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 Exploratory Trial to Evaluate the Safety and Immunogenicity of Menactra® and Menomune® Vaccines in Subjects ≥ 56 Years (NCT00874549), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With At Least One Solicited Injection Site or Systemic Reaction Post-Vaccination 1..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00874549 |
| Phase | Phase 1, Phase 2 |
| Condition | Meningococcal Infections, Meningococcal Meningitis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 216 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sanofi Pasteur, a Sanofi Company |
| Results posted | Yes |
2. Clinical Question
The trial asked whether the safety and immune responses associated with Menactra® differed across three vaccination schedules, and how these regimens compared with a single dose of Menomune®. Participants were 56 years of age or older. The study included people with meningococcal infections and meningococcal meningitis listed as conditions of interest.
The safety objective was descriptive: to record immediate reactions, solicited injection-site and systemic reactions, unsolicited adverse events, and serious adverse events after vaccination with either vaccine. The primary endpoint focused on participants experiencing at least one solicited injection-site or systemic reaction during the 0-7 days after vaccination 1. The listed injection-site reactions were pain, erythema, and swelling. The solicited systemic reactions included fever, headache, malaise, myalgia, chills, arthralgia, urticaria, anorexia, diarrhea, and vomiting.
The immunogenicity objective was to evaluate immune response to meningococcal serogroups A, C, Y, and W-135 in each of the four study groups. The registry record does not report a specific immune-response result in the registry record for this analysis. It also does not report a single primary comparison that would establish which schedule had the better safety or immunogenicity profile. Accordingly, the results should be read as a description of outcomes by regimen, not as a definitive ranking of the schedules.
Population
Subjects 56 years of age or older; the safety population after vaccination 1 was described as all enrolled and vaccinated participants, on an intent-to-treat basis.
Intervention
Menactra® given as two injections on Day 0, or as one injection on Day 0 followed by one on Day 14 or Day 28.
Comparator
A single dose of Menomune® on Day 0.
Primary question
How many participants experienced at least one solicited injection-site or systemic reaction in the 0-7 days after vaccination 1?
3. Trial Design
The registry describes a randomized, parallel-group trial with no masking. It is listed as Phase 1 and Phase 2 and as completed. Enrollment was 216. The study began in 2007-10, and primary completion was recorded as 2008-01. The sponsor was Sanofi Pasteur, a Sanofi Company.
Participants were assigned among four regimens. One group received a single Menomune® dose on Day 0. A second received two single-dose Menactra® injections on Day 0. The other Menactra® groups received one dose on Day 0 and a second dose on Day 14 or Day 28. This parallel design allows outcomes to be described separately by assigned regimen; participants were not described as crossing from one regimen to another.
Random assignment is generally intended to make treatment groups comparable at the point of assignment, reducing the chance that treatment choice is systematically related to participant characteristics. It does not guarantee that groups will be identical, particularly in a trial of this size. Because the study was unmasked, participants and study personnel knew the assigned regimen. For outcomes based on participant-reported symptoms, awareness of assignment can affect reporting or recording; the registry record does not report procedures intended to reduce that possibility.
The safety endpoint population is described as all enrolled and vaccinated participants, intent-to-treat, for the period after vaccination 1. The record also gives adverse-event denominators by group, but does not report a full account of assignment, discontinuations, or endpoint-specific missingness. Further details of the randomization procedure, allocation concealment, protocol, and statistical analysis plan are 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.
Before assignment: A total of 216 participants who met the inclusion and exclusion criteria were enrolled, vaccinated, and included in the analyses.
