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 Safety, Tolerability, and Immunogenicity of Candidate Human Cytomegalovirus Vaccine in Healthy Adults (NCT02826798), a randomized phase 1 study. The primary outcome is Number of Participants With Local and Systemic Adverse Events During Seven-Day Follow-Up Period.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02826798 |
| Phase | Phase 1 |
| Condition | Cytomegalovirus Infections |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 128 |
| Arms in the primary outcome | n/a |
| Lead sponsor | VBI Vaccines Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Healthy adults enrolled in a Phase 1 study of a candidate human cytomegalovirus vaccine. The registry lists an enrollment of 128 and describes the analysis population for the primary outcome as the total vaccinated cohort, including all immunized subjects.
Intervention
Four vaccine regimens were studied: VBI-1501A at 0.5 μg, 1.0 μg, or 2.0 μg with adjuvant, and VBI-1501 at 1.0 μg without adjuvant.
Comparator
Placebo, described as buffer/sucrose used for the VBI-1501 suspension. The study has five parallel groups, so each vaccine regimen can be considered in relation to the placebo group, although comparative estimates are not reported in the registry record.
Primary question
How many participants experienced local or systemic adverse events during the seven-day follow-up period after vaccine administration? The specified observation windows begin on days 0, 56, and 168, with follow-up through the six subsequent days. The record also lists antibody outcomes as secondary measures of immunogenicity.
The clinical question is primarily about short-term safety and tolerability, not whether vaccination prevents cytomegalovirus infection. The study description also refers to evaluating immunogenicity, and the secondary outcomes include measures of antibody binding, antibody avidity, and neutralizing antibodies against infection of fibroblast and epithelial cells. Those laboratory measures address immune response; they are not the same as observing prevention of clinical infection.
Because the registry record does not report comparative estimates, confidence intervals, or hypothesis-test results for the primary outcome, the listed group counts alone do not establish whether the groups differed. They describe recorded event experience and need to be interpreted within the stated population and follow-up framework.
3. Trial Design
This was a Phase 1, randomized, parallel-group study with a placebo control. The registry lists double masking, while the official title describes the study as observer-blind. The record does not explain how masking was implemented or identify which study roles were masked. Enrollment was 128, and the study status is completed.
Five groups received either one of four vaccine regimens or placebo. Three regimens used VBI-1501A with adjuvant at 0.5 μg, 1.0 μg, or 2.0 μg. A fourth used VBI-1501 at 1.0 μg without adjuvant. The placebo was buffer/sucrose used for the VBI-1501 suspension. These distinct formulations and doses mean that a statement about one regimen should not automatically be applied to another.
The record gives the study start as 2016-06-23 and primary completion as 2016-09-15. It describes the primary safety observation as covering the day of vaccine administration on days 0, 56, and 168 and the six subsequent days. This identifies the intended event-monitoring windows; it does not by itself give the timing or duration of any event for an individual participant.
The registry describes the primary analysis population as the total vaccinated cohort, which includes all immunized subjects. It does not report the number analyzed in each group for the primary outcome, nor does it explain how participants with missing observations were handled. The record lists eight outcome measures and names antibody outcomes among the secondary measures. It does not provide analysis entries for the outcomes.
As a randomized study, the design is intended to compare groups under assigned interventions. However, randomization alone does not supply a treatment-effect estimate: such an estimate requires outcome data analyzed according to a defined comparison. The registry record does not report a statistical comparison of the primary outcome across the five groups.
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 | VBI-1501A: 0.5µg With Adjuvant | VBI-1501A: 1.0µg With Adjuvant | VBI-1501A: 2.0 µg With Adjuvant | VBI-1501: 1.0µg Without Adjuvant | Placebo |
|---|---|---|---|---|---|
| STARTED | 25 | 26 | 26 | 25 | 26 |
| COMPLETED | 25 | 25 | 26 | 24 | 26 |
| NOT COMPLETED | 0 | 1 | 0 | 1 | 0 |
Reasons for not completing this period:
| Reason | VBI-1501A: 0.5µg With Adjuvant | VBI-1501A: 1.0µg With Adjuvant | VBI-1501A: 2.0 µg With Adjuvant | VBI-1501: 1.0µg Without Adjuvant | Placebo |
|---|---|---|---|---|---|
| Withdrawal by Subject | 0 | 1 | 0 | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: Analyses were performed on the total vaccinated cohort (TVC), which includes all immunized subjects.
