Vaccination Education Through Pharmacists and Senior Centers (VEPSC): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Vaccination Education Through Pharmacists and Senior Centers (VEPSC) (NCT03239665), a randomized na study. The primary outcome is Mean Change in Knowledge and Awareness About Vaccine-Preventable Diseases.

2. Clinical Question

This is a comparison of two education approaches, rather than a comparison of education with no education. Both approaches addressed vaccination knowledge and beliefs, with primary emphasis on pneumococcal disease and zoster and limited content on influenza. The registry description says the interventions were developed to address barriers to vaccination. It does not report whether participants received vaccinations as a result of the sessions, nor does it report a result establishing that one education approach produced a larger change in knowledge than the other.

3. Trial Design

The registry record describes a randomized, parallel-group trial with no masking. The two behavioral interventions were pharmacist-led education, PHARM, and peer-led education, PEER. The study was sponsored by Rutgers, The State University of New Jersey, and is listed as completed. Enrollment was 335. The recorded study start was 2017-10-10, and primary completion was 2018-09-28.

PHARM consisted of a formal presentation by a pharmacist about vaccine-preventable diseases and vaccination. The brief description specifies a 60-minute session with a didactic lecture and discussion, video clips of community members discussing vaccination experiences, and physicians emphasizing the importance of vaccination. PEER consisted of a 60-minute small-group session led by a peer educator, with scripted roleplaying exercises. The registry description says peer educators were trained by a pharmacist, but does not provide complete details of the training or the final session script.

The study focused on education about zoster, pneumonia, and influenza. Both interventions emphasized pneumococcal disease and zoster, with limited influenza content because participants might have questions about how influenza and its vaccine differ from pneumococcal disease and zoster. The intended setting and population were described as an older, predominantly African-American population consistent with the investigators’ prior community-based work; the actual enrolled population’s characteristics are not reported in the registry record.

Random allocation can support a comparison between groups by reducing systematic differences at assignment, although it does not guarantee that groups are alike in every respect. With no masking, participants and intervention providers knew which educational approach was being delivered. The record does not report allocation concealment, the number assigned to each group, participant flow, or details of adherence to the assigned sessions. The trial phase is listed as not applicable. A protocol-based statistical analysis plan and the rationale for the enrollment target 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.

Overall Study

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.

6. Primary Endpoint

The registry lists the primary outcome as Mean Change in Knowledge and Awareness About Vaccine-Preventable Diseases, measured over Measured at baseline (BL), immediately post-intervention (PT), and 1 month follow-up (1M).

The primary outcome was mean change in knowledge and awareness about vaccine-preventable diseases, measured with the VEPSC Knowledge Instrument. The registry describes it as a 3-section, 22-item instrument with categorical responses. Its scores count correct responses, so higher scores represent better performance.

The instrument yields disease-specific scores for pneumonia, influenza, and zoster, as well as a total score equal to the sum of those subscores. The possible ranges are 0-7 for pneumonia, 0-7 for influenza, 0-8 for zoster, and 0-22 for the total. Scores were measured at baseline (BL), immediately post-intervention (PT), and 1 month follow-up (1M). Pairwise score differences were calculated between all three timepoints for each score type. The registry states that positive differences indicate increased knowledge and negative differences indicate decreased knowledge.

Knowledge is a relevant measure for an education intervention because it captures learning about the conditions and vaccinations addressed in the sessions. It is not, by itself, a measure of vaccination receipt or a clinical health outcome. The record lists additional outcomes concerning beliefs, vaccination plans and status, satisfaction, cost, and discussion of vaccines, but does not report their results. Primary outcome values and the comparisons between the education groups are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record defines the outcome and its measurement occasions, but does not report the statistical analysis methods used for the trial’s primary comparison. The concepts below explain how the described summaries and comparisons are generally interpreted; they do not identify methods as having been used in this trial unless the registry record says so.

What does a mean change represent?

A mean change is an average of participants’ score differences between two measurement occasions. In this study, the instrument’s score is a count of correct answers, and the stated direction is that positive differences indicate increased knowledge while negative differences indicate decreased knowledge. A mean change describes the average direction and size of change in the measured group. It does not show whether every participant changed in the same way, and it can conceal variation in individual responses.

