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 Immunogenicity and Safety Study of 1 and 2 Doses of GlaxoSmithKline (GSK) Biologicals' Meningococcal Vaccine MenACWY-TT (GSK134612) in Toddlers, Persistence up to 5 Years After Vaccination and Co-administration With Pfizer's Prevenar 13™Vaccine (NCT01939158), a randomized phase 3 study. The primary outcome is Percentage of Participants With Serum Bactericidal Assay Using Rabbit Complement Antibody (rSBA) Titers >=1:8 at 1 Month After Administration of 1 Dose of MenACWY-TT in the ACWY1d, ACWY2d and Co-ad Groups.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01939158 |
| Phase | Phase 3 |
| Condition | Infections, Meningococcal |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 803 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Toddlers aged 12 to 14 months were the study population described in the registry record. The primary outcome was analyzed in the according-to-protocol cohort for persistence Year 1. The record describes that cohort as participants meeting eligibility criteria, receiving the complete primary vaccination series, having available assay results for at least one antigen, complying with protocol procedures and intervals, and meeting other stated criteria. The exact number analyzed for the primary outcome is not reported in the registry record.
Intervention
MenACWY-TT, also named GSK134612, was given as one dose in the ACWY1d group or as two doses two months apart in the ACWY2d group. In the Co-ad group, one dose of MenACWY-TT was given with Prevenar 13.
Comparator
The study included several regimen groups rather than a single comparison. The PCV-13 group received one dose of Prevenar 13 and one dose of MenACWY-TT two months later. The registry describes an objective of comparing co-administration with separate administration for vaccine immunogenicity, alongside evaluating one-dose and two-dose MenACWY-TT schedules.
Primary question
The registered primary outcome asks what percentage of participants had rabbit-complement serum bactericidal assay (rSBA) antibody titers of >=1:8 against each of the meningococcal serogroups A, C, W-135 and Y one month after the first MenACWY-TT dose. It includes the ACWY1d, ACWY2d and Co-ad groups. The numerical outcome values and confidence intervals are not reported in the registry record, so the posted information does not establish the observed response percentages or the precision of those estimates.
3. Trial Design
This was a Phase 3, randomized, open, controlled, multicentre, parallel-group study. The registry record lists enrollment of 803 and status as completed. The recorded study start was 2013-10-02, and primary completion was 2019-12-05. Masking is listed as none. The sponsor is Pfizer.
The study had four named groups. Participants in ACWY1d were to receive one dose of MenACWY-TT. Participants in ACWY2d were to receive two doses of MenACWY-TT two months apart. The Co-ad group was to receive one dose of MenACWY-TT together with Prevenar 13. In the PCV-13 group, participants were to receive one dose of Prevenar 13 and one dose of MenACWY-TT two months later. The registry identifies both vaccines as biological interventions.
The stated purpose was to assess immediate and longer-term immunogenicity and safety of one versus two MenACWY-TT doses, with persistence followed up to five years. The registry also describes assessing whether co-administration with the Prevenar 13 booster affects immunogenicity of either vaccine. The formal study title specifies a non-inferiority objective for co-administration versus separate administration. The exact non-inferiority margin, statistical analysis plan, and numerical findings for that objective are not reported in the registry record.
The primary outcome concerns the percentage of participants with an rSBA titer at or above the registered threshold one month after the first MenACWY-TT dose. Secondary outcomes include other rSBA and human-complement SBA measures, antibody geometric mean titers, and different thresholds and time points. The registry lists 30 outcome measures, but the primary outcome’s numerical results 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 803 participants were enrolled and were randomized in 1:1:1:1 ratio to either ACWY1d, ACWY2d, Co-ad and PCV13 groups.
