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 Immunogenicity and Safety Study of a Vaccine Against Lyme Borreliosis, in Healthy Adults Aged 18 to 65 Years. Randomized, Controlled, Observer-blind Phase 2 Study. (NCT03769194), a randomized phase 2 study. The primary outcome is GMTs (Geometric Mean Titers) for IgG (Immunoglobulin G) Against Each OspA (Outer Surface Protein A) Serotype ST1 to ST6.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03769194 |
| Phase | Phase 2 |
| Condition | Lyme Borreliosis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 572 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Healthy adults aged 18 to 65 years were eligible for this study. The registry record describes the analyzed primary-outcome population as participants in the per-protocol population, with geometric mean titers calculated using participants who had non-missing results. The record does not give further details about the eligibility criteria or the characteristics of the analyzed participants.
Intervention
The intervention was VLA15, a multivalent recombinant OspA-based vaccine candidate against Lyme borreliosis. Participants were assigned to low-, medium-, or high-dose VLA15; the arm descriptions state that each dose was given with Alum. The study summary says participants received three immunizations at monthly intervals.
Comparator
The comparator was placebo. The study is described as randomized, controlled, and observer-blind. Its registry masking classification is quadruple. The registry record does not provide further detail about which study roles were masked or how the placebo was administered.
Primary question
The primary outcome was the geometric mean titer of IgG against each of the OspA serotypes ST1 to ST6, measured by ELISA at Day 85 / Month 3 and expressed in U/mL. In practical terms, the outcome describes the level of serotype-specific antibody response in the analyzed participants. The record defines the measurement but does not report the numerical titers or confidence intervals by study arm. It therefore does not establish from the posted primary-outcome results how the groups differed.
3. Trial Design
This was a randomized, controlled, observer-blind Phase 2 study of a vaccine candidate against Lyme borreliosis. The registry record classifies the study as quadruple-masked, with a parallel-group model and randomized allocation. It was conducted at multiple centers and included a run-in phase and a main study phase, according to the study summary. The record describes healthy adults aged 18 to 65 years as the study population and reports an enrollment of 572.
Participants were assigned to low-, medium-, or high-dose VLA15 or placebo. The arm descriptions specify Alum with each VLA15 dose. The study summary states that participants received three immunizations at monthly intervals. The primary assessment was at Day 85 / Month 3. The registry record also lists immunogenicity outcomes at other time points and in age subgroups, but does not give enough information to describe the full schedule of those assessments.
The primary endpoint was serotype-specific IgG geometric mean titers for OspA serotypes ST1 to ST6, determined by ELISA. Secondary outcomes included serotype-specific titers, seroconversion rates, and geometric mean fold rise from baseline, with some outcomes considered separately for participants aged 18 to 49 years and 50 to 65 years. The listed outcomes reflect immunogenicity and safety objectives; the registry record does not report a clinical Lyme borreliosis endpoint.
