Explore the methodological challenges and approaches in COVID-19 epidemiology through this 52-minute seminar presented by Professor Lipsitch at the Alan Turing Institute. Delve into the complexities of understanding COVID-19 transmission, clinical course, and prevention. Examine the challenges associated with household and secondary attack studies, and learn about potential solutions to address these issues. Discover the design challenges and key findings from research conducted on a large US health insurer's database regarding the clinical course of COVID-19. Gain insights into the complexities of observational, post-approval vaccine evaluations, and understand the approach used by a collaborative team in Israel to assess the effectiveness of the BNT162b2 mRNA Covid-19 Vaccine in a nationwide mass vaccination setting.