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 Study to Evaluate the Immunogenicity and Safety of GlaxoSmithKline (GSK) Biologicals' Herpes Zoster Vaccine GSK1437173A When Co-administered With GSK Biologicals' Seasonal Influenza Vaccine GSK2321138A in Adults Aged 50 Years and Older (NCT01954251), a randomized phase 3 study. The primary outcome is Adjusted Geometric Mean ELISA Concentrations of Anti-gE Antibodies.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01954251 |
| Phase | Phase 3 |
| Condition | Herpes Zoster |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 829 |
| Arms in the primary outcome | 2 |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Adults aged 50 years and older. The registry reports total enrollment of 829. The primary immunogenicity analysis used an ATP cohort, described as including evaluable subjects who met eligibility criteria, followed protocol procedures and intervals, and had no elimination criteria during the study. The full cohort definition is truncated in the registry record.
Intervention
The co-administration group received one injection of the seasonal influenza vaccine and one injection of the herpes zoster study vaccine at the first visit. It received a second herpes zoster vaccine injection at the third visit, two months later.
Comparator
The control group received the vaccines separately: influenza vaccine at the first visit, a herpes zoster vaccine injection at the third visit, and a second herpes zoster vaccine injection at the fourth visit. The visits were two months apart.
Primary question
At one month after the second herpes zoster vaccine dose, how did adjusted anti-gE antibody geometric mean concentrations compare between the co-administration and control groups? The corresponding assessment was at Month 3 for the co-administration group and Month 5 for the control group because their vaccination schedules differed.
The study was designed to assess immunogenicity, reactogenicity, and safety when the first herpes zoster vaccine dose was given with seasonal influenza vaccine rather than separately. The primary endpoint concerns the antibody response to the herpes zoster vaccine, not influenza antibody response or clinical herpes zoster disease. The registry also lists influenza antibody outcomes and symptom outcomes, but these address different questions from the primary anti-gE comparison.
3. Trial Design
This was a Phase 3, randomized, parallel-group study with no masking. The registry lists GlaxoSmithKline as the sponsor, Herpes Zoster as the condition, total enrollment of 829, and study status as completed. The recorded start date is 2013-10-03 and the primary completion date is 2014-06-02.
The two groups differed in vaccine timing. In the co-administration group, the first herpes zoster vaccine dose and seasonal influenza vaccine were given during the first visit, followed by the second herpes zoster dose at the third visit, two months later. In the control group, influenza vaccine was given at the first visit, with the first and second herpes zoster doses at the third and fourth visits, respectively, all two months apart. Thus, the primary antibody assessment occurred at Month 3 in the co-administration group and Month 5 in the control group, each one month after the second herpes zoster dose.
Random allocation can support a fair comparison by assigning participants to groups without choosing the group based on their characteristics. The registry record does not report the allocation sequence or concealment procedures. Because masking is listed as none, the study was open-label. The registry does not report whether outcome laboratory staff were masked, or give further details of study conduct beyond the recorded schedule.
Enrollment was 829, while the primary analysis lists 382 participants in the co-administration group and 388 in the control group. These primary endpoint group counts are not the same as the safety group counts, which are 413 and 415. The registry describes the primary analysis as using the ATP cohort for immunogenicity, an evaluable-subject population. Reasons for the difference between enrollment and those endpoint counts, and the full disposition of participants, 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: Out of the 829 subjects enrolled in this trial, 1 subject did not receive vaccination even though subject number had been allocated, hence he/she was excluded from study start.
Overall Study
| Stage | GSK1437173A + GSK2321138A Group | Control Group |
|---|---|---|
| STARTED | 413 | 415 |
| COMPLETED | 400 | 396 |
| NOT COMPLETED | 13 | 19 |
Reasons for not completing this period:
| Reason | GSK1437173A + GSK2321138A Group | Control Group |
|---|---|---|
| Adverse Event | 5 | 7 |
| Lost to Follow-up | 6 | 6 |
| Withdrawal by Subject | 2 | 6 |
Analysis population for the primary outcome, as defined in the registry: The analysis was performed on the ATP cohort for immunogenicity, which included all evaluable subjects (i.e. those meeting all eligibility criteria, complying with the procedures and intervals defined in the protocol, with no elimination criteria during the study) for whom data concerning immunogenicity outcome measures were available.
