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 Vaccine Therapy in Preventing Human Papillomavirus Infection in Younger Cancer Survivors (NCT01492582), a na phase 2 study. The primary outcome is Immunogenicity of the HPV Vaccine in Cancer Survivors (Anti-HPV 16 and 18 Geometric Mean Titers) (Aim 2 [Vaccine Evaluation]).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01492582 |
| Phase | Phase 2 |
| Condition | Cancer Survivor, Prevention of Human Papillomavirus Infection |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 1499 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Alabama at Birmingham |
| Results posted | Yes |
2. Clinical Question
Population
Cancer survivors ages 9 to 26 years. The registry describes a cross-sectional survey and a vaccine evaluation in young cancer survivors.
Intervention
Quadrivalent or nonavalent human papillomavirus vaccine, given as vaccine therapy. The registry also lists survey administration, medical chart review, and laboratory biomarker analysis.
Comparator
The primary endpoint description refers to age- and sex-matched historical healthy populations. The trial itself is single-group and open-label, not a randomized comparison; the vaccine groups are not a like-for-like control comparison.
Primary question
Whether antibody responses to HPV 16 and 18 in cancer survivors ages 9 to 26 years are non-inferior to responses in historical healthy populations.
The study has two related aims in its summary: measuring the prevalence of HPV vaccine initiation among young cancer survivors, and evaluating immune response and safety/tolerability after vaccination. These are distinct questions. Vaccine initiation prevalence is descriptive, while immunogenicity concerns antibody measurements after vaccination. The primary outcome is the immunogenicity comparison, with measurement one month following the third vaccination dose.
The registry lists quadrivalent and nonavalent vaccines. It does not describe a randomized assignment between them, and the record explicitly cautions that the groups are not a like-for-like control comparison. Therefore, the central question is not a randomized head-to-head estimate of the difference between vaccine products. Instead, the primary aim invokes a historical healthy-population benchmark. The numerical antibody results and the details needed to assess the non-inferiority comparison are not reported in the registry record.
3. Trial Design
This is a completed phase II, open-label, single-group study sponsored by the University of Alabama at Birmingham. The registry lists enrollment of 1499 and describes a study of cancer survivors ages 9 to 26 years. Its official title identifies both a cross-sectional survey and a phase II vaccine trial, reflecting the combination of vaccine-initiation assessment and post-vaccination evaluation.
The vaccine intervention was quadrivalent or nonavalent HPV vaccine. The registry describes the quadrivalent product as covering HPV types 6, 11, 16, and 18, and the nonavalent product as covering types 6, 11, 16, 18, 31, 33, 45, 52, and 58. It also lists laboratory biomarker analysis, survey administration, and medical chart review. The intervention description says the vaccine was administered intramuscularly. The record does not report the full dosing schedule in the available arm description.
The study has no masking and no randomized allocation. The primary endpoint compares antibody responses with age- and sex-matched historical healthy populations, rather than with a concurrent randomized control arm. The quadrivalent and nonavalent groups should not be interpreted as randomized comparison groups. Their membership reflects vaccine type, and the registry cautions that they are not a like-for-like control comparison.
The study began in 2012-07, has a primary completion date of 2019-02-08, and is recorded as completed. These design features support description of the study’s intended questions, but they do not establish what its analyses found. Numerical primary results, the non-inferiority margin, the statistical plan, and the sample-size justification 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
| Stage | Prevention (Vaccine Therapy) | Survey Arm |
|---|---|---|
| STARTED | 453 | 1046 |
| Received First Quadrivalent Vaccine Dose | 254 | 0 |
| Received First Nonavalent Vaccine Dose | 182 | 0 |
| COMPLETED | 384 | 982 |
| NOT COMPLETED | 69 | 64 |
Analysis population for the primary outcome, as defined in the registry: Participants who returned an evaluable survey
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: Participants who consented to the study.
