Watching what was happening around the world in early 2020, University of California San Diego School of Medicine researchers knew their region would likely soon be hit with a wave of patients with COVID-19, the infection caused by the coronavirus SARS-CoV-2. They wondered how the virus persists on surfaces, particularly in hospitals, and they knew they had only a small window of time to get started if they wanted to capture a snapshot of the “before” situation—before patients with the infection were admitted.