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 | VBI-1501A: 0.5µg With Adjuvant | VBI-1501A: 1.0µg With Adjuvant | VBI-1501A: 2.0 µg With Adjuvant | VBI-1501: 1.0µg Without Adjuvant | Placebo | Total |
|---|---|---|---|---|---|---|---|
| Participants analysed | 25 | 26 | 26 | 25 | 26 | 128 | |
| Age, Continuous: Mean (standard deviation) | years | 26.4 (SD 4.58) | 27.0 (SD 5.38) | 26.5 (SD 4.60) | 26.8 (SD 5.99) | 28.3 (SD 5.58) | 27.0 (SD 5.22) |
| Sex: Female, Male: Female | Participants | 12 | 18 | 17 | 14 | 15 | 76 |
| Sex: Female, Male: Male | Participants | 13 | 8 | 9 | 11 | 11 | 52 |
| Race/Ethnicity, Customized: North American Indian | Participants | 0 | 0 | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: White, Caucasian | Participants | 22 | 24 | 23 | 22 | 24 | 115 |
| Race/Ethnicity, Customized: Chinese | Participants | 2 | 1 | 0 | 1 | 1 | 5 |
| Race/Ethnicity, Customized: Black | Participants | 0 | 0 | 0 | 1 | 0 | 1 |
| Race/Ethnicity, Customized: Filipino | Participants | 0 | 1 | 0 | 0 | 0 | 1 |
| Race/Ethnicity, Customized: West Asian | Participants | 0 | 0 | 1 | 0 | 0 | 1 |
| Race/Ethnicity, Customized: Alaskan Native | Participants | 0 | 0 | 1 | 0 | 0 | 1 |
| Race/Ethnicity, Customized: Other | Participants | 1 | 0 | 1 | 1 | 1 | 4 |
| Region of Enrollment: Canada | participants | 25 | 26 | 26 | 25 | 26 | 128 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Local and Systemic Adverse Events During Seven-Day Follow-Up Period, measured over Day of vaccine administration (days 0, 56, 168) and six subsequent days.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with local and systemic adverse events during the seven-day follow-up period. It is a count of participants experiencing an event, rather than a count of every event episode. The registry specifies observation beginning on the vaccine administration day—days 0, 56, and 168—and continuing for the six subsequent days.
Counting participants with events is a way to describe how many people in each study group had recorded safety events within the defined observation window. It is relevant to an early-phase study because safety and tolerability are central questions when candidate regimens are being evaluated. Reporting local and systemic events can also distinguish events associated with the administration area from broader symptoms, although the registry record does not provide definitions of those categories or list the individual primary-endpoint events.
The endpoint title does not establish that every event was caused by vaccination. An event recorded after administration is a safety observation; causal attribution requires assessment that is not described in the registry record. The posted adverse-event figures include counts categorized as serious and other adverse events, but the record does not establish that those counts are the primary endpoint counts for the specified seven-day windows.
The primary endpoint is therefore best read as a defined safety count, not as a direct measure of vaccine effectiveness or immune response. Comparative estimates and uncertainty for this endpoint are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry reports adverse-event counts by study group. For serious adverse events, the listed numbers of affected participants are 0 of 25 for VBI-1501A: 0.5μg With Adjuvant, 2 of 26 for VBI-1501A: 1.0μg With Adjuvant, 1 of 26 for VBI-1501A: 2.0 μg With Adjuvant, 2 of 25 for VBI-1501: 1.0μg Without Adjuvant, and 0 of 26 for placebo. The record lists zero deaths in each group.
For the separate category labeled other adverse events, the listed affected-participant counts are 18 of 25, 23 of 26, 20 of 26, 21 of 25, and 22 of 26, respectively, in the same group order. These are descriptive counts. They do not, on their own, quantify a comparative effect or establish that a difference between groups is meaningful. No confidence intervals, p-values, adjusted comparisons, or analysis results are reported in the registry record.
These adverse-event figures should not be treated as a direct substitute for the primary endpoint. The primary endpoint specifies local and systemic events during the seven-day follow-up windows, whereas the reported adverse-event categories do not state in the record that they are restricted to those windows. The record also does not provide event-level details for the primary outcome. The safest interpretation is to keep the endpoint definition separate from the broader adverse-event counts.
