TBE Seropersistence up to 10 Years After First Booster in Adults

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to evaluate TBE antibody persistence from 7 to 10 years after the first booster TBE vaccination with FSME-IMMUN 0.5ml.

Official Title
-----------------
Open-label Phase 4 Study to Investigate the Seropersistence of Tick-borne Encephalitis (TBE) Virus Antibodies From 7 to 10 Years After the First Booster and the Response to a Second Booster Vaccination With FSME-IMMUN 0.5ml in Adults

Conditions
-----------------
Tick-borne Encephalitis (TBE)

Intervention / Treatment
-----------------
* Biological: FSME-IMMUN 0.5 ml


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Subjects who participated in the first and second precursor studies will be eligible for participation in this study if: they understand the nature of the study, agree to its provisions and provide written informed consent they received the first booster vaccination with FSME-IMMUN 0.5ml during the first precursor study and did not receive a second booster vaccination in the second precursor study blood was drawn after their first booster vaccination in the first precursor study Exclusion Criteria: Subjects will be excluded from participation in this study if they: received any TBE vaccination since their first booster vaccination with FSME-IMMUN 0.5ml have a history of infection with or vaccination against other flaviviruses (e.g. dengue fever, yellow fever, Japanese B-encephalitis) since their first booster vaccination with FSME-IMMUN 0.5ml are known to be HIV positive since their first booster vaccination with FSME-IMMUN 0.5ml have a known or suspected problem with drug or alcohol abuse

Ages Eligible for Study
-----------------
Minimum Age: 25 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Seropersistence evaluation + 2nd booster vaccination<br>Blood will be drawn to assess the seropersistence of TBE virus antibodies at 82, 94, 106 and 118 months after the first booster vaccination with FSME-IMMUN 0.5ml administered during the first precursor study. Timing of the second booster vaccination will depend on the level of serum TBE antibodies observed during the study. Blood will be drawn 21 - 35 days after vaccination to assess the booster response. | Biological: FSME-IMMUN 0.5 ml<br>* Solution/suspension for injection (intramuscular injection into the deltoid muscle of the right or left upper arm). Dosage frequency of booster vaccination: dependent on serum TBE antibodies.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Seropositivity rate measured by neutralization test (NT) 82, 94, 106 and 118 months after the first booster TBE vaccination administered in the first precursor study and after the booster vaccination in this study |  | 118 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Seropositivity rate measured by ELISA test 82, 94, 106 and 118 months after the first booster TBE vaccination administered in the first precursor study and after the booster vaccination in this study |  | 118 months | 
| Antibody titers 82, 94, 106 and 118 months after the first booster TBE vaccination administered in the first precursor study and after the booster vaccination in this study measured by ELISA and by NT |  | 118 months | 
| Fold increase in antibody concentration after the booster vaccination administered as compared to before the booster vaccination in this study measured by ELISA and by NT |  | 118 months |