Outbreak Investigation of COVID-19 Among Residents and Staff of an Independent and Assisted Living Community for Older Adults in Seattle, Washington

Question  In an independent and assisted living community implementing social isolation and infection prevention, can symptom screening and testing for severe acute respiratory coronavirus 2 identify cases and reduce transmission after exposure to persons with coronavirus disease 2019 (COVID-19)?

Findings  In this case series study of 142 residents and staff exposed to persons with COVID-19, 3 asymptomatic infected residents and 2 symptomatic infected staff were identified; 1 week later, 1 additional asymptomatic infected resident was found (staff were not retested); a facility-wide outbreak did not occur.

Meaning  In independent/assisted living facilities, testing was a better strategy for identifying staff and older adults with COVID-19 than symptom screening. Adherence to social distancing and preventive guidelines may contribute to interruption of COVID-19 transmission.

Importance  Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused epidemic spread of coronavirus disease 2019 (COVID-19) in the Seattle, Washington, metropolitan area, with morbidity and mortality concentrated among residents of skilled nursing facilities. The prevalence of COVID-19 among older adults in independent/assisted living is not understood.

Objectives  To conduct surveillance for SARS-CoV-2 and describe symptoms of COVID-19 among residents and staff of an independent/assisted living community.

Design, Setting, and Participants  In March 2020, public health surveillance of staff and residents was conducted on site at an assisted and independent living residence for older adults in Seattle, Washington, after exposure to 2 residents who were hospitalized with COVID-19.

Exposures  Surveillance for SARS-CoV-2 infection in a congregate setting implementing social isolation and infection prevention protocols.

Main Outcomes and Measures  SARS-CoV-2 real-time polymerase chain reaction was performed on nasopharyngeal swabs from residents and staff; a symptom questionnaire was completed assessing fever, cough, and other symptoms for the preceding 14 days. Residents were retested for SARS-CoV-2 7 days after initial screening.

Results  Testing was performed on 80 residents; 62 were women (77%), with mean age of 86 (range, 69-102) years. SARS-CoV-2 was detected in 3 of 80 residents (3.8%); none felt ill, 1 male resident reported resolved cough and 1 loose stool during the preceding 14 days. Virus was also detected in 2 of 62 staff (3.2%); both were symptomatic. One week later, resident SARS-CoV-2 testing was repeated and 1 new infection detected (asymptomatic). All residents remained in isolation and were clinically stable 14 days after the second test.

Conclusions and Relevance  Detection of SARS-CoV-2 in asymptomatic residents highlights challenges in protecting older adults living in congregate settings. In this study, symptom screening failed to identify residents with infections and all 4 residents with SARS-CoV-2 remained asymptomatic after 14 days. Although 1 asymptomatic infection was found on retesting, a widespread facility outbreak was avoided. Compared with skilled nursing settings, in assisted/independent living communities, early surveillance to identify asymptomatic persons among residents and staff, in combination with adherence to recommended preventive strategies, may reduce viral spread.