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 A Safety And Immunogenicity Study Of A 13-valent Pneumococcal Conjugate Vaccine In Japanese Subjects Aged 6 To 64 Years. (NCT03571607), a na phase 3 study. The primary outcome is Percentage of Participants Reporting Pre-Specified Local Reactions Within 7 Days After Vaccination in Participants Aged Between 6 to <18 Years.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03571607 |
| Phase | Phase 3 |
| Condition | Pneumococcal Infections |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 206 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Japanese participants aged 6 to 64 years who were considered to be at increased risk of pneumococcal disease and were naive to pneumococcal vaccines. The primary endpoint concerned the subgroup aged 6 to <18 years.
Intervention
A single dose of 13-valent pneumococcal conjugate vaccine, abbreviated in the registry record as 13vPnC.
Comparator
There was no comparison group. This was a single-arm study, so the registry record does not provide a randomized or concurrent control group for comparison.
Primary question
Among participants aged 6 to <18 years, what percentage reported a prespecified local reaction during Day 1 up to Day 7 after vaccination?
The trial also set out to assess safety, tolerability and immune responses after vaccination. The registry lists secondary immune-response outcomes based on serotype-specific opsonophagocytic activity (OPA) and immunoglobulin G (IgG), including geometric mean titers or concentrations and geometric mean fold rises. Numerical results for those outcomes are not reported in the registry record.
The primary question is descriptive: it concerns the frequency of recorded local reactions in a defined age subgroup during the stated observation window. Without a comparator group, the study does not estimate a difference in local-reaction frequency between vaccinated and unvaccinated participants, or between different vaccines. The clinical question therefore focuses on observations after one vaccine dose in the enrolled population.
3. Trial Design
This was a phase 3, multicenter, single-arm, open-label study of a single dose of 13-valent pneumococcal conjugate vaccine in Japanese participants aged 6 to 64 years. Participants were described as being at increased risk of pneumococcal disease and naive to pneumococcal vaccines. The registry lists an enrollment of 206 and the study status as completed.
There was no randomized allocation and no masking. The study had one intervention group rather than a vaccine group and a control group. Accordingly, its design can describe events and immune measurements recorded after vaccination, but it does not provide a like-for-like treatment comparison. The record does not report a comparator or a separate control arm.
The recorded study dates are a start date of 2018-07-12 and a primary completion date of 2018-11-16. The primary endpoint concerned local reactions among participants aged 6 to <18 years, measured from Day 1 up to Day 7 after vaccination. The overall study population extended to age 64, and the registry also reports safety groupings for participants aged 18 to <65 years and for all participants.
The study was sponsored by Pfizer. The registry record does not report the sample-size justification, detailed recruitment procedures, or a statistical analysis plan. It also does not report whether any interim analyses were planned or conducted. Those design details should not be inferred from the phase designation, enrollment, or the presence of an endpoint description.
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.
Overall Study
| Stage | 13vPnC: 6 to <18 Years | 13vPnC: 18 to <65 Years |
|---|---|---|
| STARTED | 53 | 153 |
| Vaccinated | 53 | 153 |
| COMPLETED | 53 | 153 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Safety analysis set included all participants who received 1 dose of study vaccine. Here, "Number analyzed" signifies participants evaluable for each specified category.
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: Safety analysis set included all participants who received 1 dose of study vaccine.
| Characteristic | Unit | 13vPnC: 6 to <18 Years | 13vPnC: 18 to <65 Years | Total |
|---|---|---|---|---|
| Participants analysed | 53 | 153 | 206 | |
| Age, Continuous | years | 12.7 (SD 2.66) | 49.0 (SD 10.12) | 39.6 (SD 18.18) |
| Sex: Female, Male: Female | Participants | 22 | 77 | 99 |
| Sex: Female, Male: Male | Participants | 31 | 76 | 107 |
| Race/Ethnicity, Customized: Asian | participants | 53 | 153 | 206 |
| Race/Ethnicity, Customized: Non-Hispanic/non-Latino/not of Spanish origin | participants | 53 | 153 | 206 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants Reporting Pre-Specified Local Reactions Within 7 Days After Vaccination in Participants Aged Between 6 to <18 Years, measured over Day 1 up to Day 7.
| 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 aged 6 to <18 years reporting prespecified local reactions within seven days after vaccination. Local reactions were recorded using an electronic daily diary and included redness, swelling and pain at the injection site. The registry defines the timeframe as Day 1 up to Day 7.