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 | GSK1437173A + GSK2321138A Group | Control Group | Total |
|---|---|---|---|---|
| Participants analysed | 413 | 415 | 828 | |
| Age, Continuous | Years | 63.4 (SD 8.3) | 63.4 (SD 8.8) | 63.4 (SD 8.55) |
| Sex: Female, Male: Female | Participants | 211 | 218 | 429 |
| Sex: Female, Male: Male | Participants | 202 | 197 | 399 |
6. Primary Endpoint
The registry lists the primary outcome as Adjusted Geometric Mean ELISA Concentrations of Anti-gE Antibodies, measured over At one month post-dose 2 (Month 3 for GSK1437173A + GSK2321138A group and Month 5 for Control group).
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | mIU/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is adjusted geometric mean concentration of anti-gE antibodies, measured in mIU/mL. Anti-gE antibodies are an immunogenicity measure for the herpes zoster vaccine: they quantify the antibody response to glycoprotein E after vaccination. This is a laboratory outcome, rather than a count of herpes zoster cases or a direct measure of clinical protection.
The registry reports post-vaccination geometric means adjusted conditionally for pre-vaccination log-transformed anti-gE concentrations. The adjusted concentrations were calculated as least-squares means and back-transformed to the original units. The endpoint was assessed one month after dose 2: at Month 3 in the co-administration group and Month 5 in the control group. The different calendar months reflect the different group schedules; the stated interval after dose 2 is one month for both.
A geometric mean is commonly used for antibody concentrations because such measurements can be strongly right-skewed. General explanation: taking logarithms makes proportional differences easier to model, and transforming the resulting mean back gives a summary on the original concentration scale. Adjustment for pre-vaccination measurements aims to account for baseline antibody levels in the group comparison. The registry does not report why this endpoint was selected, a clinically meaningful antibody threshold for it, or a relation between a particular concentration and clinical protection.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary group estimates are adjusted anti-gE geometric mean concentrations of 52150.0 mIU/mL in the co-administration group and 56250.0 mIU/mL in the control group. Their respective 95% confidence intervals are 48360.0 to 56250.0 and 52180.0 to 60630.0. These are adjusted concentration estimates for the immunogenicity analysis population, not simple summaries of all enrolled participants.
The registry also reports an adjusted geometric mean concentration ratio of 1.08 with a 95% confidence interval from 0.97 to 1.20. This is the reported comparison measure. Its confidence interval includes 1, so the posted estimate is compatible with a range of relative values that includes equal concentrations as well as values on either side. The interval also indicates uncertainty around the estimated ratio; it should not be read as establishing that the groups are exactly equal.
The analysis is identified as non-inferiority or equivalence in the registry. However, the non-inferiority or equivalence margin, the prespecified decision rule, and a p-value are not reported in the registry record. A ratio and confidence interval alone cannot establish that a formal non-inferiority or equivalence criterion was met: that conclusion depends on the prespecified margin and decision rule. The registry record therefore supports describing the estimate and its precision, but not asserting a formal conclusion under an unreported margin.
The registry gives different post-dose assessment months for the groups because their vaccine schedules differed. Both measurements are stated as one month after dose 2, but the calendar assessment points are Month 3 and Month 5. This timing is important when interpreting the endpoint: the comparison is aligned by time after the second herpes zoster dose, not by the same study month.
The primary analysis uses an ATP immunogenicity cohort, rather than the full safety group. The registry’s abbreviated cohort description defines evaluable participants in terms of eligibility, protocol compliance, intervals, and absence of elimination criteria. The complete definition and reasons for exclusions are not reported in the registry record. The result should therefore be interpreted as applying to the analyzed cohort described in the record, with uncertainty about the participant-level exclusions and missing observations.
These results concern antibody concentrations. They do not directly show whether the vaccines prevent herpes zoster, establish a clinical benefit, or determine the frequency of influenza illness. Those questions are not answered by this primary endpoint. The registry lists separate safety and influenza immunogenicity outcomes, but their presence does not transform the anti-gE result into evidence about those distinct outcomes.
9. Statistical Methods Explained
What does a geometric mean represent?
General explanation: a geometric mean summarizes positive measurements after taking their logarithms, averaging on that transformed scale, and returning to the original scale. It is useful when values vary multiplicatively or have a skewed distribution, as antibody concentrations often can. The summary is not the same as an arithmetic average. A geometric mean ratio expresses a relative comparison on the original scale after the underlying analysis is performed on the log scale.
