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 Prevenar (PCV-7) Post-Licensure Safety Study In Russia (NCT01207583), a registered phase not stated study. The primary outcome is Percentage of Participants With Febrile Reactions Post-dose 1.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01207583 |
| Phase | Phase not stated |
| Condition | Healthy Children After Vaccination |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 100 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned healthy children after vaccination in the Russian Federation. The registry lists an enrollment of 100 and describes a primary cohort aged 3-6 Months and catch-up cohorts aged 7-11 Months and 12-23 Months. The primary endpoint population was the safety set after Dose 1: participants who received Dose 1 and had safety follow-up data after that dose.
Intervention
Prevenar (PCV-7) was administered as standard of care in an observational study. The registry says the study was intended to monitor reactions when PCV-7 was co-administered with other routine vaccines in the Russian National immunization schedule. The intervention is not a randomized assignment.
Comparator
No control treatment or randomized comparator is described. The record identifies dose and age cohorts, but these are not like-for-like control groups. Differences among cohorts or doses therefore cannot be read as randomized treatment contrasts.
Primary question
The primary question was the percentage of participants with febrile reactions after Dose 1, assessed from Day 1 to Day 3 post-dose 1. Fever was defined as body temperature at least 38 degrees Celsius, with the record specifying temperature bands. Numerical estimates and confidence intervals for this primary endpoint are not reported in the registry record.
In practical terms, the study sought to describe how often fever and other local or systemic reactions were observed during routine use of PCV-7 alongside childhood vaccines. This is a descriptive safety question. Without a randomized comparison, the study cannot isolate the contribution of PCV-7 from other vaccines, background illness, or other influences on temperature and symptoms. Its central output would be the frequency of reactions in the observed groups, rather than an estimate of a causal difference between treatments.
3. Trial Design
This was a completed, non-interventional observational safety study in Russia, sponsored by Pfizer. The registry lists a start date of 2009-12 and a primary completion date of 2011-08. Its stated purpose was to monitor local and systemic reactions and compatibility of PCV-7 with routine vaccines in the Russian National immunization schedule. Prevenar was administered as standard of care, rather than assigned as part of a randomized comparison.
The registry lists an enrollment of 100. That registry value should not be treated as the number with evaluable data for every outcome: the primary endpoint specifically uses a safety set made up of participants who received Dose 1 and had safety follow-up data after it. The safety summaries also use different dose and age-cohort groupings, with the corresponding numbers at risk listed for each outcome. The record does not explain the relationship between the listed enrollment and each outcome denominator.
The dose summaries distinguish the primary cohort aged 3-6 Months from catch-up cohorts aged 7-11 Months and 12-23 Months. They cover multiple doses, while the primary endpoint is fever after Dose 1. The additional outcomes concern pre-specified local reactions and systemic events after doses. These groupings allow descriptive reporting by dose and cohort, but they are not randomized arms and do not form a direct control comparison.
Allocation is not stated. The registry record does not report a protocol-based sample-size justification, a statistical analysis plan, or interim analyses. The posted results do not include numerical estimates for the primary fever outcome. The study status is COMPLETED, but completion alone does not establish that every planned outcome was reported or that all participants contributed data to every analysis.
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 | Primary Cohort (3-6 Months) | Catch-up Cohort (7-11 Months) | Catch-up Cohort (12-23 Months) |
|---|---|---|---|
| STARTED | 14 | 31 | 55 |
| Dose 1 | 14 | 31 | 55 |
| Dose 2 | 13 | 29 | 54 |
| Dose 3 | 13 | 27 | 0 |
| Dose 4 | 7 | 0 | 0 |
| COMPLETED | 13 | 26 | 54 |
| NOT COMPLETED | 1 | 5 | 1 |
Reasons for not completing this period:
| Reason | Primary Cohort (3-6 Months) | Catch-up Cohort (7-11 Months) | Catch-up Cohort (12-23 Months) |
|---|---|---|---|
| Withdrawal by Subject | 0 | 3 | 1 |
| Participant failed to return | 1 | 0 | 0 |
| Lost to Follow-up | 0 | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: Safety set (post-dose 1) population included all participants who received Dose 1 and who had safety follow-up data following Dose 1.