Overall Study
| Stage | Group 1: Menomune® Day 0 | Group 2: Menactra® Day 0 x 2 | Group 3: Menactra® Day 0 and 14 | Group 4: Menactra® Day 0 and 28 |
|---|---|---|---|---|
| STARTED | 51 | 56 | 51 | 58 |
| COMPLETED | 50 | 55 | 47 | 56 |
| NOT COMPLETED | 1 | 1 | 4 | 2 |
Reasons for not completing this period:
| Reason | Group 1: Menomune® Day 0 | Group 2: Menactra® Day 0 x 2 | Group 3: Menactra® Day 0 and 14 | Group 4: Menactra® Day 0 and 28 |
|---|---|---|---|---|
| Adverse Event | 0 | 0 | 1 | 0 |
| Protocol Violation | 1 | 0 | 2 | 1 |
| Lost to Follow-up | 0 | 0 | 1 | 0 |
| Withdrawal by Subject | 0 | 1 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Safety analysis post-vaccination 1 was on all enrolled and vaccinated participants, intent-to-treat population.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Group 1: Menomune® Day 0 | Group 2: Menactra® Day 0 x 2 | Group 3: Menactra® Day 0 and 14 | Group 4: Menactra® Day 0 and 28 | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 51 | 56 | 51 | 58 | 216 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 19 | 19 | 19 | 18 | 75 |
| Age, Categorical: >=65 years | Participants | 32 | 37 | 32 | 40 | 141 |
| Age Continuous | Years | 69.0 (SD 7.2) | 68.6 (SD 7.0) | 68.5 (SD 7.2) | 69.1 (SD 7.3) | 68.8 (SD 7.1) |
| Sex: Female, Male: Female | Participants | 29 | 27 | 34 | 34 | 124 |
| Sex: Female, Male: Male | Participants | 22 | 29 | 17 | 24 | 92 |
| Region of Enrollment: United States | participants | 51 | 56 | 51 | 58 | 216 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With At Least One Solicited Injection Site or Systemic Reaction Post-Vaccination 1., measured over 0-7 days post-vaccination 1.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with at least one solicited injection-site or systemic reaction during 0-7 days post-vaccination 1. It is a participant-level count: a participant who experiences more than one listed symptom still contributes to the endpoint as someone with at least one reaction. It is not a count of all reaction episodes.
The injection-site reactions named in the record are pain, erythema, and swelling. The systemic reactions are fever, headache, malaise, myalgia, chills, arthralgia, urticaria, anorexia, diarrhea, and vomiting. The endpoint therefore combines symptoms of different kinds into a single indicator of whether any solicited reaction was experienced during the stated period.
In general, a solicited safety endpoint uses a predefined list and observation period so reactions can be collected consistently across participants. An “at least one” measure gives a broad summary of whether participants reported any listed reaction, but it does not describe how many symptoms occurred, how severe they were, or how long they lasted. Those details require separate results.
The registry record identifies this measure as the primary endpoint but does not report its group-specific results in the registry record for this analysis. It also indicates that the primary outcome has several categories or time points and is not reduced to one comparison. No single comparative estimate or statistical test for this endpoint is therefore.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the trial’s design and objectives, but the available primary-outcome information does not include the number of participants with a solicited reaction in each regimen. Consequently, the primary endpoint cannot be used from this record to quantify a difference between Menactra® schedules and Menomune®. No effect estimate, confidence interval, or p-value for that endpoint is reported in the registry record.
The safety information that is available includes serious adverse-event counts by regimen. The record lists 4 affected participants among 51 at risk in the Menomune® Day 0 group, 3 among 56 in the Menactra® Day 0 x 2 group, 1 among 51 in the Menactra® Day 0 and Day 14 group, and 0 among 58 in the Menactra® Day 0 and Day 28 group. These are observed counts in the registry record. They do not, by themselves, establish that one regimen caused more or fewer serious events. The record does not provide a statistical comparison, uncertainty interval, or account of event timing and attribution for these figures.
For other adverse events, the registry gives counts of 3 among 51, 5 among 56, 8 among 51, and 12 among 58, respectively, in the same group order. The label “other adverse events” should be retained rather than assuming that every such event was non-serious or related to vaccination. The registry record does not provide the event-level detail needed to interpret these counts as causal effects.
The immunogenicity objective is stated for serogroups A, C, Y, and W-135, but no immune-response results are reported in the registry record for this analysis. The evidence therefore cannot answer which regimen produced a stronger immune response.
In general, a confidence interval expresses the range of values reasonably compatible with an estimate under a statistical model. Its width indicates precision: a wider interval reflects more uncertainty. No confidence intervals for the outcomes are reported in the registry record, so the precision of between-group differences cannot be assessed. The data support a description of listed counts and study aims, not a claim that a regimen is superior or equivalent.
9. Statistical Methods Explained
The design and endpoint definitions determine what can be learned from this trial. The record describes randomized allocation to parallel regimens, no masking, and a primary safety measure based on participants with at least one solicited reaction. The outcome is categorical: each participant is classified according to whether the event occurred during the stated observation window. The record does not report a statistical method used to compare those categories.
What does randomization contribute?
In general, randomization assigns treatment by chance rather than by participant or clinician choice. It is used to reduce systematic differences between groups at the start of a study. It cannot ensure that all characteristics are balanced, and chance imbalances can remain. The registry identifies the study as randomized but does not report the sequence-generation method, allocation concealment, stratification, or other implementation details. Those details are not reported in the registry record.
