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 Effects of Chronic Viral Infection on Immune Response to Zoster Vaccination (NCT02590068), a non-randomized na study. The primary outcome is Serum Zoster Antibody Level.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02590068 |
| Phase | NA |
| Condition | Hepatitis C |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 14 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Rockefeller University |
| Results posted | Yes |
2. Clinical Question
Population
Volunteers with chronic hepatitis C and healthy volunteers. The registry record lists an enrollment of 14; the number actually enrolled in each group is not reported in the registry record.
Intervention
Both groups were assigned to receive live zoster vaccine, described as Zostavax, at a 0.65 ml dose administered subcutaneously.
Comparator
The planned contrast was between the hepatitis C group and healthy volunteers. Because allocation was nonrandomized, the healthy volunteers do not form a like-for-like randomized control group.
Primary question
The primary outcome was serum zoster antibody level measured by gpELISA, with a stated timeframe of 18 months. Samples were collected, but none were tested for antibody levels.
The study aimed to characterize innate and adaptive immune responses following vaccination and to compare those responses between volunteers with chronic hepatitis C and healthy volunteers. For innate immunity, the description proposes RNA sequencing of whole-blood samples taken before and after vaccination, including assessment of interferon-stimulated gene expression. The adaptive response was intended to include antibody response, interferon gamma production, and the frequency of responder cells assessed by flow cytometry.
The clinical question is therefore broader than the registered primary endpoint alone: it concerns whether the measured immune response patterns differ between the two groups. However, the registry record does not report tested primary antibody measurements or analyses of group differences. The study is listed as terminated, and the available record does not establish what results, if any, were obtained for the other planned immune measures.
3. Trial Design
This was a nonrandomized, parallel-group study with no masking. It was listed as phase NA. The registry record describes two groups: volunteers with hepatitis C and healthy volunteers. Both groups were to receive live zoster vaccine, identified as Zostavax, by subcutaneous administration at a 0.65 ml dose. The study description says that half of participants would be in each group, but the actual number enrolled in each group is not reported in the registry record.
The total enrollment is listed as 14. The study began in 2015-12, had a primary completion date of 2017-09-08, and is listed as terminated. The reason for termination is not reported in the registry record. The sponsor is Rockefeller University.
The study description outlines measurements before and after vaccination. RNA sequencing of whole blood was intended to characterize innate immune signatures, including changes in interferon-stimulated gene expression. Adaptive immune response measures were described as antibody response, interferon gamma production, and responder-cell frequency, with gpELISA and flow cytometry named as measurement approaches. The listed primary outcome is serum zoster antibody level, measured by gpELISA in units/mL, with an 18 months timeframe. The registry record states that samples were collected but none were tested for antibody levels.
Because assignment was nonrandomized, the comparison between groups is observational rather than a randomized treatment contrast. Group membership may therefore reflect differences beyond hepatitis C status; details about those characteristics and any adjustment strategy are not reported in the registry record. Masking was listed as none. The registry record does not report a detailed protocol, a statistical analysis plan, or the reason the study was terminated.
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 | Hepatitis C Infected Volunteers | Healthy Volunteers |
|---|---|---|
| STARTED | 0 | 14 |
| COMPLETED | 0 | 14 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Samples were collected but none were tested for antibody levels
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: We plan to collect and freeze all samples and then run tests on all samples at the same time. As not all samples were collected/processed, many of the assays were not yet performed.
