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 Study of QIVc in Healthy Pediatric Subjects (NCT04074928), a randomized phase 3 study. The primary outcome is Immunogenicity Endpoint: Geometric Mean Titer (GMT) and GMT Ratio Against the A/H1N1, B/Victoria and B/Yamagata Vaccine Strains by Hemagglutination Inhibition (HAI) Assay Using Cell-derived Target Viruses.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04074928 |
| Phase | Phase 3 |
| Condition | Influenza, Human, Virus Diseases |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 2414 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Seqirus |
| Results posted | Yes |
2. Clinical Question
Population
Healthy children 6 months through 47 months of age. The study enrolled 2414 participants.
Intervention
QIVc, a cell-derived quadrivalent influenza vaccine containing 2 influenza type A strains and 2 influenza type B strains.
Comparator
A US-licensed Comparator QIV containing 2 influenza type A strains and 2 influenza type B strains.
Primary question
Whether the immune response after QIVc vaccination was noninferior to the response after Comparator QIV vaccination, assessed by HAI titers to A/H1N1, B/Victoria and B/Yamagata vaccine strains using cell-derived target viruses.
The study was designed around a comparison of immune responses rather than a direct comparison of influenza illness. The primary endpoint includes geometric mean titer (GMT) and the GMT ratio. The ratio is defined as the geometric mean postvaccination HAI titer for Comparator QIV divided by the corresponding geometric mean for QIVc. A ratio therefore expresses the two groups’ antibody titers relative to one another; its direction depends on which group is in the numerator.
The primary assessment was scheduled for Day 29 for previously vaccinated subjects and Day 57 for subjects not previously vaccinated. The registry record describes the intended noninferiority question, but the numerical primary outcome results and the noninferiority margin are not reported in the registry record. It is therefore not possible to determine from these registry entries whether the prespecified noninferiority criterion was met. The record also does not provide an illness-prevention comparison, so the immune-response question should not be interpreted as a direct estimate of vaccine effectiveness against clinical influenza.
3. Trial Design
This was a phase 3, randomized, observer-blind, multicenter, parallel-group study of QIVc and Comparator QIV in healthy subjects 6 months through 47 months of age. Enrollment was 2414. The registry record marks the study as completed and gives the start date as 2019-09-06 and primary completion date as 2020-09-03. Seqirus is listed as the sponsor.
Random allocation is intended to make treatment groups comparable on average, while a parallel design assigns participants to one vaccine group rather than having each participant receive both vaccines in sequence. The study is described as triple masked and observer-blind. The registry record does not explain which roles were masked or provide further details about how masking was maintained.
The comparator was a US-licensed quadrivalent vaccine containing the same number and types of influenza strains as QIVc: 2 type A strains and 2 type B strains. The study’s stated purpose was to compare immune responses to the vaccines. Its main endpoint used HAI assays with cell-derived target viruses; secondary immunogenicity outcomes included HAI and MN assays with egg-derived target viruses and comparisons using cell-derived and egg-derived targets. A safety outcome concerned solicited adverse events.
The registry record does not report the allocation ratio, the randomization procedure, the vaccination schedule in full, or a detailed account of masking. Although the study title identifies a noninferiority design, the numerical margin, its justification, and the full statistical plan are not reported in the registry record. Those omissions limit how much can be concluded about the design’s intended decision rules from the record alone.
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: In total, 2414 subjects were enrolled in the study.
Overall Study
| Stage | QIVc | Comparator QIV |
|---|---|---|
| STARTED | 1605 | 809 |
| Received Study Vaccine | 1597 | 805 |
| COMPLETED | 1370 | 710 |
| NOT COMPLETED | 235 | 99 |
Analysis population for the primary outcome, as defined in the registry: Per Protocol Set (PPS): All subjects in the FAS who received vaccine on Day 1, provided serology specimens which yielded valid serology assay results from both Day 1 and Day 29 (previously vaccinated subjects) or Day 1 and Day 57 (not previously vaccinated subjects) and for whom there was no protocol deviation that was medically assessed as having potential to impact the immunogenicity results. 1092 and 575 subjects in the QIVc and Comparator QIV groups had HAI assay data for this outcome.
