This study explains why long-term care facilities are at high risk for Covid-19 outbreaks and must identify and exclude potentially infected staff and visitors, actively monitor for potentially infected patients, and implement appropriate infection prevention and control measures.

On February 28, 2020, after a confirmed case of Covid-19 was identified, the authors launched a case investigation, contact tracing, quarantine of exposed persons, isolation of confirmed and suspected cases, and on-site enhancement of infection prevention and control. This report details their findings.

By March 18, 167 confirmed cases of Covid-19 affecting 101 residents, 50 health care personnel, and 16 visitors were linked to the facility. Most cases among residents were symptomatic, but 7 residents who were positive did not. Hospitalization rates for facility residents (55%), visitors (50%), and staff (6%) were noted. The case fatality rate for residents was 34%.

By March 18, a total of 30 long-term care facilities with at least one confirmed case of Covid-19 had been identified in King County.