How should a binary endpoint be understood?
The primary measure records whether each participant had one or more solicited reactions in the specified period. This binary summary does not distinguish a participant with one symptom from a participant with several symptoms. Nor does it convey severity, duration, or clinical importance. The full list of solicited symptoms and the observation window define what counts for this endpoint; events outside that list or time period are not represented by the endpoint as described.
In general, a group comparison for a binary endpoint might report the event count and denominator in each group, an absolute difference or relative measure, and an uncertainty interval. A formal test may also be used, depending on the prespecified analysis plan and study design. These methods answer different questions: an absolute difference describes the gap in event frequency, while a relative measure compares frequencies proportionally. Neither can be reconstructed because primary endpoint group results are not reported. The analysis method and any adjusted comparisons are also not reported in the registry record.
Why does masking matter?
The trial is listed as having no masking. In general, knowledge of treatment assignment may influence how symptoms are noticed, reported, or assessed, especially when outcomes depend on subjective reports. Randomization does not remove this possible influence after assignment. The registry does not report blinded outcome assessment or other safeguards that would clarify how symptom reporting was handled.
What do the sample-size assumptions mean?
The registry describes planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. These are planning assumptions, not results from a new trial and not evidence of observed power. A planning calculation estimates the participants per arm that would be needed under its assumptions; it does not show that a study had a particular probability of detecting an effect after the data were collected.
In general, such calculations depend on the outcome, the target effect, the variability or event frequency assumed, the type I error rate, and the power target. Changing an assumed effect changes the planned sample size. The record does not report the original protocol’s sample-size justification or identify a prespecified target effect for the trial. The stated planning assumptions should therefore not be treated as evidence that the study was designed around the calculated illustration.
Why can rare events be difficult to compare?
Serious adverse events are uncommon in these reported groups, and some recorded counts are small or zero. In general, sparse data can lead to imprecise comparisons; conventional approximations may be unreliable when event counts are very low. Exact methods or other approaches may be considered, but the registry record does not report which method, if any, was used for a serious-event comparison. A zero observed count is not proof that an event cannot occur; it only describes what was recorded in that group.
Over-dispersion is a general issue for count outcomes when variability is greater than a chosen model expects. It may affect uncertainty estimates and tests if such a model is used. The primary endpoint is defined as a participant-level binary outcome, and the registry does not report a count-model analysis or an over-dispersion assessment. It would not be appropriate to assume either was part of the analysis.
Finally, the registry does not report the statistical analysis plan, interim analyses, adjustment for multiple comparisons, or confidence intervals and p-values for the outcomes in this analysis. These absences limit reconstruction of the inferential approach. The reported design and counts can be described, but they do not permit a substitute analysis plan to be inferred.
10. Multiplicity, Missing Data and Analysis Populations
The trial had several outcomes and assessment aims: the primary solicited-reaction endpoint, safety outcomes beyond that endpoint, and immunogenicity across serogroups A, C, Y, and W-135. The primary outcome is described as having several categories or time points and is not reduced to one comparison. The registry record does not specify a hierarchy of comparisons or how the risk of false-positive findings across multiple outcomes was handled. Any multiplicity adjustment, if used, is not reported in the registry record.
Missing-data handling is also not reported. The primary safety population is described as all enrolled and vaccinated participants, intent-to-treat, after vaccination 1. That population description does not establish how participants with incomplete symptom diaries, missed visits, or unavailable measurements were treated. The registry record does not report the extent or pattern of missing data, imputation procedures, or sensitivity analyses.
In general, multiple comparisons can increase the chance of finding an apparently unusual result by chance when many hypotheses are tested. Missing outcomes can also affect estimates if the participants with unobserved measurements differ from those with recorded outcomes. These are methodological concerns, not evidence that either issue changed the results in this trial.
The record does not report a statistical analysis plan, the method used for any outcome comparison, or a detailed analysis population for immunogenicity. Those details are not reported in the registry record, so the handling of multiplicity and missingness cannot be assessed beyond the stated safety-population description.