| Characteristic | Unit | Hepatitis C Infected Volunteers | Healthy Volunteers | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 14 | 14 | |
| Age, Continuous | years | — | 57 (53 to 64) | 57 (53 to 64) |
| Sex: Female, Male: Female | Participants | — | 4 | 4 |
| Sex: Female, Male: Male | Participants | — | 10 | 10 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | — | 2 | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | — | 11 | 11 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | — | 1 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | — | 1 | 1 |
| Race (NIH/OMB): Asian | Participants | — | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | — | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | — | 5 | 5 |
| Race (NIH/OMB): White | Participants | — | 6 | 6 |
| Race (NIH/OMB): More than one race | Participants | — | 1 | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | — | 1 | 1 |
| Region of Enrollment: United States | Participants | — | 14 | 14 |
6. Primary Endpoint
The registry lists the primary outcome as Serum Zoster Antibody Level, measured over 18 months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was serum zoster antibody level, intended to be measured by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and expressed in units/mL. The stated timeframe was 18 months. The study description identifies antibody response as one traditional correlate of protection used in prior zoster research, alongside interferon gamma production and responder-cell frequency. As a general measurement principle, an antibody assay can quantify a component of the immune response after vaccination; the value itself does not, without further evidence, establish a clinical benefit.
The registry record reports that samples were collected but none were tested for antibody levels. It therefore contains no primary-endpoint values, group estimates, measure of uncertainty, or statistical comparison. Although the endpoint was specified, its planned measurement did not result in a reported antibody outcome in this record. The registry record does not explain why the samples were not tested or whether testing was performed outside the record.
The study also listed outcomes involving interferon-stimulated gene expression, serum biomarkers of immune activation, responder-cell frequency, and interferon-gamma response. These measures were intended to characterize other parts of the immune response. Their actual results and analyses are not reported in the registry record. Consequently, the endpoint definition describes what the investigators planned to measure, not an observed result that can be interpreted for the enrolled participants.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record offers a description of a planned immune-response study, but it does not report a primary antibody result. Although the record lists an enrollment of 14 and identifies serum zoster antibody level as the primary outcome, it explicitly states that samples were collected but none were tested for antibody levels. There is therefore no reported primary-outcome estimate, no comparison between the hepatitis C and healthy-volunteer groups, and no confidence interval or p-value for that endpoint.
The study description also outlines RNA sequencing, interferon-stimulated gene expression, serum biomarkers, responder-cell frequency, and interferon-gamma response. These are listed as intended immune measures or outcomes, but their results are not reported in the registry record. The analysis count is listed as 0. This does not establish that no analysis was ever conducted outside the registry; it means no analyses are posted in this record.
The design limits causal interpretation even if group measurements were available. Allocation was nonrandomized, and the groups are not a like-for-like control comparison. Differences between groups could reflect hepatitis C status or other group differences, and the registry record does not report adjustment methods that might address such differences. Both groups were described as receiving the same vaccine, so the intended contrast concerns immune responses by group, not vaccine versus no vaccine.
General statistical interpretation depends on estimates and their uncertainty, not only on whether a test is statistically significant. A confidence interval describes a range of values compatible with the data and the stated statistical model. No primary-endpoint confidence interval is reported, so precision cannot be assessed for serum antibody response. The absence of a reported result is not evidence that the groups had identical responses, nor does it show that a difference existed.
The registry status is terminated, but the reason is not reported in the registry record. The record also does not state whether termination followed a prespecified stopping rule or an interim analysis. No conclusion about those possibilities is warranted. Overall, the posted information documents the study's question, planned measurements, and absence of tested antibody results; it does not provide an estimable treatment effect or a complete account of the other planned immune outcomes.
9. Statistical Methods Explained
The study is listed as nonrandomized, unmasked, and parallel. These labels describe important features of how a comparison should be interpreted. In a parallel design, participants belong to one group during the study rather than crossing between groups. Here, the groups were volunteers with hepatitis C and healthy volunteers, and both groups were described as receiving the live zoster vaccine. Nonrandomized allocation means group membership was not assigned by random allocation. As a general principle, randomization helps balance measured and unmeasured participant characteristics on average; without it, group contrasts can be influenced by differences other than the condition of interest. The registry record does not report an adjustment plan for such differences.