Overall Study
| Stage | ACWY1d Group | ACWY2d Group | Co-ad Group | PCV13 Group |
|---|---|---|---|---|
| STARTED | 203 | 198 | 201 | 201 |
| Vaccinated | 203 | 197 | 201 | 201 |
| COMPLETED | 156 | 146 | 160 | 157 |
| NOT COMPLETED | 47 | 52 | 41 | 44 |
Reasons for not completing this period:
| Reason | ACWY1d Group | ACWY2d Group | Co-ad Group | PCV13 Group |
|---|---|---|---|---|
| Adverse Event | 1 | 0 | 0 | 0 |
| Withdrawal by Subject | 22 | 25 | 15 | 17 |
| Migrated/moved from study area | 5 | 7 | 3 | 6 |
| Lost to Follow-up | 18 | 17 | 17 | 17 |
| Death | 0 | 0 | 1 | 1 |
| No longer meets eligibility criteria | 0 | 0 | 1 | 0 |
| Other | 1 | 3 | 4 | 3 |
Analysis population for the primary outcome, as defined in the registry: Analyzed on ATP cohort for persistence Year 1 population. Here "Overall number of participants analyzed" signifies participants evaluable for this outcome measure and 'number analyzed' signifies participants evaluable for each specified category. Data for this outcome measure was not planned to be collected and analyzed for PCV13 reporting group.
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: Analysis was performed on participants, who received at least one dose of study drug.
| Characteristic | Unit | ACWY1d Group | ACWY2d Group | Co-ad Group | PCV13 Group | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 203 | 197 | 201 | 201 | 802 | |
| Age, Continuous | Months | 12.8 (SD 0.9) | 12.8 (SD 0.9) | 12.8 (SD 0.9) | 12.7 (SD 0.9) | 12.8 (SD 0.9) |
| Sex: Female, Male: Female | Participants | 94 | 85 | 98 | 98 | 375 |
| Sex: Female, Male: Male | Participants | 109 | 112 | 103 | 103 | 427 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 8 | 8 | 7 | 8 | 31 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 195 | 189 | 194 | 193 | 771 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 1 | 0 | 1 |
| Race (NIH/OMB): Asian | Participants | 1 | 3 | 2 | 3 | 9 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 1 | 1 | 2 |
| Race (NIH/OMB): Black or African American | Participants | 33 | 33 | 31 | 30 | 127 |
| Race (NIH/OMB): White | Participants | 135 | 127 | 137 | 134 | 533 |
| Race (NIH/OMB): More than one race | Participants | 34 | 34 | 29 | 33 | 130 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Serum Bactericidal Assay Using Rabbit Complement Antibody (rSBA) Titers >=1:8 at 1 Month After Administration of 1 Dose of MenACWY-TT in the ACWY1d, ACWY2d and Co-ad Groups, measured over 1 month after administration of 1st dose of MenACWY-TT (i.e. at Month 1).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with an rSBA antibody titer of >=1:8 against each of four meningococcal serogroups one month after the first MenACWY-TT dose. The serogroups are A, C, W-135 and Y. The assay uses rabbit complement, as indicated by the rSBA abbreviation. The registry specifies the ACWY1d, ACWY2d and Co-ad groups and identifies the according-to-protocol cohort for persistence Year 1 as the analysis population.
A percentage endpoint expresses the share of an analyzed group meeting a prespecified antibody threshold. The threshold turns a measured antibody titer into a classification: meeting or not meeting the specified level. As a general statistical concept, a threshold-based endpoint can be easy to interpret, but it does not convey the full distribution of antibody titers. The registry’s secondary outcomes include geometric mean titers, which describe antibody levels on a different scale.
The registry includes a 95% confidence interval as the endpoint’s measure of uncertainty. In general, a confidence interval gives a range of values compatible with the data and the statistical procedure used; wider intervals indicate less precision. The observed percentages, confidence limits, and numbers analyzed for the primary endpoint are not reported in the registry record. Consequently, the endpoint definition is clear, but its estimated magnitude and precision cannot be assessed from the posted numerical information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary outcome definition identifies the response threshold, assay, timing, population, and groups of interest. It does not, by itself, show how many participants met the threshold. The primary outcome’s numerical results are not reported in the registry record, including the group-specific percentages and their 95% confidence intervals. Therefore, the posted information does not permit a quantitative comparison of the one-dose, two-dose, and co-administration groups for this endpoint.
