This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety and Immunogenicity of a Group B Streptococcus Vaccine in Healthy Women (NCT01150123), a randomized phase 1 study. The primary outcome is Percentage of Subjects Achieving Specific Thresholds of Antibody Concentrations for Subjects in Enrollment Group 1.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01150123 |
| Phase | Phase 1 |
| Condition | Group B Streptococcus |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 678 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Vaccines |
| Results posted | Yes |
2. Clinical Question
Population
Healthy women 18–40 years of age were eligible for this phase Ib study. The primary endpoint was defined for the primary Per Protocol Set: participants who received vaccine correctly, provided evaluable serum samples at baseline and Day 61, and had no major protocol violations as defined before analysis.
Intervention
The study evaluated a Group B Streptococcus vaccine across dose and adjuvant combinations. The recorded arms include 5 µg and 20 µg formulations, with no adjuvant, Alum, or MF59 at 4.87 mg or 9.75 mg, and schedules of one or two injections. The arm descriptions also contain a 20 µg Alum entry whose description says 5 µg.
Comparator
Saline placebo was used as a controlled comparison. The record describes placebo recipients as receiving two injections one month apart, and lists placebo arms for Enrollment Group 1 and Enrollment Group 2.
Primary question
Among participants in Enrollment Group 1, what percentage achieved an antibody concentration threshold of ≥ 0.5 µg/mL by ELISA at Day 61? The endpoint description also refers to cohorts 1 and 2 and potential use in pregnant women. Primary outcome results and comparative estimates are not reported in the registry record.
3. Trial Design
This was a randomized, observer-blind, controlled, single-center, dose-ranging phase Ib study conducted in a parallel-group design. It enrolled healthy women 18–40 years of age and evaluated a Group B Streptococcus vaccine. The registry lists the study as completed, with enrollment of 678. The recorded start is 2010-05 and primary completion is 2011-11.
Active vaccine arms varied by antigen dose, adjuvant, and injection schedule. The listed dose levels were 5 µg and 20 µg. Formulations included vaccine without adjuvant, with Alum, and with MF59-H or MF59-F; the arm descriptions associate MF59-H with 4.87 mg and MF59-F with 9.75 mg. Several arms received either one or two injections. Placebo recipients received two saline injections one month apart.
The record describes random allocation and single masking, and the official title specifies observer-blind. It does not report the allocation ratio, the randomization method, or which study roles were masked. A single-center setting may limit how directly the experience represents other research settings, while the dose-ranging structure allows different formulations and schedules to be considered. These design features describe the trial structure; they do not establish the magnitude or precision of an antibody response.
There is an inconsistency in the arm descriptions: the 20 µg Alum entry is labelled 20 µg, but its description says participants received 5 µg. The registry record does not resolve that discrepancy. No protocol details beyond those recorded are assumed.
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: Group1: 5 µg-1Inj-No Adj, 5 µg-2Inj-No Adj, 20 µg-1Inj-No Adj, 20 µg-2Inj-No Adj (Cohort 1), 5 µg-1Inj-Alum, 5 µg-2Inj-Alum, 20 µg-1Inj-Alum, 20 µg-2Inj-Alum (Cohort 2). Group 2: 5 µg-1Inj-MF59\_F, 5 µg-2Inj-MF59\_F, 20 µg-1Inj-MF59\_F, 20 µg-2Inj-MF59\_F (Cohort 3), 5 µg-1Inj-MF59\_H, 5 µg-2Inj-MF59\_H, 20 µg-1Inj-MF59\_H, 20 µg-2Inj-MF59\_H (Cohort 4)
Only the first 6 of 18 groups are shown.
