Validation of the COVID-19 IgG/IgM Rapid Test Cassette (BNCP - 402 and BNCP402) in a South African setting.

Background: Different diagnostic tools could improve early detection of coronavirus disease 2019 (COVID-19). A number of antibody-based serological point-of-care tests have been developed to supplement real-time reverse transcriptase polymerase chain reaction (RT-PCR)-based diagnosis. This study describes the validity of an antibody test, namely the immunoglobulin G (IgG)/immunoglobulin M (IgM) Rapid Test Cassette® (BNCP - 402 and BNCP402), manufactured by Spring Healthcare Services. Methods: A prospective cohort validation study was undertaken at Chris Hani Baragwanath Academic Hospital between 16 July 2020 and 12 August 2020. A total of 101 patients admitted as COVID-19 cases under investigation were included in the study. They were divided into two categories depending on time since symptom onset: testing performed within seven days (early cohort) and after seven days (late cohort). The rapid antibody test was compared to the RT-PCR. Results: Overall, the test has a sensitivity and specificity of 85.2% and 80.0%, respectively, for a combination of IgG and IgM. Sensitivity and specificity of IgG testing alone were 81.5% and 85%. Sensitivity improved for testing with increasing time from symptom onset; however, specifity was not significantly different. Conclusion: The study data adds to the body of evidence that because of relatively low sensitivity and specificity, there is a limited role for antibody-based point-of-care testing in the acute phase of COVID-19 infection, as was the case with this IgG/IgM Rapid Test Cassette (BNCP - 402 and BNCP402). There may exist a role for such testing in patients recovered from prior COVID-19 infection or in seroprevalence studies; however, additional evaluations at later timepoints from symptom onset are required.

Vitamin D status and COVID-19 severity.

Background: Age, body mass index (BMI) and pre-existing comorbidities are known risk factors of severe coronavirus disease 2019 (COVID-19). In this study we explore the relationship between vitamin D status and COVID-19 severity. Methods: We conducted a prospective, cross-sectional descriptive study. We enrolled 100 COVID-19 positive patients admitted to a tertiary level hospital in Johannesburg, South Africa. Fifty had symptomatic disease (COVID-19 pneumonia) and 50 who were asymptomatic (incidental diagnosis). Following written informed consent, patients were interviewed regarding age, gender and sunlight exposure during the past week, disease severity, BMI, calcium, albumin, magnesium and alkaline phosphatase levels. Finally, blood was collected for vitamin D measurement. Results: We found an 82% prevalence rate of vitamin D deficiency or insufficiency among COVID-19 patients. Vitamin D levels were lower in the symptomatic group (18.1 ng/mL ± 8.1 ng/mL) than the asymptomatic group (25.9 ng/mL ± 7.1 ng/mL) with a p-value of 0.000. The relative risk of symptomatic COVID-19 was 2.5-fold higher among vitamin D deficient patients than vitamin D non-deficient patients (confidence interval [CI]: 1.14-3.26). Additional predictors of symptomatic disease were older age, hypocalcaemia and hypoalbuminaemia. Using multiple regression, the only independent predictors of COVID-19 severity were age and vitamin D levels. The patients exposed to less sunlight had a 2.39-fold increased risk for symptomatic disease compared to those with more sunlight exposure (CI: 1.32-4.33). Conclusion: We found a high prevalence of vitamin D deficiency and insufficiency among patients admitted to hospital with COVID-19 and an increased risk for symptomatic disease in vitamin D deficient patients.

Evaluation of the modified Wells score in predicting venous thromboembolic disease in patients with tuberculosis or HIV in a South African setting.

Background: There is paucity of data on the modified Wells score (MWS) utility on patients with venous thromboembolism (VTE) in a South African setting where there is a high burden of HIV and tuberculosis (TB). This study analyses the performance of this score in HIV/TB-infected patients compared with non-infected patients. Objectives: To assess the performance of the MWS as an additional risk factor for VTE in hospitalised patients with a high burden of HIV/TB infections. Method: This study was a retrospective cross-sectional cohort analysis of the utility of the MWS in 156 HIV/TB-infected and non-infected adult patients diagnosed with VTE on compression ultrasonography (CUS) or computed tomography pulmonary angiography (CTPA) in a medical inpatient setting over six months. Patients with HIV and/or TB were assessed as having an additional risk factor (1 point for each), and this was compared with the MWS. A McNeymar's paired sample chi-squared test was used to compare the sensitivity of this score against the MWS. Results: Of the 156 patients with VTE who were enrolled, HIV was the commonest risk factor (42.31%) with TB accounting for 10.90% of cases. When the MWS adjusted for HIV/TB was used, the sensitivity increased from 25% to 100% for the HIV-/TB+ category, it increased from 77.36% to 98.11% in the HIV+/TB- category and it increased from 84.62% to 92.95% in the HIV+/TB+ category. These differences were statistically significant at P < 0.05 in all categories. Conclusion: The MWS performs better when the infectivity of HIV/TB is included as an additional risk factor in the score.

Demographic, clinical, electrocardiographic and echocardiographic characteristics of patients hospitalized with COVID-19 and cardiac disease at a tertiary hospital, South Africa.

BACKGROUND: Coronavirus associated disease 2019 (COVID-19) is associated with higher morbidity and mortality in patients with cardiovascular disease. There is a paucity of data regarding COVID-19 and cardiac disease from Africa. We aimed to describe the demographic, clinical, electrocardiographic and echocardiographic characteristics of patients with COVID-19 and cardiac disease at a tertiary hospital in South Africa. METHODS: This was a retrospective cross-sectional descriptive study (Aug 2020 to March 2021) of 200 patients with COVID-19 and confirmed cardiac disease, conducted at Chris Hani Baragwanath. Demographic, clinical, electrocardiographic and echocardiographic characteristics were systematically collected. RESULTS: Majority (86%) of patients were Africans with mean age 56.4±15.6 years (57.5% females). Fifty three percent were unemployed and 28% were pensioners. Main comorbidities were hypertension (69.5%), diabetes mellitus (31.5%) and human immunodeficiency virus (HIV) (22.5%). Majority of the patients were overweight or obese (65.5%). All except 8 patients were on chronic medication. Dyspnoea on admission was noted in 88.5% of patients. Seventy nine percent of patients had abnormal chest X-Ray. Frequently documented electrocardiography findings were sinus tachycardia (63%) and atrial fibrillation, noted in 7% of patients. The most common indication for echocardiography was heart failure (30%). Severe left ventricular dysfunction was noted in 21.5%. Features of pulmonary hypertension were present in 45.5%. The right ventricle was enlarged in 59% of patients, and functional tricuspid regurgitation was noted in 54.5%. The most common diagnoses were hypertensive heart disease with preserved ejection fraction (35.8%), cardiomyopathies (20%), cor pulmonale (15.7%), acute coronary syndrome (6.5%), infective endocarditis (5.5%) and valvular heart disease (2.5%). Echocardiography modified management in 53% of cases. An in-hospital mortality of 17.5% was noted. On multivariate logistic regression analysis sinus tachycardia was the most important independent predictor of mortality (odds ratio, OR: 2.52, 95% confidence interval, CI: 1.08-5.85, P=0.03). CONCLUSIONS: Most patients were obese females with underlying hypertension. Echocardiography altered management in about half the patients. Mortality amongst this cohort of patients was high and were predominantly males.