Explore the insights from the REal-time Assessment of Community Transmission-1 (REACT-1) study tracking SARS-CoV-2 spread in England in this informative lecture. Discover how this large-scale community-based surveillance study, involving over 2 million participants, has provided critical situational awareness and unbiased infection prevalence estimates since May 2020. Learn about the study's role in documenting key viral developments, including the Alpha to Delta variant transition and Omicron's initial spread. Gain an understanding of the importance of random sampling in COVID-19 surveillance and how studies like REACT-1 have informed policymakers and stakeholders throughout the pandemic.