The record labels the study completed and gives a start date of 2018-12-17 and a primary completion date of 2019-12-18. These administrative details identify the recorded study timeline but do not substitute for outcome data. Numerical primary-endpoint results and arm-level comparisons 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 | VLA15 Low Dose | VLA15 Medium Dose | VLA15 High Dose | Placebo |
|---|---|---|---|---|
| STARTED | 29 | 214 | 205 | 124 |
| COMPLETED | 25 | 196 | 197 | 115 |
| NOT COMPLETED | 4 | 18 | 8 | 9 |
Reasons for not completing this period:
| Reason | VLA15 Low Dose | VLA15 Medium Dose | VLA15 High Dose | Placebo |
|---|---|---|---|---|
| Withdrawal by Subject | 0 | 7 | 4 | 1 |
| moved from study area | 0 | 2 | 1 | 1 |
| Lost to Follow-up | 3 | 6 | 3 | 6 |
| other | 1 | 3 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Overall Number of Participants Analyzed Per Protocol population
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 | VLA15 Low Dose | VLA15 Medium Dose | VLA15 High Dose | Placebo | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 29 | 214 | 205 | 124 | 572 | |
| Age, Continuous | years | 29.2 (SD 6.13) | 41.7 (SD 13.26) | 41.6 (SD 12.56) | 40.7 (SD 12.80) | 40.8 (SD 12.90) |
| Sex: Female, Male: Female | Participants | 16 | 117 | 108 | 71 | 312 |
| Sex: Female, Male: Male | Participants | 13 | 97 | 97 | 53 | 260 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | number of participants | 0 | 1 | 0 | 0 | 1 |
| Race/Ethnicity, Customized: Asian | number of participants | 0 | 2 | 0 | 0 | 2 |
| Race/Ethnicity, Customized: Black or African American | number of participants | 4 | 3 | 6 | 4 | 17 |
| Race/Ethnicity, Customized: Native Hawaiian or Other Pacific Islander | number of participants | 0 | 0 | 0 | 0 | 0 |
| Race/Ethnicity, Customized: White | number of participants | 25 | 208 | 196 | 120 | 549 |
| Race/Ethnicity, Customized: Other | number of participants | 0 | 0 | 3 | 0 | 3 |
6. Primary Endpoint
The registry lists the primary outcome as GMTs (Geometric Mean Titers) for IgG (Immunoglobulin G) Against Each OspA (Outer Surface Protein A) Serotype ST1 to ST6, measured over at Day 85 / Month 3.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | U/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint measures geometric mean titers of IgG antibodies against each OspA serotype, ST1 to ST6. Titers were determined by ELISA and are expressed in U/mL. The planned assessment is identified as Day 85 / Month 3. The registry record states that the geometric mean titers were calculated from participants with non-missing results in the overall per-protocol population.
A geometric mean is a way to summarize measurements that are positive and may vary substantially in scale. In general, this summary is calculated on a logarithmic scale and then expressed back on the original measurement scale. It can be a useful description of antibody levels when a small number of high values might otherwise strongly influence an arithmetic average. The geometric mean does not describe every participant’s result or the spread of individual responses.
The endpoint is used to characterize the antibody response to each vaccine-targeted serotype. Reporting the serotypes separately matters because an overall value could conceal different response patterns across them. The confidence interval is intended to convey uncertainty around the estimated geometric mean; narrower intervals generally indicate greater precision, while wider intervals indicate less precision. The registry record specifies a 95% confidence interval for the endpoint but does not report its numerical limits or the titer estimates. As a result, the endpoint definition is available, but its observed values and precision cannot be assessed from the posted primary results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a study designed to measure immunogenicity and safety, but its posted primary-outcome information is a definition rather than a set of numerical results. It names geometric mean IgG titers for OspA serotypes ST1 to ST6, identifies ELISA as the measurement method, and specifies Day 85 / Month 3. It does not report the arm-specific estimates, their 95% confidence intervals, or numerical contrasts between VLA15 dose groups and placebo. Those missing estimates prevent a quantitative interpretation of the primary endpoint.
The outcome is not a single pooled antibody result. It includes multiple serotypes, and the record lists several VLA15 dose groups and a placebo group. The registry also lists secondary outcomes for seroconversion rates and geometric mean fold rise, including age-subgroup outcomes. The record’s note that the primary outcome has several categories or time points and is not reduced to one comparison is important: a single summary comparison would not represent all the outcome dimensions identified in the record. Without the corresponding estimates and analysis details, the magnitude and precision of any group differences cannot be evaluated.
Confidence intervals, when reported, help show the range of values compatible with the data under the statistical model. They are not guarantees that the true value lies within a particular interval, and they do not by themselves establish the importance of an observed difference. Here, the interval method is identified, but the limits are not reported in the registry record. No p-values or formal treatment-effect estimates are reported for the primary outcome, so there is no basis in this record for describing statistical significance.
The safety information does include counts of participants with serious adverse events and other adverse events by group. These are descriptive counts, not randomized comparisons with reported uncertainty. The groups are not the same size, and no adjusted analysis or formal comparison is reported. Such counts can describe what was recorded in the study, but they do not by themselves establish whether an event was caused by an intervention or how reliably event frequencies differ between groups.