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: Full Analysis Set (FAS), defined as all enrolled subjects who were randomized and received a study vaccination.
| Characteristic | Unit | QIVc | Comparator QIV | Total |
|---|---|---|---|---|
| Participants analysed | 1597 | 805 | 2402 | |
| Age, Categorical: <=18 years | Participants | 1597 | 805 | 2402 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | months | 28.1 (SD 11.54) | 28.2 (SD 11.63) | 28.1 (SD 11.57) |
| Sex: Female, Male: Female | Participants | 794 | 399 | 1193 |
| Sex: Female, Male: Male | Participants | 803 | 406 | 1209 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 434 | 226 | 660 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 1160 | 575 | 1735 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 3 | 4 | 7 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | Participants | 11 | 11 | 22 |
| Race/Ethnicity, Customized: Asian | Participants | 13 | 8 | 21 |
| Race/Ethnicity, Customized: Native Hawaiian or Other Pacific Islander | Participants | 8 | 6 | 14 |
| Race/Ethnicity, Customized: Black or African American | Participants | 455 | 209 | 664 |
| Race/Ethnicity, Customized: White | Participants | 1039 | 539 | 1578 |
| Race/Ethnicity, Customized: Other | Participants | 71 | 32 | 103 |
| Region of Enrollment: United States | Participants | 1597 | 805 | 2402 |
6. Primary Endpoint
The registry lists the primary outcome as Immunogenicity Endpoint: Geometric Mean Titer (GMT) and GMT Ratio Against the A/H1N1, B/Victoria and B/Yamagata Vaccine Strains by Hemagglutination Inhibition (HAI) Assay Using Cell-derived Target Viruses, measured over Day 29 for previously vaccinated subjects; Day 57 for not previously vaccinated subjects.
| 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 combines GMTs and a GMT ratio for HAI titers against the A/H1N1, B/Victoria and B/Yamagata vaccine strains, using cell-derived target viruses. GMT is a geometric average, a summary suited to measurements that are commonly analyzed on a logarithmic scale. It describes the overall antibody-titer level in a group without treating the measurements as though they were ordinarily distributed on their original scale.
The ratio compares the geometric mean postvaccination HAI titer in the Comparator QIV group with that in the QIVc group. The registry defines the numerator as Comparator QIV and the denominator as QIVc. The postvaccination titer is described as being measured 28 days after the last vaccination. The scheduled assessment was Day 29 for previously vaccinated subjects and Day 57 for subjects not previously vaccinated.
GMTs and their ratio are used to summarize an immune response across participants and to compare groups. For a noninferiority question, the ratio is interpreted against a prespecified margin, with uncertainty taken into account. The margin and numerical estimates needed for that assessment are not reported in the registry record. The primary population is described as a per-protocol set, but the registry’s population description does not provide the complete eligibility criteria.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s question and design, but the numerical primary immunogenicity findings are not reported in the registry record. The primary outcome is not reduced to a single comparison in the posted results because it has several categories or time points. No numerical GMTs, GMT ratio estimates, confidence intervals, or primary-outcome p-values are included in the registry record for this analysis. Consequently, there is no basis for stating whether QIVc met the study’s noninferiority objective.
That distinction matters because a noninferiority conclusion is not established simply by observing similar-looking group averages. It ordinarily depends on a prespecified margin and an estimate of the between-group contrast with its uncertainty. Neither the margin nor those numerical primary results is reported in the registry record. The registry’s stated definition fixes the ratio direction as Comparator QIV divided by QIVc, but no numerical estimate is present to interpret against a decision threshold.
The record does identify the planned assay targets and assessment timing. The primary immune-response comparison concerned HAI titers to A/H1N1, B/Victoria and B/Yamagata using cell-derived target viruses. Previously vaccinated subjects were assessed on Day 29; subjects not previously vaccinated were assessed on Day 57. These are distinct assessment times, and the record does not present a single combined result that can represent all categories or time points.
Several secondary outcomes were planned, including GMTs, GMT ratios, seroconversion rates and differences in seroconversion rates. The specified secondary assessments also cover A/H3N2 with an MN assay and comparisons involving egg-derived and cell-derived target viruses. The record lists 14 outcome measures and 16 analyses. These counts describe the scope of reported outcomes and analyses; they do not, by themselves, say how many statistical tests were treated as confirmatory or how their error rates were controlled.
Safety counts are available in the registry record. Serious adverse events were recorded for 15 participants in the QIVc group, with 1597 at risk, and 7 participants in the Comparator QIV group, with 805 at risk. Death counts were 2 and 0, respectively. These counts are descriptive. They do not establish that a vaccine caused an event, and the record details do not include an inferential comparison or enough detail to assess event timing, relatedness, or differences in follow-up.
The sample-size calculations associated with this analysis are planning illustrations based on the observed effect, not the trial’s design justification and not observed power. Their stated assumptions are a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. Because the primary outcome has several categories or time points and is not reduced to one comparison, a single primary-effect planning interpretation is not available from the registry record.
