Clinical diagnostic performance evaluation of five immunoassays for antibodies to SARS-CoV-2 diagnosis in a real-life routine care setting.

While molecular techniques remain the gold standard for diagnosis of acute SARS-CoV-2 infection, serological tests have the unique potential to ascertain how much of the population has been exposed to the COVID-19 pathogen. There have been limited published studies to date documenting the performance of SARS-CoV-2 antibody assays in Nigeria and so we evaluated the diagnostic performance of five (5) immunoassay on a set of clinical samples. Five automated immunoassays (2019-nCoV IgG/IgM antibody determination kit, Tigsun COVID-19 combo IgM/IgG rapid test, rapid response COVID-19 IgG/IgM test, COVID-19 IgM-IgG combined antibody rapid test, iChroma COVID-19 Ab) were tested. Three hundred and fourteen specimens were analyzed from health care workers who tested positive PCR for SARS-CoV-2 with symptoms consistent with SARS-CoV-2 receiving treatment at two treatment centres in Nasarawa State from March to September, 2020 with control of 134 health care workers who tested negative PCR for SARS-CoV-2 with no symptoms to SARS-CoV-2. The median patients' age was 40 years (IQR 39.8-41), majority were male and were on admission. The SARS-CoV-2 IgG/IgM antibody evaluated kits had a sensitivity of 33% (2019-nCoV IgG/IgM antibody determination kit), 22% (Tigsun COVID-19 combo IgM/IgG rapid test), 43% (rapid response COVID-19 IgG/IgM test), 44% (COVID-19 IgM-IgG combined antibody rapid test), 25% (iChroma COVID-19 Ab), 100% sensitivity, accuracy of 68.5% and Kappa coefficient of 0.7 and rapid response COVID-19 IgG/IgM test cassette had a sensitivity of 33%, specificity of 100% and accuracy of 72.5% with Kappa coefficient 0.7. The Tigsun COVID-19 combo IgM/IgG rapid test (lateral flow), positive, COVID-19 IgM-IgG combined antibody rapid test and iChroma COVID-19 Ab RT all had sensitivity of zero percent. Serology was complementary to RT-PCR for the diagnosis of COVID-19 at least 14 days after onset of symptoms. The assay panel needs to be improved to serve as an option for the diagnosis of SARS-CoV-2 in resource constrained settings where there are limited molecular diagnostics testing panels.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection among health care workers in Nasarawa State, Nigeria: implications for infection prevention and control measures.

INTRODUCTION: health care workers (HCWs) are on the frontline, waging war against SARS-CoV-2 and have a higher risk of infection with exposure to an infected person with SARS-CoV-2. There is a paucity of information on clinical characteristics and infection risk gradient of HCWs with SARS-CoV-2 with the view to marshal preventive measures. METHODS: we conducted a multi-center case series analysis of 648 HCWs who were randomly selected in private and public hospitals across Nasarawa State, managing cases of SARS-CoV-2. Demographic and epidemiological information, were abstracted from electronic medical records of cases from February to July 2020. Throat and Nasopharyngeal swabs and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) tests for SARS-CoV-2 nucleic acid were performed. RESULTS: overall, 134 of 648 HCWs across health centers in Nasarawa State tested positive for SARS-CoV-2. Eighty male HCWs constituted 30.9% of respondents with a median (interquartile range) age of 36.7 (30.0-47.0) years. Overall, 50 of 134 HCWs (67.5%) with SAR-COV-2 had mild disease. The five most common symptoms amongst cases were fever (67 [90.5%]), myalgia or fatigue (60 [81.1%]), cough (50[67.6%]), sore throat (50 [67.6%]), and muscle ache (50 [67.6%]). Contact with index patients (65 [59.1%]) and colleagues with infection (10 [13.9%]) as well as community-acquired infection (14 [18.9%]) were the main routes of exposure for HCWs. CONCLUSION: HCWs in Nasarawa State face an unprecedented occupational risk of morbidity and mortality as a result of SARS-CoV-2. There is need for rapid development of sustainable infection prevention control measures that protect HCWs from the SARS-CoV-2 ongoing pandemic.