Virus DiseasesPhase 4NCT03294135

The Aim of This Study is to Investigate the Persistence of Antibody Response in Adults up to 15 Years After One Booster Dose of GlaxoSmithKline (GSK) Biologicals' Encepur Adults Vaccine

A Phase 4 study testing Encepur Adults in people with Virus Diseases, run by GlaxoSmithKline at 1 site in Czechia.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

The purpose of this study is to continue the evaluation of antibody persistence through 11 to 15 years after first booster with Tick-Borne Encephalitis (TBE) vaccine. This study will further investigate the booster response in subjects who will receive their second booster dose* in this study. Read more about this study

Who is it for?: Ages 25 years and olderHealthy volunteers can take part
Conditions the study is for: Virus Diseases
What is being tested?: Encepur Adults
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 194 participants
Where: 1 siteCzechia
Study dates: 5 Oct 2017to 25 Oct 2021
Phase: Phase 4
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 25 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol.
Written informed consent obtained from the subject prior to performance of any study specific procedure.
Subjects who have participated in study V48P7E2 (NCT01562444) and who received in the parent V48P7 study one of the following schedules: rapid, conventional, or accelerated conventional and a booster vaccination in study V48P7E1 (NCT00387634) or before study V48P7E1 (NCT00387634) (only rapid schedule).
Additional inclusion criteria for subjects who will need a second booster dose:
Healthy subjects as established by medical history and clinical examination before entering into the study.
Female subjects of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy or post-menopause.
Female subjects of childbearing potential can receive the booster vaccine in the study, if the subject: has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination, and has agreed to continue adequate contraception for 2 months after booster administration.

Who cannot join

Each subject must not be:
Unwilling or unable to give written informed consent to participate in the study.
Perceived to be unreliable or unavailable to complete the study.
Each subject must not have:
Clinical conditions representing a contraindication to blood draws.
Any other clinical condition that, in the opinion of the investigator, might interfere with the results of the study or pose additional risk to the subject due to participation in the study.

Show all 29Show fewer

Received an investigational or non-registered medicinal product within 30 days prior to informed consent.
Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product.
Levels of NT<10 in V48P7E2 (NCT01562444) study.
Previous vaccination against TBE or other Flavivirus diseases with other TBE and Flavivirus vaccines (e.g. Yellow fever vaccine, Dengue fever vaccine, Japanese encephalitis vaccine) before, during and after completion of the V48P7E2 (NCT01562444) and before starting TBEV POLYGELINE FREE-025 EXT 21 study.
Primary immunization with TBE vaccine in the parent study V48P7 according to the modified conventional (MC) schedule.
History of confirmed TBE infection.
Known exposure to other Flaviviruses.
Each subject who will receive the second booster vaccination in this study additionally to the exclusion criteria above must not have:
Hypersensitivity, including allergy, to any component of vaccines, medicinal products or medical equipment whose use is foreseen in this study.
Clinical conditions representing a contraindication to intramuscular vaccination.
Progressive, unstable or uncontrolled clinical conditions.
Abnormal function of the immune system resulting from: Clinical conditions. Systemic administration of corticosteroids for more than 14 consecutive days within 90 days prior to informed consent. This will mean prednisone ≥20 mg/day (for adult subjects) or equivalent. Inhaled and topical steroids are allowed. Administration of antineoplastic and immuno-modulating agents or radiotherapy within 90 days prior to vaccination.
Received immunoglobulins or any blood products within 180 days prior to vaccination.
Administration of long-acting immune-modifying drugs at any time during the study period.
Acute disease and/or fever at the day of booster vaccination.
Expected general decrease in immune response.
Organic brain disturbances, including seizure disorders.
Progressive neurological disorders.
Suffered febrile or afebrile convulsions.
Serious chronic illness.
History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine or chemically related substances.
Individuals who received any other vaccines within 14 days (for inactivated vaccines) or 28 days (for live vaccines) prior to vaccination in this study or who are planning to receive any vaccine within 28 days from the study vaccines.
Pregnant.

Trial locations and contacts

1 site in 1 country.

Czechia1 site

GSK Investigational Site
Hradec Králové, 50002

Other trials in Czechia

About this study

Official title: Long Term Immunogenicity up to 15 Years After the First Booster Immunization With GSK Biologicals' Encepur Adults (Polygeline-free Tick-Borne Encephalitis Vaccine for Adults) in Adults Who Received 1 of 3 Different Primary Vaccination Schedules

Any booster given in this study will be the second that the subject has received (with regard to the follow-up of the previous study).

