Human Challenge Models

OVG's development of Human Challenge models - studies where volunteers are intentionally given an infection in a safe way - helps to study various diseases and pathogens in a uniquely valuable way

Acceleration of pharmaceutical drug and vaccine development is imperative to reduce costs and time, particularly for current and future pandemic preparedness. Human vaccine development is particularly challenging because the immune response in animal models of infection does not accurately predict the immune response in humans.

Controlled Human Infection models (CHIM) address these needs effectively for vaccines and other therapeutics, particularly antivirals. The models are designed to minimise risk of infection while providing more accurate evidence of efficacy (particularly immune response for vaccines) than animal models. This data accelerates products at reduced cost through clinical trials. It is well recognised that human challenge models are an important tool to prepare for and respond to emerging diseases (Palacios & Shah 2019; Schaefer et al 2020). Challenge study models can potentially speed up vaccine development and approval by 2-3 years by testing the efficacy on human volunteers over a short period of time in a quarantine clinic.

OVG pioneered the use of human challenge models to support vaccine development for typhoid and paratyphoid, work which has now expanded since 2022 to include pneumococcus, RSV, and plans for influenza and malaria. The typhoid vaccine was rolled out following WHO guidance in 2018 and since 2022 some 60 million doses have been deployed.