SARS-COV-2 SEROLOGICAL TESTING: WHAT IS IT ANDWHAT DOES ITMEAN?

MAY 13,2020

COVID-19 Testing –from RNA and Antigens to Antibodies

Jennifer L. Rakeman, PhDAssistant Commissioner, Laboratory DirectorPublic Health LaboratoryNYC Department of Health and Mental Hygiene

NEW YORK CITY PUBLIC HEALTH

LABORATORY

• Part of the NYC Department of Health and Mental Hygiene

• Testing focused on health of the population of NYC

• Outbreak detection and response• Infectious disease• Biothreats• Environmental

testing• Approx. 200 staff

Detection of VIRAL NUCLEIC ACID: Nucleic acid amplification test (NAAT)• Molecular test detect viral genetic material (SARS-CoV-2 RNA)• Best test to diagnose acute infection, inform clinical evaluation and

direct infection prevention and control practices • Performed on respiratory specimens (nasopharyngeal or

oropharyngeal swab, nasal swab, saliva, sputum)

Detection of VIRAL ANTIGENS: • Detect viral proteins in patient specimens• Diagnosis of acute infection, may be less sensitive than NAAT• Performed on respiratory specimens (nasal swab, NP swab)

Detection of IMMUNE RESPONSE to virus: Antibody/Serology tests• Detect SARS-CoV-2 specific antibodies – present 1-3 weeks after

infection• Evidence of a previous infection, NOT for diagnostic purposes• Performed on blood (serum, dried blood spot)

LABORATORY TESTING COVID-19:TEST TYPES

• NAAT tests detect viral RNA• First tests developed for SARS-CoV-2• Based on sequence of viral genome• Amplify virus-specific nucleic acid and detect• May be manual or automated, low or high

throughput

LABORATORY TESTING COVID-19:VIRAL NUCLEIC ACID DETECTION

LABORATORY TESTING COVID-19:VIRAL NUCLEIC ACID DETECTION

• Three main steps:

• COLLECTION – shortages of collection kits: SWABS and VTM

• Alternate devices – 3D printed swabs, saline• Alternate specimen types – Nasal swabs, saliva

• RNA EXTRACTION – shortages of reagents• Alternate platforms• “No-extraction” methods

• AMPLIFICATION – shortages of PCR reagents• Largely mitigated

• Three main steps:

• COLLECTION – shortages of collection kits: SWABS and VTM

• Alternate devices – 3D printed swabs, saline• Alternate specimen types – Nasal swabs, saliva

• RNA EXTRACTION – shortages of reagents• Alternate platforms• “No-extraction” methods

• AMPLIFICATION – shortages of PCR reagents• Largely mitigated

LABORATORY TESTING COVID-19:VIRAL NUCLEIC ACID DETECTION

• NEW TECHNOLOGY - CRISPR• Sherlock CRISPR SARS-CoV-2 test• Upper respiratory swab specimen• Extract RNA, Amplify target (RT-LAMP)• Detection with Cas, activates CRISPR complex• Cleavage of reporter - DETECTION

LABORATORY TESTING COVID-19:VIRAL NUCLEIC ACID DETECTION

Kellner, M.J., Koob, J.G., Gootenberg, J.S. et al. SHERLOCK: nucleic acid detection with CRISPR nucleases. Nat Protoc 14, 2986–3012 (2019). https://doi.org/10.1038/s41596-019-0210-2

• Antigen test• Quidel Sofia2 SARS Antigen FIA – detects

nucleocapsid protein from SARS-CoV and SARS –CoV-2

• Specimen -> reaction tube• Virus disrupted, nucleocapsid protein exposed

• Apply to test cartridge• Protein is “captured” and detected in reader

• Can be performed Point-of-Care

• Lower sensitivity than NAAT

LABORATORY TESTING COVID-19:ANTIGEN TESTS

LABORATORY TESTING COVID-19:SEROLOGIC TESTS

• Serologic tests are intended to detect anti-SARS CoV-2 antibodies

• Tests can be for a specific antibody type (e.g., IgG or IgM) or a combination (e.g., IgG/IgM, total)

• A positive result indicates the presence of antibodies that likely resulted from an infection with SARS-CoV-2

• Some tests may cross react with related coronavirus

• A negative result is interpreted as NO previous infection, or tested too soon

• It may take 1 to 3 weeks for antibodies to reach a detectable level following infection

• For persons who are currently or recently infected, test for viral RNA is indicated

• Repeat testing may be indicated in persons with recent illness

LABORATORY TESTING COVID-19:SEROLOGIC TESTS

• At this time, it is NOT known if antibodies provide protection against re-infection

• As such, a positive test should not be used for return-to-work decisions or relaxation of other precautions

• Serology testing can be used to:• Determine prevalence of SARS-CoV-2 infection

among a population• Identify individual patients who may be candidates to

donate plasma for therapeutic purposes

LABORATORY TESTING COVID-19:SEROLOGIC TESTS

1. NYC Health Department. Health alert #11: current status of SARS-CoV-2 serologic testing. April 22, 2020.https://www1.nyc.gov/assets/doh/downloads/pdf/han/alert/2020/covid-19-status-of-serologic-testing.pdf2. Infectious Diseases Society of America. IDSA COVID-19 antibody testing primer. May 4, 2020. https://www.idsociety.org/globalassets/idsa/public-health/covid-19/idsa-covid-19-antibody-testing-primer.pdf3. World Health Organization. “Immunity passports” in the context of COVID-19: scientific brief. April 24, 2020. https://apps.who.int/iris/handle/10665/331866