The planned innate immune assessment used RNA sequencing of whole-blood samples collected before and after vaccination. The study description says it would compare changes in gene-expression profiles within individuals and between the two groups, including interferon-stimulated genes. In general, RNA sequencing measures the abundance of RNA transcripts and can be used to identify patterns of gene expression. A pre-vaccination and post-vaccination comparison can describe change over time, while a comparison of those changes across groups addresses whether the observed patterns differ by group. The actual sequencing results, analytic model, and handling of multiple gene-level tests are not reported in the registry record.
The adaptive immune response was planned to include antibody response, interferon gamma production, and responder-cell frequency. The primary antibody outcome was to use gpELISA, and the description also refers to IgG/IgM targeting. Flow cytometry was named for characterizing the number and frequency of responder cells. In general, these assays capture distinct aspects of immune response and should not be treated as interchangeable measures. The record does not report assay results for these measures. It specifically states that samples were collected but none were tested for the primary antibody outcome.
The listed primary outcome was serum zoster antibody level in units/mL at the 18 months timeframe. The registry record does not give a statistical parameter or measure of dispersion for that endpoint. It also does not report a primary analysis method, a model, a test, or a method for constructing confidence intervals. Consequently, there is no basis in the record for describing an adjusted or unadjusted primary analysis.
In general, a confidence interval communicates uncertainty around an estimated effect, conditional on the data and the assumptions of the method used. A p-value assesses how compatible data are with a specified null hypothesis under a statistical model; it does not measure the size or importance of an effect. Neither is reported for the primary endpoint in this record. With no tested antibody values, the magnitude and precision of the planned antibody comparison cannot be assessed.
General count-data methods may need to account for over-dispersion, which occurs when variability exceeds what a simple count model assumes. This matters when outcomes are counts or frequencies, because underestimated variability can make uncertainty appear too small. The record mentions responder-cell frequency and biomarker measures, but does not report their data distributions, models, or whether over-dispersion was assessed. It is therefore not possible to say that a particular count-data method was used or was appropriate.
RNA sequencing can involve testing many genes, so multiplicity is a general concern: the more hypotheses assessed, the greater the chance of obtaining apparently notable results by chance if no adjustment is made. Methods such as controlling a false discovery rate are sometimes used in this setting, but the registry record does not report a multiplicity method. No claim can be made about how many genes were analyzed or how their results were handled.
The sample-size information associated with this record is described as a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation; the target effect is stated as a fraction of the observed effect. It is not the trial's own design justification and should not be read as observed power. The registry record does not report a sample-size justification from the study protocol. Because no primary antibody result is posted, any planning illustration should not be interpreted as evidence that the study was adequately powered or that a particular effect was detected.
In general, power is a design-stage probability tied to a specified effect, variability, analysis, and sample size. It is not a measure of whether a study result is true. Retrospective observed power does not substitute for an estimate with a confidence interval. For this record, the absence of a tested primary outcome means no endpoint estimate is available for judging the study's precision.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary antibody outcome and several secondary immune outcomes, including interferon-stimulated gene expression, serum biomarkers of immune activation, responder-cell frequency, and interferon-gamma response. The study description also proposes RNA sequencing across gene-expression profiles. When several outcomes or many genes are examined, multiplicity is a general statistical concern: the chance of finding an apparently notable result by chance can increase when many hypotheses are tested. The registry record does not report a plan for controlling multiplicity, prioritizing secondary outcomes, or interpreting gene-level tests.
The primary antibody endpoint has no reported results because the registry record states that samples were collected but none were tested for antibody levels. Results for the other planned outcomes are also not reported in the registry record. The number of analyses is listed as 0, so there are no posted analyses to assess for multiplicity or reproduce.
Information about missing data, exclusions, analysis populations, and reasons for unavailable measurements is not reported in the registry record. The reason the antibody samples were not tested is also not reported in the registry record. Without those details, it is not possible to determine whether missingness was related to participant characteristics, group membership, sample quality, or other factors. The record does not describe an intention-to-treat population, a per-protocol population, or another defined analysis set.