The registry lists several serious adverse-event terms with associated percentages: Laceration, 4.0%; Depression, 4.0%; Hepatitis, 3.8%; Meningitis Aseptic, 3.8%; and Deep Vein Thrombosis, 3.8%. It does not provide further context for those percentages in the record, such as the denominator or group distribution, so they should not be used to infer comparative risk or attribution.
Antibody binding to CMV gB, avidity against gB, and neutralizing antibody titers against infection of fibroblast and epithelial cells are listed as secondary outcomes. Their names indicate the types of immune response measured, but numerical antibody results are not reported in the registry record. Consequently, the available record supports a description of the design and adverse-event counts, but not a conclusion about comparative immunogenicity or a treatment effect.
In general, a confidence interval would describe the range of estimates compatible with the data and the analysis assumptions, while a p-value would summarize how unusual the data would be under a specified null hypothesis. Neither can be recovered from group counts alone without choosing an analysis and its assumptions. No recalculated comparison is presented because the registry record does not report the corresponding primary-endpoint results.
9. Statistical Methods Explained
The study is randomized and parallel-group. Randomization assigns participants to study groups using a chance-based process, which is intended to make baseline characteristics comparable on average. A parallel design means participants remain in their assigned group rather than crossing over between regimens. General statistical interpretation still depends on how allocation was conducted, whether the assigned treatment was received, and how outcomes were collected; those operational details are not reported in the registry record.
What does a participant count represent?
The primary endpoint is framed as a count of participants with local and systemic adverse events. For a binary outcome such as whether a participant had at least one event, each participant contributes to the event or no-event category for the defined interval. This differs from counting all episodes: a participant with repeated events may still be counted once for a participant-level measure. The registry record does not report the event-level data or the rule used to combine multiple events.
The listed adverse-event counts have group-specific numbers at risk and numbers affected. Such counts are useful for describing what was recorded in each group. A comparison requires an explicit estimand and method—for example, whether the aim is to compare event proportions, event rates, or time to first event. These approaches answer different questions. The registry record does not identify a comparative method for the primary outcome.
Why do confidence intervals matter?
General statistical explanation: a confidence interval expresses the uncertainty around an estimated quantity under a specified model and repeated-sampling procedure. A narrow interval indicates greater precision for that estimate, while a wide interval indicates less precision. The interval does not guarantee that the true value lies within it, and it does not resolve questions about bias, outcome definitions, or applicability. No confidence interval for the primary endpoint is reported in the registry record.
A point estimate alone can be difficult to interpret because it does not show how much uncertainty accompanies the estimate. With a small early-phase study, estimates can be imprecise even when a numerical difference is visible. This is a general consideration, not a claim about an unreported effect in this trial. The record gives enrollment and group counts for the adverse-event categories, but it does not report the precision of a between-group comparison.
What does a p-value say?
General statistical explanation: a p-value measures how compatible observed data are with a specified null model, assuming the model and test conditions hold. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of an effect. A small p-value does not by itself establish causality, and a larger p-value does not establish equivalence. The registry record reports no p-values or hypothesis tests for the primary outcome.
With five study groups, there are multiple possible comparisons. A statistical plan would ordinarily clarify which comparisons were primary and how multiplicity was handled. The registry record does not report the comparison hierarchy or any multiplicity adjustment. It would therefore be inappropriate to select a comparison after seeing the counts and treat it as a prespecified test.
How should planning illustrations be read?
General statistical explanation: a sample-size calculation depends on assumptions about the outcome, the effect to detect, the significance level, allocation, and the statistical method. A planning illustration based on an observed effect is not an observed power calculation and does not show that a trial had adequate power for a particular conclusion. The planning assumptions stated for this record use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of the observed effect. These assumptions describe an illustration, not necessarily the design decisions made by the sponsor.
The registry record does not report its own sample-size justification or the assumptions used to choose enrollment. The study enrolled 128 participants, but that number alone does not show the precision of a safety estimate or whether the study could detect a particular difference. For event outcomes, the information available depends on how many participants experience events, not only on total enrollment. A sample-size illustration should therefore be treated as a planning aid rather than a finding about the trial.
Why can event distributions matter?
