ITECH Discussion of COVID-19: April 20, 2020 Matthew Golden, MD, - - PowerPoint PPT Presentation

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ITECH Discussion of COVID-19: April 20, 2020 Matthew Golden, MD, - - PowerPoint PPT Presentation

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University of Washington Public Health Capacity Building Center ITECH Discussion of COVID-19: April 20, 2020 Matthew Golden, MD, MPH Director, PHSKC HIV/STD Program Professor of Medicine, University of Washington Faculty, I-TECH Last

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University of Washington Public Health Capacity Building Center

Last Updated: April 19, 2020

Matthew Golden, MD, MPH Director, PHSKC HIV/STD Program Professor of Medicine, University of Washington Faculty, I-TECH

ITECH Discussion of COVID-19: April 20, 2020

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Agenda

  • Laboratory testing
  • Predicting severe disease
  • Household transmission
  • COVID19 and HIV
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Sensitivity of PCR

  • Wuhan study serological response in 140

cases (Gou L CID 2020)

  • Single PCR 52% sensitive
  • Serial PCR in Singapore (Lee HL CID 2020)
  • 102 suspected cases - all travelers from

China with respiratory symptoms

  • Tested on admission & at 24 hours
  • First PCR 89% sensitive – 2nd PCR ↑

sensitivity to 96%

  • PCR & chest CT (Fang Y. Radiology 2020)
  • 51 patients in Wuhan – 50 abnormal chest CT
  • First PCR 69% sensitive
  • 2nd PCR identified additional 29% of cases

PCR & Serological Positivity 1-25 after Symptoms

Days

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Antibody to COVID19

  • 535 samples from 173 patients in China
  • 93% developed IgG and/or IgM - Median time seroconversion 11 days

Zhao J. CID 2020 (epub) Days after onset Sensitivity RNA Sensitivity Antibody 1-7 (n=94) 67% 38% 8-14 (n=135) 54% 90% 15-39 (n=90) 45% 100% Total 67% 93% Sensitivity of RNA and Antibody Tests for SARS-CoV-2, by Time Since Onset of Symptoms

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Antibody to COVID19

10 20 30 40 50 60 70 80 90 100

<=5 6-9 10-13 14-17 18-21 22-25 26-29 >=30 Percent

IgM IgG

  • ELISA IgG/IgM

testing

  • 216 samples from

85 patients in China

  • IgG positive in

~80% at 2 weeks

  • IgG a little earlier

Ziang E. CID 2020 (epub)

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Testing for COVID

  • Nasopharyngeal swabs are 50-90% sensitive for COVID-19
  • Retest people at high risk if diagnosis is important
  • A negative test does not rule out infection in a person at high risk –

quarantine cannot be discontinued

  • Antibody tests typically positive by 2 weeks
  • IgM appears first
  • CAUTION: Not all antibody tests are the same. Hard to know how

any marketed test will perform

  • Role of antibody testing uncertain
  • Could help identify healthcare workers who are immune
  • Uncertain if antibody confers immunity
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Household Transmission Risk

16 4 20 18 28 17

20 40 60 80 100

Percent

  • 105 index cases exposed in

Wuhan, or to people from Wuhan or “high-risk sites”

  • 392 household contacts

PCR tested at the mid-point

  • f 14 day quarantine
  • 16% contacts PCR+
  • Transmission higher than

flu or MERS

  • Prior COVID19 reports 3-

10% positivity in close contacts

  • 9/64 (14%) infected contacts

were asymptomatic

  • Quarantine worked

Li W. CID 2020 (epub) * Excludes children

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Predicting Severe Disease

  • 373 patients admitted with

non-severe COVID19 in Wuhan

  • 19% patients developed

severe COVID19

  • Cutpoint of 189 points

was 78% sensitive and 78% specific in predicting severe COVID19 (AUC 0.853) in validation cohort (n=165)

  • Uncertain when labs
  • btained

Gong J CID 2020 (epub) Age Points

  • D. bili

RDWi BUN CRP LDH ALB Total points Probability severe COVID-19

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DISCUSSION