As a general principle, missing outcomes can affect both the estimate and its uncertainty, and the direction of any effect depends on why data are missing. No imputation or sensitivity analysis is reported in the registry record. The posted information therefore does not support conclusions about how missing measurements were handled or whether analyses were robust to alternative assumptions.
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 |
|---|---|---|---|
| Healthy Volunteers | 1 | 14 | 7.1% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Hepatitis C Infected Volunteers | 0 of 0 |
| Healthy Volunteers | 0 of 14 |
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 |
|---|---|
| Hepatitis C Infected Volunteers | 0 of 0 |
| Healthy Volunteers | 4 of 14 |
Most frequent serious adverse event terms
| Event term | Organ system | Hepatitis C Infected Volunteers | Healthy Volunteers |
|---|---|---|---|
| Dyspnea | Cardiac disorders | 0 of 0 | 1 of 14 |
| Chest Pain | Cardiac disorders | 0 of 0 | 1 of 14 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hepatitis C Infected Volunteers | Healthy Volunteers |
|---|---|---|---|
| Mild Anemia | Blood and lymphatic system disorders | 0 of 0 | 1 of 14 |
| Mild Back Pain | Musculoskeletal and connective tissue disorders | 0 of 0 | 1 of 14 |
| Dental Filling Fell Out | Gastrointestinal disorders | 0 of 0 | 1 of 14 |
| Anxiety | Psychiatric disorders | 0 of 0 | 1 of 14 |
| Lightheadedness | General disorders | 0 of 0 | 1 of 14 |
Serious events with the highest arm-level rate: dyspnea (7.1%), chest pain (7.1%).
The safety record lists 14 participants at risk in the healthy-volunteer group, with 1 serious adverse event and 0 deaths. For the hepatitis C infected volunteers, the listed number at risk is 0, with 0 serious adverse events and 0 deaths. Because the record lists no participants at risk for that group, its zero event count should not be read as evidence that no serious events occurred among enrolled hepatitis C volunteers.
Dyspnea and chest pain are each listed among the top serious adverse event terms at 7.1%. Those terms do not establish that the events were caused by vaccination. The record does not provide enough detail to determine whether the terms refer to distinct participants or events, their timing, severity beyond the serious classification, or relationship to vaccination. The number of non-serious events listed for the healthy-volunteer group is 4; the registry record does not provide further detail in the posted summary.
These figures describe adverse-event reporting in the registry, not a comparative safety analysis. The nonrandomized design, group-specific at-risk counts, and absence of a like-for-like control comparison limit interpretation. The reason the hepatitis C group has 0 listed at-risk participants is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that a study was planned to examine immune responses to live zoster vaccination in volunteers with chronic hepatitis C and healthy volunteers. It identifies the groups, the vaccine and route, the primary antibody endpoint, and several additional immune measures. It also reports that the study was terminated and that antibody samples were collected but not tested.
It does not establish the size, direction, or precision of an antibody response in either group. No primary antibody values, group estimates, confidence intervals, or p-values are reported. The other immune measures are described as planned outcomes, but their results are not reported in the registry record. Thus, the record cannot show whether immune responses differed between the groups.
The study was nonrandomized, so even a reported group difference would not automatically identify hepatitis C status as its cause. General observational comparisons can be affected by differences between groups, and the record does not report adjustment methods. Both groups were described as receiving vaccine, so the study's intended comparison was not vaccination versus no vaccination.
Absence of a posted result should not be interpreted as evidence of no effect or as evidence of a difference. It indicates that the relevant outcome and analysis are not available in the registry record. The record also does not explain why the study was terminated or why antibody samples were not tested. Those unknowns cannot be resolved from the posted information.
Accordingly, the record is informative about the research question and the limits of the available reporting, but it does not provide an efficacy conclusion or a complete assessment of immune response. The sample-size illustrations associated with the record are planning illustrations, not observed power and not evidence of a treatment effect.