Conditions: Virus Diseases
Being tested: Encepur Adults
Keywords: Encepur, Adults, Long term immunogenicity, Tick-borne Encephalitis vaccine, Booster
Medical subject headings: Virus Diseases

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Encepur AdultsBiological
One dose of the vaccine can be administered at any one unscheduled visit depending on the detection of NT below 10. It will be administered intramuscularly into the non-dominant deltoid.

Study groups in NCT03294135
Study group	Role	What they receive
Conventional Group	Experimental	Participants who received primary vaccination in study V48P7 on Days 0, 28 (+10) and 300 (+21) (55 participants) and who received a booster vaccination in study V48P7E1 (NCT00387634) (55 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their Neutralization Test (NT) titer resulted below 10. Receives: Biological: Encepur Adults
Accelerated/Rapid Group	Experimental	Participants who received primary vaccination in study V48P7 on Days 0, 7 (+3) and 21 (+7) (66 participants) and who received a booster vaccination either in study V48P7E1 (NCT00387634) (9 participants) or before enrolment in study V48P7E1 (NCT00387634) (40 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their NT titer resulted below 10. Receives: Biological: Encepur Adults
Accelerated Conventional Group	Experimental	Participants who received primary vaccination in study V48P7 on Days 0, 14 (+3) and 300 (+21) (133 participants) and who received a booster vaccination in study V48P7E1 (NCT00387634) (109 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their NT titer resulted below 10. Receives: Biological: Encepur Adults

What is being measured

The primary outcome is the main question the study is designed to answer.

Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 11
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Measured: At Year 11
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 12
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Measured: At Year 12
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 13
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Measured: At Year 13
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 14
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Measured: At Year 14
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 15
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Measured: At Year 15
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 11
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 11. GMTs were assessed for following age subgroups: 25 to 49 years, equal to or above (>=) 50 years and >= 60 years.
Measured: At Year 11
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 12
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 12. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Measured: At Year 12
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 13
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 13. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Measured: At Year 13
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 14
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 14. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Measured: At Year 14
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 15
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 15. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Measured: At Year 15

Secondary outcomes (5)

Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 2 and Equal to or Above 10 as Measured by GSK Biologicals' NT, Overall and by Study Group
Immunogenicity was planned to be measured in terms of percentage of participants with TBE Neutralizing Antibody Titers >= 2 and >= 10 at 21 days after the booster vaccination.
Measured: At 21 days after the booster vaccination
Geometric Mean Antibody Titers (GMTs) as Measured by GSK Biologicals' NT, Overall and by Study Group
Immunogenicity was planned to be measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at 21 days after the booster vaccination.
Measured: At 21 days after the booster vaccination
Geometric Mean Ratios (GMRs) Blood Draw After/Before Booster as Measured by GSK Biologicals' NT, Overall and by Study Group
Immunogenicity was planned to be measured in terms of GMRs of serum TBE Neutralizing Antibody Titers at 21 days after the booster vaccination.
Measured: At 21 days after the booster vaccination
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to and Above 10 as Measured by GSK Biologicals' NT, Overall and by Study Group
Immunogenicity was measured in terms of percentage of participants with TBE Neutralizing Antibody Titers >= 10 from Year 1 to Year 15.
Measured: From Year 1 up to Year 15
Number of Participants With Serious Adverse Events (SAEs)
SAEs are defined as any untoward medical occurrence that results in death, is life- threatening, requires hospitalisation or prolongation of existing hospitalisation, results in disability/incapacity or is a congenital anomaly/birth defect in the offspring of a study subject.
Measured: From Day 0 to Day 21 after booster vaccination

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

5 Oct 201725 Oct 2021

First posted26 Sep 2017
Study start5 Oct 2017
Primary completion25 Oct 2021
Study completion25 Oct 2021

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Virus DiseasesStudies of the same condition, open and under way.
More trials run by GlaxoSmithKlineThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 4
Primary purpose: Prevention
Allocation: Non-randomised
Intervention model: Parallel groups
Model description: All subjects will come to the yearly scheduled blood draw visit for investigation of 11 to 15 year persistence of Neutralization Test (NT) titres. Subjects who have an NT titre below 10 at one of the scheduled visits will receive a second booster dose 6 months after this visit at an unscheduled visit. Subsequent data of these subjects will be analysed separately in a subgroup.
Masking: None (open label)
Enrolment: 194 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03294135
Sponsor's protocol ID: 205847
Other IDs: 2017-001356-59, 2017
Status last verified: Sep 2023
First submitted: 22 Sep 2017
Last updated: 28 Mar 2024
Results posted: Yes, on ClinicalTrials.gov
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