• During a public health emergency, FDA can issue emergency use authorization (EUA) which expedites test review process and, if granted, allows temporary authorization for use during emergency

• CLIA (Clinical Laboratory Improvement Amendments) categorization of tests is determined after FDA authorization is granted

• determines the allowable setting for tests: • High complexity – difficult to perform, require quality control, quality

assurance, trained personnel, proficiency testing• Moderate complexity – more complex, require a lab setting,

requirements for quality control, quality assurance, proficiency testing • Waived – simple to perform, low risk for erroneous results, requires a

Certificate of Waiver

• Tests without FDA EUA default to being categorized as HIGH complexity

LABORATORY TESTING COVID-19:FDA EMERGENCY USE AUTHORIZATIONand CLIA CATEGORIZATION

U.S. Food and Drug Administration. Emergency use authorizations (EUA) for COVID-19. https://www.fda.gov/medical-devices/emergency-situations-medical-devices/medical-devices-and-covid-19-pandemic#EUA

• Serology tests with Emergency Use Authorizations • May be performed only in lab with EUA – 2 tests

• Wadsworth MIA test• Mt. Sinai IgG ELISA

• Commercially available kits – 10 currently available • all must be performed in a laboratory setting

• Performance data and NPV/PPV calculator:• https://www.fda.gov/medical-devices/emergency-situations-

medical-devices/eua-authorized-serology-test-performance

LABORATORY TESTING COVID-19:SEROLOGY TESTS AVAILABLE

U.S. Food and Drug Administration. Emergency use authorizations (EUA) for COVID-19. https://www.fda.gov/medical-devices/emergency-situations-medical-devices/medical-devices-and-covid-19-pandemic#EUA

• Under Section IV.D. of the FDA Policy for Coronavirus Disease-2019 Tests, manufacturers could “validate” a test, notify FDA, and then market and distribute the test

• NO review by FDA• Default to HIGH complexity status• 191 test kits listed on FDA website under this policy• Report must include multiple disclaimers

• Manufacturers were falsely representing tests as “FDA approved” or “FDA authorized” and as “point-of-care” tests

• Used in point of care settings – however, NOT ALLOWABLE!!!• Performance unreviewed

LABORATORY TESTING COVID-19:FDA POLICIESand SEROLOGY TESTS

U.S. Food and Drug Administration. Policy for Coronavirus Disease-2019 Tests During the Public Health Emergency (Revised). https://www.fda.gov/regulatory-information/search-fda-guidance-documents/policy-coronavirus-disease-2019-tests-during-public-health-emergency-revisedU.S. Food and Drug Administration. FAQs on Testing for SARS-CoV-2. https://www.fda.gov/medical-devices/emergency-situations-medical-devices/faqs-testing-sars-cov-2

• NEW: FDA POLICY CHANGE as of May 4, 2020

• All commercial manufacturers of serology tests must submit EUA requests with validation data within 10 business days of notification to the FDA of their validation testing (or May 18) or remove the test from the market

• Specific performance thresholds for sensitivity and specificity of serology tests recommended by FDA

• Streamlined process for EUA submissions for serology tests introduced

• https://covidtestingproject.org/

LABORATORY TESTING COVID-19:SEROLOGY TESTS AND FDA

https://www.medrxiv.org/content/10.1101/2020.04.25.20074856v1.full.pdfU.S. Food and Drug Administration. Emergency use authorizations (EUA) for COVID-19. https://www.fda.gov/medical-devices/emergency-situations-medical-devices/medical-devices-and-covid-19-pandemic#EUAU.S. Food and Drug Administration. Policy for coronavirus disease 2019 tests during the public health emergency (revised). May 2020. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/policy-coronavirus-disease-2019-tests-during-public-health-emergency-revised

• Use of testing in the coming months, as we begin to relax mitigation policies

• Diagnosis of cases: Viral RNA, Viral Antigen testing• Contact tracing will be used to curb spread of SARS-

CoV-2

• How serosurvey testing data will be used • Detection of past cases: Serology testing• Determine how widespread COVID-19 was in NYC• Provide insight into the immune response to the

virus

LABORATORY TESTING COVID-19:MOVING FORWARD

NYC Health Department:• Provider page: on.nyc.gov/covid19provider• Data page: on.nyc.gov/covid19data• Weekly webinars: Fridays, 2 PM (sign up on provider page)• Dear Colleague COVID-19 newsletters (sign up for City Health

Information subscription at: nyc.gov/health/register) • NYC Health Alert Network (sign up at

https://www1.nyc.gov/site/doh/providers/resources/health-alert-network.page)

• Provider Access Line: 866-692-3641Other sources:• CDC: https://www.cdc.gov/coronavirus/2019-ncov/index.html• Vital Strategies/Resolve to Save Lives:

https://www.vitalstrategies.org/covid• ASTHO: https://www.astho.org/COVID-19• NACCHO: https://www.naccho.org/programs/our-covid-19-response• APHL: https://www.aphl.org/programs/preparedness/Crisis-

Management/COVID-19-Response/Pages/default.aspx

NYC DOHMH RESOURCES ON COVID-19