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 |
|---|---|---|---|
| Menomune® Day 0 | 4 | 51 | 7.8% |
| Menactra® Day 0 x 2 | 3 | 56 | 5.4% |
| Menactra® Day 0 and Day 14 | 1 | 51 | 2.0% |
| Menactra® Day 0 and Day 28 | 0 | 58 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Menomune® Day 0 | 3 of 51 |
| Menactra® Day 0 x 2 | 5 of 56 |
| Menactra® Day 0 and Day 14 | 8 of 51 |
| Menactra® Day 0 and Day 28 | 12 of 58 |
Most frequent serious adverse event terms
| Event term | Organ system | Menomune® Day 0 | Menactra® Day 0 x 2 | Menactra® Day 0 and Day 14 | Menactra® Day 0 and Day 28 |
|---|---|---|---|---|---|
| Non-cardiac chest pain | Respiratory, thoracic and mediastinal disorders | 1 of 51 | 0 of 56 | 1 of 51 | 0 of 58 |
| Syncope | Cardiac disorders | 1 of 51 | 0 of 56 | 0 of 51 | 0 of 58 |
| Femoral artery occlusion | Vascular disorders | 1 of 51 | 0 of 56 | 0 of 51 | 0 of 58 |
| Transient ischaemic attack | Vascular disorders | 1 of 51 | 0 of 56 | 0 of 51 | 0 of 58 |
| Deep vein thrombosis | Vascular disorders | 1 of 51 | 0 of 56 | 0 of 51 | 0 of 58 |
| Diabetes mellitus non-insulin-dependent | Endocrine disorders | 0 of 51 | 1 of 56 | 0 of 51 | 0 of 58 |
| Myocardial infarction | Cardiac disorders | 0 of 51 | 1 of 56 | 0 of 51 | 0 of 58 |
| Diverticulitis | Gastrointestinal disorders | 0 of 51 | 1 of 56 | 0 of 51 | 0 of 58 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Menomune® Day 0 | Menactra® Day 0 x 2 | Menactra® Day 0 and Day 14 | Menactra® Day 0 and Day 28 |
|---|---|---|---|---|---|
| Upper respiratory tract infection | Infections and infestations | 1 of 51 | 1 of 56 | 5 of 51 | 5 of 58 |
| Back pain | Musculoskeletal and connective tissue disorders | 1 of 51 | 1 of 56 | 2 of 51 | 4 of 58 |
| Cough | Respiratory, thoracic and mediastinal disorders | 1 of 51 | 3 of 56 | 2 of 51 | 1 of 58 |
| Pharyngolaryngeal pain | Respiratory, thoracic and mediastinal disorders | 0 of 51 | 0 of 56 | 0 of 51 | 3 of 58 |
Serious events with the highest arm-level rate: syncope (2.0%), femoral artery occlusion (2.0%), transient ischaemic attack (2.0%), deep vein thrombosis (2.0%), non-cardiac chest pain (2.0%).
The serious adverse-event figures are participant counts with their listed at-risk denominators. In the order of the regimens, the record reports 4 of 51 for Menomune® Day 0, 3 of 56 for Menactra® Day 0 x 2, 1 of 51 for Menactra® Day 0 and Day 14, and 0 of 58 for Menactra® Day 0 and Day 28. These figures describe what was recorded in each group; they are not adjusted estimates of treatment effects.
The registry also lists serious-event terms and percentages: syncope, femoral artery occlusion, transient ischaemic attack, deep vein thrombosis, and non-cardiac chest pain are each listed at 2.0%; diabetes mellitus non-insulin-dependent is listed at 1.8%. The denominator and method behind these term percentages are not reported in the registry record. The percentages should therefore be read as registry-listed descriptors, not used to infer participant counts.
In general, serious adverse events should be interpreted with attention to their definitions, timing, severity, and relationship to treatment. The record does not report enough event-level context to make those assessments. Death counts are not reported in the registry record. Differences in the observed counts alone do not establish causation or a reliable difference in risk.
12. What the Result Does, and Does Not, Mean
The results described in the registry record have a limited but useful meaning. They identify four randomized vaccination regimens, specify a primary safety outcome, and report adverse-event counts for each group. The serious-event counts and other-adverse-event counts are descriptive observations. Without a reported comparison method and uncertainty estimates, they cannot establish whether the regimens differ in safety.
The primary endpoint concerns participants with at least one specified reaction in the 0-7 days after vaccination 1. Its result is not reported in the registry record for this analysis. The immunogenicity objective is likewise stated, but its results are not reported. Therefore, the record as described does not quantify the solicited-reaction outcome or show how immune responses compared across regimens.
