Clinical Trial: Long Term Persistence and Effect of a Booster Dose of the Japanese Encephalitis Vaccine IC51

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Long Term Persistence and Effect of a Booster Dose of the Japanese Encephalitis Vaccine IC51

Brief Summary: The study investigates the long term persistence the Japanese encephalitis vaccine IC51 and the need of a booster dose

Detailed Summary: This is an open label, non‐randomized multi‐center phase 3 follow‐up study. All volunteers having completed trial IC51‐304 (NCT00595790) will be enrolled into this trial at 2 sites
Sponsor: Valneva Austria GmbH

Current Primary Outcome: Long Term Immunogenicity of IC51 Vaccine 24 Months After the Primary Vaccination [ Time Frame: - 24 months ]

Seroprotection rate (SPR) (anti-JEV neutralizing antibody titer ≥ 1:10) 24 months (M24) after the primary vaccination - imputed; Persistence of immunogenicity (SPR) at M24 defined as:

  • pos. (positive) (persistent): Subjects

    • with a non-missing, pos. seroconversion at D56 (Study IC51-304) and
    • without booster at M11 or M23 and
    • with non-missing, seroprotection (SP) pos. PRNT50 at M6 or M12 and
    • with non-missing, SP pos. PRNT50 at M24

  • neg. (negative) (non-persistent): Subjects with

    • missing or neg. seroconversion at D56 (Study IC51-304) or
    • booster at M11 or at M23, or
    • non-missing, SP neg. PRNT50 at M6 or M12 or
    • missing PRNT50 at both M6 and M12 or
    • missing or SP neg. PRNT50 (serum dilution giving 50% reduction in plaques in a Plaque Reduction Neutralization Test) at M24


Original Primary Outcome: Long Term Immunogenicity of IC51 Vaccine 24 Months After the Primary Vaccination

Current Secondary Outcome:

  • SPR 24 Months After the Primary Vaccination (Observed) [ Time Frame: 24 months ]

    Persistence of immunogenicity (SPR) at M24 (observed) defined as :

    • positive (persistent): Subjects

      • with a non-missing, positive seroconversion at D56 (Study IC51-304), and
      • who did not receive a booster dose at Visit 2 (M11) or Visit 4 (M23), and
      • with a non-missing, SP positive PRNT50 result at Visit 1 (M6) or Visit 3 (M12), and
      • with a non-missing, SP positive PRNT50 result at Visit 5 (M24)

    • negative (non-persistent): Subjects

      • with missing or negative seroconversion at D56 (Study IC51-304), or
      • who did receive a booster dose at Visit 2 (M11) or at Visit 4 (M23), or
      • with a non-missing, SP negative PRNT50 result at Visit 1 (M6) or Visit 3 (M12), or
      • with a missing PRNT50 result at both Visit 1 (M6) and Visit 3 (M12), or
      • with a non-missing, SP negative PRNT50 result at Visit 5 (M24)
  • Persistent and Actual SPR 6, 12 and 24 Months After Primary Vaccination [ Time Frame: - 24 months ]
  • Persistent and Actual GMT 6, 12 and 24 Months After Primary Vaccination [ Time Frame: 24 months ]
  • SCR 1 Month After the Booster Doses [ Time Frame: 1 month ]
  • GMT 1month After Booster Doses [ Time Frame: 1 month ]
  • Safety Profile of IC51 [ Time Frame: study duration ]


Original Secondary Outcome: Immunogenicity of IC51 vaccine 6 and 12 months after the primary vaccination

Information By: Valneva Austria GmbH

Dates:
Date Received: January 4, 2008
Date Started: October 2005
Date Completion:
Last Updated: February 5, 2014
Last Verified: February 2014