ABSTRACT
BackgroundEight months after the detection of the first COVID-19 case in Africa, 1,262,476 cases have been reported in African countries compared to 72 million worldwide. The real burden of SARS-CoV-2 infection in West Africa is not clearly defined. The aim of the study was to evaluate the seroprevalence of SARS-CoV-2 in half of the 3,380 workers of several mining companies operating in two mines in the Ivory Coast and having its headquarters in the economic capital Abidjan. MethodsFrom 15th July to 13th October 2020, a voluntary serological test campaign was performed in the 3 sites where the companies operate: two mines, and the headquarters in Abidjan.We performed a COVID-PRESTO rapid test for the detection of IgG and IgM on capillary blood. A multivariate analysis was performed to identify independent sociodemographic characteristics associated with a higher SARS-CoV-2 seroprevalence rate. ResultsA total of 1,687 subjects were tested. 91% were male (n= 1,536) and mean age was 37 years old. The overall crude seroprevalence rate was 25.1% (n=422), but differing significantly between different sites, rising from 13.6% (11.2%-16.1%) in mine A to 34.4% (31.1%-37.7%) in mine B and 34.7% (26.2%-43.2%) in Abidjan. Non-resident workers in mines had a significantly lower prevalence rate than those living full-time in mines. Seroprevalence was 26.5% in natives of the Ivory Coast, while people coming from countries other than Africa were less likely to be SARS-CoV-2 seropositive. Among the 422 positive subjects, 74 reported mild symptoms in the three previous months and one was hospitalized for a severe COVID-19 infection. ConclusionThe prevalence of SARS-CoV-2 infection among mine workers in Ivory Coast is high. The low morbidity observed has probably led to an underestimation of the burden of this infection in West Africa. The high prevalence reported in subjects living in Abidjan, who have not any close contact with mine workers, may be indicative of the real seroprevalence in the Ivory Coast capital.
ABSTRACT
IntroductionThe SARS-CoV-2 pandemic has become a major public health issue worldwide. Developing and evaluating rapid and easy-to-perform diagnostic tests is an absolute priority. The current study was designed to assess diagnostic performances of an antigen-based rapid detection test (COVID-VIRO(R)) in a real-life setting. MethodsTwo nasopharyngeal specimens of symptomatic or asymptomatic adult patients hospitalized in the Infectious Diseases Department or voluntarily accessing the COVID-19 Screening Department of the Regional Hospital of Orleans, France, were concurrently collected. COVID VIRO(R) diagnostic specificity and sensitivity were assessed in comparison to real-time reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) results. A subset of patients underwent an additional oropharyngeal and/or a saliva swab for rapid testing. Results121 patients already having a confirmed infection and 127 patients having no evidence of recent or ongoing infection were enrolled, for a total of 248 couple of nasopharyngeal swab specimens. Overall COVID-VIRO(R) sensitivity was 96.7% (IC: 93.5%-99.9%). In asymptomatic patients, symptomatic patients having symptoms for more than 4 days and those having a RT-qPCR Cycle threshold value [≥]32, sensitivity was of 100%, 95.8% and 91.9% respectively. The concordance between RT-qPCR and COVID VIRO(R) rapid test was 100% for the 127 patients with no SARS-CoV-2 infection. ConclusionCOVID-VIRO(R) test had 100% specificity and above 95% sensitivity, better than WHO recommendations (specificity [≥]97-100%, sensitivity [≥]80%). These rapid tests are particularly interesting for large-scale screening in Emergency Department, low resource settings and airports.
ABSTRACT
BackgroundThe SARS-CoV-2 virus is responsible for the infectious respiratory disease called COVID-19 (COronaVIrus Disease). In response to the growing COVID-19 pandemic, Rapid Diagnostic Tests (RDTs) have been developed to detect specific antibodies, IgG and IgM, to SARS-CoV-2 virus in human whole blood. We conducted a real-life study to evaluate the performance of two RDTs, COVID-PRESTO(R) and COVID-DUO(R), compared to the gold standard, RT-PCR. MethodsRT-PCR testing of SARS-Cov-2 was performed from nasopharyngeal swab specimens collected in adult patients visiting the infectious disease department at the hospital (Orleans, France). Fingertip whole blood samples taken at different time points after onset of the disease were tested with RDTs. The specificity and sensitivity of the rapid test kits compared to test of reference (RT-PCR) were calculated. ResultsAmong 381 patients with symptoms of COVID-19 who went to the hospital for a diagnostic, 143 patients were RT-PCR negative. Results of test with RDTs were all negative for these patients, indicating a specificity of 100% for both RDTs. In the RT-PCR positive subgroup (n=238), 133 patients were tested with COVID-PRESTO(R) and 129 patients were tested with COVID-DUO(R) (24 patients tested with both). The further the onset of symptoms was from the date of collection, the greater the sensitivity. The sensitivity of COVID-PRESTO(R) test ranged from 10.00% for patients having experienced their 1st symptoms from 0 to 5 days ago to 100% in patients where symptoms had occurred more than 15 days before the date of tests. For COVID-DUO(R) test, the sensitivity ranged from 35.71% [0-5 days] to 100% (> 15 days). ConclusionCOVID-PRESTO(R) and DUO(R) RDTs turned out to be very specific (none false positive) and to be sensitive enough after 15 days from onset of symptom. These easy to use IgG/IgM combined test kits are the first ones allowing a screening with capillary blood sample, by typing from a finger prick. These rapid tests are particularly interesting for screening in low resource settings.
