Safety and Immunogenicity of 2 Doses Versus 1 Dose of Acellular Pertussis Vaccines Containing Genetically-detoxified Pertussis Toxin in Young Adults Previously Primed With Acellular Pertussis Vaccines

• Status: Recruiting
• Trial end date: 2023-03-30

Summary

A significant increase of pertussis incidence is reported in a growing number of countries. This resurgence is considered as resulting from the limited durability of aP-vaccine-induced immunity and is associated with increased mortality in young infants and morbidity at all age groups. As the pertussis immunity acquired through immunization or infection is short-lived, its maintenance or reactivation requires repeat boosting at regular time points. Thus, novel strategies capable of reactivating pertussis immunity are needed.

The efficacy of current acellular pertussis vaccines (which contain chemically-detoxified pertussis toxoid (PT)) rapidly wanes, in part because priming and repeat immunization with acellular vaccines induce antibodies specific for the chemically-detoxified PT but unable to efficiently recognize the native PT expressed by B. pertussis.

Clinical studies have shown the superior immunogenicity profile of acellular pertussis vaccines including genetically-detoxified PT (rPT) in adults and adolescents previously primed with aP. In particular, the investigators showed in a past Geneva study in teenagers previously primed with aP that rPT/FHA induced a stronger recall response than the current aP-vaccine at one month post-vaccination. However, the difference was less clear one year after vaccination, suggesting that 2 doses may be needed for more sustained immunity.

In the present study, the investigators would like to assess whether giving two doses of rPT/FHA at 6 months interval induces stronger immune responses than a single dose.

• Phase: Phase 2/Phase 3

Details

• Lead Sponsor: University Hospital, Geneva
• Treatments: Hemagglutinins