9. Statistical Methods Explained
Immunogenicity endpoints summarize laboratory measurements of immune response. Here, the primary assay is HAI, which measures the ability of antibodies in a sample to inhibit hemagglutination. The reported target viruses are cell-derived and correspond to the A/H1N1, B/Victoria and B/Yamagata vaccine strains. As a general statistical concept, assay measurements can be skewed, so analyses often work with their logarithms and then express the group summary back on the original scale as a geometric mean.
What does a geometric mean summarize?
A geometric mean averages values on a logarithmic scale and transforms that average back to the measurement scale. It is useful when values vary multiplicatively rather than additively. This summary is not the same as an arithmetic mean. The registry identifies GMT as the primary summary, with a 95% confidence interval as the stated dispersion measure. A confidence interval describes uncertainty in an estimated quantity under the analysis assumptions; it is not a range containing a fixed proportion of individual participants’ titers.
The primary comparison is a ratio of geometric means. The registry defines this as the postvaccination GMT for Comparator QIV divided by the postvaccination GMT for QIVc. In general, ratios are interpreted relative to a reference value indicating equality, but a noninferiority decision also requires a prespecified margin and a confidence interval interpreted according to the analysis plan. The margin and detailed decision rule are not reported in the registry record. No numerical ratio estimate or confidence interval is available in the registry record for this analysis.
Why are assessment times and populations important?
The primary endpoint is assessed at different scheduled times according to prior vaccination status: Day 29 for previously vaccinated subjects and Day 57 for subjects not previously vaccinated. This means that endpoint interpretation needs to retain the relevant vaccination-history category and assessment time. Combining results across these categories without an explicit analysis plan could obscure differences in the populations or timing being summarized. The registry record does not report a single result that resolves these categories into one comparison.
The primary population is called the Per Protocol Set (PPS). The record describes it as subjects in the FAS who received vaccine on Day 1 and provided valid serology results from Day 1 and the specified follow-up visit, with further wording about protocol deviations. That description is incomplete in the registry record. The full definition of the FAS, the complete PPS criteria, and the rules for handling missing or invalid serology are not reported in the registry record.
What does noninferiority testing require?
As a general concept, a noninferiority design asks whether the uncertainty around a treatment contrast is compatible with ruling out an unacceptable loss relative to a comparator. The acceptable loss is set by a margin chosen before evaluating the results. The estimate alone is not enough: interpretation depends on the confidence interval, the margin, and the analysis population and method specified in advance. The registry identifies the study as noninferiority, but the margin, its clinical or statistical justification, and the full testing procedure are not reported in the registry record. The numerical primary results are also not reported, so the decision cannot be reconstructed.
The study includes additional immune-response measures. The registry lists GMT and GMT-ratio outcomes, seroconversion rates and differences in seroconversion rates, and geometric mean ratios comparing cell-derived and egg-derived target viruses. It also lists outcomes using an MN assay, including A/H3N2. These endpoints address different summaries or assay-target comparisons; they should not be treated as interchangeable with the primary HAI GMT comparison. The registry lists 14 outcome measures and 16 analyses. Their full analysis specifications and the rationale for the number of analyses are not reported in the registry record.
How should safety counts be interpreted?
Safety outcomes are counts of participants recorded with events, accompanied by group-specific numbers at risk. Such counts describe what was recorded during the study. In general, interpretation also depends on how events were defined and collected, the observation period, exposure, event severity, and whether events were judged related to vaccination. The registry entries do not give those details for the serious-event counts, nor do they provide an adjusted comparison or confidence interval. The listed serious-event terms and percentages are descriptive entries, not evidence on their own of a causal relationship.
The sample-size illustrations are distinct from the original study design. Their stated framework uses a two-sided significance level of 0.05, equal allocation between groups and a normal approximation, with a target effect expressed as a stated fraction of the observed effect. In general, such calculations explore the sample size associated with an assumed effect and statistical framework. They are planning illustrations, not observed power, and do not establish the study’s actual design rationale. The trial’s sample-size justification is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The study includes multiple immunogenicity outcomes, strains, assay types, target-virus sources, vaccination-history categories and assessment times. The registry lists 14 outcome measures and 16 analyses. This breadth raises a general multiplicity issue: when many statistical comparisons are made, the chance of at least one apparently notable result can increase unless the analysis plan specifies how the comparisons are prioritized or controlled. The registry record does not report a multiplicity adjustment, a testing hierarchy, or which analyses were confirmatory.
The record identifies a per-protocol population for the primary endpoint, with a partial description involving receipt of vaccine on Day 1 and valid serology specimens at baseline and the relevant follow-up visit. The full population definition is not reported in the registry record. The full definition of the FAS is also not reported. As a result, the relationship between the analysis populations and the randomized participants cannot be fully assessed from these registry entries.
