Canada has entered Phase 2 clinical trials of AeroVax, an inhaled Covid-19 vaccine developed by researchers at McMaster University. Unlike traditional injected vaccines, AeroVax is designed to be inhaled directly into the lungs, offering localized immune protection where respiratory viruses first enter the body.

https://www.news-medical.net/news/20250310/Next-generation-inhaled-COVID-19-vaccine-enters-phase-2-clinical-trial.aspx