General statistical explanation: methods for counts often rely on assumptions about how events are distributed. If variability is greater than a model expects—often called over-dispersion—standard errors can be too small and confidence intervals too narrow when the extra variability is ignored. Over-dispersion is particularly relevant when analyzing numbers of repeated events, but this endpoint is described as the number of participants with events, not the total number of episodes. The registry record does not report a model or information needed to assess over-dispersion.
For binary participant-level outcomes, other considerations include the definition of an event, completeness of follow-up, and whether participants are analyzed in their assigned groups or according to treatment received. The record identifies the total vaccinated cohort as the population for primary analyses, but does not describe the handling of missing data, deviations, or participants who did not complete follow-up. No statistical model or covariate adjustment is reported in the registry record.
These method concepts explain what would be needed for a full comparative interpretation. They do not create estimates that are absent from the record. The posted results are best treated as descriptive safety counts, with the endpoint-specific time window, analysis population, and unreported details kept in view.
10. Multiplicity, Missing Data and Analysis Populations
There are five groups and several possible pairwise comparisons, as well as multiple outcomes. This creates a multiplicity question: when many hypotheses are examined, the chance of at least one apparently notable result can increase. A prespecified comparison strategy or an adjustment procedure can address that concern, but neither is described in the registry record. No comparative tests are reported, so the record does not establish whether any multiplicity procedure was used.
The study lists eight outcome measures and names antibody binding, avidity, and neutralizing antibody outcomes among the secondary measures. The registry record does not provide numerical results for those antibody outcomes, their analysis populations, or a hierarchy identifying confirmatory versus exploratory analyses. It also does not report interim analyses or a statistical analysis plan.
The primary outcome population is the total vaccinated cohort, described as including all immunized subjects. This definition identifies the population intended for the primary analyses but does not explain how the analysis dealt with missing observations or incomplete follow-up. Rules for imputation, exclusions, protocol deviations, or sensitivity analyses are not reported in the registry record. Nor does the record give group-specific numbers with complete primary-endpoint data.
Missing-data handling matters because participants without recorded outcomes may differ from those with complete observations. General statistical explanation: an analysis based only on observed outcomes can be biased if missingness is related to outcome risk or treatment experience. The registry record does not provide enough information to assess that possibility. The absence of reported analysis entries should not be interpreted as evidence that no analysis was performed; the registry record simply does not report those results.
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 |
|---|---|---|---|
| VBI-1501A: 0.5µg With Adjuvant | 0 | 25 | 0.0% |
| VBI-1501A: 1.0µg With Adjuvant | 2 | 26 | 7.7% |
| VBI-1501A: 2.0 µg With Adjuvant | 1 | 26 | 3.8% |
| VBI-1501: 1.0µg Without Adjuvant | 2 | 25 | 8.0% |
| Placebo | 0 | 26 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| VBI-1501A: 0.5µg With Adjuvant | 0 of 25 |
| VBI-1501A: 1.0µg With Adjuvant | 0 of 26 |
| VBI-1501A: 2.0 µg With Adjuvant | 0 of 26 |
| VBI-1501: 1.0µg Without Adjuvant | 0 of 25 |
| Placebo | 0 of 26 |
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 |
|---|---|
| VBI-1501A: 0.5µg With Adjuvant | 18 of 25 |
| VBI-1501A: 1.0µg With Adjuvant | 23 of 26 |
| VBI-1501A: 2.0 µg With Adjuvant | 20 of 26 |
| VBI-1501: 1.0µg Without Adjuvant | 21 of 25 |
| Placebo | 22 of 26 |
Most frequent serious adverse event terms
| Event term | Organ system | VBI-1501A: 0.5µg With Adjuvant | VBI-1501A: 1.0µg With Adjuvant | VBI-1501A: 2.0 µg With Adjuvant | VBI-1501: 1.0µg Without Adjuvant | Placebo |
|---|---|---|---|---|---|---|
| Hepatitis | Hepatobiliary disorders | 0 of 25 | 1 of 26 | 0 of 26 | 0 of 25 | 0 of 26 |