The distinction between an endpoint definition and an endpoint result matters. The definition tells readers what the investigators intended to measure: rSBA titers of >=1:8 one month after the first MenACWY-TT dose, evaluated for each named serogroup. A result would additionally need to report the participants evaluated and the percentage meeting the threshold, with uncertainty. Without those figures, neither the direction nor the size of any group difference can be described.
The registered title identifies a non-inferiority objective for co-administration versus separate administration. Non-inferiority questions require an explicit margin and an estimate with uncertainty interpreted in relation to that margin. The margin and the numerical comparison are not reported in the registry record. The title alone cannot establish that non-inferiority was demonstrated. Nor can the secondary outcome descriptions substitute for the primary comparison: they describe planned measures, not numerical results.
The safety entries are descriptive counts. The record lists serious adverse events affecting 12 participants in ACWY1d, 11 in ACWY2d, 13 in Co-ad, and 16 in PCV-13, with corresponding at-risk counts of 203, 197, 201, and 201. It also lists other adverse events affecting 199, 196, 197, and 197 participants, respectively, with those same group-specific at-risk counts. These entries do not establish that an event was caused by vaccination. The registry does not report the detailed event definitions, timing, exposure adjustment, or comparative statistical analyses needed to interpret these counts as causal or to assess differences formally.
The registry lists deaths as 0 in ACWY1d, 0 in ACWY2d, 1 in Co-ad, and 1 in PCV-13. The listed serious-event terms include pneumonia and upper respiratory tract infection at 1.5% each, and bronchiolitis, gastroenteritis, bronchitis, and tonsillitis at 1.0% each. These are registry entries and should be read as descriptive reporting, not as evidence of treatment effect. Detailed denominators and the relationship of these terms to the groups are not reported in the registry record.
Overall, the record describes the design, outcome definitions and selected safety counts, but it does not report the primary antibody-response estimates. The findings therefore cannot be judged for magnitude, precision, or the registered non-inferiority objective using the posted information.
9. Statistical Methods Explained
The registry identifies a binary percentage endpoint: whether an assay titer meets a specified threshold. It also identifies the uncertainty measure as a 95% confidence interval. The statistical analysis plan and the precise method used to calculate the confidence intervals are not reported in the registry record. The concepts below are general explanations, not claims about unreported analysis choices in this trial.
What does a percentage endpoint represent?
For an endpoint expressed as a percentage of participants, each analyzed participant is classified according to whether the specified criterion is met. The percentage describes the proportion meeting it in the analyzed group. In this study, the criterion is an rSBA titer of >=1:8 against a specified serogroup at the stated assessment time. Each serogroup has its own endpoint result. These percentages do not retain all the information in the underlying titer measurements, because participants with different titers may fall into the same threshold category.
As a general statistical matter, a percentage is most informative when reported with its numerator, denominator, and uncertainty. The denominator shows how many participants contributed to the estimate, while the numerator shows how many met the criterion. The registry description explains that “overall number of participants analyzed” refers to participants evaluable for the outcome and that “number analyzed” refers to participants evaluable for each category. However, the actual primary-outcome counts and estimates are not reported in the registry record.
How should a confidence interval be understood?
A confidence interval communicates uncertainty around an estimate under a specified statistical procedure. In general, a narrower interval indicates greater precision and a wider interval indicates less precision. It is not a guarantee that the true value lies inside the particular interval, and it does not replace consideration of the study design, population, or analysis set. The record specifies 95% confidence intervals for the primary endpoint, but does not provide their limits or identify the calculation method.
For a group comparison, uncertainty around each group’s percentage is not the same as uncertainty around the difference between groups. A formal comparison would need an estimate of the contrast and its uncertainty, alongside the prespecified analysis approach. The registry record does not report primary-outcome contrasts, p-values, or a statistical analysis plan. No comparative conclusion can be derived from the endpoint description alone.
Why are antibody titers reported in more than one way?
The registry’s secondary outcomes include percentages above antibody thresholds and geometric mean titers (GMTs). A threshold percentage summarizes how many participants reached a specified level. A GMT summarizes titer levels using a geometric scale, which is commonly useful for quantities that vary multiplicatively. In general, the two summaries answer different questions: one focuses on reaching a threshold, while the other reflects the distribution’s central level. Neither summary should be treated as a substitute for the other.