Detailed missing-data methods are not reported in the registry record. The record does not specify how missing visits, invalid assays, protocol deviations, or participants lacking a postvaccination result were handled in the analyses. It also does not report sensitivity analyses for missing data or the treatment of missing safety observations. These matters can influence which participants contribute to an estimate and how robust a result is to exclusions.
The sample-size illustrations use stated planning assumptions and should not be read as observed power or as evidence of the original protocol’s sample-size justification. The registry record does not report the rationale for the enrollment target, the noninferiority margin, interim analyses, or a complete statistical analysis plan.
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 |
|---|---|---|---|
| QIVc | 15 | 1597 | 0.9% |
| Comparator QIV | 7 | 805 | 0.9% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| QIVc | 2 of 1597 |
| Comparator QIV | 0 of 805 |
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 |
|---|---|
| QIVc | 926 of 1597 |
| Comparator QIV | 490 of 805 |
Most frequent serious adverse event terms
| Event term | Organ system | QIVc | Comparator QIV |
|---|---|---|---|
| Bronchiolitis | Infections and infestations | 1 of 1597 | 3 of 805 |
| Asthma | Respiratory, thoracic and mediastinal disorders | 2 of 1597 | 1 of 805 |
| Pneumonia | Infections and infestations | 3 of 1597 | 0 of 805 |
| Seizure | Nervous system disorders | 2 of 1597 | 0 of 805 |
| Dehydration | Metabolism and nutrition disorders | 1 of 1597 | 1 of 805 |
| Rhinovirus infection | Infections and infestations | 1 of 1597 | 1 of 805 |
| Road traffic accident | Injury, poisoning and procedural complications | 1 of 1597 | 0 of 805 |
| Acute Respiratory Failure | Respiratory, thoracic and mediastinal disorders | 1 of 1597 | 0 of 805 |
| Unresponsive to stimuli | Nervous system disorders | 0 of 1597 | 1 of 805 |
| Constipation | Gastrointestinal disorders | 0 of 1597 | 1 of 805 |
Most frequent non-serious adverse event terms
| Event term | Organ system | QIVc | Comparator QIV |
|---|---|---|---|
| Injection site tenderness | General disorders | 436 of 1564 | 235 of 784 |
| Irritability | Psychiatric disorders | 436 of 1564 | 232 of 784 |
| Sleepiness | Nervous system disorders | 420 of 1564 | 200 of 784 |
| Injection site erythema | General disorders | 403 of 1564 | 193 of 784 |
| Change of eating habits | Metabolism and nutrition disorders | 272 of 1564 | 138 of 784 |
| Diarrhea/loose stools | Gastrointestinal disorders | 280 of 1564 | 128 of 784 |
| Injection site induration | General disorders | 270 of 1564 | 125 of 784 |
| Injection site ecchymosis | General disorders | 168 of 1564 | 85 of 784 |
| Fever (≥38.0°C) | General disorders | 107 of 1564 | 54 of 784 |
| Vomiting/throwing up | Gastrointestinal disorders | 106 of 1564 | 49 of 784 |
Serious events with the highest arm-level rate: bronchiolitis (0.4%), pneumonia (0.2%), asthma (0.1%), seizure (0.1%), unresponsive to stimuli (0.1%).
The registry record lists serious adverse events in both groups. The QIVc group had 15 serious adverse event cases among 1597 at risk, and the Comparator QIV group had 7 among 805 at risk. Recorded deaths were 2 in the QIVc group and 0 in the Comparator QIV group. These are counts, not adjusted estimates of comparative risk. No new percentages or statistical comparisons should be inferred from them.
The record also lists serious-event terms with percentages: Bronchiolitis, 0.4%; Pneumonia, 0.2%; Asthma, 0.1%; Seizure, 0.1%; Unresponsive to stimuli, 0.1%; and Constipation, 0.1%. The posted details do not give arm-specific counts for these terms, so they cannot be used to compare the vaccine groups. A listed event does not establish that vaccination caused it.
Safety interpretation depends on the event definitions, the collection and follow-up periods, the number of doses received, and any assessment of relatedness. Those details are not reported in the registry record. The counts are therefore best read as descriptive safety reporting, not as a standalone causal or comparative conclusion.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized comparison intended to assess whether QIVc elicited an immune response noninferior to that of a US-licensed Comparator QIV in healthy children 6 months through 47 months of age. It identifies the primary immune measures, assay targets and assessment times. It also reports group-specific serious adverse event counts and deaths.