Overall Study
| Stage | 5 µg-1 Inj - No Adj | 5 µg-2 Inj - No Adj | 20 µg-1 Inj - No Adj | 20 µg-2 Inj - No Adj | 5 µg-1 Inj - Alum | 5 µg-2 Inj - Alum |
|---|---|---|---|---|---|---|
| STARTED | 40 | 40 | 39 | 40 | 40 | 40 |
| COMPLETED | 37 | 38 | 35 | 37 | 37 | 34 |
| NOT COMPLETED | 3 | 2 | 4 | 3 | 3 | 6 |
Reasons for not completing this period:
| Reason | 5 µg-1 Inj - No Adj | 5 µg-2 Inj - No Adj | 20 µg-1 Inj - No Adj | 20 µg-2 Inj - No Adj | 5 µg-1 Inj - Alum | 5 µg-2 Inj - Alum |
|---|---|---|---|---|---|---|
| Withdrawal by Subject | 1 | 1 | 2 | 1 | 1 | 1 |
| Lost to Follow-up | 2 | 1 | 2 | 2 | 2 | 5 |
Analysis population for the primary outcome, as defined in the registry: Analysis was done on primary Per Protocol Set (PPS) - The subjects who received the vaccine correctly; provided evaluable serum samples at baseline and Day 61; and had no major protocol violations as defined prior to analysis.
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.
Only the first 6 of 19 groups are shown.
| Characteristic | Unit | 5μg-1 Inj - No Adj | 5μg-2 Inj - No Adj | 20 μg-1 Inj - No Adj | 20 μg-2 Inj - No Adj | 5μg-1 Inj - Alum | 5μg-2 Inj - Alum |
|---|---|---|---|---|---|---|---|
| Participants analysed | 40 | 40 | 39 | 40 | 40 | 40 | |
| Age, Continuous | years | 24.3 (SD 5.5) | 26.2 (SD 7.2) | 25.5 (SD 5.0) | 24.1 (SD 4.6) | 26.5 (SD 6.2) | 25.1 (SD 5.3) |
| Sex: Female, Male: Female | Participants | 40 | 40 | 39 | 40 | 40 | 40 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Subjects Achieving Specific Thresholds of Antibody Concentrations for Subjects in Enrollment Group 1, measured over Day 1 and Day 61.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of subjects |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of subjects achieving an antibody concentration threshold of ≥ 0.5 µg/mL, measured by ELISA at Day 61. The endpoint description names Enrollment Group 1 in its title, while its description refers to cohorts 1 and 2. The stated timeframe is Day 1 and Day 61, with the threshold assessed at Day 61. The specified analysis population is the primary Per Protocol Set: participants who received vaccine correctly, had evaluable serum samples at baseline and Day 61, and had no major protocol violations defined before analysis.
As a general statistical point, expressing threshold attainment as a percentage makes the outcome a proportion: each participant is classified according to whether the measured antibody concentration meets the stated cutoff. This can make a response criterion easier to interpret than a continuous concentration alone, but it also discards information about how far measurements fall above or below the cutoff. Results can depend on the threshold and on the completeness and quality of serum measurements.
The endpoint measures an antibody response, not a clinical disease outcome. The record frames the measure as potentially relevant to use in pregnant women, but the endpoint itself does not establish prevention of infection or another clinical benefit. The primary endpoint results are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record provides the primary endpoint definition but no corresponding result values. It therefore does not establish the percentage of participants who crossed the antibody threshold, how that percentage differed across vaccine formulations, or how precisely any group estimate was measured. The record also lists zero analyses, so no inferential result or comparative estimate is available to interpret.
The primary measure is a percentage, and the listed safety outcomes are counts of participants reporting events. For either kind of outcome, a point estimate alone would not describe its precision; an interval estimate would show the range of values reasonably compatible with the data under the analysis assumptions. No primary outcome confidence interval or comparative effect estimate is reported in the registry record. Without those quantities, it is not possible to judge whether apparent differences between formulations, if any, are precise or compatible with chance variation.
The safety data list serious adverse event counts within each recorded group. Examples include 6 participants with serious adverse events among 40 at risk in the 5µg-1 Inj - Alum group, and 0 among 39 at risk in the 20 µg-1 Inj - No Adj group. These are group-level event summaries, not evidence that the vaccine caused an event. The registry does not provide a causal assessment in these figures. The record lists other adverse events separately; interpretation depends on the event definitions, ascertainment period, and completeness of reporting.
The primary Per Protocol Set is a restricted analysis population. It includes participants meeting the recorded adherence, specimen, and protocol criteria, so it does not necessarily represent everyone enrolled or randomized. Results from such a population can be sensitive to exclusions if missing samples or protocol deviations are related to response. The record does not report the numbers excluded from this set or how missing endpoint measurements were handled.