| Characteristic | Unit | Prevention (Vaccine Therapy) | Survey | Total |
|---|---|---|---|---|
| Participants analysed | 453 | 1046 | 1499 | |
| Age, Customized: 9-15 years | Participants | 249 | 508 | 757 |
| Age, Customized: 16-26 years | Participants | 204 | 538 | 742 |
| Sex: Female, Male: Female | Participants | 195 | 473 | 668 |
| Sex: Female, Male: Male | Participants | 258 | 573 | 831 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 52 | 142 | 194 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 400 | 900 | 1300 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 | 4 | 5 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 | 5 | 6 |
| Race (NIH/OMB): Asian | Participants | 6 | 32 | 38 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 3 | 3 |
| Race (NIH/OMB): Black or African American | Participants | 96 | 170 | 266 |
| Race (NIH/OMB): White | Participants | 338 | 796 | 1134 |
| Race (NIH/OMB): More than one race | Participants | 10 | 24 | 34 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 | 16 | 18 |
| Region of Enrollment: United States | participants | 453 | 1046 | 1499 |
6. Primary Endpoint
The registry lists the primary outcome as Immunogenicity of the HPV Vaccine in Cancer Survivors (Anti-HPV 16 and 18 Geometric Mean Titers) (Aim 2 [Vaccine Evaluation]), measured over 1 month following vaccination dose #3.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Standard Deviation |
| Unit | mMu/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the geometric mean titer of antibodies to HPV 16 and HPV 18, measured one month following vaccination dose #3. The unit is mMu/mL, and the registry identifies standard deviation as the dispersion measure. The endpoint is intended to quantify the antibody response after vaccination in cancer survivors ages 9 to 26 years.
Geometric means are commonly used for antibody titers because these measurements can be skewed, with some values much larger than others. A geometric mean is based on the logarithms of the measurements and then expressed back on the original scale. This can make the central response less dominated by unusually high values than an arithmetic mean. This is a general statistical explanation; the registry does not report the specific analysis transformation or estimation procedure used.
The endpoint is used to address the stated non-inferiority aim: comparing the antibody responses in cancer survivors with responses in age- and sex-matched historical healthy populations. A non-inferiority conclusion requires a defined margin and an estimate with uncertainty evaluated against that margin. The margin, numerical geometric mean titers, confidence intervals, and test results are not reported in the registry record. The endpoint description alone therefore identifies the intended measure and comparison, not whether the non-inferiority criterion was met.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the study’s objective and design but does not report numerical results for its primary immunogenicity endpoint. It names anti-HPV 16 and anti-HPV 18 geometric mean titers one month after dose #3, and states that the aim was to demonstrate non-inferiority relative to age- and sex-matched historical healthy populations. Without the posted titers, their uncertainty, and the non-inferiority margin, the primary comparison cannot be interpreted from the registry record.
The distinction between an objective and a finding is important. A stated aim to demonstrate non-inferiority is not evidence that non-inferiority was demonstrated. The record does not report the estimated response in either population, the historical comparison values, a confidence interval for the contrast, or the inferential result. It also does not report how the historical comparator was selected or how age and sex matching was implemented. Those details affect how comparable the populations are and how much uncertainty should be attributed to the contrast.
The study is open-label and single-group, with vaccine types listed in separate groups. The registry cautions that the vaccine groups are not a like-for-like control comparison. Accordingly, the quadrivalent and nonavalent groups should not be treated as randomized arms for causal product comparisons. Differences between groups, if reported elsewhere, could reflect how participants entered each group or other group characteristics; the registry record does not report a design that would support a randomized head-to-head interpretation.
For safety, the registry lists 11 serious adverse event-affected participants among 253 at risk in the quadrivalent group, and 7 among 182 at risk in the nonavalent group. It reports zero deaths in each group. It also lists other adverse event counts of 129 among 253 and 108 among 182, respectively. These counts describe events recorded in the registry; they do not by themselves establish that vaccination caused them. The record does not give a concurrent unvaccinated control group for safety comparison.
The registry lists three outcome measures and 23 analyses, but does not report the analysis plan, the handling of missing observations, or analysis populations. Multiple analyses can increase the chance of apparently notable findings if results are interpreted without regard to multiplicity. No adjustment strategy or hierarchy of tests is reported. As a result, the registry record supports a careful account of intended measurement and posted safety counts, but not a conclusion about the magnitude, precision, or statistical significance of the primary immune response comparison.
9. Statistical Methods Explained
The methods implied by the stated endpoint require attention to both the scale of antibody measurements and the historical comparison. The registry identifies geometric mean titers for HPV 16 and HPV 18, with standard deviation, at one month following vaccination dose #3. It does not report the actual values or the detailed estimation method. The explanations below describe general statistical concepts rather than methods confirmed to have been used in this study.
Why use a geometric mean for antibody titers?
Antibody titers are positive measurements that may have a right-skewed distribution: many observations can cluster at lower or middle values while a smaller number are much higher. An arithmetic mean can be pulled upward by extreme values. The geometric mean summarizes measurements on a multiplicative scale. In a common approach, values are transformed using logarithms, averaged on that scale, and transformed back. The result is expressed in the original measurement units but reflects multiplicative rather than additive differences.
