Timely intervention and control of a novel coronavirus (COVID-19) outbreak at a large skilled nursing facility—San Francisco, California, 2020

Karmarkar, Ellora N.; Blanco, Irin; Amornkul, Pauli N.; DuBois, Amie; Deng, Xianding; Moonan, Patrick K.; Rubenstein, Beth L.; Miller, David A.; Kennedy, Idamae; Yu, Jennifer; Dauterman, Justin P.; Ongpin, Melissa; Hathaway, Wilmie; Hoo, Lisa; Trammell, Stephanie; Dosunmu, Ejovwoke F.; Yu, Guixia; Khwaja, Zenith; Lu, Wendy; Talai, Nawzaneen Z.; Jain, Seema; Louie, Janice K.; Philip, Susan S.; Federman, Scot; Masinde, Godfred; Wadford, Debra A.; Bobba, Naveena; Stoltey, Juliet; Smith, Adrian; Epson, Erin; Chiu, Charles Y.; Bennett, Ayanna S.; Vasquez, Amber M.; Williams, Troy

OBJECTIVE: To describe epidemiologic and genomic characteristics of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in a large skilled-nursing facility (SNF), and the strategies that controlled transmission. DESIGN, SETTING, AND PARTICIPANTS: This cohort study was conducted during March 22–May 4, 2020, among all staff and residents at a 780-bed SNF in San Francisco, California. METHODS: Contact tracing and symptom screening guided targeted testing of staff and residents; respiratory specimens were also collected through serial point prevalence surveys (PPSs) in units with confirmed cases. Cases were confirmed by real-time reverse transcription–polymerase chain reaction testing for SARS-CoV-2, and whole-genome sequencing (WGS) was used to characterize viral isolate lineages and relatedness. Infection prevention and control (IPC) interventions included restricting from work any staff who had close contact with a confirmed case; restricting movement between units; implementing surgical face masking facility-wide; and the use of recommended PPE (ie, isolation gown, gloves, N95 respirator and eye protection) for clinical interactions in units with confirmed cases. RESULTS: Of 725 staff and residents tested through targeted testing and serial PPSs, 21 (3%) were SARS-CoV-2 positive: 16 (76%) staff and 5 (24%) residents. Fifteen cases (71%) were linked to a single unit. Targeted testing identified 17 cases (81%), and PPSs identified 4 cases (19%). Most cases (71%) were identified before IPC interventions could be implemented. WGS was performed on SARS-CoV-2 isolates from 4 staff and 4 residents: 5 were of Santa Clara County lineage and the 3 others were distinct lineages. CONCLUSIONS: Early implementation of targeted testing, serial PPSs, and multimodal IPC interventions limited SARS-CoV-2 transmission within the SNF.