Redness and swelling were graded using size thresholds that differed by age. For participants aged 6 to <12 years, mild reactions were 0.5 to 2.0 centimeter, moderate reactions were greater than 2.0 to 7.0 centimeter, and severe reactions were greater than 7.0 centimeter. For participants aged 12 to <18 years, the corresponding descriptions were mild at 2.5 to 5.0 centimeter, moderate at greater than 5.0 to 10.0 centimeter, and severe at greater than 10.0 centimeter. Pain was graded by its effect on activity: mild did not interfere with activity, moderate interfered with activity, and severe prevented daily activity.
A percentage describes how common the specified event was in the evaluated group. The registry indicates that a 95% confidence interval was intended to accompany the endpoint. In general, a confidence interval conveys uncertainty around an estimate; it does not replace the estimate itself. The numerical percentage and confidence interval for this primary endpoint are not reported in the registry record, so its observed frequency and precision cannot be described.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary outcome as the percentage of participants aged 6 to <18 years who reported a prespecified local reaction during Day 1 up to Day 7 after vaccination. However, it does not report the endpoint's observed percentage, the number analyzed for that endpoint, or its 95% confidence interval. As a result, the primary endpoint cannot be quantified from the registry record. No claim about the observed frequency or precision of local reactions can be made from the endpoint description alone.
The record does contain safety figures for serious and other adverse events in three age groupings. For serious adverse events, the number affected is 0 among 53 participants aged 6 to <18 years, 0 among 153 participants aged 18 to <65 years, and 0 among 206 participants overall. Deaths are recorded as 0 in each of those groupings. These counts describe what the registry reports; they do not establish that the risk of a serious event is absent. The registry record does not provide a confidence interval or further detail that would quantify uncertainty around these serious-event observations.
For other adverse events, the registry reports 49 affected among 53 participants aged 6 to <18 years, 121 among 153 participants aged 18 to <65 years, and 170 among 206 participants overall. The record does not provide further event-level descriptions in the registry record for these groups, so these counts do not identify which specific events occurred, their severity, or their timing. They should not be mistaken for the primary local-reaction endpoint, which has its own specified definition and observation window.
The study enrolled participants who received the vaccine, but it had no control group. Therefore, these observations cannot show how the recorded event counts compare with what would have occurred without vaccination or under another intervention. The design is also not a randomized comparison between the age groups. Differences in group counts cannot be interpreted as comparative effects, and the overall grouping includes the age subgroups rather than functioning as an independent control.
Immune-response outcomes are listed, including OPA titers, IgG concentrations and fold rises, but their numerical results are not reported in the registry record. The record lists nine outcome measures and zero analyses. The posted information therefore supports a description of the design, outcome definitions and reported adverse-event counts, but not a numerical assessment of the primary endpoint or the immune-response results.
9. Statistical Methods Explained
The trial's design determines what statistical conclusions can be drawn. This was a single-arm study: participants received one dose of vaccine, and the registry record does not describe a concurrent control group. A single-arm design can describe outcomes observed after an intervention. It cannot, by itself, separate an intervention-related effect from changes that might have occurred for other reasons, or provide a randomized comparison with another intervention. The study was also open-label, meaning masking was not used according to the registry record. The record does not report further details about how open-label status was handled in endpoint assessment.