Standard deviation describes dispersion on the scale on which it is calculated. For geometric means, it is important to know whether the reported standard deviation is on the original or log scale, or whether another summary convention was used. The registry names standard deviation but does not specify that detail. It also does not report whether antibody values below an assay’s detection limit occurred or how such values were handled.
What does non-inferiority ask?
A non-inferiority analysis asks whether the response in a target group is not worse than a comparator by more than a prespecified, acceptable amount. That amount is the non-inferiority margin. Statistical interpretation depends on the direction of the contrast, the margin, and an interval estimate for the contrast. If the interval is compatible with responses worse than the margin, the evidence does not establish non-inferiority. If the interval excludes differences beyond the margin in the unfavorable direction, that can support the stated criterion, subject to the design and assumptions.
The registry describes the comparator as an age- and sex-matched historical healthy population. Historical comparisons can be useful when a concurrent control is unavailable, but their validity depends on comparability across populations, measurement procedures, and time. Matching on age and sex does not necessarily ensure similarity in other characteristics. The registry record does not report the source population, matching procedures, adjustment methods, non-inferiority margin, or uncertainty estimate. Thus, the goal is clear, but the evidence needed to judge the comparison is not reported in the registry record.
Why do design features matter?
This is a single-group, open-label study with no randomized allocation. The registry also identifies quadrivalent and nonavalent vaccine groups and cautions against treating them as like-for-like controls. Without randomized assignment and a concurrent comparison group, a difference between these groups cannot automatically be attributed to vaccine type. The primary question instead uses historical healthy-population responses as a benchmark. Statistical adjustment can address measured differences, but it cannot guarantee that all relevant differences between historical and study populations have been removed.
Open-label status means the record does not describe masking of participants or study personnel. Antibody laboratory measures may be less subjective than self-reported outcomes, but the registry does not say whether laboratory personnel were masked. The methods for survey assessment and chart review are also not detailed enough to evaluate measurement consistency.
How should planning calculations be understood?
Any sample-size illustrations associated with this study are planning calculations, not observed power and not evidence about the trial’s actual design. The listed assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They use the observed effect as a reference and consider detecting specified portions of that effect. The registry’s planning assumptions also distinguish calculations expressed as participants per arm from time-to-event calculations expressed as total events. These are generic planning conventions; they do not establish that this single-group trial was designed with equal randomized allocation.
A planning calculation can show how sample size changes under different assumed effects and variability, but it cannot establish that a study had adequate power after the results are known. The trial’s own sample-size justification, target for the immunogenicity analysis, and assumptions about historical data are not reported in the registry record. The overall enrollment of 1499 should not be read as the number in the primary antibody analysis: the record does not report that analysis population or its size.
How should uncertainty be read?
A confidence interval is a range of values compatible with the observed data under a specified statistical model and procedure. Narrower intervals generally indicate greater precision, while wider intervals indicate more uncertainty. For a non-inferiority question, the interval must be read in relation to the margin and the direction of the comparison, rather than in isolation. Neither the primary confidence intervals nor the margin is reported in the registry record, so the precision of the primary estimate cannot be assessed.
Variability also matters. A standard deviation describes how individual measurements vary around a mean or other summary, while a confidence interval describes uncertainty in an estimated quantity. They answer different questions and should not be substituted for one another. The registry identifies standard deviation as the dispersion measure, but does not report values or clarify the analysis details needed to reconstruct uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists three outcome measures and 23 analyses. Multiple outcomes, time points, subgroups, or analytic choices can create multiplicity: when many statistical tests are conducted, the chance of at least one apparently unusual result can rise. This is a general statistical concern, not evidence that any particular result in this study is spurious. The registry record does not report a multiplicity adjustment, a prespecified testing hierarchy, or which analyses were designated confirmatory versus exploratory.
The primary endpoint description identifies two antibody targets, HPV 16 and HPV 18, but the registry does not report how success across the targets was defined or whether a joint criterion was used. The non-inferiority margin and statistical plan are not reported in the registry record. Without those details, it is not possible to determine how the analyses addressed multiple endpoints or what inferential threshold was intended for the primary aim.
Missing-data methods and analysis populations are also not reported in the registry record. The record does not state how many participants contributed antibody measurements, how incomplete vaccination or missed measurements were handled, or whether analyses used an intention-to-treat, per-protocol, or other population. In non-inferiority studies, different analysis populations can provide complementary checks because exclusions or nonadherence may affect estimates. That is a general consideration; no such analysis strategy can be attributed to this study from the registry record.
The registry’s overall enrollment is 1499, while safety group denominators are smaller. These figures refer to different reported quantities and do not identify the primary endpoint analysis population. The record does not explain the flow from enrollment to the immune response analysis. Consequently, the completeness and representativeness of the primary outcome data cannot be assessed from the registry record.