The registry defines pairwise differences between baseline, immediately post-intervention, and 1 month follow-up. These comparisons can address different questions: change between baseline and the immediate assessment, change between baseline and follow-up, and change between the two assessments after baseline. Each difference is tied to a particular time interval. The record does not state which of these comparisons was designated as the primary inferential contrast, or how comparisons between the randomized groups were estimated.

What does the standard deviation describe?

The record identifies the standard deviation as the measure of dispersion for the continuous outcome. In general, a standard deviation describes how variable participant scores are around a mean. A relatively larger spread means that individual observations are more dispersed; it does not, on its own, indicate that a group mean is more or less precisely estimated. Precision of an estimated mean or difference is usually conveyed by a standard error or confidence interval, neither of which is reported for the primary outcome in this record.

Why distinguish within-group change from a group comparison?

A within-group change describes what happened over time among participants in one intervention group. A between-group comparison asks whether the changes differ between PHARM and PEER. These are distinct estimands. For example, evidence that one group’s average score changed from its own baseline would not by itself show that its change was larger than the other group’s. A direct comparison needs an estimate that represents the difference between groups, together with uncertainty appropriate to that estimate. The registry record does not report such estimates.

Because the same participants were measured repeatedly, scores from one person across time are generally related rather than independent. General methods for repeated measurements account for this dependence in some way; treating all observations as unrelated can give misleading uncertainty. The registry record does not state whether the investigators used a repeated-measures model, analyzed change scores, used another approach, or how they handled correlations among measurements. No particular model should therefore be attributed to this trial.

How should uncertainty and statistical tests be read?

In general, a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. Its width reflects precision: wider intervals indicate greater uncertainty. A p-value describes the compatibility of the observed data with a specified null hypothesis under a statistical model; it is not the probability that the null hypothesis is true, and it does not measure the size or practical importance of an effect. No confidence intervals or p-values for the primary outcome are reported in the registry record, and no test procedure is specified.

Knowledge scores are bounded by the instrument’s possible ranges: 0-7 for pneumonia, 0-7 for influenza, 0-8 for zoster, and 0-22 for the total. A score cannot extend beyond its defined range. The distribution and shape of the observed scores are not reported, so it is not possible to assess whether a particular statistical model’s assumptions fit the outcome. The registry’s use of a mean and standard deviation defines the intended summary, but does not establish the analysis model or its adequacy.

What do the planning assumptions mean?

The record describes sample-size planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are planning illustrations, not evidence about the trial’s original design, and they do not constitute observed power. The registry does not report a protocol-based sample-size justification or the trial’s original assumptions. The actual illustration values and an observed effect estimate are not reported in the registry record, so they cannot be used to quantify the study’s ability to detect a difference.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several outcomes, timepoints, score types, or analyses are examined. The registry lists 8 outcome measures and 85 analyses. The primary knowledge outcome alone includes pneumonia, influenza, zoster, and total scores, with pairwise comparisons among baseline, immediately post-intervention, and 1 month follow-up. Considering many comparisons can increase the chance that at least one result appears notable by chance. Statistical approaches can address this issue, but the registry record does not report whether any multiplicity adjustment was used, which comparisons were prioritized, or whether a hierarchy of outcomes was prespecified.

The record does not report the primary outcome estimates, the number of participants contributing data at each timepoint, or the pattern of missing measurements. It also does not describe how missing data were handled, whether participants were analyzed according to randomized assignment, or whether another analysis population was used. These details are important because participants without follow-up measurements may differ from those with observed outcomes. No assumption about the amount or effect of missing data can be made from the enrollment total alone.

Randomization is reported, but the allocation concealment method and the analysis plan are not. The record does not report interim analyses, stopping rules, or prespecified handling of deviations from the assigned intervention. These aspects of the protocol and analysis are therefore not reported in the registry record. Without the analysis population, missing-data approach, and multiplicity procedures, the statistical context for interpreting any outcome result would remain incomplete; in this case, the outcome results themselves are also not reported.

11. What the Result Does, and Does Not, Mean

This trial record describes a randomized comparison of two ways to deliver vaccination education in senior centers: a pharmacist-led presentation and a peer-led small-group session. It defines a knowledge instrument and assessments at baseline, immediately after the intervention, and 1 month follow-up. Those details clarify what the investigators intended to measure and the broad contrast being studied.