In general, a non-significant result would not by itself show that groups are equivalent, and a difference would not by itself establish a clinically important effect. Those judgments require the estimated effect, its uncertainty, the analysis plan, and a clinically meaningful interpretation. Since the primary outcome results and analysis details are not reported in the registry record, no such conclusion can be drawn from the endpoint entry alone.
9. Statistical Methods Explained
What does a percentage endpoint represent?
As a general statistical explanation, a percentage is the number of participants meeting a defined criterion relative to the participants assessed for that outcome. Here, the criterion is an antibody concentration of ≥ 0.5 µg/mL by ELISA at Day 61. The registry record identifies a Per Protocol Set for the primary endpoint, but does not report the number assessed or the number meeting the criterion. The percentage therefore cannot be reconstructed from the endpoint description.
Turning a continuous measurement into a threshold outcome can simplify communication: the result distinguishes participants above the cutoff from those who do not reach it. The trade-off is loss of detail. Two participants with measurements on opposite sides of the cutoff may be classified differently despite similar values, while participants far apart on the same side are treated alike for this endpoint. This is a general feature of dichotomizing continuous data, not a finding about the trial’s unreported results.
Why do denominators matter?
A percentage is only interpretable alongside its denominator and the population from which that denominator was drawn. In this study, the primary endpoint definition restricts the analysis to participants who received vaccine correctly, provided evaluable serum samples at baseline and Day 61, and had no major protocol violations. A percentage in this set would answer a question about that defined population. It would not automatically describe all enrolled participants. The record does not report how many participants met these criteria or how missing samples were handled.
In general, confidence intervals describe uncertainty around an estimate. For a proportion, interval width depends in part on the number of assessed participants and the observed proportion. A narrow interval indicates greater precision under the model used; a wide interval indicates more uncertainty. No primary endpoint estimate or interval is reported in the registry record, so the precision of antibody-threshold attainment cannot be evaluated.
What can group comparisons establish?
Randomization can support comparisons between assigned groups by reducing systematic differences at the time of assignment, on average. It does not remove uncertainty from finite samples, missing outcome data, deviations from assigned treatment, or outcome measurement. A comparative analysis would ordinarily report the group estimates and an effect measure with uncertainty. The registry record lists no analyses and does not report a primary comparison, p-value, confidence interval, or model for the primary endpoint.
The record identifies a parallel design and several dose, adjuvant, and schedule combinations. Comparing many groups can raise a multiplicity concern: the more comparisons considered, the greater the chance of finding an apparently notable difference by chance if no adjustment or prespecified hierarchy is used. This is a general statistical issue. The registry record does not report a multiplicity strategy or a statistical analysis plan, so it is not possible to determine how comparisons were prioritized or whether any adjustment was intended.
How should safety counts be read?
For the safety summaries, the record gives the number at risk and the number affected for serious adverse events and other adverse events by group. These counts describe reported participants in the recorded risk sets. They do not, on their own, show whether events were caused by study treatment or whether the groups differ beyond sampling variation. A comparative safety interpretation would require consistent definitions, observation periods, completeness of follow-up, and uncertainty around group estimates. Those details are not reported in the registry record.
The serious-event term list includes percentages, but the record does not explain the precise denominator or whether terms can overlap within participants. Those listed percentages should therefore be read as registry-reported figures, not converted into participant counts or added together. In general, event categories may overlap, and summing percentages can misrepresent the number of affected participants.
What do planning calculations mean?
In general, a sample-size calculation describes a planning scenario under stated assumptions; it is not an observed trial result and is not observed power. The planning assumptions recorded for this study use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect set as a fraction of the observed effect. The record says that non-time-to-event illustrations report participants per arm, while time-to-event illustrations report total events.
The record does not report the trial’s own sample-size justification. Since the primary outcome result is not reported in the registry record, the observed effect underlying a planning illustration is not available in the registry record for interpretation. Any planning illustration should be distinguished from the study’s actual enrollment and from evidence about the precision or success of the primary endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The primary analysis population is described as the primary Per Protocol Set. Participants had to receive the vaccine correctly, provide evaluable serum samples at baseline and Day 61, and have no major protocol violations as defined before analysis. This definition clarifies which participants were intended for the primary endpoint analysis, but the registry record does not report how many participants qualified or how that set related to all randomized participants.