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 | Primary Cohort (3-6 Months) | Catch-up Cohort (7-11 Months) | Catch-up Cohort (12-23 Months) | Total |
|---|---|---|---|---|---|
| Participants analysed | 14 | 31 | 55 | 100 | |
| Age, Customized: 3 to 6 months | Participants | 14 | 0 | 0 | 14 |
| Age, Customized: 7 to 11 months | Participants | 0 | 31 | 0 | 31 |
| Age, Customized: 12 to 23 months | Participants | 0 | 0 | 55 | 55 |
| Sex: Female, Male: Female | Participants | 5 | 13 | 19 | 37 |
| Sex: Female, Male: Male | Participants | 9 | 18 | 36 | 63 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Febrile Reactions Post-dose 1, measured over Day 1 to Day 3 post-dose 1.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | Percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with febrile reactions post-dose 1, assessed from Day 1 to Day 3 post-dose 1. The defined population is the safety set after Dose 1: participants who received that dose and had safety follow-up data. Fever is described as a rise in body temperature to at least 38 degrees Celsius. The record specifies categories around 38, 39, and 40 degrees Celsius, although the wording of the category boundaries is not fully consistent between the brief summary and primary outcome description.
A percentage is a way to express how frequently an event occurred among the participants assessed. The confidence interval is intended to communicate uncertainty around that estimated frequency: a wider interval generally indicates less precision, while a narrower one indicates greater precision. The registry identifies a 95% Confidence Interval as the measure of dispersion for this endpoint, but numerical estimates and intervals are not reported in the registry record.
Fever is used as a measurable systemic reaction that can be classified by temperature and observation period. That makes the endpoint suitable for describing the frequency and degree of recorded febrile reactions after vaccination. It does not, by itself, establish that vaccination caused a fever, nor does it compare the observed frequency with a control group. The registry also lists local and systemic reaction outcomes after further doses as secondary outcomes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes the question the study set out to answer, but the posted results do not include a numerical estimate for its primary endpoint. In particular, no percentage of participants with fever after Dose 1, or accompanying 95% Confidence Interval, is reported in the registry record. The record therefore does not support a conclusion about the observed frequency or precision of the primary fever outcome.
There are descriptive safety counts by dose and cohort. For example, the serious-event summaries list participants at risk and participants affected for each group. Those counts need to be read within their named cohort and dose, using the corresponding number at risk as the denominator. They should not be combined across groups or interpreted as an estimate from a randomized comparison. The registry also reports selected serious-event terms as percentages, but the denominator and calculation details for those terms are not stated in the record.
The study is observational, and no randomized comparator is described. Co-administration with routine vaccines was part of the use being monitored. As a result, a reaction recorded after vaccination cannot be attributed to PCV-7 alone on the basis of this study description. The counts describe what was recorded in the study context; they do not distinguish a vaccine-related event from coincident illness or other causes.
The listed enrollment is 100, but it is not a universal denominator for all outcomes. The primary safety set requires receipt of Dose 1 and follow-up data, and later dose summaries have their own at-risk counts. Missing follow-up or different eligibility for each dose can affect which participants contribute to a given summary. The registry record does not explain missing outcome data or provide a detailed account of how incomplete observations were handled.
In general, a confidence interval helps readers judge how precisely an event frequency has been estimated; it does not remove limitations from selection, incomplete follow-up, or lack of a comparator. Because the primary endpoint estimates are absent, its precision cannot be evaluated from the registry record. The findings that are available should be interpreted as descriptive safety reporting, not as proof of causation or as evidence of a treatment effect.
9. Statistical Methods Explained
The registry describes a percentage endpoint with a 95% Confidence Interval. The interpretation below distinguishes what this record specifies from general statistical principles. Numerical primary-outcome estimates are not reported in the registry record, so the endpoint’s observed frequency and interval width cannot be assessed.
What does a percentage measure?
For a binary outcome, each assessed participant is classified according to whether the event occurred during the defined observation period. The event count is related to the number of participants assessed, and the resulting percentage describes the observed frequency in that group. The registry’s primary outcome is the percentage with a febrile reaction after Dose 1 during Day 1 to Day 3 post-dose 1.
The denominator matters. The registry defines the primary safety set as participants who received Dose 1 and had safety follow-up data after that dose. It does not say that every participant listed in the enrollment contributed to this endpoint. In the dose-specific safety summaries, the record gives an at-risk count for each group; those are the relevant denominators for interpreting the corresponding counts. It would be misleading to substitute the enrollment figure for an outcome-specific denominator without evidence that the populations match.
What does a confidence interval add?
In general, a confidence interval expresses uncertainty around an estimated frequency. It is not a range of individual participant outcomes, and it does not by itself indicate whether a result is clinically important. Its width depends in part on the amount of information in the data and on the observed event frequency. When event counts are small, estimates can be imprecise; the interval helps make that uncertainty visible. Here the registry names a 95% Confidence Interval but does not report its numerical limits for the primary endpoint.
