Open-label, phase 1/2, dose-escalation and dose-confirmation clinical trial to establish a Controlled Human Infection Model (CHIM) by determining and confirming the optimal, safe, and reproducible Influenza A:H3N2 dose administered intranasally to healthy adults 18-40 years of age that induces mild symptomatic infection and detection of Influenza A:H3N2 in nasal secretions by culture and/or PCR

This clinical trial is designed to establish a Controlled Human Infection Models (CHIM) for influenza A virus. In a CHIM, a pathogen of interest (such as a virus) is safely given to healthy volunteers 18 to 40 years of age under closely controlled conditions in an inpatient isolation facility in order to safely study the immune response to the infection and to test the safety and efficacy of new vaccines to prevent and antivirals to treat the infection. CHIMs are an efficient way to assess whether new vaccines and treatments are safe and if they work and can accelerate the approval process when there is a public health emergency like a pandemic. In this study, we will give gradually increasing amounts of virus to small groups of volunteers until we find the dose that infects 70-90% of the group and produces mild influenza-like symptoms. Once mild symptoms occur in any participant, they will be treated with an antiviral to clear the virus from their body.The methodology developed by this study can be adapted for establishing CHIMs for other pathogens of pandemic potential. This CHIM for pathogens of pandemic potential can become an important part in Canada's pandemic preparedness armamentarium and accelerate the expeditious translation of Canadian innovative technology to commercialization and market readiness.