The Antibody Response to SARS-CoV-2 Infection
Open Access
- 27 August 2020
- journal article
- research article
- Published by Oxford University Press (OUP) in Open Forum Infectious Diseases
- Vol. 7 (9), ofaa387
- https://doi.org/10.1093/ofid/ofaa387
Abstract
Testing for SARS-CoV-2-specific antibodies has become an important tool, complementing nucleic acid tests (NATs) for diagnosis and for determining the prevalence of COVID-19 in population serosurveys. The magnitude and persistence of antibody responses are critical for assessing the duration of immunity. A SARS-CoV-2-specific immunofluorescent antibody (IFA) assay for IgG, IgA and IgM was developed, and prospectively evaluated by comparison to the reference standard of NAT on respiratory tract samples from individuals with suspected COVID-19. Neutralizing antibody responses were measured in a subset of samples using a standard microneutralization assay. 2753 individuals were eligible for the study (126 NAT positive, prevalence 4·6%). The median ‘window period’ from illness onset to appearance of antibody was 10·2 days (range 5·8 – 14·4). The sensitivity and specificity of either SARS-CoV-2 IgG, IgA or IgM when collected 14 days or more after symptom onset was 91·3% (95% CI 84·9-95·6) and 98·9% (98·4-99·3), respectively. The negative predictive value was 99·6% (99·3-99·8). The positive predictive value of detecting any antibody class was 79·9% (73·3-85·1); this increased to 96·8% (90·7-99·0) for the combination of IgG and IgA. Measurement of SARS-CoV-2-specific antibody by IFA is an accurate method to diagnose COVID-19. Serological testing should be incorporated into diagnostic algorithms for SARS-CoV-2 infection to identify additional cases where NAT was not performed, and resolve cases where false-negative and false-positive NATs are suspected. The majority of individuals develop robust antibody responses following infection, but the duration of these responses and implications for immunity remain to be established.Funding Information
- New South Wales Government’s Office for Health and Medical Research
- Snow Medical Research Foundation
- National Health and Medical Research Council
- Centre of Research Excellence in Emerging Infectious Diseases
This publication has 35 references indexed in Scilit:
- MERS-CoV Antibody Responses 1 Year after Symptom Onset, South Korea, 2015Emerging Infectious Diseases, 2017
- Persistence of Antibodies against Middle East Respiratory Syndrome CoronavirusEmerging Infectious Diseases, 2016
- Commensal–Pathogen Interactions along the Human Nasal PassagesPLoS Pathogens, 2016
- Kinetics of Serologic Responses to MERS Coronavirus Infection in Humans, South KoreaEmerging Infectious Diseases, 2015
- Viral Shedding and Antibody Response in 37 Patients With Middle East Respiratory Syndrome Coronavirus InfectionClinical Infectious Diseases, 2015
- Serological assays for emerging coronaviruses: Challenges and pitfallsVirus Research, 2014
- Comparison of Immunological Responses of Plague Vaccines F1 + rV270 and EV76 in Chinese-Origin Rhesus Macaque, Macaca mulattaScandinavian Journal of Immunology, 2010
- Duration of Antibody Responses after Severe Acute Respiratory SyndromeEmerging Infectious Diseases, 2007
- Longitudinal profile of antibodies against SARS‐coronavirus in SARS patients and their clinical significanceRespirology, 2006
- Serological Responses in Patients with Severe Acute Respiratory Syndrome Coronavirus Infection and Cross-Reactivity with Human Coronaviruses 229E, OC43, and NL63Clinical and Vaccine Immunology, 2005