For the primary outcome, the registry describes adjusted post-vaccination concentrations conditional on pre-vaccination log-transformed anti-gE concentrations. It reports adjusted least-squares means, a difference of least-squares means, and back-transformed geometric mean concentrations. The posted comparison is an adjusted geometric mean concentration ratio. The exact model specification, covariates beyond the pre-vaccination concentration, and handling of values below assay limits are not reported in the registry record.
Why adjust for baseline concentration?
General explanation: antibody levels before vaccination can differ among participants. Including baseline measurements in an analysis can improve the comparison by accounting for those starting levels rather than comparing post-vaccination values without adjustment. The registry says the post-vaccination means were calculated conditionally on pre-vaccination log-transformed concentrations. It does not report the fitted model in enough detail to identify every modeling assumption or diagnostic check.
How should the confidence interval be read?
General explanation: a confidence interval describes the uncertainty associated with an estimated quantity under the analysis assumptions. It gives a range of values compatible with the data and model at the stated confidence level; it does not mean that the true value has a particular probability of falling within the one calculated interval. The primary ratio is 1.08, and its 95% confidence interval is 0.97 to 1.20. That interval includes 1, the ratio corresponding to equal concentrations. The interval is not, by itself, a test of non-inferiority or equivalence because the required margin is not reported.
The group concentration estimates also have 95% confidence intervals: 48360.0 to 56250.0 for the co-administration group and 52180.0 to 60630.0 for the control group. Overlap between separate group confidence intervals is not a substitute for the confidence interval of the adjusted comparison. The reported ratio and its interval are the direct summary for the comparison.
What does randomization contribute?
General explanation: random allocation is intended to reduce systematic differences between groups at assignment, supporting a causal comparison when the trial is appropriately conducted and analyzed. It does not ensure that every measured or unmeasured characteristic is identical between groups, and it does not remove uncertainty from sampling. This study is listed as randomized and parallel, but the registry record does not describe the randomization sequence, concealment, or further balance assessments.
The study is listed as having no masking. In an open-label study, participants and study personnel know the assigned group, which can matter for subjective outcomes such as reported symptoms. The primary antibody endpoint is a laboratory measurement, but whether laboratory staff were masked is not reported in the registry record. No conclusion about the effect of masking on this result can be drawn from the available description.
Why do analysis populations matter?
The primary endpoint was analyzed in an ATP cohort for immunogenicity. The registry describes this as an evaluable-subject cohort, with eligibility, protocol adherence, timing, and elimination criteria determining inclusion. Such a population can differ from the participants initially randomized. If inclusion depends on post-randomization events, the analyzed groups may not retain all the protections of randomization. The record does not provide the complete cohort definition, participant flow, reasons for exclusion, or missing-data methods, so the potential effect of exclusions cannot be assessed fully.
The safety group counts are 413 in the co-administration group and 415 in the control group, whereas the primary endpoint counts are 382 and 388. This reflects different posted populations for safety and immunogenicity; it does not establish why participants were absent from the primary analysis. The record does not report an intention-to-treat primary analysis alongside the ATP analysis.
What is needed for a non-inferiority interpretation?
General explanation: a non-inferiority design asks whether the result rules out a loss larger than a prespecified acceptable margin. The margin and the direction of the comparison must be defined before interpreting the estimate. Equivalence uses criteria that assess whether the difference lies within prespecified bounds on both sides. In either case, the confidence interval must be evaluated against the applicable margin, not simply against equal values. The registry labels the analysis non-inferiority or equivalence but does not report the margin or decision rule. It is therefore not possible to verify a formal non-inferiority or equivalence conclusion from the posted estimate alone.
General explanation: over-dispersion matters when the observed variation in data is greater than an assumed statistical model allows. In that situation, standard errors and confidence intervals based on the narrower assumption can be too small. The primary endpoint is a continuous antibody concentration analyzed on a log scale according to the description, but the registry does not report an over-dispersion assessment or model diagnostic. There is no basis in the record to claim that over-dispersion was present or that a particular correction was used.
What is reported about the other analyses?
