SARS‐CoV‐2 antibody persistence in COVID‐19 convalescent plasma donors: Dependency on assay format and applicability to serosurveillance

Abstract

Background: Antibody response duration following severe acute respiratory syndrome coronavirus 2 infection tends to be variable and depends on severity of disease and method of detection. Study design and methods: COVID-19 convalescent plasma from 18 donors was collected longitudinally for a maximum of 63-129 days following resolution of symptoms. All the samples were initially screened by the Ortho total Ig test to confirm positivity and subsequently tested with seven additional direct sandwich or indirect binding assays (Ortho, Roche, Abbott, Broad Institute) directed against a variety of antigen targets (S1, receptor binding domain, and nucleocapsid [NC]), along with two neutralization assays (Broad Institute live virus PRNT and Vitalant Research Institute [VRI] Pseudovirus reporter viral particle neutralization [RVPN]).Results: The direct detection assays (Ortho total Ig total and Roche total Ig) showed increasing levels of antibodies over the time period, in contrast to the indirect IgG assays that showed a decline. Neutralization assays also demonstrated declining responses; the VRI RVPN pseudovirus had a greater rate of decline than the Broad PRNT live virus assay.

SARS-CoV-2 Seroprevalence in a Rural and Urban Household Cohort during First and Second Waves of Infections, South Africa, July 2020–March 2021

“…Although previous studies have shown that antibodies against the SARS-CoV-2 nucleocapsid wanes more quickly than those against the spike protein ( 22 , 23 ), 93% of persons who showed seroconversion at BD2 still had detectable nucleocapsid antibodies 6 months later. Direct antigen-sandwich format assays, such as the Roche anti-N assay used in our study, have been found to reliably detect antibodies in longitudinal samples ( 24 ). Of the few that seroreverted in this timeframe, the starting COI was low.…”

Risk Factors for Being Seronegative following SARS-CoV-2 Infection in a Large Cohort of Health Care Workers in Denmark

“…These controversies could be partly due to different ELISAs that were applied. Unlike traditional indirect ELISAs (antigen-antibody-antibody), antigen sandwich assay (antigen-antibody-antigen) uses a labeled virus antigen instead of labeled secondary anti-human antibody for detection, so that each anti-SARS-CoV-2 antibody bridges two recombinant antigens of the virus that affect the sensitivity of the test ( 13 ).…”

Reinfection by the SARS-CoV-2 Gamma variant in blood donors in Manaus, Brazil

“…The samples were first tested using an anti-N SARS-CoV-2 IgG chemiluminescence microparticle assay (CIMA, Abbott Park, IL, USA), and then the samples with enough volume were retested using the Abbott anti-S SARS-CoV-2 IgG CIMA. These are high specificity assays whose reactivity consistently wanes during convalescence [1,13,14] and presents small measurement error (see Supplemental Appendix).…”