactogenicity objectives, but the primary posted result is a laboratory endpoint. Distinguishing measurement scale, uncertainty, comparison structure, missing-data reporting, and clinical meaning is central to reading the results appropriately.
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.
Several limitations specific to this record constrain interpretation. The primary outcome is reported as an arm-level Day 43 GMT with confidence intervals, but a primary between-group comparison is not reported. The registry record also does not provide a detailed statistical analysis plan, a sample-size justification, or a description of interim analyses. As a result, the prespecified inferential framework cannot be assessed from the record.
The population is described as healthy males and non-pregnant females aged 19 years and older, with age-stratified enrollment. The posted primary results are not broken out by age, and the record does not report an age-adjusted comparison. The findings therefore do not show how the primary antibody responses varied between the age categories.
The primary endpoint analysis includes only participants meeting the modified intent-to-treat criteria, including valid HAI results. The registry record does not explain all differences in endpoint counts, reasons for missing samples, or handling of missing results. This prevents a full assessment of whether missing data could have affected the estimates.
The secondary results cover multiple antibody measures and comparisons, but a multiplicity strategy is not reported. Some secondary calculations are unadjusted, and no sponsor-reported analyses are listed. Their inferential strength is consequently limited, particularly when interpreting an isolated p-value.
Finally, the outcomes are laboratory immunogenicity measures and reported adverse-event counts. The record does not report clinical influenza outcomes, a relationship between antibody titers and protection, or comparative causal assessments of adverse events. These limitations restrict conclusions to the posted measurements and the population studied.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Sanofi 2017 H7N9 With/Without AS03 in Adults/Elderly — NCT03312231.
- Registry record last updated 2024-09-19; status last verified 2018-02-06.
- Results first posted 2020-10-12.
- 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
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18. Record Summary
The registry record describes a completed, randomized, double-blinded, parallel-group Phase II study of a 2017 inactivated H7N9 vaccine in healthy adults aged 19 years and older. Participants were assigned to five groups receiving two doses on days 1 and 22, with different vaccine doses and with or without AS03 adjuvant. Total enrollment was 720.
The primary posted outcome is the Day 43 HAI antibody GMT, analyzed in a modified intent-to-treat population. The record reports group-specific GMTs and 95% confidence intervals, but no primary between-group comparison. Secondary measures include HAI and neutralizing antibody outcomes. Serious adverse events and deaths are reported by group, without a posted comparative causal analysis.
The registry record does not report the detailed statistical plan, sample-size justification, multiplicity procedure, or missing-data sensitivity analyses. Findings are best interpreted as descriptive immunogenicity and safety results for this study population, not as evidence of clinical protection.