The study’s completion status and enrollment indicate that the trial was registered as completed with 572 participants enrolled. They do not reveal how many participants contributed to each endpoint, whether every randomized participant was included in each analysis, or how missing observations affected the results. These details are not reported in the registry record. The defensible interpretation is therefore limited: the trial plan and some safety counts are documented, while the numerical immunogenicity findings needed to assess the primary outcome are not reported.
9. Statistical Methods Explained
The registry record identifies a geometric mean as the summary measure for the primary immunogenicity outcome. The endpoint comprises IgG titers against OspA serotypes ST1 to ST6, determined by ELISA and expressed in U/mL at Day 85 / Month 3. The stated confidence-interval measure is 95%. The analysis population is described as the overall per-protocol population, and the geometric means are calculated from participants with non-missing results. These descriptions establish what was intended to be summarized, but the numerical estimates and the detailed statistical procedures are not reported in the registry record.
What does a geometric mean describe?
In general, a geometric mean summarizes measurements after applying a logarithmic transformation, averaging on that transformed scale, and converting the summary back to the original scale. This approach can be appropriate for positive measurements whose values span a wide range or whose distribution is asymmetric. Compared with an arithmetic mean, a geometric mean is less dominated by very large observations. It is a summary of the group, not a description of each participant’s antibody level or the proportion of participants who reached a particular threshold.
Because the endpoint is reported separately for ST1 to ST6, each value would summarize antibody titers for a particular serotype. The record does not state a single combined score across serotypes. In general, separate endpoints can reveal whether response patterns vary by target, but they also create multiple results to interpret. The numerical titers are absent, so it is not possible to characterize the size or pattern of the recorded responses.
How should a confidence interval be read?
In general, a confidence interval expresses statistical uncertainty around an estimate under the assumptions of the analysis. Its width reflects precision: an estimate with a wider interval is less precisely determined than one with a narrower interval, all else being equal. A confidence interval is not a range containing a fixed proportion of individual participant values. Nor does overlap or non-overlap alone provide a complete test of a difference between groups; the comparison estimate and its uncertainty are the relevant quantities for that question.
The registry record specifies 95% confidence intervals but does not report their bounds. It also does not give the method used to construct them, such as the assumed distribution, transformation details, or handling of values below or above assay limits. Those analytic choices can matter for antibody measurements. They are not reported in the registry record and should not be inferred from the endpoint label.
What do the secondary immunogenicity measures add?
The listed secondary outcomes include geometric mean titers, seroconversion rates, and geometric mean fold rise from baseline. In general, a seroconversion rate summarizes the proportion meeting a specified change or threshold; the exact definition is needed to interpret it. A geometric mean fold rise describes the average multiplicative change from baseline on a transformed scale. These measures answer different questions from a titer at a particular assessment: a post-vaccination titer describes the level at assessment, while a change measure relates that level to baseline. The record lists these outcomes but does not provide the numerical results or the operational definition used for seroconversion.
The record also identifies some secondary outcomes by age group, with groups aged 18 to 49 years and 50 to 65 years. Subgroup results can describe whether estimates differ across the listed age categories, but subgroup estimates often have less precision than an overall estimate. In general, an apparent difference between subgroup estimates does not itself establish that the effect differs by subgroup; that requires an appropriate interaction analysis. Such an analysis is not reported in the registry record.
What can be learned from the safety counts?
Safety counts are descriptive summaries of participants with recorded events. A count alongside the number at risk provides context for how many participants were represented in that group. It does not by itself provide an adjusted comparison, account for duration of observation, or establish causation. In general, interpretation also depends on event definitions, collection procedures, severity and timing, and whether events were judged related to study intervention. Those details are not reported in the registry record. The counts should therefore be read as recorded events within the study groups, not as proof of a causal effect or a precise estimate of comparative risk.