What a percentage estimates
The primary endpoint is a percentage of participants with one or more prespecified local reactions during the stated observation window. In general, a percentage summarizes the proportion of evaluated participants who met an event definition. Its interpretation depends on the population included in the denominator, how the event was defined, how consistently it was recorded, and which participants had evaluable data. Here, the registry says local reactions were recorded in an electronic daily diary and defines the age-specific grading criteria for redness, swelling and pain.
The registry describes a safety analysis set as including all participants who received one dose of study vaccine. It also says that the number analyzed signifies the participants evaluable for each specified category. Thus, the number in the overall safety group need not automatically be the denominator for every individual endpoint category. The endpoint-specific analyzed counts and primary percentage are not reported in the registry record.
How to interpret a confidence interval
The primary endpoint lists a 95% confidence interval as its dispersion measure. In general, a confidence interval expresses the statistical uncertainty associated with an estimate, taking account of the observed data and the method used to calculate the interval. A narrower interval generally indicates greater precision under that method, while a wider interval indicates less precision. An interval is not a guarantee about the true value, and it does not correct limitations such as the absence of a control group or incomplete outcome reporting.
The registry record does not report the interval itself or the statistical method used to calculate it. Without the endpoint estimate and interval, it is not possible to discuss the observed rate or how precisely it was estimated. The existence of a planned confidence-interval field is not evidence that a numerical result is available in the registry record.
Why the one-arm structure matters
In a randomized controlled study, random allocation can support comparisons between intervention groups by reducing systematic differences between them, subject to the design and conduct of the trial. This study had no randomized allocation and no comparator. Therefore, its event counts are descriptive rather than estimates of a relative effect. A comparison among age groupings would also be observational within this study, not a randomized treatment contrast: age groups may differ in characteristics other than age, and the record does not report an analysis adjusting for such differences.
The registry includes three adverse-event groupings: participants aged 6 to <18 years, participants aged 18 to <65 years, and all participants. The overall grouping contains the participants represented in the age-specific groupings; it should not be treated as an additional independent cohort. The record provides participant counts affected and at risk, but it does not give event-level detail for the other adverse events.
Immune-response measures
The listed secondary outcomes use OPA and IgG measurements. Geometric mean titers and geometric mean concentrations summarize measurements on a multiplicative scale, which is useful when values vary over a wide range and are naturally interpreted through ratios. A geometric mean fold rise describes change relative to a baseline measurement. These are general interpretations of the named statistical measures; the registry record does not provide the numerical immune-response results, the calculation details, or a reported analysis of those outcomes.
The record lists nine outcome measures and zero analyses. It does not report the analysis methods used for each outcome, how missing observations were handled, or whether adjustments for multiple outcomes were made. Those details cannot be reconstructed from the outcome names alone. The sample-size justification and any interim-analysis plan are also not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists nine outcome measures, including a primary local-reaction endpoint and secondary measures of serotype-specific OPA and IgG responses. It lists zero analyses. This means the registry record does not provide analysis-level results that would allow the reported estimates, tests or model specifications for those outcomes to be reviewed. The record does not report a multiplicity adjustment or explain how the family of outcomes was considered when interpreting statistical evidence. It would not be appropriate to assume that an adjustment was or was not performed beyond what the registry record states.
Missing-data methods are not reported in the registry record. The record describes the safety analysis set as all participants who received one dose of study vaccine and explains that the number analyzed is the number evaluable for each specified category. It does not describe the amount or pattern of missing diary entries, how incomplete diaries were treated, or whether participants with incomplete measurements were included in each endpoint analysis. The primary endpoint's numerical result and analyzed count are not reported, so its denominator and the influence of any unevaluable data cannot be assessed.
The population for the primary endpoint is participants aged 6 to <18 years, whereas the safety summaries also include participants aged 18 to <65 years and all participants. These are different populations for different purposes, and the broader safety group should not be substituted for the primary endpoint population. The registry record does not report additional analysis-population definitions for the immune-response outcomes. It also does not report a statistical analysis plan, so further details about endpoint hierarchy, handling of missing observations, or multiplicity are unavailable.
