Risk analysis for outpatient experimental infection as a pathway for affordable RSV vaccine development

Area of Science:

• Vaccinology
• Infectious Diseases
• Clinical Trials

Background:

• Controlled human infection models (CHIMs) are crucial for accelerating vaccine development.
• High costs associated with quarantine facilities in traditional inpatient CHIMs present a barrier.
• Outpatient CHIMs offer potential cost reductions and enhanced participant-friendliness.

Purpose of the Study:

• To analyze the safety, logistical, and ethical risks of conducting respiratory syncytial virus (RSV) CHIMs in an outpatient setting.
• To assess the feasibility and transmission risks of outpatient CHIMs for respiratory pathogens.
• To propose a framework for implementing outpatient RSV CHIMs to support affordable vaccine development.

Main Methods:

• Literature review of outpatient CHIMs involving respiratory pathogens.
• Assessment of RSV transmission risk using data from inpatient and outpatient CHIMs (EudraCT 020-004137-21).
• Inclusion of 59 outpatient CHIMs (RSV, Streptococcus pneumoniae, rhinovirus) and an ongoing Bordetella Pertussis CHIM.

Main Results:

• One transmission event was recorded across the studied outpatient CHIMs.
• Standard isolation measures in inpatient RSV CHIMs effectively limited transmission.
• No symptomatic third-party transmission was observed in the initial outpatient RSV CHIM.

Conclusions:

• Outpatient CHIMs present significant logistical and ethical advantages for vaccine development.
• A framework with risk mitigation strategies can facilitate the adoption of outpatient RSV CHIMs.
• Outpatient CHIMs can enhance the affordability and efficiency of vaccine development, particularly for RSV.