The registry record includes serious-event counts, other adverse-event counts, and a list of serious terms with percentages. It does not provide a formal statistical comparison of these safety data. The group counts may be useful for descriptive context, but differences between counts should not be treated as statistically established differences. No new comparison or rate calculation is made from these summaries.
Why is the missing numerical output consequential?
A statistical method is interpretable only alongside the estimate it produced and enough information to understand its uncertainty. Here, the endpoint definition and confidence-interval type are recorded, but the titers, intervals, and formal comparisons are absent. The registry record lists 20 outcome measures and 0 analyses. It does not report whether analyses were adjusted, which hypotheses were prioritized, or whether any interim analyses were conducted. These omissions prevent a full assessment of the statistical evidence and make it inappropriate to infer an effect from the trial design alone.
10. Multiplicity, Missing Data and Analysis Populations
The record lists multiple outcomes: serotype-specific IgG geometric mean titers for ST1 to ST6, seroconversion rates, and geometric mean fold rises, with some measures also listed for age subgroups. Multiple endpoints and groups create a multiplicity issue in general: when many statistical questions are examined, the chance of at least one apparently unusual result can increase. How that concern is handled depends on the prespecified analysis plan, such as an ordering of outcomes or an adjustment procedure. The registry record does not report a multiplicity strategy, a hierarchy of hypotheses, or adjusted inferential results.
The primary endpoint description says that calculations use participants with non-missing results and identifies the overall per-protocol population. This indicates that the summarized titers do not include participants without a result for the relevant measure. It does not explain why data were missing, how much was missing, whether missingness differed by group, or whether any imputation or sensitivity analysis was used. Those details are not reported in the registry record.
The record does not give the number analyzed for each endpoint or a complete account of exclusions from the per-protocol population. It also does not report interim analyses or enough detail about the statistical analysis plan to assess whether the outcomes and analyses were selected before results were known. The listed enrollment cannot be assumed to equal the analysis population for any particular endpoint. These limits matter because both missingness and analysis-population definitions can affect estimates and their interpretation.
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 |
|---|---|---|---|
| VLA15 Low Dose | 0 | 29 | 0.0% |
| VLA15 Medium Dose | 4 | 214 | 1.9% |
| VLA15 High Dose | 5 | 205 | 2.4% |
| Placebo | 3 | 124 | 2.4% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| VLA15 Low Dose | 0 of 29 |
| VLA15 Medium Dose | 0 of 214 |
| VLA15 High Dose | 0 of 205 |
| Placebo | 0 of 124 |
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 |
|---|---|
| VLA15 Low Dose | 26 of 29 |
| VLA15 Medium Dose | 203 of 214 |
| VLA15 High Dose | 202 of 205 |
| Placebo | 85 of 124 |
Most frequent serious adverse event terms
| Event term | Organ system | VLA15 Low Dose | VLA15 Medium Dose | VLA15 High Dose | Placebo |
|---|---|---|---|---|---|
| Cellulitis | Infections and infestations | 0 of 29 | 1 of 214 | 0 of 205 | 0 of 124 |
| Herpes zoster | Infections and infestations | 0 of 29 | 0 of 214 | 1 of 205 | 0 of 124 |
| Multiple injuries | Injury, poisoning and procedural complications | 0 of 29 | 0 of 214 | 1 of 205 | 0 of 124 |
| Urinary retention | Renal and urinary disorders | 0 of 29 | 1 of 214 | 0 of 205 | 0 of 124 |
| Appendicitis | Infections and infestations | 0 of 29 | 1 of 214 | 0 of 205 | 0 of 124 |
| Diverticulitis | Infections and infestations | 0 of 29 | 0 of 214 | 0 of 205 | 1 of 124 |
| Neurosyphilis | Infections and infestations | 0 of 29 | 0 of 214 | 0 of 205 | 1 of 124 |
