Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional
Official Title: Open Randomized Trial Evaluating Four Anti-pneumococcal Vaccine Strategies With Fractionated Doses of Non Conjugate Polysaccharide Vaccine to Prevent Hyporesponse in Healthy Volunteers
Brief Summary:
Immune response analysis after the combination of PCV13 and PPV23 will lead to evaluate if a prime with PCV13 help to obtain a good response to repeated dose of PPV23.The hyporesponsiveness following the unconjugated vaccine is associated with high polysaccharide antigen concentration. Several issues limit the development and recommendation of anti-pneumococcal vaccine in adult's patients at risk. Reduced doses of unconjugated polysaccharide antigens would bypass the hyporesponsiveness and maintain the expanded coverage serotype.
A better knowledge of immune response following the combination of two vaccines in adults is essential. In addition, adults are required to be exposed to repeated doses of polysaccharide antigens by vaccine or by natural exposure, it is important to determine the extend and duration of any hyporesponsiveness.
The main objective is to evaluate if non conjugate polysaccharidique fractionated doses administered after a conjugate vaccine help to avoid hyporesponse in a schedule with repeated injections of pneumococcal polysaccharidique vaccine