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 |
|---|---|---|---|
| 13vPnC: 6 to <18 Years | 0 | 53 | 0.0% |
| 13vPnC: 18 to <65 Years | 0 | 153 | 0.0% |
| 13vPnC: All Participants | 0 | 206 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| 13vPnC: 6 to <18 Years | 0 of 53 |
| 13vPnC: 18 to <65 Years | 0 of 153 |
| 13vPnC: All Participants | 0 of 206 |
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 |
|---|---|
| 13vPnC: 6 to <18 Years | 49 of 53 |
| 13vPnC: 18 to <65 Years | 121 of 153 |
| 13vPnC: All Participants | 170 of 206 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 13vPnC: 6 to <18 Years | 13vPnC: 18 to <65 Years | 13vPnC: All Participants |
|---|---|---|---|---|
| Pain at the injection site | General disorders | 41 of 52 | 96 of 145 | 137 of 197 |
| Fatigue | General disorders | 18 of 48 | 47 of 142 | 65 of 190 |
| Myalgia | Musculoskeletal and connective tissue disorders | 15 of 49 | 38 of 139 | 53 of 188 |
| Headache | Nervous system disorders | 12 of 49 | 33 of 141 | 45 of 190 |
| Injection site swelling | General disorders | 16 of 47 | 17 of 136 | 33 of 183 |
| Diarrhoea | Gastrointestinal disorders | 4 of 48 | 26 of 141 | 30 of 189 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 3 of 48 | 19 of 138 | 22 of 186 |
| Redness | General disorders | 10 of 47 | 10 of 135 | 20 of 182 |
| Pyrexia | General disorders | 7 of 48 | 8 of 134 | 15 of 182 |
| Nasopharyngitis | Infections and infestations | 1 of 53 | 8 of 153 | 9 of 206 |
The serious adverse-event figures are participant counts: 0 affected among 53 participants aged 6 to <18 years, 0 among 153 aged 18 to <65 years, and 0 among 206 overall. The death count is 0 in each grouping. The registry record lists no serious-event terms. These figures indicate that no participants are recorded as affected by a serious adverse event in the reported group summaries; they do not establish that the underlying risk is zero.
For other adverse events, the record reports 49 affected among 53 participants aged 6 to <18 years, 121 among 153 aged 18 to <65 years, and 170 among 206 overall. These are separate from the serious-event counts. The registry record does not identify the specific other adverse events, their severity, or their timing in the registry record, so the counts alone cannot describe the clinical nature of those events. They also should not be interpreted as the primary local-reaction result, which is defined separately for the younger age subgroup and the Day 1 up to Day 7 timeframe.
Because there is no control group, the safety summaries describe events recorded in the vaccinated study population without providing a comparative rate. The record does not report confidence intervals for these counts.
12. What the Result Does, and Does Not, Mean
The study addresses safety, tolerability and immunogenicity after one dose of 13-valent pneumococcal conjugate vaccine in Japanese participants aged 6 to 64 years who were considered at increased risk of pneumococcal disease and naive to pneumococcal vaccines. Its primary endpoint is specifically about local reactions reported by participants aged 6 to <18 years during Day 1 up to Day 7. That definition provides a focused question about recorded reactions in a defined population and observation period.
The registry record reports zero participants affected by serious adverse events in each of its three safety groupings, and zero deaths. It also reports counts for other adverse events. Those are descriptions of the recorded participants and do not establish a comparison with another treatment, an untreated group, or the background frequency of events. The single-arm, open-label design does not support a randomized estimate of a comparative effect.
The primary endpoint percentage and 95% confidence interval are not reported in the registry record. Numerical results for the listed OPA and IgG outcomes are also not reported. Consequently, the record does not permit a numerical assessment of the primary local-reaction frequency or of the immune-response measurements. The endpoint definitions and stated aims should not be mistaken for results.