The record does not report primary outcome results. It therefore cannot show whether scores changed, whether changes differed between the education groups, or how precise any estimated difference was. It also cannot establish whether education affected vaccination receipt: vaccination status and plans are among the listed secondary outcomes, but their results are not reported. Knowledge scores, even if available, would describe performance on this instrument and would not on their own demonstrate a change in vaccination behavior or clinical outcomes.

The enrollment count of 335 is the total listed for the study, not a reported count of participants with complete outcome data or participants analyzed in either group. Without group-specific participant counts, follow-up information, and estimates with uncertainty, the evidence available in the registry record is insufficient to assess the statistical strength or generalizability of a comparison.

The appropriate conclusion is limited to the design and measurement information that is recorded. The record does not support a claim that either approach produced greater knowledge, nor does it support a claim that the approaches were equivalent. A finding of no reported difference would not be the same as evidence of equivalence, especially without an estimate and its precision. The adverse-event entries list zeros, but those entries do not supply the missing effectiveness results or establish a broader safety conclusion.

12. Why This Trial Matters Statistically

The trial poses a useful statistical comparison because both groups received structured education, while the delivery approach differed. A randomized, parallel-group design can support estimation of a comparative effect, provided that the analysis preserves the randomized comparison and reports the relevant outcome estimates. The focus on a senior center model also raises a practical question about how education can be delivered in a community setting. The statistical interpretation, however, depends on the results and analysis details, which are not reported in the registry record.

The primary measure captures knowledge through a bounded score with disease-specific and total components, assessed over time. This structure makes it important to distinguish changes within each intervention group from differences in change between groups, and to account for repeated measurements on the same participants. The multiple score types, timepoints, and listed analyses also make transparent reporting of the analysis plan and multiplicity handling important. Those methods are not reported in the registry record.

The record is informative about the intended comparison, intervention content, and measurement schedule, but not about the trial’s primary statistical result. That distinction is consequential: design details explain what a result would mean, while estimates and their uncertainty are needed to judge its magnitude and precision. The trial’s enrollment of 335 does not replace those estimates, nor does a planning illustration establish observed power. Without outcome results, the record supports discussion of the statistical questions the trial raises, not a conclusion about which approach yielded greater measured knowledge.

13. 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.

A key trial-specific limitation for interpreting the record is the absence of reported primary outcome estimates. Although the instrument, scoring direction, score ranges, and timepoints are described, there are no group means, changes, uncertainty intervals, or inferential results. This prevents assessment of the direction, magnitude, or precision of the measured knowledge outcomes.

The record gives a total enrollment of 335 but does not report how many participants were randomized to each group, completed each assessment, or contributed to each analysis. Participant characteristics beyond the intended description of an older, predominantly African-American population are not reported. The age eligibility cutoff and the demographic makeup of those enrolled are also not reported, limiting assessment of how closely the participants represented the target population.

The descriptions of the interventions are not equally complete. The brief summary explains the session formats, but the arm descriptions are incomplete, and the full details of peer educator training, the scripts, and intervention delivery are not reported. Fidelity to the intended content, attendance, and exposure to each intervention are not described in the registry record. These gaps make it difficult to assess how consistently the approaches were delivered.

The record does not report the statistical analysis plan, missing-data methods, analysis population, multiplicity procedures, or details of allocation concealment. The lists of secondary outcomes and analyses make those details relevant to interpretation. The registry record also does not report the results for secondary outcomes. These are limitations of what can be evaluated from the record and should not be read as proof that such procedures or analyses were absent from the trial itself.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Vaccination Education Through Pharmacists and Senior Centers (VEPSC) — NCT03239665.
• Registry record last updated 2020-07-01; status last verified 2020-06.
• Results first posted 2020-07-01.
• 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.

17. Record Summary

NCT03239665, titled Vaccination Education Through Pharmacists and Senior Centers (VEPSC), is listed as a completed randomized, parallel-group trial with no masking. Enrollment was 335. The sponsor was Rutgers, The State University of New Jersey. The study start was 2017-10-10, and primary completion was 2018-09-28.

The trial compared pharmacist-led and peer-led behavioral education about zoster, pneumonia, and influenza vaccination. Its primary outcome was mean change in knowledge and awareness, measured with the VEPSC Knowledge Instrument at baseline, immediately post-intervention, and 1 month follow-up. The registry record lists 8 outcome measures and 85 analyses. It does not report the primary outcome results, statistical analysis methods, missing-data approach, or multiplicity handling. The adverse-event entries list zero affected participants and zero deaths in both groups.