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

Valneva

Status and phase: Completed; Phase 3

Conditions: Japanese Encephalitis

Treatments: Biological: IC51

Study type: Interventional

Funder types: Industry

Identifiers

NCT00595270

IC51-305

Details and patient eligibility

About

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

Full description

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

Enrollment: 349 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• At least 18 years of age
• Written informed consent obtained prior to study entry
• Subjects correctly included in and having completed study IC51-304 according to the protocol.

Exclusion criteria

• Use of any other investigational or non-registered drug or vaccine in addition to the study vaccine during the study period
• Immunodeficiency including post-organ-transplantation or immunosuppressive therapy
• Pregnancy, lactation or unreliable contraception in female subjects

Trial design

Primary purpose: Prevention

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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349 participants in 1 patient group

IC51

Other group

Description:

In study IC51-305, subjects who had received IC51 in study IC51-304 were tested for seroconversion 6 months after the first vaccination. Subjects who had protective titers were again tested for persistence of immunity at 12 months after the first immunization,whereas subjects who had titers below the seroconversion threshold by Month 6 received a booster dose of 1x6 mcg IC51 at Month 11. Their immune response was also assessed at Month 12. Thereafter, subjects who had no protective titer by Month 12 received a booster dose of 1x6 mcg IC51 at Month 23, regardless of prior treatment; and neutralizing antibody titers were reassessed at Month 24. Subjects who had protective titers at month 12 did not receive a booster at Month 23, and their neutralizing antibody titer was also assessed at Month 24.

Treatment:

Biological: IC51