Missing-data handling is not reported in the registry record. The record does not explain how participants without evaluable serum samples, or participants with other missing endpoint information, were treated in the analysis. In general, excluding participants with missing measurements can affect an estimate if missingness is associated with antibody response or study group. The available description is not sufficient to assess whether that concern arose in this trial.
The endpoint title refers to Enrollment Group 1, while the description refers to cohorts 1 and 2. The record also lists secondary outcomes across Enrollment Groups 1 and 2, including solicited and unsolicited adverse events, persistence of antibody concentrations by serotype, and geometric mean ratios of serum GBS IgG antibody levels by serotype. It lists 14 outcome measures overall, but reports no analyses. The endpoint entry does not clarify how the primary and secondary outcomes were ordered for interpretation.
Multiplicity adjustment, a prespecified testing hierarchy, and interim analyses are not reported in the registry record. In general, evaluating multiple outcomes, formulations, or pairwise comparisons can increase the risk of chance findings if the analysis does not account for the number of tests. The absent analysis details mean it is not possible to determine whether this issue was addressed. The primary endpoint result and its uncertainty are also not reported, limiting assessment of the intended analysis population and the role of missing data.
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 |
|---|---|---|---|
| 5µg-1 Inj - No Adj | 1 | 40 | 2.5% |
| 5µg-2 Inj - No Adj | 1 | 40 | 2.5% |
| 20 µg-1 Inj - No Adj | 0 | 39 | 0.0% |
| 20 µg-2 Inj - No Adj | 2 | 40 | 5.0% |
| 5µg-1 Inj - Alum | 6 | 40 | 15.0% |
| 5µg-2 Inj - Alum | 2 | 40 | 5.0% |
| 20 µg-1 Inj - Alum | 2 | 39 | 5.1% |
| 20 µg-2 Inj- Alum | 0 | 40 | 0.0% |
| Placebo - Group 1 | 2 | 20 | 10.0% |
| 5µg-1 Inj - MF59_H | 2 | 40 | 5.0% |
| 5µg-2 Inj - MF59_H | 2 | 40 | 5.0% |
| 20 µg-1 Inj - MF59_H | 0 | 40 | 0.0% |
| 20 µg-2 Inj - MF59_H | 3 | 40 | 7.5% |
| 5µg-1 Inj - MF59_F | 3 | 40 | 7.5% |
| 5µg-2 Inj - MF59_F | 2 | 40 | 5.0% |
| 20 µg-1 Inj - MF59_F | 6 | 40 | 15.0% |
| 20 µg-2 Inj- MF59_F | 2 | 40 | 5.0% |
| Placebo - Group 2 | 1 | 20 | 5.0% |
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 |
|---|---|
| 5µg-1 Inj - No Adj | 37 of 40 |
| 5µg-2 Inj - No Adj | 38 of 40 |
| 20 µg-1 Inj - No Adj | 38 of 39 |
| 20 µg-2 Inj - No Adj | 39 of 40 |
| 5µg-1 Inj - Alum | 39 of 40 |
| 5µg-2 Inj - Alum | 39 of 40 |
Most frequent serious adverse event terms
| Event term | Organ system | 5µg-1 Inj - No Adj | 5µg-2 Inj - No Adj | 20 µg-1 Inj - No Adj | 20 µg-2 Inj - No Adj | 5µg-1 Inj - Alum | 5µg-2 Inj - Alum |
|---|---|---|---|---|---|---|---|
| Appendicitis | Infections and infestations | 1 of 40 | 0 of 40 | 0 of 39 | 2 of 40 | 0 of 40 | 0 of 40 |
| Mitral Valve Incompetence | Cardiac disorders | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Constipation | Gastrointestinal disorders | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Lyme Disease | Infections and infestations | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Pharyngotonsillitis | Infections and infestations | 0 of 40 | 1 of 40 | 0 of 39 | 0 of 40 | 0 of 40 | 0 of 40 |
| Ankle Fracture | Injury, poisoning and procedural complications | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Ligament Rupture | Injury, poisoning and procedural complications | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Post Lumbar Puncture Syndrome | Injury, poisoning and procedural complications | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 1 of 40 | 0 of 40 |
| Tendon Injury | Injury, poisoning and procedural complications | 0 of 40 | 0 of 40 | 0 of 39 | 0 of 40 | 0 of 40 | 1 of 40 |