The registry also names serum bactericidal assays using human complement (hSBA) for secondary outcomes, in addition to rSBA outcomes. These assay labels describe different laboratory measures. The listed secondary outcomes specify several time points, thresholds and groups, but their numerical results are not reported in the registry record. The available descriptions therefore do not support conclusions about agreement or differences between assay results.
What does over-dispersion mean in general?
For count data, over-dispersion means that variability is greater than a statistical model assumes. If it is ignored, uncertainty can be understated and confidence intervals or tests may be too optimistic. This general concept does not establish that over-dispersion occurred in this trial: the primary endpoint is a percentage, and the registry record does not identify a model or an over-dispersion assessment.
The record’s sample-size section describes planning illustrations based on an observed effect, not the trial’s own design. It specifies a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. Such illustrations are planning scenarios, not observed power and not evidence of the actual study’s design assumptions. The numerical planning outputs are not reported in the registry record. The study’s own sample-size justification is also not reported in the registry record.
None of these general statistical explanations supplies missing estimates or analysis details. The registered endpoint, its confidence-interval type, and the stated analysis population are identifiable, while the actual primary results and the methods used to produce them are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 30 outcome measures, including results across multiple serogroups, assay types, antibody thresholds, vaccination schedules and assessment times. When many outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase. As a general statistical principle, an analysis plan may address multiplicity by prioritizing outcomes, adjusting inference, or clearly distinguishing primary from exploratory findings. The registry record does not report whether or how multiplicity was handled. It is therefore not possible to determine whether the listed outcomes were treated as a family for statistical inference.
The registry identifies the primary analysis population as the according-to-protocol cohort for persistence Year 1. Its description requires participants to meet eligibility criteria, receive the complete primary vaccination series, have assay results for at least one antigen, comply with protocol procedures and intervals, and satisfy other stated conditions. Such criteria define an analysis population, but they can also mean that the analyzed participants differ from everyone enrolled. The registry does not report how many participants were excluded from this cohort, why they were excluded, or how missing assay results were handled.
The primary outcome description states that data were not planned to be collected in the manner indicated by a truncated phrase. The complete meaning of that note and any missing-data strategy are not reported in the registry record. The record does not describe imputation, sensitivity analyses, or an alternative analysis population for this endpoint. It also does not report interim analyses or stopping rules. These details should not be inferred from the design label or the stated outcome timeframe.
Because group-specific primary estimates and analysis counts are absent, readers cannot evaluate the impact of missing data, exclusions, or multiple comparisons on the primary conclusions. This limits assessment of both statistical precision and the robustness of any comparisons.
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 |
|---|---|---|---|
| ACWY1d Group | 12 | 203 | 5.9% |
| ACWY2d Group | 11 | 197 | 5.6% |
| Co-ad Group | 13 | 201 | 6.5% |
| PCV13 Group | 16 | 201 | 8.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| ACWY1d Group | 0 of 203 |
| ACWY2d Group | 0 of 197 |
| Co-ad Group | 1 of 201 |
| PCV13 Group | 1 of 201 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| ACWY1d Group | 199 of 203 |
| ACWY2d Group | 196 of 197 |
| Co-ad Group | 197 of 201 |
| PCV13 Group | 197 of 201 |
Most frequent serious adverse event terms
| Event term | Organ system | ACWY1d Group | ACWY2d Group | Co-ad Group | PCV13 Group |
|---|---|---|---|---|---|
| Pneumonia | Infections and infestations | 1 of 203 | 3 of 197 | 3 of 201 | 1 of 201 |
| Bronchiolitis | Infections and infestations | 1 of 203 | 2 of 197 | 1 of 201 | 0 of 201 |