The registry lists 17 outcome measures and 5 analyses. The posted secondary outcomes cover influenza haemagglutination inhibition antibody measures, solicited symptoms, and potential immune-mediated diseases. For the potential immune-mediated diseases outcome, the record includes a risk difference and associated uncertainty, as well as an unadjusted p-value. The planning illustrations tied to that outcome are based on the observed effect and are not the trial’s original sample-size justification or evidence of observed power. The registry does not report the trial’s original sample-size calculation, interim analyses, or a complete statistical analysis plan.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| not stated | Adjusted Geometric mean concentration ra 1.08 | 0.97 to 1.20 | not reported |
The registry’s sponsor-reported primary comparison is an adjusted geometric mean concentration ratio of 1.08, with a 95% confidence interval of 0.97 to 1.20. The group-level adjusted concentrations are 52150.0 mIU/mL for the co-administration group and 56250.0 mIU/mL for the control group. The record labels the comparison as non-inferiority or equivalence, but does not state the margin, formal decision rule, or p-value.
No discrepancy is flagged between the sponsor-reported result and the available primary comparison. There is no separate recalculated primary estimate in the posted analysis that would replace or challenge the sponsor’s reported ratio. The appropriate reading is therefore to describe the reported estimate and confidence interval directly, while recognizing that a formal non-inferiority or equivalence judgment requires information not reported in the registry record.
The reported comparison is adjusted, whereas a simple calculation from group summaries would not necessarily reproduce that adjustment. General explanation: an adjusted model can account for baseline measurements and other specified features; a calculation based only on group summaries cannot generally recreate it. The registry’s description identifies baseline anti-gE concentration as part of the adjustment, but does not fully specify the model. Consequently, the sponsor’s adjusted estimate is the relevant posted comparison, and it should not be replaced by an unadjusted contrast inferred from the group estimates.
11. Multiplicity, Missing Data and Analysis Populations
The registry does not report a multiplicity plan for the primary and secondary outcomes. It lists 17 outcome measures, 13 posted secondary outcomes, and 5 analyses, but does not state which outcomes formed a confirmatory testing hierarchy, whether any adjustment for multiple testing was applied, or how decisions across outcomes were intended to be made. Without that information, secondary p-values should not be treated as if each were the sole prespecified test. General explanation: examining many outcomes without adjustment can increase the likelihood of observing a nominally unusual result by chance.
The primary comparison is labeled non-inferiority or equivalence, but the margin and decision rule are not reported in the registry record. This missing detail is central to judging whether the confidence interval meets the trial’s stated objective. The record also does not report a full statistical analysis plan, a sample-size justification for the original trial, or interim analyses. Planning illustrations based on an observed secondary effect are not a substitute for the original design justification and do not represent observed power.
The primary endpoint uses an ATP cohort for immunogenicity. The registry provides a partial definition of that population, but the full wording is truncated. Participant flow, reasons for exclusion, and the relationship between randomized participants and the analyzed cohort are not fully reported. The record does not state how missing antibody data were handled, whether missingness was assessed, or whether sensitivity analyses were performed.
The safety counts use group sizes of 413 and 415, while the primary immunogenicity counts are 382 and 388. The record does not explain the differences or identify whether missingness, protocol deviations, or other eligibility rules account for them. This prevents a complete assessment of how analysis-population choices may have affected the results.
The registry describes adjustment for pre-vaccination log-transformed anti-gE concentrations, but does not provide the full model specification, diagnostic checks, or details about assay values that may not have been measurable. It also does not report whether laboratory personnel were masked, despite the study’s no-masking designation. These omissions limit independent assessment of model assumptions and potential sources of bias. The record does not report a missing-data strategy for the secondary outcomes either.