| Meningitis Aseptic | Infections and infestations | 0 of 25 | 0 of 26 | 1 of 26 | 0 of 25 | 0 of 26 |
| Laceration | Injury, poisoning and procedural complications | 0 of 25 | 0 of 26 | 0 of 26 | 1 of 25 | 0 of 26 |
| Depression | Psychiatric disorders | 0 of 25 | 0 of 26 | 0 of 26 | 1 of 25 | 0 of 26 |
| Deep Vein Thrombosis | Vascular disorders | 0 of 25 | 1 of 26 | 0 of 26 | 0 of 25 | 0 of 26 |
Most frequent non-serious adverse event terms
| Event term | Organ system | VBI-1501A: 0.5µg With Adjuvant | VBI-1501A: 1.0µg With Adjuvant | VBI-1501A: 2.0 µg With Adjuvant | VBI-1501: 1.0µg Without Adjuvant | Placebo |
|---|---|---|---|---|---|---|
| Nasopharyngitis | Infections and infestations | 11 of 25 | 5 of 26 | 9 of 26 | 6 of 25 | 8 of 26 |
| Headache | Nervous system disorders | 6 of 25 | 8 of 26 | 5 of 26 | 6 of 25 | 5 of 26 |
| Upper Respiratory Tract Infection | Infections and infestations | 4 of 25 | 7 of 26 | 2 of 26 | 3 of 25 | 3 of 26 |
| Fatigue | General disorders | 3 of 25 | 2 of 26 | 4 of 26 | 3 of 25 | 1 of 26 |
| Malaise | General disorders | 4 of 25 | 2 of 26 | 2 of 26 | 0 of 25 | 2 of 26 |
| Orophyngeal Pain | Respiratory, thoracic and mediastinal disorders | 4 of 25 | 1 of 26 | 0 of 26 | 2 of 25 | 1 of 26 |
| Lymphadenopathy | Blood and lymphatic system disorders | 1 of 25 | 1 of 26 | 1 of 26 | 1 of 25 | 2 of 26 |
| Influenza Like Illness | General disorders | 0 of 25 | 2 of 26 | 1 of 26 | 2 of 25 | 1 of 26 |
| Urinary Tract Infection | Infections and infestations | 1 of 25 | 4 of 26 | 0 of 26 | 1 of 25 | 0 of 26 |
| Back Pain | Musculoskeletal and connective tissue disorders | 2 of 25 | 1 of 26 | 2 of 26 | 0 of 25 | 1 of 26 |
Serious events with the highest arm-level rate: laceration (4.0%), depression (4.0%), hepatitis (3.8%), meningitis aseptic (3.8%), deep vein thrombosis (3.8%).
The serious adverse-event counts are listed as affected participants over the number at risk in each group: 0 of 25, 2 of 26, 1 of 26, 2 of 25, and 0 of 26, in the order of the four vaccine regimens followed by placebo. The record lists zero deaths in all five groups. These counts describe what was recorded; they do not establish whether events were caused by the study intervention.
The record separately lists other adverse events, with affected-participant counts of 18 of 25, 23 of 26, 20 of 26, 21 of 25, and 22 of 26. Serious and other adverse-event categories should not be combined or treated as interchangeable. The record does not supply a comparative statistical analysis for either category.
The listed serious-event terms and percentages are Laceration, 4.0%; Depression, 4.0%; Hepatitis, 3.8%; Meningitis Aseptic, 3.8%; and Deep Vein Thrombosis, 3.8%. The registry record does not explain the denominator or distribution behind these percentages. These figures therefore cannot be assigned to a particular arm or used to compare regimens.
The primary endpoint has a specified seven-day window after administrations on days 0, 56, and 168. The adverse-event group counts do not state that they use only this window. They should not be read as primary-endpoint counts without that link being established in the registry record.
12. What the Result Does, and Does Not, Mean
The study evaluates four candidate vaccine regimens and placebo in healthy adults, with safety and immunogenicity among its stated aims. The registry record provides the design, the primary safety endpoint definition, and group-level counts for serious and other adverse events. It also lists antibody outcomes, but does not report their numerical results or comparative analyses.
These data can support a descriptive account of the adverse-event categories recorded in each group. They do not, by themselves, show that one regimen is safer or less safe than another. The counts do not include comparative estimates or uncertainty, and the registry record does not establish that the reported categories correspond exactly to the primary endpoint's seven-day follow-up windows. The listed serious-event terms also lack enough context to interpret their percentages by treatment group.
The primary outcome concerns short-term local and systemic adverse events. It is not a direct measure of protection against cytomegalovirus infection. Antibody titers and avidity can describe immune responses, but those secondary measures are not clinical infection outcomes. With no numerical antibody results reported, no conclusion about comparative immunogenicity can be drawn from this registry record.