| Bronchitis | Infections and infestations | 1 of 203 | 0 of 197 | 2 of 201 | 0 of 201 |
| Gastroenteritis | Infections and infestations | 0 of 203 | 2 of 197 | 0 of 201 | 1 of 201 |
| Tonsillitis | Infections and infestations | 0 of 203 | 1 of 197 | 0 of 201 | 2 of 201 |
| Upper respiratory tract infection | Infections and infestations | 0 of 203 | 0 of 197 | 3 of 201 | 0 of 201 |
| Asthma | Respiratory, thoracic and mediastinal disorders | 0 of 203 | 1 of 197 | 1 of 201 | 1 of 201 |
| Bronchospasm | Respiratory, thoracic and mediastinal disorders | 0 of 203 | 1 of 197 | 2 of 201 | 0 of 201 |
| Laryngitis | Infections and infestations | 1 of 203 | 1 of 197 | 0 of 201 | 0 of 201 |
| Skin laceration | Injury, poisoning and procedural complications | 0 of 203 | 1 of 197 | 0 of 201 | 1 of 201 |
Most frequent non-serious adverse event terms
| Event term | Organ system | ACWY1d Group | ACWY2d Group | Co-ad Group | PCV13 Group |
|---|---|---|---|---|---|
| Irritability/Fussiness | General disorders | 89 of 199 | 116 of 196 | 107 of 197 | 108 of 197 |
| Redness | General disorders | 68 of 199 | 88 of 196 | 94 of 197 | 108 of 197 |
| Drowsiness | General disorders | 62 of 199 | 99 of 196 | 85 of 197 | 89 of 197 |
| Pain | General disorders | 52 of 199 | 91 of 196 | 94 of 197 | 91 of 197 |
| Loss Of Appetite | General disorders | 56 of 199 | 78 of 196 | 54 of 197 | 83 of 197 |
| Swelling | General disorders | 35 of 199 | 57 of 196 | 75 of 197 | 73 of 197 |
| Temperature/(Rectal) (°C) | General disorders | 26 of 199 | 46 of 196 | 34 of 197 | 63 of 197 |
| Upper respiratory tract infection | Infections and infestations | 12 of 203 | 28 of 197 | 15 of 201 | 24 of 201 |
| Pyrexia | General disorders | 12 of 203 | 19 of 197 | 12 of 201 | 13 of 201 |
| Cough | Respiratory, thoracic and mediastinal disorders | 13 of 203 | 21 of 197 | 8 of 201 | 12 of 201 |
Serious events with the highest arm-level rate: pneumonia (1.5%), upper respiratory tract infection (1.5%), bronchiolitis (1.0%), gastroenteritis (1.0%), bronchitis (1.0%).
The registry lists serious adverse events affecting 12 participants among 203 at risk in ACWY1d, 11 among 197 in ACWY2d, 13 among 201 in Co-ad, and 16 among 201 in PCV-13. For other adverse events, the listed affected counts are 199 among 203, 196 among 197, 197 among 201, and 197 among 201, respectively. The record lists deaths as 0, 0, 1, and 1 in those groups. These are descriptive registry entries; they do not establish that an event was caused by either vaccine.
The listed serious-event terms include pneumonia and upper respiratory tract infection at 1.5% each, with bronchiolitis, gastroenteritis, bronchitis and tonsillitis at 1.0% each. The registry entry does not give group-specific counts for each term or explain the period over which these events were collected. A percentage or count alone does not indicate severity beyond the recorded category, duration, or relationship to vaccination. The registry record also does not report comparative safety estimates, confidence intervals, or a causal assessment. Consequently, these figures should be read as reported event summaries, not as evidence that one regimen has a safer or less safe profile.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this was a randomized, open, controlled study of MenACWY-TT schedules in toddlers, with a separate group receiving co-administered Prevenar 13 and a group receiving the vaccines separately. It defines the primary immunogenicity outcome as the percentage meeting an rSBA threshold one month after the first MenACWY-TT dose. It also describes a longer-term persistence objective and several secondary antibody outcomes.
However, the primary outcome’s numerical results are not reported in the registry record. Without the group-specific estimates, confidence intervals and numbers analyzed, the posted information cannot show the observed antibody response level, how precisely it was estimated, or whether groups differed. The study title’s non-inferiority objective does not itself demonstrate non-inferiority; the margin, comparison estimate and uncertainty needed to evaluate that question are not reported in the registry record.
The safety entries provide counts of participants with serious and other adverse events and deaths by group, as well as selected event terms. They do not establish causation, and the registry does not provide enough detail to assess event timing, exposure, or comparative risk formally. These entries should not be used to claim that vaccination caused a listed event or that one schedule is safer than another.
