During the press conference where President Trump announced that Vice President Mike Pence would be taking charge of domestic efforts to combat SARS-CoV-2, the new coronavirus spreading internationally, the Centers for Disease Control and Prevention also announced that the outbreak had entered a new phase in the US. The agency reported the first patient infected via “community spread”—which is to say, the patient hadn’t traveled to places where the virus is common and had no known exposure to anyone with Covid-19. WIRED has learned that the patient has been in a northern California hospital for a week, but went undiagnosed until Sunday. In a note to staff at UC Davis Medical Center, CEO David Lubarsky confirmed that the CDC is investigating a patient at the center who may be the first to have contracted the infection from community exposure. The patient arrived at the facility on Feb. 19 after being transferred from another hospital in Northern California, Lubarsky said in the note. He said the patient wasn’t immediately tested for the new coronavirus because the person didn’t fit the existing CDC criteria for the test, a protocol that UC Davis said it does not control. The CDC ordered coronavirus testing on Sunday and confirmed Wednesday that the patient tested positive, UC Davis said.