| Upper limb fracture | Injury, poisoning and procedural complications | 0 of 29 | 0 of 214 | 1 of 205 | 0 of 124 |
| Acute myocardial infarction | Cardiac disorders | 0 of 29 | 0 of 214 | 0 of 205 | 1 of 124 |
| Biliary colic | Hepatobiliary disorders | 0 of 29 | 0 of 214 | 0 of 205 | 1 of 124 |
Most frequent non-serious adverse event terms
| Event term | Organ system | VLA15 Low Dose | VLA15 Medium Dose | VLA15 High Dose | Placebo |
|---|---|---|---|---|---|
| Injection site pain | General disorders | 26 of 29 | 198 of 214 | 196 of 205 | 30 of 124 |
| Myalgia | Musculoskeletal and connective tissue disorders | 15 of 29 | 106 of 214 | 97 of 205 | 21 of 124 |
| Headache | Nervous system disorders | 10 of 29 | 73 of 214 | 84 of 205 | 33 of 124 |
| Fatigue | General disorders | 8 of 29 | 66 of 214 | 81 of 205 | 29 of 124 |
| Injection site erythema | General disorders | 8 of 29 | 68 of 214 | 72 of 205 | 12 of 124 |
| Injection site induration | General disorders | 3 of 29 | 64 of 214 | 65 of 205 | 2 of 124 |
| Injection site swelling | General disorders | 4 of 29 | 57 of 214 | 68 of 205 | 4 of 124 |
| Influenza like illness | General disorders | 3 of 29 | 32 of 214 | 42 of 205 | 20 of 124 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 2 of 29 | 42 of 214 | 37 of 205 | 12 of 124 |
| Nausea | Gastrointestinal disorders | 5 of 29 | 23 of 214 | 32 of 205 | 11 of 124 |
Serious events with the highest arm-level rate: diverticulitis (0.8%), neurosyphilis (0.8%), acute myocardial infarction (0.8%), biliary colic (0.8%), herpes zoster (0.5%).
The registry record reports serious adverse events for each study group as a count of affected participants alongside the number at risk: VLA15 low dose, 0 of 29; VLA15 medium dose, 4 of 214; VLA15 high dose, 5 of 205; and placebo, 3 of 124. It reports 0 deaths in each group. These are descriptive counts. They do not indicate whether an event was judged related to study intervention, and the record does not provide a formal statistical comparison or uncertainty estimates for these counts.
For other adverse events, the record reports 26 of 29 in the VLA15 low-dose group, 203 of 214 in the medium-dose group, 202 of 205 in the high-dose group, and 85 of 124 in the placebo group. These counts should be interpreted according to the registry’s event category; they do not identify the nature, severity, or duration of each event. A count of participants with events is distinct from a count of all event episodes.
The listed serious terms include Diverticulitis, Neurosyphilis, Acute myocardial infarction, and Biliary colic, each at 0.8%, and Herpes zoster and Multiple injuries, each at 0.5%. The record does not identify the group attribution for those terms in this summary. The figures alone cannot establish causality or comparative risk.
12. What the Result Does, and Does Not, Mean
This record documents a randomized Phase 2 study of VLA15 at low, medium, and high doses against placebo in healthy adults aged 18 to 65 years. It specifies an immunogenicity endpoint based on IgG geometric mean titers against OspA serotypes ST1 to ST6, measured by ELISA at Day 85 / Month 3. It also lists seroconversion and fold-rise outcomes, including some age-subgroup measures, and reports descriptive safety counts.
The registry record does not report the numerical primary-endpoint results. It gives no arm-specific geometric mean titers, no 95% confidence-interval limits, and no numerical comparisons between dose groups and placebo. Consequently, the posted information does not allow readers to assess the magnitude, precision, or pattern of the antibody responses. The endpoint definition alone is not evidence that a particular response was observed, and the trial’s completion status does not fill this gap.
The study’s immunogenicity outcomes concern antibody measurements. They are not themselves a reported clinical outcome of Lyme borreliosis. The registry record does not provide a result showing whether participants developed Lyme borreliosis or whether vaccination changed that outcome. Nor does the record’s safety summary establish that any listed event was caused by a study intervention.