12. 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 |
|---|---|---|---|
| GSK1437173A + GSK2321138A Group | 42 | 413 | 10.2% |
| Control Group | 39 | 415 | 9.4% |
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 |
|---|---|
| GSK1437173A + GSK2321138A Group | 370 of 413 |
| Control Group | 369 of 415 |
Most frequent serious adverse event terms
| Event term | Organ system | GSK1437173A + GSK2321138A Group | Control Group |
|---|---|---|---|
| Coronary artery disease | Cardiac disorders | 3 of 413 | 1 of 415 |
| Osteoarthritis | Musculoskeletal and connective tissue disorders | 1 of 413 | 3 of 415 |
| Atrial fibrillation | Cardiac disorders | 1 of 413 | 2 of 415 |
| Cerebrovascular accident | Nervous system disorders | 3 of 413 | 0 of 415 |
| Hypertension | Vascular disorders | 1 of 413 | 2 of 415 |
| Pneumonia | Infections and infestations | 3 of 413 | 0 of 415 |
| Syncope | Nervous system disorders | 2 of 413 | 1 of 415 |
| Lumbar spinal stenosis | Musculoskeletal and connective tissue disorders | 1 of 413 | 2 of 415 |
| Acute myocardial infarction | Cardiac disorders | 1 of 413 | 1 of 415 |
| Angina unstable | Cardiac disorders | 2 of 413 | 0 of 415 |
Most frequent non-serious adverse event terms
| Event term | Organ system | GSK1437173A + GSK2321138A Group | Control Group |
|---|---|---|---|
| Pain | General disorders | 344 of 411 | 318 of 413 |
| Fatigue | General disorders | 224 of 411 | 186 of 413 |
| Myalgia | General disorders | 201 of 411 | 201 of 413 |
| Shivering | General disorders | 174 of 411 | 181 of 413 |
| Headache | General disorders | 183 of 411 | 170 of 413 |
| Redness | General disorders | 153 of 411 | 144 of 413 |
| Arthralgia | General disorders | 154 of 411 | 135 of 413 |
| Temperature/(Oral) | General disorders | 107 of 411 | 119 of 413 |
| Swelling | General disorders | 99 of 411 | 86 of 413 |
| Gastrointestinal | General disorders | 90 of 411 | 92 of 413 |
Serious events with the highest arm-level rate: coronary artery disease (0.7%), cerebrovascular accident (0.7%), pneumonia (0.7%), osteoarthritis (0.7%), syncope (0.5%).
The safety group counts are 413 participants in the co-administration group and 415 in the control group. Serious adverse events are recorded for 42 participants in the co-administration group and 39 in the control group. Other adverse events are recorded for 370 and 369 participants, respectively. The registry does not report deaths in these fields. These are counts, and the record does not provide a comparative statistical analysis for them in the posted safety summary.
The registry lists coronary artery disease, cerebrovascular accident, pneumonia, and osteoarthritis at 0.7% each, and syncope and unstable angina at 0.5% each, among the top serious terms. The listed percentages are not clearly attributed to a particular group in the record. A serious adverse event is not necessarily caused by vaccination; the available information does not establish causality. The event terms and counts describe what was recorded, but do not by themselves show whether risk differs between groups.
The registry does not give further information about event timing, severity grading, relatedness assessments, or the exact safety observation window for these totals. It also does not report a formal comparison or uncertainty interval for serious adverse events. The figures should therefore be read as descriptive safety observations, not as proof of equivalence or of a causal difference between schedules.
13. What the Result Does, and Does Not, Mean
The primary result is an adjusted comparison of anti-gE antibody concentrations after the second herpes zoster vaccine dose. The reported ratio is 1.08, with a 95% confidence interval of 0.97 to 1.20. This gives a point estimate and an interval describing its uncertainty under the analysis, while leaving values on either side of equal concentrations compatible with the interval.
The result does not, by itself, establish non-inferiority or equivalence. Although the registry labels the analysis as non-inferiority or equivalence, it does not report the margin or decision rule needed to assess that claim. The estimate also does not establish that the groups are exactly equal. A confidence interval is not a declaration that differences are absent; it represents uncertainty around an estimate.
The endpoint is immunogenicity, measured by anti-gE antibody concentration. It is not a clinical outcome such as herpes zoster illness, hospitalization, or influenza illness. The registry record does not report a validated antibody threshold for clinical protection, so the concentration result should not be translated into a claim about protection or disease prevention.
The study compares vaccination schedules: giving the first herpes zoster dose with seasonal influenza vaccine versus giving the vaccines separately. The timing of the primary assessment was one month after dose 2 for both groups, but at different study months. The interpretation is restricted to the schedule, endpoint, analysis population, and follow-up described in the record. It does not automatically extend to other populations, products, schedules, or outcomes.
Safety counts and secondary outcomes add context but do not resolve the missing non-inferiority margin or change the meaning of the primary endpoint. The posted secondary information covers multiple domains and is not accompanied by a reported multiplicity strategy. The safety summary is descriptive and does not establish causality. Overall, the registry supports a careful account of the measured antibody response and recorded events, while important elements needed for stronger claims are not reported in the registry record.
