Comparison of SARS-CoV-2 IgM and IgG seroconversion profiles among hospitalized patients in two US cities

Abstract

Background The clinical and public health utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing requires a better understanding of the dynamics of the humoral response to infection. Objective To track seroconversion of IgG and IgM antibodies in patients with SARS-CoV-2 infection and its association with patient and clinical factors and outcomes. Methods Residual patient specimens were analyzed on the Abbott ARCHITECT i2000 instrument using the Abbott SARS-CoV-2 IgG assay and prototype SARS-CoV-2 IgM assay. Age, sex, comorbidities, symptom onset date, mortality, and specimen collection date were obtained from electronic medical records. Results 359 longitudinal samples were collected from 89 hospitalized patients 0-82 days post-symptom onset. 51.7% of patients developed IgG and IgM antibodies simultaneously; 32.8% seroconverted for IgM before IgG. On average, patients seroconverted for IgG by 8 days and for IgM by 7 days post-symptom onset. All patients achieved IgG seropositivity by 19 days and IgM seropositivity by 17 days. Median time to IgG and IgM seroconversion was prolonged and initial levels of IgG were lower in immunocompromised patients and patients <65 years of age compared to immune competent patients and those ≥65 years of age. Immunocompromised patients also had persistently lower levels of IgM that peaked on day 17.6 and decreased thereafter compared to immune competent patients. IgM seroconversion in patients who died reached significantly higher levels later after symptom onset than in those who recovered. Conclusions SARS-CoV-2 infected patients have similar time to seroconversion for IgG and IgM. However, differences in immune status and age alter time to seroconversion. These results may help guide serologic testing application in COVID-19 management.

Disparities of SARS-CoV-2 Nucleoprotein-Specific IgG in Healthcare Workers in East London, UK

“…Discrepant samples with a positive Panbio TM test device reading and a negative Architect TM test reading were further analysed on the Roche Cobas e801 analyzer using the Elecsys R anti-SARS-CoV-2 assay (Elecsys R ; Roche Diagnostics International Ltd, Rotkreuz, Switzerland; Roche Elecsys R ) according to the manufacturer's instructions. The assay detects IgG against the SARS-CoV-2 nucleocapsid (N) antigen, as well as SARS-CoV-2 IgM and IgA antibodies which are provided as a combined result (3,9).…”

“…Serological tests are being developed and evaluated to detect humoral immune responses, specifically immunoglobulins (Ig)G, IgM and total Ig to SARS-CoV-2 ( 3 ), to be widely employed across communities irrespective of the presence or absence of symptoms, thus complementing diagnosis outside of the window of positivity for polymerase chain reaction (PCR)-based SARS-CoV-2 test (the gold standard) ( 4 ). There are currently two types of antibody tests available: (i) quantitative laboratory tests with antibodies titrated by enzyme-linked immunosorbent assay (ELISA) or Chemiluminescent Microparticle Immunoassay (CMIA), (ii) point-of-care (POC) tests, mainly based on lateral flow chromatographic immunoassays ( 4 , 5 ), designed primarily to provide easy and relatively inexpensive access to diagnostics.…”

Seroprevalence of SARS-CoV-2 Antibodies in Symptomatic Individuals Is Higher than in Persons Who Are at Increased Risk Exposure: The Results of the Single-Center, Prospective, Cross-Sectional Study

“…The seroconversion of specific SARS-CoV-2 IgG/IgM antibodies can start as early as 4 days [11], with the median time of 7-8 days [12], after the onset of illness, and both IgG and IgM titers plateau within 6 days after seroconversion [13]. Most patients have neutralizing titers on days 14-20 with great titer variability [14].…”

Mater Artium Necessitas: The Birth of a COVID-19 Command Center

“…Eventually over 6000 blood and respiratory specimens were collected, organized, and stored. These specimens have been used to establish a lab-developed SARS-CoV-2 antibody detection assay, 5 examined differences in immune responses to SARS-CoV-2 between adult and pediatric patients, 6 discover evidence of secondary thrombotic microangiopathy in COVID-19, 7 establish that extended storage of respiratory specimen doesn’t significantly impact molecular testing results, 8 inspired multicenter collaborations in areas such as antibody studies, 9 and for countless current and future studies that will continue to add to the growing understanding of SARS-CoV-2 and COVID-19 disease.…”