| Abortion Spontaneous | Pregnancy, puerperium and perinatal conditions | 0 of 40 | 1 of 40 | 0 of 39 | 0 of 40 | 0 of 40 | 0 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 5µg-1 Inj - No Adj | 5µg-2 Inj - No Adj | 20 µg-1 Inj - No Adj | 20 µg-2 Inj - No Adj | 5µg-1 Inj - Alum | 5µg-2 Inj - Alum |
|---|---|---|---|---|---|---|---|
| Injection Site Pain | General disorders | 28 of 40 | 28 of 40 | 31 of 39 | 35 of 40 | 39 of 40 | 37 of 40 |
| Headache | Nervous system disorders | 19 of 40 | 15 of 40 | 16 of 39 | 21 of 40 | 21 of 40 | 19 of 40 |
| Fatigue | General disorders | 19 of 40 | 11 of 40 | 18 of 39 | 21 of 40 | 19 of 40 | 13 of 40 |
| Injection Site Warmth | General disorders | 11 of 40 | 11 of 40 | 9 of 39 | 13 of 40 | 11 of 40 | 14 of 40 |
| Injection Site Induration | General disorders | 9 of 40 | 13 of 40 | 7 of 39 | 9 of 40 | 12 of 40 | 16 of 40 |
| Injection Site Erythema | General disorders | 8 of 40 | 8 of 40 | 9 of 39 | 8 of 40 | 9 of 40 | 12 of 40 |
| Malaise | General disorders | 8 of 40 | 6 of 40 | 11 of 39 | 11 of 40 | 8 of 40 | 9 of 40 |
| Upper Respiratory Tract Infection | Infections and infestations | 10 of 40 | 7 of 40 | 6 of 39 | 7 of 40 | 8 of 40 | 8 of 40 |
| Nausea | Gastrointestinal disorders | 6 of 40 | 6 of 40 | 9 of 39 | 7 of 40 | 7 of 40 | 8 of 40 |
| Injection Site Swelling | General disorders | 6 of 40 | 6 of 40 | 5 of 39 | 5 of 40 | 7 of 40 | 8 of 40 |
Serious events with the highest arm-level rate: appendicitis (5.0%), intervertebral disc degeneration (5.0%), abortion spontaneous (5.0%), decompression sickness (5.0%), migraine (2.6%).
The registry record reports serious adverse event counts by group, with the number at risk and the number affected. For example, 6 of 40 participants were reported with serious adverse events in the 5µg-1 Inj - Alum group; 0 of 39 were reported in the 20 µg-1 Inj - No Adj group. Other group counts are recorded separately. Death counts are not reported in the registry record.
These figures are descriptive safety summaries. A count does not establish that an event was caused by the vaccine, and a difference between group counts does not by itself establish a true difference in risk. The record does not provide a comparative safety analysis, confidence intervals, or event attribution for these figures. The observation period and detailed event definitions are not reported in the registry record.
The registry also lists serious-event terms with percentages, including Appendicitis, Intervertebral Disc Degeneration, Abortion Spontaneous, and Decompression Sickness at 5.0% each, and Migraine and Eating Disorder at 2.6% each. The record does not specify the denominator or whether a participant could contribute to more than one term. These percentages should not be added or treated as a complete account of the trial’s safety experience.
12. What the Result Does, and Does Not, Mean
The record documents a randomized, observer-blind, dose-ranging study of Group B Streptococcus vaccine formulations in healthy women and defines a primary antibody-threshold endpoint. It also records safety outcomes and several secondary immunogenicity measures. Those features establish what the study was designed to assess, but they do not reveal the primary endpoint result.
The primary question concerns the percentage reaching an ELISA antibody concentration of ≥ 0.5 µg/mL at Day 61. The registry record does not report that percentage, a comparison among vaccine groups, or an uncertainty interval. It therefore does not support a conclusion about the size or precision of the antibody response. It also does not report a clinical disease endpoint, so the antibody measure alone cannot establish prevention of Group B Streptococcus disease or another clinical outcome.
