Detection and Response to an HIV Cluster: People Living Homeless and Using Drugs in Seattle, Washington.

INTRODUCTION: The HIV epidemic in King County, Washington has traditionally been highly concentrated among men who have sex with men, and incidence has gradually declined over 2 decades. In 2018, King County experienced a geographically concentrated outbreak of HIV among heterosexual people who inject drugs. METHODS: Data sources to describe the 2018 outbreak and King County's response were partner services interview data, HIV case reports, syringe service program client surveys, hospital data, and data from a rapid needs assessment of homeless individuals and people who inject drugs. In 2020, the authors examined the impact of delays in molecular sequence analyses and cluster member size thresholds, for identifying genetically similar clusters, on the timing of outbreak identification. RESULTS: In 2018, the health department identified a North Seattle cluster, growing to 30 people with related HIV infections diagnosed in 2008-2019. In total, 70% of cluster members were female, 77% were people who inject drugs, 87% were homeless, and 27% reported exchanging sex. Intervention activities included a rapid needs assessment, 2,485 HIV screening tests in a jail and other outreach settings, provision of 87,488 clean syringes in the outbreak area, and public communications. A lower cluster size threshold and more rapid receipt and analyses of data would have identified this outbreak 4-16 months earlier. CONCLUSIONS: This outbreak shows the vulnerability of people who inject drugs to HIV infection, even in areas with robust syringe service programs and declining HIV epidemics. Although molecular HIV surveillance did not identify this outbreak, it may have done so with a lower threshold for defining clusters and more rapid receipt and analyses of HIV genetic sequences.

Prolonged persistence of PCR-detectable virus during an outbreak of SARS-CoV-2 in an inpatient geriatric psychiatry unit in King County, Washington.

BACKGROUND: We describe key characteristics, interventions, and outcomes of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak within an inpatient geriatric psychiatry unit at the University of Washington Medical Center - Northwest. METHODS: After identifying 2 patients with SARS-CoV-2 infection on March 11, 2020, we conducted an outbreak investigation and employed targeted interventions including: screening of patients and staff; isolation and cohorting of confirmed cases; serial testing; and enhanced infection prevention measures. RESULTS: We identified 10 patients and 7 staff members with SARS-CoV-2 infection. Thirty percent of patients (n = 3) remained asymptomatic over the course of infection. Among SARS-CoV-2 positive patients, fever (n = 5, 50%) and cough (n = 4, 40%) were the most common symptoms. Median duration of reverse transcription polymerase chain reaction (RT-PCR) positivity was 25.5 days (interquartile range [IQR] 22.8-41.8) among symptomatic patients and 22.0 days (IQR 19.5-25.5) among asymptomatic patients. Median initial (19.0, IQR 18.7-25.7 vs 21.7, IQR 20.7-25.6) and nadir (18.9, IQR 18.2-20.3 vs 19.8, IQR 17.0-20.7) cycle threshold values were similar across symptomatic and asymptomatic patients, respectively. CONCLUSIONS: Asymptomatic infection was common in this cohort of hospitalized, elderly individuals despite similar duration of SARS-CoV-2 RT-PCR positivity and cycle threshold values among symptomatic and asymptomatic patients.