Publications

Beran J, Lattanzi M, Costantini M, Pammolli A, Galgani I. Sustained antibody persistence for at least 15 years after a booster vaccination against tick-borne encephalitis following different primary vaccination schedules: Third 5-year follow-up. Vaccine. 2023 May 26;41(23):3518-3524. doi: 10.1016/j.vaccine.2023.04.061. Epub 2023 May 3.
PubMed 37142462

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 28 Mar 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Long Term Immunogenicity up to 15 Years After the First Booster Immunization With GSK Biologicals' Encepur Adults (Polygeline-free Tick-Borne Encephalitis Vaccine for Adults) in Adults Who Received 1 of 3 Different Primary Vaccination Schedules
ClinicalTrials.gov ID: NCT03294135
Acronym / sponsor ID: 205847
Conditions: Virus Diseases
Keywords: Encepur, Adults, Long term immunogenicity, Tick-borne Encephalitis vaccine, Booster
Phase: Phase 4
Study type: Interventional
Recruitment status: Completed
Enrolment: 194 participants (actual)
Lead sponsor: GlaxoSmithKlineIndustry (pharma, biotech, devices)
Study start: 5 Oct 2017 (actual)
Primary completion: 25 Oct 2021 (actual)
Study completion: 25 Oct 2021 (actual)
First posted: 26 Sep 2017 (actual)
Results: Posted 28 Mar 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Any booster given in this study will be the second that the subject has received (with regard to the follow-up of the previous study).

Study design

Primary purpose: Prevention
Allocation: Non-randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 3
Model description: All subjects will come to the yearly scheduled blood draw visit for investigation of 11 to 15 year persistence of Neutralization Test (NT) titres. Subjects who have an NT titre below 10 at one of the scheduled visits will receive a second booster dose 6 months after this visit at an unscheduled visit. Subsequent data of these subjects will be analysed separately in a subgroup.

Arm	Type	Receives
Conventional Group	Experimental	Biological: Encepur AdultsParticipants who received primary vaccination in study V48P7 on Days 0, 28 (+10) and 300 (+21) (55 participants) and who received a booster vaccination in study V48P7E1 (NCT00387634) (55 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their Neutralization Test (NT) titer resulted below 10.
Accelerated/Rapid Group	Experimental	Biological: Encepur AdultsParticipants who received primary vaccination in study V48P7 on Days 0, 7 (+3) and 21 (+7) (66 participants) and who received a booster vaccination either in study V48P7E1 (NCT00387634) (9 participants) or before enrolment in study V48P7E1 (NCT00387634) (40 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their NT titer resulted below 10.
Accelerated Conventional Group	Experimental	Biological: Encepur AdultsParticipants who received primary vaccination in study V48P7 on Days 0, 14 (+3) and 300 (+21) (133 participants) and who received a booster vaccination in study V48P7E1 (NCT00387634) (109 participants). For these participants a second booster vaccination within six months after the annual blood draw was to be administered within the present study only in case their NT titer resulted below 10.

Who may qualify

Ages: 25 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (7 listed)

Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol.
Written informed consent obtained from the subject prior to performance of any study specific procedure.
Subjects who have participated in study V48P7E2 (NCT01562444) and who received in the parent V48P7 study one of the following schedules: rapid, conventional, or accelerated conventional and a booster vaccination in study V48P7E1 (NCT00387634) or before study V48P7E1 (NCT00387634) (only rapid schedule).
Healthy subjects as established by medical history and clinical examination before entering into the study.
Female subjects of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy or post-menopause.

Key exclusion criteria (29 listed)

Unwilling or unable to give written informed consent to participate in the study.
Perceived to be unreliable or unavailable to complete the study.
Clinical conditions representing a contraindication to blood draws.
Any other clinical condition that, in the opinion of the investigator, might interfere with the results of the study or pose additional risk to the subject due to participation in the study.
Received an investigational or non-registered medicinal product within 30 days prior to informed consent.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Encepur AdultsOne dose of the vaccine can be administered at any one unscheduled visit depending on the detection of NT below 10. It will be administered intramuscularly into the non-dominant deltoid.	Biological	Accelerated Conventional Group, Accelerated/Rapid Group, Conventional Group

Primary outcome

Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 11
Time frame: At Year 11
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 12
Time frame: At Year 12
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 13
Time frame: At Year 13
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 14
Time frame: At Year 14
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 15
Time frame: At Year 15
Antibody titers were measured by GSK Biologicals' Neutralization test. Analysis of the percentages of participants with antibody titers >= 2 was not performed as planned in the protocol, as only 3 participants had antibody titers between 2 and 10 during the whole study period.
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 11
Time frame: At Year 11
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 11. GMTs were assessed for following age subgroups: 25 to 49 years, equal to or above (>=) 50 years and >= 60 years.
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 12
Time frame: At Year 12
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 12. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 13
Time frame: At Year 13
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 13. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 14
Time frame: At Year 14
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 14. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.
Geometric Mean Antibody Titers (GMTs) by Age Categories at Year 15
Time frame: At Year 15
Immunogenicity was measured in terms of GMTs of serum TBE Neutralizing Antibody Titers at Year 15. GMTs were assessed for following age subgroups: 25 to 49 years, >= 50 years and >= 60 years.