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 |
|---|---|---|---|
| Prevention (Vaccine Therapy)- Quadrivalent | 11 | 253 | 4.3% |
| Prevention (Vaccine Therapy)- Nonavalent Vaccine | 7 | 182 | 3.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Prevention (Vaccine Therapy)- Quadrivalent | 0 of 253 |
| Prevention (Vaccine Therapy)- Nonavalent Vaccine | 0 of 182 |
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 |
|---|---|
| Prevention (Vaccine Therapy)- Quadrivalent | 129 of 253 |
| Prevention (Vaccine Therapy)- Nonavalent Vaccine | 108 of 182 |
Most frequent serious adverse event terms
| Event term | Organ system | Prevention (Vaccine Therapy)- Quadrivalent | Prevention (Vaccine Therapy)- Nonavalent Vaccine |
|---|---|---|---|
| Relapse of primary cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 3 of 253 | 1 of 182 |
| Hospitalization for musculoskeletal issue | Musculoskeletal and connective tissue disorders | 4 of 253 | 0 of 182 |
| Pregnancy | Pregnancy, puerperium and perinatal conditions | 2 of 253 | 1 of 182 |
| Hospitalization for endocrine disorder | Endocrine disorders | 2 of 253 | 0 of 182 |
| Subsequent malignant neoplasm | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 253 | 1 of 182 |
| Erythema nodosum | Skin and subcutaneous tissue disorders | 0 of 253 | 1 of 182 |
| Hospitalization for fluid-electrolyte disorder | Metabolism and nutrition disorders | 0 of 253 | 1 of 182 |
| Hospitalization for neurologic disorder | Nervous system disorders | 0 of 253 | 1 of 182 |
| Hospitalization for psychiatric disorder | Psychiatric disorders | 0 of 253 | 1 of 182 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Prevention (Vaccine Therapy)- Quadrivalent | Prevention (Vaccine Therapy)- Nonavalent Vaccine |
|---|---|---|---|
| Injection Site Pain or Tenderness, any | General disorders | 90 of 253 | 84 of 182 |
| Headache | General disorders | 51 of 253 | 33 of 182 |
| Fatigue | General disorders | 47 of 253 | 24 of 182 |
| Nausea | Gastrointestinal disorders | 29 of 253 | 41 of 182 |
| Injection Site Erythema, any | General disorders | 15 of 253 | 17 of 182 |
| Fever (≥100.0⁰F) | General disorders | 17 of 253 | 15 of 182 |
| Injection Site Swelling, any | General disorders | 15 of 253 | 15 of 182 |
Serious events with the highest arm-level rate: hospitalization for musculoskeletal issue (1.6%), relapse of primary cancer (1.2%), pregnancy (0.8%), hospitalization for endocrine disorder (0.8%), subsequent malignant neoplasm (0.5%).
The registry reports serious adverse event counts by vaccine group. In the quadrivalent group, 11 participants were affected among 253 at risk; in the nonavalent group, 7 were affected among 182 at risk. Deaths are recorded as zero in both groups. The registry also reports other adverse event counts of 129 among 253 and 108 among 182, respectively. These are descriptive counts, not a randomized safety comparison.
The listed serious event terms include hospitalization for musculoskeletal issue at 1.6%, relapse of primary cancer at 1.2%, pregnancy at 0.8%, hospitalization for endocrine disorder at 0.8%, subsequent malignant neoplasm at 0.5%, and erythema nodosum at 0.5%. The registry does not identify these listed percentages as group-specific, nor does the record establish that the events were caused by vaccination. Serious events may have varied in nature and timing; detailed case-level information is not reported in the registry record.
Because the study is single-group and does not provide a randomized unvaccinated safety comparator, the counts cannot isolate vaccine-attributable risk. The denominators describe participants at risk in the listed groups, but the registry record does not provide follow-up duration or a comparative analysis accounting for exposure time. These data describe reported safety experience, not proof of causation or a direct comparison between vaccine types.
12. What the Result Does, and Does Not, Mean
The registry record supports a description of the study’s purpose: assessing HPV vaccine initiation, immune response, and safety/tolerability among young cancer survivors. Its primary endpoint was antibody response to HPV 16 and 18, measured one month after dose #3, with an intended non-inferiority comparison to age- and sex-matched historical healthy populations. The study is recorded as completed, but completion status does not itself indicate the outcome.
The posted record does not report the numerical primary antibody results, confidence intervals, non-inferiority margin, or test result. It therefore does not show whether the intended non-inferiority criterion was met or how precisely the response was estimated. A purpose statement is not a result, and absence of the numerical result in the registry record should not be interpreted as evidence for either a favorable or unfavorable conclusion.