A confidence interval also does not correct for bias, missing observations, or confounding. In an observational study, measured event frequency can reflect the participants followed, how events were recorded, and the context in which vaccination occurred. An interval around a descriptive estimate quantifies sampling uncertainty under its statistical assumptions; it cannot turn an observational estimate into a randomized treatment comparison.
Why does the design affect interpretation?
The study is identified as non-interventional and observational, with PCV-7 given as standard of care. Allocation is not stated, and the record does not describe a randomized comparator. The dose and age cohorts are useful descriptive groupings, but they are not equivalent to treatment and control arms. Participants in different cohorts may differ in age, dose history, follow-up, or other circumstances. Any differences in counts across those groups should therefore be treated as descriptive rather than as causal contrasts.
PCV-7 was monitored alongside routine vaccines. The design can describe events occurring in that routine-use context, but the record does not establish which component, if any, caused a given event. This limitation applies even when an event follows a dose within the specified period. Timing is part of outcome definition, not proof of attribution.
How should the planning illustrations be understood?
In general, sample-size planning calculations estimate how much information a future study might need under stated assumptions. The record describes planning illustrations based on a fraction of an observed effect, with two-sided significance level 0.05, equal allocation, and a normal approximation. For time-to-event outcomes, the stated convention concerns a total number of events; for other outcomes, it concerns participants per arm. These illustrations are not the original trial’s design justification and do not describe an observed study result.
Planning calculations are not observed power. They do not establish that this study had a particular probability of detecting an effect after its results were known. The registry does not report the trial’s own sample-size justification or a statistical analysis plan. Since the primary endpoint estimate is not reported in the record, the descriptive meaning of any calculation based on an observed effect must not be confused with evidence about the endpoint itself.
What analysis details remain unclear?
The registry lists 12 outcome measures and 0 analyses. It does not report analysis procedures for the primary endpoint beyond its outcome definition, time frame, population, and confidence-interval measure. The record also does not describe confidence-interval construction, covariate adjustment, handling of repeat events, or a plan for comparing dose groups. These details are not reported in the registry record and should not be inferred.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 12 outcome measures, including the primary fever endpoint and secondary outcomes for pre-specified local reactions and systemic events after doses. Multiple outcomes create a multiplicity issue: when many results are examined, the chance of finding an apparently unusual result by chance can increase. In general, a pre-specified analysis plan may define which outcomes are primary and how secondary findings are interpreted or adjusted. The registry record does not report a multiplicity adjustment or a broader statistical analysis plan, so it is not possible to determine whether or how multiple testing was addressed.
The record lists 0 analyses. This does not explain the analysis methods used for the posted safety summaries, and no inferential comparison plan is described. The primary endpoint specifies a 95% Confidence Interval, but numerical estimates and intervals are not reported in the registry record. No conclusions about statistical significance can be drawn from the endpoint description alone.
Missing data are also important because the primary safety set includes participants with safety follow-up after Dose 1. Later dose summaries have group-specific numbers at risk, but the registry record does not state why participants may not be represented at each dose, how missing observations were handled, or whether follow-up differed across participants. In general, estimates based only on observed follow-up can be affected if missingness is related to the likelihood of an event.
The registry identifies the primary endpoint population, but it does not describe additional analysis populations, sensitivity analyses, or imputation methods. These matters are not reported in the registry record. Accordingly, the available information supports reading the safety counts as descriptive records for the stated groups, while leaving uncertainty about the effects of missing data and multiple outcomes.