5 secondary outcomes

Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 2 and Equal to or Above 10 as Measured by GSK Biologicals' NT, Overall and by Study Group
Time frame: At 21 days after the booster vaccination
Geometric Mean Antibody Titers (GMTs) as Measured by GSK Biologicals' NT, Overall and by Study Group
Time frame: At 21 days after the booster vaccination
Geometric Mean Ratios (GMRs) Blood Draw After/Before Booster as Measured by GSK Biologicals' NT, Overall and by Study Group
Time frame: At 21 days after the booster vaccination
Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to and Above 10 as Measured by GSK Biologicals' NT, Overall and by Study Group
Time frame: From Year 1 up to Year 15
Number of Participants With Serious Adverse Events (SAEs)
Time frame: From Day 0 to Day 21 after booster vaccination

Results and safety

Results posted to the registry on 28 Mar 2024, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Conventional Group	50	46
Accelerated/Rapid Group	43	43
Accelerated Conventional Group	101	99

Primary outcome: Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 11

Time frame: At Year 11. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Conventional Group n = 48	Accelerated/Rapid Group n = 43	Accelerated Conventional Group n = 101
Value	100 (92.6 to 100)	100 (91.8 to 100)	99.0 (94.6 to 100)

Population analysed: The analysis was performed on the Per Protocol set-1 (PPS-1) which consisted of all participants who provided evaluable serum samples at the relevant time points and have no major protocol violation.

Primary outcome: Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 12

Time frame: At Year 12. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Conventional Group n = 50	Accelerated/Rapid Group n = 43	Accelerated Conventional Group n = 101
Value	98.0 (89.4 to 99.9)	100 (91.8 to 100)	99.0 (94.6 to 100)

Population analysed: The analysis was performed on the PPS-1 which consisted of all participants who provided evaluable serum samples at the relevant time points and have no major protocol violation.

Primary outcome: Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 13

Time frame: At Year 13. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Conventional Group n = 49	Accelerated/Rapid Group n = 43	Accelerated Conventional Group n = 101
Value	95.9 (86.0 to 99.5)	100 (91.8 to 100)	99.0 (94.6 to 100)

Population analysed: The analysis was performed on the PPS-1 which consisted of all participants who provided evaluable serum samples at the relevant time points and have no major protocol violation.

Primary outcome: Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 14

Time frame: At Year 14. Number (95% Confidence Interval). Unit: Percentage of participants

Measure	Conventional Group n = 49	Accelerated/Rapid Group n = 43	Accelerated Conventional Group n = 101
Value	95.9 (86.0 to 99.5)	100 (91.8 to 100)	99.0 (94.6 to 100)

Population analysed: The analysis was performed on the PPS-1 which consisted of all participants who provided evaluable serum samples at the relevant time points and have no major protocol violation.

5 secondary outcomes are reported in the full results.

Adverse events

Time frame: Serious adverse events that led to withdrawal or were related to study vaccination were collected throughout the study period (Year 11 to Year 15). Other serious adverse events were collected only after the booster vaccination administration (Day 0-Day 21).. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Conventional Group	1 of 50 (2%)	0 of 0	1 of 50
Accelerated/Rapid Group	0 of 43 (0%)	0 of 0	0 of 43
Accelerated Conventional Group	1 of 101 (1%)	0 of 0	1 of 101

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 28 Mar 2024.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Background: PubMed 37142462Beran J, Lattanzi M, Costantini M, Pammolli A, Galgani I. Sustained antibody persistence for at least 15 years after a booster vaccination against tick-borne encephalitis following different primary vaccination schedules: Third 5-year follow-up. Vaccine. 2023 May 26;41(23):3518-3524. doi: 10.1016/j.vaccine.2023.04.061. Epub 2023 May 3.
Individual participant dataSharing planned: No

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

GSK Clinical Trials study director

GlaxoSmithKline

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Encepur Adults in people with Virus Diseases, run by GlaxoSmithKline at 1 site in Czechia.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 7 inclusion and 29 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 28 Mar 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 28 Mar 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of Participants With Detectable TBE Neutralizing Antibody Titers Equal to or Above 10 at Year 11 (time frame: At Year 11). The study lists 10 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03294135, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Mar 2024.