Those design details do not establish the primary result. Numerical GMTs, GMT ratios, confidence intervals and the noninferiority margin are not reported in the registry record. Without those items, the primary objective cannot be judged in the registry record. The study’s stated noninferiority purpose should not be mistaken for evidence that noninferiority was demonstrated.
The immune-response endpoint is a laboratory measure, not a direct measure of influenza illness or clinical protection. The registry record does not report a clinical illness comparison in the registry record considered for this analysis. Thus, even a favorable immune-response finding would not by itself quantify prevention of influenza disease. No such favorable finding is asserted because the numerical primary results are absent.
The safety figures describe recorded events in the two groups. They do not establish causation, and the available information does not include the event-level context or statistical comparisons needed to interpret them as evidence of a group difference. The deaths are counts in the registry record, without information about causes or attribution.
Finally, the scope of the secondary outcomes makes clear that the study examined several strains, assays and comparisons. The registry record does not provide enough statistical-plan detail to determine how multiplicity, missing observations, or analysis-population choices were handled. These are important limits when interpreting a noninferiority study, especially when its numerical primary results and decision margin are unavailable.
13. Why This Trial Matters Statistically
This trial illustrates how a clinical question can be framed through an immunogenicity endpoint when comparing vaccines. The design specifies a randomized, parallel-group comparison, a licensed comparator containing the same types and number of strains, and a primary immune-response measure based on GMTs and their ratio. These features define the intended comparison more precisely than a general statement that two vaccines were studied.
It also highlights that a noninferiority label alone does not supply the statistical evidence needed to evaluate noninferiority. Interpretation requires the estimated contrast, its uncertainty, and the margin that defines an unacceptable loss. The registry record identifies the endpoint and ratio direction but does not report the margin or numerical primary results. That makes it possible to describe the question, but not to resolve it from the registry record.
The record further shows why the unit of interpretation matters. The primary outcome varies by prior vaccination status and scheduled assessment time, while secondary outcomes use multiple strains, assays and target-virus sources. A reader needs the endpoint definitions and analysis plan to understand which findings were intended to answer the main question and how other comparisons fit into the evidence.
Safety counts add a separate descriptive dimension. They should be considered alongside their denominators and the limits of the available event detail, rather than treated as causal evidence. Overall, the trial is statistically informative as an example of how design, endpoint definition, analysis populations, uncertainty and reporting completeness all shape what can be concluded from a 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 primary endpoint is described, but its numerical results are not reported in the registry record. The noninferiority margin and its justification are also not reported. Without them, the central noninferiority question cannot be evaluated, even though the study title and summary state that this was the purpose of the trial.
The primary endpoint includes several strains and distinct scheduled assessment times based on prior vaccination status. The registry entries do not provide estimates for each category or explain how results were combined, if they were combined. The primary population description is incomplete, and the complete criteria for the FAS and PPS are not reported in the registry record. Handling of missing or invalid serology results is likewise not reported.
The record lists multiple secondary measures and analyses but does not report a testing hierarchy or multiplicity strategy. It also does not provide the full statistical analysis plan, details of interim analyses, or the study’s sample-size justification. The planning assumptions associated with sample-size illustrations do not fill those gaps and are not the trial’s design rationale.
Safety information is limited to event counts, numbers at risk, death counts and a list of serious-event terms with percentages. The registry entries do not specify event timing, duration of follow-up, severity criteria, relatedness, or arm-specific counts for the listed terms. These limitations prevent a detailed comparative safety interpretation and do not support causal conclusions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity Study of QIVc in Healthy Pediatric Subjects — NCT04074928.
- Registry record last updated 2022-01-12; status last verified 2021-12.
- Results first posted 2022-01-12.
- 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
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT04074928 is a completed phase 3 randomized, observer-blind, multicenter, parallel-group study sponsored by Seqirus. It compared cell-derived QIVc with a US-licensed Comparator QIV in healthy children 6 months through 47 months of age. Enrollment was 2414; the study start date was 2019-09-06 and the primary completion date was 2020-09-03.
The primary endpoint was GMT and GMT ratio against A/H1N1, B/Victoria and B/Yamagata vaccine strains using HAI assays with cell-derived target viruses. The assessment was scheduled for Day 29 in previously vaccinated subjects and Day 57 in subjects not previously vaccinated. Numerical primary results and the noninferiority margin are not reported in the registry record.
The record reports serious adverse event counts of 15 for QIVc and 7 for Comparator QIV, with 1597 and 805 at risk, respectively. Recorded deaths were 2 and 0. The available safety details are descriptive and do not establish causation.