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 |
|---|---|---|---|
| Dose 1 (Primary Cohort [3-6 Months]) | 0 | 14 | 0.0% |
| Dose 2 (Primary Cohort [3-6 Months]) | 0 | 13 | 0.0% |
| Dose 3 (Primary Cohort [3-6 Months]) | 0 | 13 | 0.0% |
| Dose 4 (Primary Cohort [3-6 Months]) | 0 | 7 | 0.0% |
| Dose 1 (Catch-up Cohort [7-11 Months]) | 1 | 31 | 3.2% |
| Dose 2 (Catch-up Cohort [7-11 Months]) | 0 | 29 | 0.0% |
| Dose 3 (Catch-up Cohort [7-11 Months]) | 0 | 26 | 0.0% |
| Dose 1 (Catch-up Cohort [12-23 Months]) | 1 | 55 | 1.8% |
| Dose 2 (Catch-up Cohort [12-23 Months]) | 0 | 54 | 0.0% |
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 |
|---|---|
| Dose 1 (Primary Cohort [3-6 Months]) | 6 of 14 |
| Dose 2 (Primary Cohort [3-6 Months]) | 6 of 13 |
| Dose 3 (Primary Cohort [3-6 Months]) | 6 of 13 |
| Dose 4 (Primary Cohort [3-6 Months]) | 2 of 7 |
| Dose 1 (Catch-up Cohort [7-11 Months]) | 17 of 31 |
| Dose 2 (Catch-up Cohort [7-11 Months]) | 8 of 29 |
Most frequent serious adverse event terms
| Event term | Organ system | Dose 1 (Primary Cohort [3-6 Months]) | Dose 2 (Primary Cohort [3-6 Months]) | Dose 3 (Primary Cohort [3-6 Months]) | Dose 4 (Primary Cohort [3-6 Months]) | Dose 1 (Catch-up Cohort [7-11 Months]) | Dose 2 (Catch-up Cohort [7-11 Months]) |
|---|---|---|---|---|---|---|---|
| Upper respiratory tract infection | Infections and infestations | 0 of 14 | 0 of 13 | 0 of 13 | 0 of 7 | 1 of 31 | 0 of 29 |
| Acute sinusitis | Infections and infestations | 0 of 14 | 0 of 13 | 0 of 13 | 0 of 7 | 0 of 31 | 0 of 29 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Dose 1 (Primary Cohort [3-6 Months]) | Dose 2 (Primary Cohort [3-6 Months]) | Dose 3 (Primary Cohort [3-6 Months]) | Dose 4 (Primary Cohort [3-6 Months]) | Dose 1 (Catch-up Cohort [7-11 Months]) | Dose 2 (Catch-up Cohort [7-11 Months]) |
|---|---|---|---|---|---|---|---|
| Restless sleep | General disorders | 1 of 14 | 3 of 13 | 6 of 13 | 2 of 7 | 10 of 31 | 7 of 29 |
| Unusual crying | General disorders | 2 of 14 | 3 of 13 | 2 of 13 | 1 of 7 | 8 of 31 | 6 of 29 |
| Redness | Skin and subcutaneous tissue disorders | 1 of 14 | 3 of 13 | 2 of 13 | 1 of 7 | 6 of 31 | 4 of 29 |
| Fever | General disorders | 2 of 14 | 3 of 13 | 2 of 13 | 0 of 7 | 6 of 31 | 3 of 29 |
| Unusual irritability | General disorders | 3 of 14 | 3 of 13 | 1 of 13 | 1 of 7 | 6 of 31 | 2 of 29 |
| Tenderness | Skin and subcutaneous tissue disorders | 1 of 14 | 0 of 13 | 1 of 13 | 0 of 7 | 9 of 31 | 2 of 29 |
| Decreased appetite | General disorders | 1 of 14 | 2 of 13 | 1 of 13 | 0 of 7 | 6 of 31 | 3 of 29 |
| Unusual fussiness | General disorders | 1 of 14 | 2 of 13 | 2 of 13 | 0 of 7 | 2 of 31 | 2 of 29 |
| Diarrhea | General disorders | 1 of 14 | 2 of 13 | 2 of 13 | 0 of 7 | 1 of 31 | 1 of 29 |
| Vomiting | General disorders | 0 of 14 | 1 of 13 | 2 of 13 | 0 of 7 | 2 of 31 | 0 of 29 |
Serious events with the highest arm-level rate: upper respiratory tract infection (3.2%), acute sinusitis (1.8%).
The safety summaries distinguish serious events from other reported events and give participants at risk and participants affected within each dose and age cohort. For serious events, the listed affected counts are 0 for most dose groups, with 1 listed for Dose 1 in each catch-up cohort. These are group-specific counts; they should be read with their corresponding at-risk counts, not added together or treated as a comparison between randomized arms.
The registry also lists upper respiratory tract infection at 3.2% and acute sinusitis at 1.8% among the top serious terms. The denominator and calculation details for these percentages are not reported in the registry record. They therefore cannot be directly reconciled with individual group counts using the information available.
For the other-event category, the record reports affected counts separately by dose and cohort. The meaning of this category should not be expanded beyond the registry’s classification. The record does not report a value for deaths; a missing value is not the same as a reported count of zero. Nor does an event recorded after vaccination establish that the vaccination caused it. These summaries describe reported safety events in the observed study context, without a control group for causal comparison.
12. What the Result Does, and Does Not, Mean
The study’s stated purpose was to describe fever and other reactions following PCV-7 use alongside routine childhood vaccines in Russia. The registry identifies the primary fever endpoint, the observation period, and the safety population. It also provides adverse-event counts for dose and age-cohort groups. However, numerical results for the primary endpoint are not reported in the registry record. The frequency of fever after Dose 1 and the precision of that frequency therefore cannot be assessed from this record.