General statistical explanation: evidence of a difference, evidence of no difference, and evidence of equivalence are distinct conclusions. Demonstrating equivalence usually requires a prespecified margin and an analysis with adequate precision. Neither comparative estimates nor an equivalence framework is reported in the registry record. The absence of a reported test is not evidence that the regimens had identical outcomes.
The study is Phase 1 and includes 128 participants. Those details describe its stage and enrollment, but enrollment alone does not determine what can be concluded. Interpretation depends on the endpoint, observation period, completeness of outcomes, analysis method, and uncertainty around comparisons. The available record supports a cautious description of recorded adverse events, not a conclusion about efficacy, definitive safety, or the relative performance of the regimens.
13. Why This Trial Matters Statistically
This trial is statistically instructive because its design includes several active regimens and a placebo group, while its main endpoint is a participant-level safety count. That combination makes the distinction between descriptive data and comparative inference important. Counts can show how many participants were recorded with events, but a formal comparison also requires a defined contrast, an analysis method, and an account of uncertainty.
The study also illustrates why endpoint wording and follow-up timing matter. The primary outcome specifies local and systemic adverse events during defined seven-day windows after administrations on days 0, 56, and 168. The adverse-event counts in the registry are grouped as serious and other events, and the record does not link them explicitly to those windows. Clear alignment between endpoint definitions and reported results is needed before counts can be interpreted as answering the primary question.
Multiple regimens and several outcomes can create many potential comparisons. Without a reported hierarchy or multiplicity approach, readers cannot know which comparisons were intended to carry the principal inferential weight. This is important even when the goal is exploratory: exploratory findings can generate questions, but should not be mistaken for prespecified confirmatory conclusions.
Finally, early-phase studies often have descriptive safety and immune-response aims. Here, antibody measures are listed as secondary outcomes, but their numerical results are not reported in the registry record. The study therefore provides a useful example of how a registry can identify the questions and outcomes under study while leaving key elements of statistical interpretation—effect estimates, precision, missing-data handling, and analysis methods—not reported.
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 registry record does not report comparative estimates, confidence intervals, p-values, or model-based results for the primary endpoint. Although the endpoint is defined as participants with local and systemic adverse events during specified seven-day windows, the record does not provide the corresponding arm-specific counts for those windows. The serious and other adverse-event counts should not be assumed to be the primary endpoint results.
There is no event-level description of the local and systemic outcomes, no account of how multiple events in a participant were treated, and no explanation of event attribution. The record also does not report the number of participants with complete primary-outcome follow-up in each group. Missing-data methods and sensitivity analyses are not reported in the registry record.
The registry identifies five groups and several outcomes but does not report a statistical analysis plan, a prespecified comparison hierarchy, multiplicity handling, or interim analyses. It does not report the sponsor's sample-size justification. The planning assumptions described for an illustration should not be taken as evidence of the trial's original design rationale or of its power for a particular comparison.
Antibody outcomes are listed, but their numerical results are not reported in the registry record. The listed serious-event terms and percentages lack contextual information about denominators and group allocation. These limitations restrict interpretation to the design and descriptive adverse-event counts that are recorded; they prevent a well-supported assessment of comparative safety or immunogenicity.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study to Evaluate Safety, Tolerability, and Immunogenicity of Candidate Human Cytomegalovirus Vaccine in Healthy Adults — NCT02826798.
- Registry record last updated 2020-04-20; status last verified 2020-04.
- Results first posted 2020-04-20.
- 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
NCT02826798 is a completed Phase 1 randomized, parallel, placebo-controlled study of a candidate human cytomegalovirus vaccine in healthy adults. The registry lists double masking and the official title describes an observer-blind study. Enrollment was 128, with four vaccine regimens and a placebo group.
The primary endpoint is the number of participants with local and systemic adverse events during seven-day follow-up after administrations on days 0, 56, and 168. The registry describes the primary analysis population as the total vaccinated cohort, including all immunized subjects. Secondary measures include antibody binding, avidity, and neutralizing antibody titers.
Group-level counts are reported for serious and other adverse events, along with zero deaths in each group. Comparative statistical results and numerical antibody findings are not reported in the registry record. The record does not report how missing outcomes or multiplicity were handled.