Open Study of the Duration of Immunity After Vaccination With GamEvac-Combi
Condition: Ebola Hemorrhagic Fever
MeSH terms: Hemorrhagic Fever, Ebola; Hemorrhagic Fevers, Viral
Study type: Observational

Summary: 
      The purpose of this study is to evaluate the post-vaccination immune status at different time
      points in subjects immunized against Ebola Virus Disease; to select an optimal regimen of
      product administration; and, to assess safety of medicinal product GamEvac-Combi - Combined
      Vector-Based Vaccine against Ebola Virus Disease, 0.5 ml+0.5 ml/dose, following the
      immunization with a half (0.25 ml+0.25 ml/dose) and full (0.5 ml+0.5 ml/dose) therapeutic
      doses.
    

Detailed description: 
      This clinical trial is designed as an open study to evaluate the duration of immunity
      persistence following the administration of medicinal product GamEvac-Combi - Combined
      Vector-Based Vaccine against Ebola Virus Disease.

      It is an observational study; no interventions are planned in the course of common clinical
      practices during the study period; investigated therapeutic agents or special methods of
      examination will not be used in the study, except the blood sampling procedure specified in
      this Protocol. Only those patients who have signed the information consent form for
      participation in the study and have been informed by physician on the objectives and methods
      of this project will be involved in the study.

      The study consists of a single stage which is designed as a follow-up period to observe
      volunteers vaccinated in the course of evaluation of safety, reactogenic properties and
      immunogenicity of product GamEvac-Combi - Combined Vector-Based Vaccine against Ebola Virus
      Disease in the dosages of 0.25 ml and 0.5 ml, during the study under Protocol 01-COMBI-2015
      in October-November 2015. Vaccination will not be made within the present study. Screening of
      volunteers is not required: the study will involve as many of the volunteers as possible (but
      not more than 60 subjects) who had been immunized earlier with GamEvac-Combi - Combined
      Vector-Based Vaccine against Ebola Virus Disease, provided that they have no medical
      contraindications for blood sampling.

      Study Schedule Visit 1 (outpatient): the goal of this visit is to assess whether a patient
      meets the inclusion/exclusion criteria. All procedures should be carried out upon receipt of
      the informed consent form signed by patient. The visit will be held 12 months after the
      vaccination.

      Visit 2 (outpatient): 18 months after the vaccination. Visit 3 (outpatient): 24 months after
      the vaccination. The duration of immunity persistence following product administration will
      be assessed in healthy volunteers based on the measurements of specific antibody titers.

        -  by ELISA method 12, 18 and 24 months after the vaccination vs. baseline values;

        -  in virus neutralization reaction 12 months after the vaccination vs. baseline values.
    

Intervention name(s): blood sampling collection
Intervention type(s): Procedure
Intervention description(s): It is an observational study; no interventions are planned in the course of common clinical practices during the study period; investigated therapeutic agents or special methods of examination will not be used in the study, except the blood sampling procedure and clinical observation specified in this Protocol.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study will enroll up to 60 healthy volunteers of both genders aged 18-55 inclusive who
        had been earlier immunized with medicinal product GamEvac-Combi in the dosages of 0.25 ml
        and 0.5 ml, during the study under Protocol 01-COMBI-2015 in October-November 2015.
      
Biospecimen description: 
      The duration of immunity persistence following product administration will be assessed in
      healthy volunteers based on the measurements of specific antibody titers.

        -  by ELISA method 12, 18 and 24 months after the vaccination vs. baseline values;

        -  in virus neutralization reaction 12 months after the vaccination vs. baseline values.
    
Keywords: Ebola; Ebola Virus Vaccines; Haemorrhagic Fever; Ebola Infection; GP protein, Ebola virus