14. Why This Trial Matters Statistically
This trial illustrates why the design question and the statistical endpoint must be kept distinct. The practical comparison concerns co-administration versus separate administration, while the primary statistical outcome is adjusted anti-gE antibody concentration. That outcome can inform an immunogenicity comparison, but it does not directly answer whether disease outcomes differ.
The study also demonstrates the importance of alignment by time since vaccination. The primary endpoint is assessed one month after dose 2 in both groups, but at Month 3 for the co-administration group and Month 5 for the control group. Reporting both the interval after vaccination and the study month helps clarify what is being compared when schedules differ.
Its non-inferiority or equivalence label highlights a key interpretive requirement: a relative estimate and confidence interval need a prespecified margin and decision rule to support that kind of conclusion. The reported ratio of 1.08 and 95% confidence interval of 0.97 to 1.20 are meaningful descriptive statistics, but the registry does not give the margin required to judge the formal objective.
The analysis-population distinction is also important. The primary immunogenicity counts differ from the safety counts, and the endpoint analysis uses an ATP cohort. Understanding how participants entered each analysis is necessary for assessing the relevance and potential bias of results. The registry’s partial cohort description and absent participant-flow detail leave uncertainty about those choices.
Finally, the range of influenza antibody, symptom, and safety outcomes shows why outcome multiplicity matters. Without a reported hierarchy or adjustment strategy, secondary findings deserve cautious interpretation. These features make the study a useful example of reading endpoints, schedules, populations, uncertainty, and reporting gaps together rather than treating a single estimate as a complete answer.
15. 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 for interpreting the primary objective is that the registry labels the analysis non-inferiority or equivalence but does not report the margin, decision rule, or p-value. The adjusted ratio and confidence interval can be described, but the formal criterion cannot be checked from the record.
The primary analysis is based on an ATP immunogenicity cohort rather than the safety group. The cohort description is truncated, and the record does not provide participant flow, exclusion reasons, the complete analysis population definition, or a full account of missing data. The difference between primary endpoint counts and safety counts is not explained. These omissions make it difficult to assess selection after randomization or the possible influence of missing observations.
The study was randomized but had no masking. Randomization procedures and allocation concealment are not described, and masking of laboratory personnel is not reported. Since some secondary outcomes involve solicited symptoms, open-label knowledge of assignment may be relevant to their reporting, although the record does not establish that any bias occurred.
The endpoint measures antibody concentrations, not clinical disease. The registry does not report a clinically meaningful anti-gE threshold or explain how concentrations relate to clinical protection. The primary assessment occurred at different study months for the two schedules, although it was one month after dose 2 in both groups.
The registry does not report the complete statistical analysis plan, original sample-size justification, interim analyses, multiplicity strategy, or full model specification. It also provides limited detail on safety-event timing, relatedness, and group attribution for listed serious-event terms. These trial-specific reporting gaps restrict independent assessment of the assumptions and conclusions, without demonstrating that the study was conducted improperly.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Study to Evaluate the Immunogenicity and Safety of GlaxoSmithKline (GSK) Biologicals' Herpes Zoster Vaccine GSK1437173A When Co-administered With GSK Biologicals' Seasonal Influenza Vaccine GSK2321138A in Adults Aged 50 Years and Older — NCT01954251.
- Registry record last updated 2018-05-02; status last verified 2018-03.
- Results first posted 2016-02-10.
- 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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19. Record Summary
The registry record describes a completed, randomized, open-label, parallel Phase 3 study sponsored by GlaxoSmithKline. Total enrollment was 829 adults aged 50 years and older. The study compared giving the first herpes zoster vaccine dose with seasonal influenza vaccine against giving the vaccines separately.
The primary outcome was adjusted anti-gE antibody geometric mean concentration one month after dose 2, assessed at Month 3 in the co-administration group and Month 5 in the control group. The reported adjusted geometric mean concentration ratio was 1.08, with a 95% confidence interval of 0.97 to 1.20. The registry labels the analysis non-inferiority or equivalence, but does not report the margin or decision rule.
Secondary outcomes included influenza antibody measures, solicited symptoms, and potential immune-mediated diseases. Safety totals are descriptive. The full analysis plan, multiplicity approach, missing-data methods, and complete primary cohort definition are not reported in the registry record.