The study can be described as a randomized, controlled comparison with a defined vaccine candidate, placebo, dose groups, and antibody outcomes. However, the absence of numerical outcome results and detailed analysis methods limits what can be concluded statistically. No conclusion about the direction, size, or statistical certainty of an immunogenicity difference can be drawn from the posted primary-outcome information. The safety counts remain descriptive rather than formal comparative estimates.
13. Why This Trial Matters Statistically
This trial is statistically notable for its structure: it compares three VLA15 dose groups with placebo and defines serotype-specific antibody outcomes. The outcome set includes geometric mean titers, seroconversion rates, and geometric mean fold rises, with additional measures by age subgroup. These distinct summaries address different aspects of antibody response, so they should not be treated as interchangeable or compressed into a single result without a stated rationale.
The primary endpoint is measured separately for OspA serotypes ST1 to ST6. That allows serotype-level description rather than assuming one antibody response represents all targets. At the same time, multiple outcomes and groups make interpretation dependent on a transparent analysis plan, including how comparisons were prioritized and how multiplicity was addressed. Such details are not reported in the registry record.
The endpoint also illustrates why estimates and uncertainty must accompany a statistical definition. A geometric mean and a 95% confidence interval describe a planned summary and its intended precision framework, but without the actual values readers cannot evaluate the observed response or compare groups. The record reports an analysis population and says that non-missing results were used, yet does not describe missing-data patterns or the number analyzed for each outcome.
The safety counts show another distinction in trial reporting: descriptive event summaries are not equivalent to a comparative safety analysis. Counts can tell readers how many participants were recorded in each category, while causal interpretation and estimates of between-group uncertainty require additional information. The available registry entries therefore make the study design and intended statistical questions visible, while leaving key evidence needed to answer those questions unreported.
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 central limitation is that numerical results for the primary endpoint are not reported in the registry record. The endpoint is defined, including its assay, unit, assessment time, and confidence-interval type, but the titers and interval bounds are absent. Without them, the antibody response cannot be quantified or compared across the VLA15 dose groups and placebo. The record also does not report numerical results for the listed secondary immunogenicity outcomes.
The analysis description is limited. The registry identifies the overall per-protocol population and says that geometric mean titers are based on non-missing results, but it does not explain the per-protocol criteria, the number analyzed for each outcome, or the extent and handling of missing data. It does not report the statistical model, interval-construction method, adjustment factors, or formal comparisons. Multiplicity handling and interim analyses are not reported in the registry record.
Some safety information is available as counts, but the record does not provide inferential comparisons, confidence intervals, event timing, or the relationship of events to intervention. The listed serious-event terms are not attributed to individual study groups in the summary. The counts therefore support description of recorded events, not a causal or comparative conclusion.
The registered primary outcome is an antibody measure rather than a reported clinical Lyme borreliosis outcome. The record also does not provide enough information to assess whether the analysis population represents all randomized participants. These limitations constrain interpretation to the design, endpoint definitions, and descriptive safety information that are recorded.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Immunogenicity and Safety Study of a Vaccine Against Lyme Borreliosis, in Healthy Adults Aged 18 to 65 Years. Randomized, Controlled, Observer-blind Phase 2 Study. — NCT03769194.
- Registry record last updated 2023-01-10; status last verified 2022-12.
- Results first posted 2021-06-30.
- 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.
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18. Record Summary
The registry record describes NCT03769194 as a completed, randomized, controlled, observer-blind Phase 2 study of VLA15 for Lyme borreliosis in healthy adults aged 18 to 65 years. It reports an enrollment of 572, a parallel-group model, and quadruple masking. The study compared low-, medium-, and high-dose VLA15 with placebo; the vaccine arms included Alum. Participants received three immunizations at monthly intervals, according to the study summary.
The primary outcome was IgG geometric mean titers against OspA serotypes ST1 to ST6, measured by ELISA at Day 85 / Month 3 in the overall per-protocol population. The record specifies a 95% confidence interval and says calculations use participants with non-missing results. Numerical primary-outcome estimates and formal comparisons are not reported in the registry record. Safety information includes group-specific counts of serious and other adverse events, with 0 deaths in each group.