These findings also concern a specific population: Japanese participants with the stated increased-risk and vaccine-naive characteristics. The record does not establish how observations would apply to people outside those eligibility characteristics. The results available in the registry are best read as a description of the study design and the reported safety counts, with important outcome-level uncertainty because the principal numerical results are not reported.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how design determines the scope of an answer. The registry describes a phase 3 study with 206 participants, a single intervention group and an open-label design. Such a study can collect structured safety and immune-response observations after vaccination. It cannot provide the same kind of comparative estimate as a randomized study with a control group, because no concurrent comparator is reported.
The primary endpoint is clearly defined in several important respects: it identifies the age subgroup, the local reactions of interest, the recording method, the grading criteria and the observation window. Those details matter because an event rate depends on what qualifies as an event and which participants are counted. The age-specific grading definitions also make clear that the criteria used for redness and swelling differed between younger and older participants within the primary subgroup.
At the same time, the registry record does not report the numerical primary endpoint result or its confidence interval. This distinction between a well-described outcome and an available estimate is important when interpreting trial records. An endpoint description explains what was intended to be measured; it does not reveal the observed result or its precision. The same issue applies to the listed OPA and IgG outcomes, for which the record gives outcome names but no numerical results.
The adverse-event summaries show how counts can be reported by age grouping, while also illustrating the limits of descriptive data. The serious-event and death counts are recorded as zero, but the absence of a control group and of uncertainty intervals means the summaries cannot quantify comparative risk. For statistical readers, the central lesson is to distinguish endpoint definitions, observed counts and comparative evidence, and to avoid treating one as a substitute for another.
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 most direct limitation is that the registry record does not report the numerical result for the primary endpoint. It provides neither the percentage of participants aged 6 to <18 years with a prespecified local reaction nor the 95% confidence interval. The endpoint-specific number analyzed is also not reported. Therefore, neither the event frequency nor its precision can be assessed from the registry record.
The study was single-arm and had no comparator. The reported safety observations cannot be used to estimate a difference against another vaccine, no vaccination, or usual care. The open-label design also means masking was not used, and the registry record does not describe additional procedures to limit possible reporting or assessment effects. The primary endpoint relied on an electronic daily diary, but the record does not report diary completion or missing-data handling.
The primary endpoint covers local reactions during Day 1 up to Day 7 and focuses on participants aged 6 to <18 years. It does not, by itself, describe outcomes outside that defined window or answer the same endpoint question for the older age group. The study population was Japanese, considered at increased risk of pneumococcal disease, and naive to pneumococcal vaccines; the record does not establish how well the observations apply to populations with different characteristics.
Numerical results for the listed immune-response outcomes are not reported in the registry record. Other adverse-event counts are reported without event-level descriptions in the registry entries. The analysis plan, sample-size justification, multiplicity methods, missing-data methods and interim-analysis plans are not reported in the registry record. These omissions limit assessment of the results beyond the reported design and safety counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Safety And Immunogenicity Study Of A 13-valent Pneumococcal Conjugate Vaccine In Japanese Subjects Aged 6 To 64 Years. — NCT03571607.
- Registry record last updated 2020-02-18; status last verified 2020-02.
- Results first posted 2019-12-10.
- 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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18. Record Summary
The registry record describes NCT03571607, a completed phase 3, multicenter, single-arm, open-label study sponsored by Pfizer. It enrolled 206 Japanese participants aged 6 to 64 years who were considered at increased risk of pneumococcal disease and naive to pneumococcal vaccines. Participants received a single dose of 13-valent pneumococcal conjugate vaccine. The recorded start date is 2018-07-12, and the primary completion date is 2018-11-16.
The primary endpoint concerned the percentage of participants aged 6 to <18 years reporting prespecified local reactions from Day 1 up to Day 7. Its numerical result and 95% confidence interval are not reported in the registry record. The safety summaries record 0 serious adverse events and 0 deaths in each reported age grouping. Other adverse-event counts are also listed. Numerical results for the secondary OPA and IgG outcomes, and further statistical-analysis details, are not reported in the registry record.