This is a single-center trial to develop a Bordetella pertussis Controlled Human Infection Model (CHIM) using a two-study approach: the first study is a human infectious dose 70%-90% (HID70-90) identification study, and the second an HID70-90 dose confirmation study to verify and confirm that the infectious endpoint has been reached. The infectious endpoint is positive nasopharyngeal culture(s) and/or polymerase chain reaction(s) (PCR(s)) for B. pertussis with concurrent or subsequent development of mild pertussis disease symptoms such as rhinorrhea and cough within the 16-day inpatient period following challenge.~The trial is an open-label, phase 1, dose escalation, self-contained trial; participants will be allocated to challenge dose groups to receive a single intranasal dose of challenge inoculum. All participants will receive a 5-day course of azithromycin eradication therapy either 24-48 hours after they develop symptoms or at the end of the 16-day postchallenge observation period.~The optimal/target inoculum is one that induces mild symptomatic infection and detection of B. pertussis in nasopharyngeal cultures in 70%-90% of participants receiving it, to establish a safe and reproducible pertussis CHIM.~Safety monitoring includes close clinical observation during a 16-21-day inpatient postchallenge period in the Canadian Center for Vaccinology's Challenge Unit, a Data and Safety Monitoring Board, and participant Diary Cards.
This study aims to establish a Controlled Human Infection Model of Bordetella pertussis by determining a reproducible and safe infectious bacterial dose (challenge inoculum) that achieves colonization and mild symptomatic infection in healthy adults.