Severe Acute Respiratory Syndrome Coronavirus 2 Seroassay Performance and Optimization in a Population With High Background Reactivity in Mali.
J Infect Dis
; 224(12): 2001-2009, 2021 12 15.
Article
in English
| MEDLINE | ID: covidwho-1575924
ABSTRACT
BACKGROUND:
False positivity may hinder the utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests in sub-Saharan Africa.METHODS:
From 312 Malian samples collected before 2020, we measured antibodies to the commonly tested SARS-CoV-2 antigens and 4 other betacoronaviruses by enzyme-linked immunosorbent assay (ELISA). In a subset of samples, we assessed antibodies to a panel of Plasmodium falciparum antigens by suspension bead array and functional antiviral activity by SARS-CoV-2 pseudovirus neutralization assay. We then evaluated the performance of an ELISA using SARS-CoV-2 spike protein and receptor-binding domain developed in the United States using Malian positive and negative control samples. To optimize test performance, we compared single- and 2-antigen approaches using existing assay cutoffs and population-specific cutoffs.RESULTS:
Background reactivity to SARS-CoV-2 antigens was common in prepandemic Malian samples. The SARS-CoV-2 reactivity varied between communities, increased with age, and correlated negligibly/weakly with other betacoronavirus and P falciparum antibodies. No prepandemic samples demonstrated functional activity. Regardless of the cutoffs applied, test specificity improved using a 2-antigen approach. Test performance was optimal using a 2-antigen assay with population-specific cutoffs (sensitivity, 73.9% [95% confidence interval {CI}, 51.6-89.8]; specificity, 99.4% [95% CI, 97.7-99.9]).CONCLUSIONS:
We have addressed the problem of SARS-CoV-2 seroassay performance in Africa by using a 2-antigen assay with cutoffs defined by performance in the target population.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Spike Glycoprotein, Coronavirus
/
SARS-CoV-2
/
COVID-19
/
Antibodies, Viral
Type of study:
Diagnostic study
/
Experimental Studies
/
Observational study
Limits:
Adult
/
Humans
Country/Region as subject:
Africa
Language:
English
Journal:
J Infect Dis
Year:
2021
Document Type:
Article
Affiliation country:
Infdis
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