The safety information is also descriptive. Serious adverse event counts and selected event terms are recorded, along with zero deaths in each vaccine group. The single-group design and lack of a concurrent randomized control mean these figures cannot establish that vaccination caused the events, nor can they establish that the two vaccine groups had equivalent safety. The registry does not report a causal safety analysis.
More broadly, the study does not provide a randomized comparison of quadrivalent versus nonavalent vaccine. Its historical comparator is relevant to the stated primary aim but raises questions about population comparability and measurement that cannot be resolved from the posted record. The registry does not report the methods needed to assess these issues in detail. The defensible interpretation is therefore limited: the record describes a completed phase II study and its intended questions, but does not contain enough numerical primary outcome information to judge the immune response comparison.
13. Why This Trial Matters Statistically
This study raises statistical questions that are common in clinical research when randomization is not part of the design. Its primary aim compares a post-vaccination antibody response in cancer survivors with a historical healthy-population benchmark. That makes the choice and comparability of the external reference central to interpretation. Age and sex matching are stated, but the registry record does not report the details needed to assess how well the populations align or whether other differences were addressed.
The endpoint also illustrates why scale matters. Antibody titers are summarized with geometric means, a measure suited to multiplicative data and often-skewed distributions. Interpreting such a summary requires knowing the underlying analysis and uncertainty, not only the central estimate. The registry identifies standard deviation as the dispersion measure but does not include the primary numerical results or confidence intervals.
Non-inferiority questions require more than comparing two reported averages. A prespecified margin defines what degree of lower response would be considered acceptable, and an interval estimate must be evaluated against that margin. Neither the margin nor the result is reported in the registry record. This makes it especially important not to infer success from the stated aim.
Finally, the registry lists two vaccine groups but cautions that they are not a like-for-like control comparison. This is a useful reminder that having multiple groups does not by itself create a controlled comparative trial. Design, allocation, population comparability, and analysis determine what claims a contrast can support. The posted safety counts likewise provide descriptive context without a randomized comparator or causal attribution.
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 immediate limitation of interpretation is that numerical results for the primary immunogenicity endpoint are not reported in the registry record. The non-inferiority margin, confidence intervals, statistical test, and results for HPV 16 and HPV 18 are also not reported. The stated objective therefore cannot be assessed against its criterion from this record.
The historical healthy-population comparator is not a concurrent randomized control. Although the endpoint description refers to age- and sex-matched populations, the record does not report the source of the historical data, matching procedures, assay comparability, or adjustment for other differences. These omissions limit assessment of the validity and precision of the historical comparison.
The registry describes a single-group, open-label trial and specifically cautions that the quadrivalent and nonavalent groups are not a like-for-like control comparison. It does not report randomized allocation between products. Consequently, the group labels should not be used to imply a causal head-to-head effect. The record also does not report the full dosing schedule in the available arm description or detailed vaccine exposure information.
Analysis populations, missing-data procedures, outcome-specific sample sizes, and participant flow into the primary analysis are not reported in the registry record. The total enrollment of 1499 does not establish how many participants contributed to the primary endpoint. The statistical plan, multiplicity approach, and sample-size justification are also absent. Safety interpretation is constrained by the lack of a concurrent control and by the absence of detailed event timing, duration of follow-up, and causal assessment. These limitations concern what can be concluded from the registry record, not necessarily what may be described in other study materials.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Vaccine Therapy in Preventing Human Papillomavirus Infection in Younger Cancer Survivors — NCT01492582.
- Registry record last updated 2021-10-27; status last verified 2021-10.
- Results first posted 2020-04-30.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
This completed phase II study evaluated HPV vaccine initiation, immune response, and safety/tolerability among cancer survivors ages 9 to 26 years. The registry lists enrollment of 1499 and describes a cross-sectional survey alongside an open-label vaccine trial. Quadrivalent and nonavalent vaccines are listed, and the study is recorded as single-group with no masking.
The primary endpoint is the geometric mean titer for antibodies to HPV 16 and 18 one month following vaccination dose #3. Its stated aim is non-inferiority compared with age- and sex-matched historical healthy populations. Numerical primary endpoint results, the non-inferiority margin, and the analysis details are not reported in the registry record.
Safety entries include serious adverse event-affected counts of 11 among 253 and 7 among 182 in the two vaccine groups, with zero deaths recorded in each. The registry cautions that the vaccine groups are not a like-for-like control comparison. These safety entries are descriptive and do not establish causation.