The safety summaries show reported counts of participants with serious and other adverse events within named groups. Such counts can describe what was recorded during the study, but without attribution and comparative analysis they do not establish causation or a difference in safety between formulations. The record’s serious-event term percentages likewise lack enough denominator detail for broader interpretation.
More generally, a biological response measured in a study is not interchangeable with evidence of clinical benefit. Interpreting an antibody threshold requires the actual endpoint results, the analysis population, missing-data handling, and an account of uncertainty. The record states that the threshold was considered for potential use in pregnant women, but this study enrolled healthy women 18–40 years of age. The registry information alone does not establish how results would generalize beyond the study population.
13. Why This Trial Matters Statistically
This trial is statistically notable for its dose-ranging and formulation structure. The recorded groups varied by vaccine dose, adjuvant, and one- or two-injection schedule, with placebo groups also included. Such a design can address several immunogenicity and safety questions, but it also creates a need for clear prespecification of which comparisons and outcomes are primary. The registry record does not report that hierarchy or the analysis plan.
The primary endpoint converts antibody concentration into a threshold-based percentage. This is a useful occasion to distinguish a clinically interpretable response criterion from the underlying continuous measurement. Thresholds can simplify summaries, while obscuring the distribution of values and sensitivity to the chosen cutoff. Because the registry record does not report the endpoint results, neither the proportion meeting the threshold nor its precision can be assessed.
The record also illustrates why analysis population definitions matter. The primary endpoint was defined for a Per Protocol Set requiring correct vaccine receipt, evaluable samples at baseline and Day 61, and no major protocol violations. That population definition is clear, but the number included and the handling of missing data are not reported. A reader therefore cannot evaluate how exclusions may have influenced the endpoint estimate.
Finally, the group-level safety counts should be interpreted descriptively rather than as treatment-attributed effects. The registry lists outcome measures but no analyses, making it especially important not to infer comparative conclusions from counts alone. The available record supports understanding the planned questions and reported safety summaries, while leaving the primary statistical results and their uncertainty unresolved.
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 central limitation is the absence of primary outcome results. Although the endpoint threshold, assay, timeframe, and analysis population are described, the percentage meeting the threshold and any comparative estimate are not reported in the registry record. No confidence intervals or p-values are listed, and the record lists no analyses. This prevents assessment of effect magnitude, precision, or group differences.
There is ambiguity in the endpoint description: its title names Enrollment Group 1, while the description refers to cohorts 1 and 2. The record does not resolve whether the same primary endpoint analysis was intended for both groups. There is also an arm-description inconsistency for 20 µg Alum: its label says 20 µg, but its description says 5 µg. These details make the recorded definitions less clear without further documentation.
The record does not report the randomization method or ratio, allocation concealment, detailed masking procedures, missing-data approach, multiplicity strategy, interim analyses, or the trial’s sample-size justification. The primary Per Protocol Set is defined, but its size and the numbers excluded are not reported. These omissions limit evaluation of bias, analysis choices, and precision.
Safety summaries are reported as counts by group, but event definitions, observation periods, causal attribution, and a comparative analysis are not reported in the registry record. The listed serious-event terms include percentages without a stated denominator or clarification about overlap. These limitations constrain interpretation of the safety summaries and preclude treating them as a complete or causal account.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity of a Group B Streptococcus Vaccine in Healthy Women — NCT01150123.
- Registry record last updated 2017-05-15; status last verified 2017-05.
- Results first posted 2017-05-15.
- 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
The registry record describes a completed, randomized, observer-blind, controlled, single-center, parallel-group phase Ib dose-ranging study of a Group B Streptococcus vaccine in healthy women 18–40 years of age. Enrollment was 678. The recorded study start is 2010-05, and primary completion is 2011-11.
Active formulations varied by dose, adjuvant, and injection schedule, with saline placebo groups. The primary endpoint was the percentage reaching an antibody concentration of ≥ 0.5 µg/mL by ELISA at Day 61, in a defined Per Protocol Set. Primary outcome results and comparative analyses are not reported in the registry record. Safety counts and serious-event terms are listed, but the record does not provide enough detail to infer causation or comparative risk.