70 - lack of sars-cov-2 Antibody Seroconversion After Prompt Identification and Cohorting of Sentinel sars-cov-2-positive Residents in a Skilled Nursing Facility

Background: Despite numerous outbreaks, antibody responses to SARS-CoV-2 in residents of skilled nursing facilities (SNF) are not well described.  We reviewed serological test results in a cohort of SNF residents who had been repetitively screened for SARS-CoV-2 infection by nasopharyngeal swab PCR.

Methods: In late March 2019, we identified symptomatic SARS-CoV-2 PCR positive residents at a SNF. In response, all remaining SNF patients were serially screened, and all SARS-CoV-2 PCR positive patients were transferred to the acute care hospital or cohorted in a separate COVID Recovery Unit (CRU) in the SNF. In early June, all SNF residents (SARS-CoV-2 PCR positive and negative) underwent serologic testing for SARS-CoV-2 Spike (S1/S2) IgG (DiaSorin). DiaSorin IgG-positive results for patients that were SARS-CoV-2 PCR-negative were reflexed to nucleocapsid IgG (Abbott). Antibody testing occurred a median of 69 days (63-70 IQR) after PCR positivity.

Results: Nineteen SARS-CoV-2 PCR positive residents were identified from the outbreak and an additional 9 were transferred from the acute care hospital to the CRU; 1 died and 1 received convalescent plasma leaving 26 SARS-CoV-2 PCR positive residents, including 6 who were asymptomatic, that were eligible for serologic testing. Twenty-four of the 26 were positive for IgG by the DiaSorin assay; one seronegative resident was one of the asymptomatic residents. There were an additional 121 residents in the SNF whose SARS-CoV-2 PCR was negative at least once.  Among these 121 SNF residents with negative SARS-CoV-2 RT-PCR, all but two were seronegative by the Diasorin assay. The two seropositive residents had no nucleocapsid antibodies when reflex tested by the Abbott assay.Figure 1. Cohort Diagram


Conclusion: In a limited sample of SNF residents with SARS-CoV-2 PCR positivity, the sensitivity of the Diasorin assay was 92% (24/26) and the specificity was 98% (119/121).  None of the residents with negative SARS-CoV-2 PCR had confirmed positive antibody results using reflex testing (DiaSorin/Abbott).  Despite high risk exposure in congregate living facilities, we found no evidence of additional SARS-CoV-2 exposure, reinforcing the importance of serial surveillance SARS-CoV-2 testing and early cohorting in SNF settings.

Co-Author(s)

• DB

  Debika Bhattacharya, MD MSc

  Associate Clinical Professor
  David Geffen School of Medicine, University of California, Los Angeles; Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: Abbvie : Scientific Research Study Investigator (Status: Ongoing); Gilead : Grant/Research Support (Status: Ongoing); Regeneron : Scientific Research Study Investigator (Status: Ongoing)

Presenting Author(s)

• 

  Alexander Winnett, BS

  MD/PhD Student
  University of California Los Angeles - California Institute of Technology
  Los Angeles, CA

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

  Slides Slides and Audio

Co-Author(s)

• JF

  Jennifer A. Fulcher, MD, PhD

  Assistant Professor
  David Geffen School of Medicine, University of California, Los Angeles; Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• LS

  Linda Sohn, MD, MPH

  Assistant Professor
  David Geffen School of Medicine, University of California, Los Angeles; Division of Geriatrics and Extended Care, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• FC

  Feliza Calub, NP

  Nurse Practitioner
  VA Greater Los Angeles Healthcare System
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• IL

  Ian Lee-Chang, BS

  CRS Coordinator
  Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• WS

  William A. Schwartzman, MD

  Associate Clinical Professor of Medicine
  David Geffen School of Medicine, University of California, Los Angeles; Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• 

  David O. Beenhouwer, MD

  Professor of Medicine
  David Geffen School of Medicine, University of California, Los Angeles; Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• JV

  John Vallone, MD

  Chief of Pathology
  Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• CG

  Christopher J. Graber, MD, MPH

  Associate Clinical Professor of Medicine
  VA Greater Los Angeles Healthcare System/UCLA
  Los Angeles, California

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
• 

  Matthew B. Goetz, MD

  Chief, Infectious Diseases
  VA Greater Los Angeles Healthcare System and David Geffen School of Medicine at UCLA, VA-CDC Practice-Based Research Network
  Los Angeles, CA

  Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.