In general, a study can be informative about feasibility and observed outcomes without providing precise evidence about comparative effects. The interpretation of any group difference depends on both the size of the estimate and its uncertainty, as well as the study’s design and measurement procedures. Here, group-specific primary results and inferential statistics are not reported, so neither the size nor precision of a primary-outcome difference can be evaluated.
The findings should not be read as proof that a regimen is safer, less safe, more immunogenic, or equivalent to another. A zero serious-event count in one group is not proof of zero risk. Conversely, a nonzero count does not establish that vaccination caused the event. Those conclusions require information and analyses not reported in the registry record.
The scope is also specific: the trial enrolled subjects aged 56 years or older and examined the listed schedules. The record does not support extending results to other ages, schedules, or settings. Its stated aims and descriptive safety counts are best understood as limited evidence from this particular randomized study, rather than a complete answer to every comparative safety or immunogenicity question.
13. Why This Trial Matters Statistically
This trial is statistically interesting because it compares several schedules while combining a descriptive safety objective with an immunogenicity objective. The schedules differ in the number and timing of Menactra® injections, while the comparator is a single Menomune® dose. Randomized parallel allocation provides a framework for comparing groups, but interpretation still depends on complete outcome reporting and appropriate analysis.
The primary endpoint illustrates a common design choice in safety research: summarize whether a participant experiences at least one event on a predefined list during a fixed period. That measure is straightforward to interpret as a participant-level outcome, but it compresses potentially different symptoms and experiences into a single indicator. Separate outcome details are needed to understand symptom type, number, severity, and duration.
The record also illustrates why rare safety outcomes need careful interpretation. The serious-event counts are small, including a group with no recorded affected participants. In general, sparse counts provide limited information for precise comparisons, and the absence of an event in a group does not establish that its true risk is zero. Event descriptions, follow-up, denominators, and uncertainty estimates all matter.
Finally, the contrast between stated aims and available results is important. The registry describes the primary safety question and immunogenicity targets but does not report the primary endpoint results or immune-response results in the registry record for this analysis. Statistical interpretation depends not only on design but also on transparent reporting of estimates, uncertainty, analysis populations, and methods. Without those elements, the record supports a description of the trial and selected safety counts, but not a firm comparative conclusion.
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 main limitation for interpreting the primary question is that group-specific results for the primary solicited-reaction endpoint are not reported in the registry record. No comparative estimate, confidence interval, p-value, or analysis method is reported for that endpoint. The immunogenicity results for serogroups A, C, Y, and W-135 are also not reported in the registry record for this analysis.
The trial was unmasked. For solicited symptoms, awareness of assignment may affect reporting or assessment; the record does not describe measures used to address this possibility. The record also does not provide detailed event definitions beyond the listed solicited symptoms, nor does it provide severity or duration results for those reactions.
Although the serious and other adverse-event counts are reported by group, the record does not provide event-level narratives, attribution, timing, follow-up detail, or a statistical comparison. Serious-event term percentages are listed, but the denominator and calculation method for those terms are not reported. Death counts are not reported in the registry record.
Further limitations include the absence of reported details on allocation concealment, randomization implementation, missing-data handling, multiplicity control, interim analyses, and the statistical analysis plan. The record describes the safety population after vaccination 1 as all enrolled and vaccinated participants, intent-to-treat, but does not report how incomplete observations were handled. These omissions restrict assessment of bias, precision, and reproducibility. The trial’s stated age group and schedules also define the scope of what its results could address; broader applicability is not established by this record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Exploratory Trial to Evaluate the Safety and Immunogenicity of Menactra® and Menomune® Vaccines in Subjects ≥ 56 Years — NCT00874549.
- Registry record last updated 2013-09-20; status last verified 2013-09.
- Results first posted 2010-03-25.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry describes a completed randomized, unmasked, parallel Phase 1/Phase 2 trial with enrollment of 216 and sponsor Sanofi Pasteur, a Sanofi Company. It began in 2007-10, with primary completion in 2008-01. Participants aged 56 years or older were assigned to a single Menomune® dose on Day 0 or to one of three Menactra® schedules: two injections on Day 0, doses on Day 0 and Day 14, or doses on Day 0 and Day 28.
The primary safety endpoint was the number of participants with at least one solicited injection-site or systemic reaction in 0-7 days post-vaccination 1. The registry states an immunogenicity objective for serogroups A, C, Y, and W-135. Serious and other adverse-event counts are reported by regimen, but primary endpoint and immunogenicity results, inferential comparisons, and detailed statistical methods are not reported in the registry record.