Performance of the Abbott SARS-CoV-2 IgG serological assay in South African 2 patients.

Sarika Jugwanth,Jaya A George,Jurette S Grove,Jonathan M Blackburn,Wendy Stevens,Anura David,Nakampe Mampeule,Ian Sanne,Maemu P Gededzha,Elizabeth S Mayne,Wendy A Burgers,Nontobeko Zwane,Lesley Scott,Han-Chung Wu

doi:10.1371/journal.pone.0262442

Abstract

In late December 2019, pneumonia cases of unknown origin were reported in Wuhan, China. This virus was named SARS-CoV2 and the clinical syndrome was named coronavirus disease 19 (COVID-19). South Africa, despite strict and early lockdown has the highest infection rate in Africa. A key component of South Africa’s response to SARSCoV2 was the rapid scale-up of diagnostic testing. The Abbott SARS-CoV2 assay detects IgG antibodies against the Nucleocapsid (N) protein of the SARS-CoV2 virus. This study undertook to validate and evaluate performance criteria of the Abbott assay and to establish whether this assay would show clinical utility in our population. Positive patients (n = 391) and negative controls (n = 139) were included. The Architect-i and Alinity-i systems were analyzers that were used to perform the SARS-CoV-2 IgG assay. In-house ELISA was incorporated into the study as a confirmatory serology test. A total of number of 530 participants was tested, 87% were symptomatic with infection and 13% were asymptomatic. When compared to RT-qPCR, the sensitivity of Architect and Alinity SARS-CoV2 assays was 69.5% and 64.8%, respectively. Specificity for Architect and Alinity assays was 95% and 90.3%, respectively. The Abbott assay was also compared to in house ELISA assay, with sensitivity for the Architect and Alinity assays of 94.7% and 92.5%, respectively. Specificity for Abbott Alinity assays was 91.7% higher than Abbott Architect 88.1%. Based on the current findings testing of IgG after 14 days is recommended in South Africa and supports other studies performed around the world.

Highlights

In late December 2019, pneumonia cases of unknown origin were reported in Wuhan, the Hubei province of China [1]
The cumulative sensitivity of both the Abbott SARS-CoV2 Architect and Abbott SARS-CoV2 Alinity assays when compared to RT-qPCR was 69.5% and 64.8%, respectively
The diagnostic specificity was for the Abbott SARS-CoV2 Architect and Abbott SARS-CoV2 Alinity assays was 95% and 90.3% out of a total of 526 and 435 samples tested, respectively (Table 3)

Summary

Introduction

In late December 2019, pneumonia cases of unknown origin were reported in Wuhan, the Hubei province of China [1]. Due to its genetic similarity to SARS-CoV, this virus was named SARS-CoV-2 [3] and the clinical syndrome was named coronavirus disease 19 (COVID-19) by the WHO [1, 4, 5]. The course of the pandemic in Africa was of concern because of weaknesses in health systems in some African countries and the high burden of both non-communicable and communicable disease [10]. South Africa, despite its strict and early lockdown, is the country in Africa with the highest infection rate. This lockdown was one of the most stringent worldwide and aimed to protect the healthcare services and to protect vulnerable populations, especially those with Human Immunodeficiency Virus (HIV) infection and tuberculosis (TB) [2, 10–12]

Methods

Results

Conclusion