Saturday, March 28, 2020

MMWR: Asymptomatic & Presymptomatic SARS-CoV-2 Infections in Residents of a LTCF








#15,147


While anyone can be infected by SARS-CoV-2 - the  novel virus that causes COVID-19 - the elderly and those with high risk comorbidities are at greatest risk of severe illness and/or death.  This makes LTCFs (Long Term Care Facilities) and SNFs (Skilled Nursing Facilities) a target rich environment for this novel coronavirus.
In late February the King County/Seattle Public Health department began to investigate a COVID-19 outbreak at the LifeCare SNF, which led to dozens of patients and HCWs to become infected and numerous deaths.
Seattle became the first epicenter of COVID-19 activity in the United State, and while it has now been well surpassed by New York City, continues to report high numbers of cases. From yesterday's update:
Seattle & King County announced 251 new cases of COVID-19 today, bringing the official case count in King County to 1828. In addition, 16 new deaths are reported, bringing the total of deaths in King County to 125.
Across Washington State, the total number of cases is roughly 3,700, with 175 deaths (cite KIRO-TV), with 28 of those deaths reported on Friday. The (much) higher preliminary CFR in King County (6.8% vs 2.6%) is due in large part to their large number of infections inside LTCFs.

Ten days ago the CDC published an MMWR Early Release and held a COCA Call on the unique challenges of dealing with COVID-19 in an LTCF.
COVID-19 in a Long-Term Care Facility — King County, Washington, February 27–March 9, 2020
Coronavirus Disease 2019 (COVID-19) Update and Information for Long-term Care Facilities

Yesterday, the CDC published another study from King County in their MMWR, which focused on asymptomatic and presymptomatic COVID-19 infections inside an LTCF.  I've only included the summary, and some excerpts from a much longer report, so follow the link to read it in its entirety..

Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility — King County, Washington, March 2020
Early Release / March 27, 2020 / 69
Anne Kimball, MD1,2; Kelly M. Hatfield, MSPH1; Melissa Arons, MSc1,2; Allison James, PhD1,2; Joanne Taylor, PhD1,2; Kevin Spicer, MD1; Ana C. Bardossy, MD1,2; Lisa P. Oakley, PhD1,2; Sukarma Tanwar, MMed1,2; Zeshan Chisty, MPH1; Jeneita M. Bell, MD1; Mark Methner, PhD1; Josh Harney, MS1; Jesica R. Jacobs, PhD1,3; Christina M. Carlson, PhD1,3; Heather P. McLaughlin, PhD1; Nimalie Stone, MD1; Shauna Clark4; Claire Brostrom-Smith, MSN4; Libby C. Page, MPH4; Meagan Kay, DVM4; James Lewis, MD4; Denny Russell5; Brian Hiatt5; Jessica Gant, MS5; Jeffrey S. Duchin, MD4; Thomas A. Clark, MD1; Margaret A. Honein, PhD1; Sujan C. Reddy, MD1; John A. Jernigan, MD1; Public Health – Seattle & King County; CDC COVID-19 Investigation Team (View author affiliations)View suggested citation
Summary
What is already known about this topic?
Once SARS-CoV-2 is introduced in a long-term care skilled nursing facility (SNF), rapid transmission can occur.
What is added by this report?
Following identification of a case of coronavirus disease 2019 (COVID-19) in a health care worker, 76 of 82 residents of an SNF were tested for SARS-CoV-2; 23 (30.3%) had positive test results, approximately half of whom were asymptomatic or presymptomatic on the day of testing.
What are the implications for public health practice?
Symptom-based screening of SNF residents might fail to identify all SARS-CoV-2 infections. Asymptomatic and presymptomatic SNF residents might contribute to SARS-CoV-2 transmission. Once a facility has confirmed a COVID-19 case, all residents should be cared for using CDC-recommended personal protective equipment (PPE), with considerations for extended use or reuse of PPE as needed.


Older adults are susceptible to severe coronavirus disease 2019 (COVID-19) outcomes as a consequence of their age and, in some cases, underlying health conditions (1). A COVID-19 outbreak in a long-term care skilled nursing facility (SNF) in King County, Washington that was first identified on February 28, 2020, highlighted the potential for rapid spread among residents of these types of facilities (2). 
On March 1, a health care provider at a second long-term care skilled nursing facility (facility A) in King County, Washington, had a positive test result for SARS-CoV-2, the novel coronavirus that causes COVID-19, after working while symptomatic on February 26 and 28. By March 6, seven residents of this second facility were symptomatic and had positive test results for SARS-CoV-2. On March 13, CDC performed symptom assessments and SARS-CoV-2 testing for 76 (93%) of the 82 facility A residents to evaluate the utility of symptom screening for identification of COVID-19 in SNF residents.
Residents were categorized as asymptomatic or symptomatic at the time of testing, based on the absence or presence of fever, cough, shortness of breath, or other symptoms on the day of testing or during the preceding 14 days. Among 23 (30%) residents with positive test results, 10 (43%) had symptoms on the date of testing, and 13 (57%) were asymptomatic. 
Seven days after testing, 10 of these 13 previously asymptomatic residents had developed symptoms and were recategorized as presymptomatic at the time of testing. The reverse transcription–polymerase chain reaction (RT-PCR) testing cycle threshold (Ct) values indicated large quantities of viral RNA in asymptomatic, presymptomatic, and symptomatic residents, suggesting the potential for transmission regardless of symptoms. Symptom-based screening in SNFs could fail to identify approximately half of residents with COVID-19. Long-term care facilities should take proactive steps to prevent introduction of SARS-CoV-2 (3). Once a confirmed case is identified in an SNF, all residents should be placed on isolation precautions if possible (3), with considerations for extended use or reuse of personal protective equipment (PPE) as needed (4).
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