In general, a trial’s design and outcome definitions explain what was intended to be studied, while estimates and their uncertainty are needed to interpret what was observed. The available registry information supports a description of the trial’s structure and selected safety reporting, but not a conclusion about the primary immunogenicity result or the non-inferiority objective. It also does not support medical advice or conclusions beyond the measures and details recorded.
13. Why This Trial Matters Statistically
This trial raises several statistical questions that are important in vaccine studies. First, the primary endpoint is a threshold-based percentage, while the secondary outcomes include geometric mean titers. These summaries capture different aspects of an antibody response: the threshold measure classifies participants by whether a level is reached, whereas the GMT summarizes measured levels on a geometric scale. Keeping those estimands distinct helps avoid treating a threshold percentage as a complete description of the titer distribution.
Second, the design includes one-dose and two-dose schedules and examines co-administration versus separate administration. Such questions require comparisons aligned with the study objective. In particular, a non-inferiority claim depends on the prespecified margin and on the estimate and uncertainty for the relevant contrast. Those details and the numerical primary results are not reported in the registry record, so the objective can be identified but not evaluated from the posted information.
Third, the analysis population is specified as an according-to-protocol cohort for persistence Year 1, with eligibility, vaccination, assay availability and compliance conditions. Clear population definitions matter because exclusions and unavailable measurements affect which participants contribute to an estimate. The exact primary analysis count and handling of missing data are not reported in the registry record.
Finally, the study lists many outcome measures across serogroups, assays, thresholds and times. Multiplicity and transparent reporting are therefore relevant to interpretation, but the registry record does not report a multiplicity strategy. Together, these features illustrate why endpoint estimates, uncertainty, analysis populations and prespecified comparisons are essential alongside a trial’s design description.
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 its numerical results are not reported in the registry record. The record defines the endpoint and a 95% confidence-interval measure but does not provide the percentages, interval limits, or numbers analyzed. The magnitude and precision of the antibody response, and any differences among the named groups, therefore cannot be assessed from the posted information.
The registry record also does not report the non-inferiority margin or the numerical comparison needed to evaluate the stated co-administration objective. The statistical analysis plan, sample-size justification, and any interim analyses are not reported in the registry record. Planning illustrations based on an observed effect do not supply evidence about the trial’s original design or observed power.
Although the analysis population is described, the number of participants contributing to the primary endpoint and the handling of unavailable assay results are not reported in the registry record. The description of the primary outcome includes an incomplete note about data collection, and its full meaning is not reported. The registry also does not report how multiplicity across the listed outcomes was handled.
Safety entries are limited to group-level counts, deaths, and selected serious-event terms. Event-specific group counts, detailed collection periods, causal assessments and comparative uncertainty are not reported in the registry record. The open-label design is recorded, but the registry provides no further information on how knowledge of assignment may have affected assessment or reporting. These limitations constrain interpretation of the posted record and do not establish that the study itself lacked further analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Immunogenicity and Safety Study of 1 and 2 Doses of GlaxoSmithKline (GSK) Biologicals' Meningococcal Vaccine MenACWY-TT (GSK134612) in Toddlers, Persistence up to 5 Years After Vaccination and Co-administration With Pfizer's Prevenar 13™Vaccine — NCT01939158.
- Registry record last updated 2021-10-05; status last verified 2021-09.
- Results first posted 2021-10-05.
- 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 record describes NCT01939158 as a completed Phase 3, randomized, open, controlled, multicentre, parallel-group study sponsored by Pfizer. Enrollment was 803. The study evaluated one or two doses of MenACWY-TT in toddlers and included co-administration with Prevenar 13 as well as separate administration. The recorded study start was 2013-10-02 and primary completion was 2019-12-05.
The primary outcome was the percentage with rSBA titers of >=1:8 one month after the first MenACWY-TT dose, assessed across serogroups A, C, W-135 and Y. Its numerical results are not reported in the registry record. The record also lists serious and other adverse-event counts and deaths by group, but these descriptive entries do not establish causation or comparative safety.