Clinical Trial: Immunogenicity and Safety of a Tetravalent Dengue Vaccine Booster Injection in Subjects Who Previously Completed a 3-dose Schedule

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional

Official Title: Immunogenicity and Safety of a Tetravalent Dengue Vaccine Given as a Booster Injection in Adolescents and Adults Who Previously Completed the 3-dose Schedule in a Study Conducted in Singapore

Brief Summary:

The aim of the study is to assess and describe the booster effect of a CYD dengue vaccine dose administered 5 years after the completion of a 3-dose vaccination schedule.

Primary Objective:

To demonstrate the non-inferiority in terms of geometric mean of titer ratios (GTMR) of a CYD dengue vaccine booster compared to the third CYD dengue vaccine injection in subjects from CYD 28 trial (subjects from Group 1 only).

Secondary Objectives:

If the primary objective of non-inferiority is achieved: To demonstrate the superiority, in terms of GMTRs, of a CYD dengue vaccine booster compared to the third CYD dengue vaccine injection in subjects from CYD28 trial (subjects from Group 1 only).
To describe the immune responses elicited by the CYD dengue vaccine booster or placebo injection in subjects who received three doses of the CYD dengue vaccine in the CYD28 trial in all subjects.
To describe the neutralizing Abs levels of each dengue serotype post-dose 3 (CYD28 subjects) and immediately prior to booster or placebo injection in all subjects.
To describe the neutralizing Ab persistence 6 months, 1 year and 2 years post booster or placebo injection in all study subjects.
To evaluate the safety of booster vaccination with CYD dengue vaccine in all study subjects.