The reported safety counts can describe what was recorded in the groups listed. They do not establish that PCV-7 caused an event, because the study was observational, vaccination occurred with routine vaccines, and no randomized comparator is described. Dose or cohort differences also do not establish a treatment effect: the groups are not stated to be like-for-like comparisons.
In general, an observed frequency is not the same as a causal effect. A causal interpretation requires a design and analysis capable of separating the treatment’s contribution from other possible explanations. The registry record does not report such a comparison. Likewise, the listed enrollment does not guarantee complete follow-up or an outcome record for every participant; the defined safety population and group-specific at-risk counts determine who contributes to each summary.
The record is informative about the planned safety question and the way some event counts were organized, but it leaves the primary endpoint’s numerical result unavailable. Its findings should therefore be read as descriptive registry information, with limitations in precision, attribution, and completeness. They do not establish whether a particular reaction was caused by vaccination or provide a randomized estimate comparing treatments.
13. Why This Trial Matters Statistically
Observational safety studies address what is recorded during routine use, where vaccination may occur alongside other standard vaccines and care. That context can be relevant to describing the kinds of reactions monitored in practice. This study’s focus on fever thresholds, local reactions, systemic events, and dose-specific follow-up makes the outcome definitions important to interpretation.
The record also illustrates why population and denominator definitions matter. The primary endpoint is based on a safety set with follow-up after Dose 1, while safety summaries are organized by dose and age cohort. Those groups do not automatically share a common denominator, and the listed enrollment is not necessarily the denominator for each outcome. Reading counts in their specified groups avoids mistaking changes in group size for changes in risk.
Statistically, the central limitation is that the record describes the primary question without reporting its numerical estimate or confidence interval. An endpoint definition alone cannot tell a reader how frequently fever was observed or how precisely it was estimated. The additional event counts offer descriptive context, but the absence of randomization and a comparator limits causal interpretation.
The study is therefore useful as an example of the distinction between monitoring and comparative evaluation. Safety surveillance can record events and their timing, while causal attribution requires stronger comparative evidence and sufficiently detailed analysis. The registry also shows why clear reporting of missing data, analysis populations, and multiplicity matters when several outcomes are assessed. Those methods are not reported in the registry record, so the available results should be interpreted within their descriptive scope.
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.
Several limitations are specific to the information in this registry record. Although the study is marked COMPLETED and lists an enrollment of 100, the numerical result for the primary fever endpoint is not reported. The record supplies the endpoint definition and identifies a 95% Confidence Interval, but not the percentage or interval limits. Readers cannot evaluate the primary estimate or its precision.
The design is observational and non-interventional. Prevenar was administered as standard of care and co-administered with routine childhood vaccines; allocation is not stated, and no randomized control group is described. The record itself cautions that the dose and cohort groups are not a like-for-like control comparison. Consequently, between-group contrasts would be vulnerable to differences beyond the vaccine exposure.
The primary endpoint definition gives fever thresholds, but the temperature-band boundary wording differs between the brief summary and the primary outcome description. The record does not clarify that discrepancy. It also does not report detailed statistical methods, missing-data handling, multiplicity procedures, interim analyses, or the trial’s own sample-size justification. Details such as the denominators for the listed top serious-event percentages are not stated.
The registry describes the primary safety population and gives at-risk counts for the adverse-event groups, but does not explain why the numbers represented vary by dose or how incomplete follow-up was handled. The reported counts should therefore be interpreted for their stated groups only. A missing deaths value cannot be interpreted as zero, and event timing alone cannot establish causation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Prevenar (PCV-7) Post-Licensure Safety Study In Russia — NCT01207583.
- Registry record last updated 2012-08-31; status last verified 2012-07.
- Results first posted 2012-08-31.
- 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
This is a completed, non-interventional observational study of PCV-7 safety in Russia, sponsored by Pfizer. The registry lists a start date of 2009-12, a primary completion date of 2011-08, and enrollment of 100. It describes routine-use monitoring with other childhood vaccines, including a primary endpoint of febrile reactions from Day 1 to Day 3 post-dose 1.
The primary endpoint is defined for participants who received Dose 1 and had safety follow-up data. The registry identifies fever as a temperature of at least 38 degrees Celsius and specifies a 95% Confidence Interval, but numerical primary results are not reported in the registry record. Adverse-event counts are listed by dose and age cohort, with selected serious-event terms also reported as percentages.
No randomized comparator is described. The available information supports descriptive reading of the reported safety groups, not causal attribution or a treatment comparison. Analysis details, handling of missing observations, and several other statistical procedures are not reported in the registry record.