13. Why This Trial Matters Statistically
This study raises a useful statistical question: how should immune-response measurements be compared when groups differ by a chronic infection status but are not formed by random allocation? The registry identifies a parallel comparison between hepatitis C infected volunteers and healthy volunteers, with both groups described as receiving the same vaccine. That design can describe group-specific measurements if results are available, but causal interpretation requires caution because group membership may coincide with other differences.
The planned measures also illustrate why endpoint definition matters. Antibody level, gene-expression patterns, interferon gamma, and responder-cell frequency address different components of immune response. A single endpoint cannot stand in for all the others, and a collection of outcomes requires a clear analysis and multiplicity strategy. The registry record identifies several measures but does not report the corresponding analysis methods or results.
The central statistical limitation is that the designated primary endpoint was not tested. With no antibody values or analysis, there is no effect estimate or precision measure to interpret. A registry record can therefore document a research aim without supplying evidence that answers it. This distinction matters when readers encounter planned endpoints alongside absent results: an endpoint description is not an outcome finding.
The entry also shows why enrollment and analytic sample information should be distinguished. Total enrollment is listed as 14, while the group-specific number actually enrolled is not reported in the registry record. The safety listing gives an at-risk count of 0 for the hepatitis C group, so the group cannot be interpreted as having had no events merely from its zero event count. Transparent reporting of participant flow, tested samples, and analysis populations would be needed to clarify these points.
For biostatisticians and clinical researchers, the record is a reminder to separate study design, planned measurement, observed data, and statistical inference. Here, the design and intended outcomes are described, but primary antibody findings and other outcome analyses are not posted. Conclusions should remain bounded by that distinction.
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 primary endpoint has no reported result. The registry record states that samples were collected but none were tested for antibody levels. The reason is not reported in the registry record, and no antibody estimate or uncertainty measure is available.
The record lists total enrollment as 14 but does not report the number actually enrolled in each group. Although the study description says half would be hepatitis C infected volunteers and half healthy volunteers, that plan does not establish the achieved group sizes. The safety listing reports 0 participants at risk in the hepatitis C group, which makes its zero event count unsuitable for interpreting safety among enrolled members of that group.
The study was nonrandomized and unmasked. The registry record does not report adjustment for baseline characteristics, a detailed statistical plan, or the reason for termination. It also does not report results for the secondary immune outcomes or explain whether those measures were completed. The analysis count is listed as 0.
Information about missing data, exclusions, analysis populations, sample-size justification, interim analyses, and multiplicity handling is not reported in the registry record. These omissions prevent assessment of the intended inferential procedures, the potential impact of unavailable measurements, and the precision that the design was expected to achieve. The study description and the available registry entries therefore support interpretation of the aims and reporting gaps, but not conclusions about immune-response differences.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Chronic Viral Infection on Immune Response to Zoster Vaccination — NCT02590068.
- Registry record last updated 2019-12-18; status last verified 2019-12.
- Results first posted 2019-12-18.
- 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
NCT02590068, titled “Effects of Chronic Viral Infection on Immune Response to Zoster Vaccination,” is listed as a nonrandomized, unmasked, parallel study sponsored by Rockefeller University. It enrolled 14 participants, began in 2015-12, reached primary completion on 2017-09-08, and is listed as terminated.
The study compared planned immune-response measurements in hepatitis C infected volunteers and healthy volunteers after live zoster vaccine, described as a 0.65 ml subcutaneous dose. The primary endpoint was serum zoster antibody level by gpELISA at 18 months. The registry record states that samples were collected but none were tested for antibody levels. Results for the listed secondary immune outcomes are not reported in the registry record, and the number of analyses is listed as 0.
The registry record does not report the reason for termination, actual group enrollment, or a detailed statistical analysis plan. Its safety listing reports 14 at-risk healthy volunteers and 0 at-risk hepatitis C volunteers, so group safety counts require caution.