This lecture covers the immune response to Covid-19, discussing virology, infection strategies, clinical aspects, different pathogenic human coronaviruses, the role of ACE2 as the virus entry point, innate immunity, and severe Covid-19 symptoms. It also explores the immune response phases, vaccine development phases, types of vaccines, and the benefits of mRNA vaccines. The presentation emphasizes the importance of ACE2 in SARS-CoV-2 pathophysiology, the role of innate immunity in combating the virus, and the severity of Covid-19 due to cytokine storms, hypertension, and endothelial damage.