Mid-term subclinical myocardial injury detection in patients recovered from COVID-19 according pulmonary lesion severity (preprint)

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) may cause damage of the cardiovascular system during the acute phase of infection. However, Recent studies described a mid and long-term subtle cardiac injuries after recovery from acute Coronavirus disease 19 (COVID-19).The aim of this study was to determine the relationship between the severity of chest computed tomography (CT) lesions and the persistence of subtle myocardial injuries at mid-term follow-up of patients recovered from COVID-19 infection. Methods All COVID-19 patients were enrolled prospectively in this study. Sensitive troponin T (hsTnT) and chest CT scan was performed in all patients at the acute phase of Covid-19 infection. At the mid-term follow up, conventional transthoracic echocardiograph and global longitudinal strain (GLS) of left and right ventricles (LV and RV) were determined and compared between patients with chest CT scan lesions less than 50% (Group 1) and those with severe chest CT scan greater or equal to 50% (Group 2). Results The mean age was 55 more or less than 14 years. Both LV GLS and RV GLS were significantly decreased in the group 2 (p=0.013 and p=0.011, respectively). LV GLS value more than -18% was noted in 43% of all the patients and RV GLS value more than -20% was observed in 48% of them. The group with severe chest CT scan lesions included more patients with reduced LV GLS and reduced RV GLS than the group with mild chest CT scan lesions (G1:29% vs. G2:57%, p=0.002) and (G1:36% vs. G2:60 %, p=0.009) respectively). Conclusion Patients with severe chest CT scan lesions are more likely to develop subclinical myocardial damage. TTE could be recommended in patients recovering from COVID-19 to detect subtle LV and RV lesions. Trial registration The cohort of patients is a part of the research protocol (IORG 00093738 N°102/OMB 0990-0279) approved by the Hospital Ethics Committee.

Effect of vitamin D supplementation versus placebo on recovery delay among COVID-19 patients: A randomized-controlled clinical trial (preprint)

Introduction : The present study aimed to determine the impact of vitamin D supplementation on recovery delay among COVID-19 patients. Methods : We performed a randomized controlled clinical trial in the national center for COVID-19 confinement, from May to August 2020. Simple randomization was done in a 1:1 allocation ratio. We included patients aged more than 18 years who had confirmed RT PCR and who remained positive on the 14 th day. The intervention group received vitamin D supplementation (200,000 IU / 1 ml of Cholecalciferol), the control group received a placebo treatment (physiological saline (1 ml)). We measured the recovery delay and the E gene SARS-CoV-2 RT-PCR Cycle threshold (Ct) values. The Log rank test and Hazard ratios (HR) were calculated. Results : A total of 117 participants were enrolled. The mean age was 42.7 years (SD 14). Males represented 55.6%.The median duration of viral RNA conversion was 37 days ( 95% CI: 29-45.50) in intervention group and 28 days ( 95% CI: 23-39) in the placebo group (p=0.010). HR was 1.58 ( 95% CI: 1.09-2.29, p=0.015). Ct values revealed a stable trends over time in both groups. Conclusion : Vitamin D supplementation was not associated with a shortened recovery delay when given to patients for whom the RT-PCR remained positive on the 14th day. Trial registration: This study was approved by the Human Subjects Protection Tunisia center (TN2020-NAT-INS-40) on May 05, 2020 and by clinical trial.gov with approval number Clinical Trials.gov ID: NCT04883203.

Factors associated with a prolonged negative conversion of viral RNA in patients with COVID-19.

OBJECTIVES: The aim of this study was to identify the factors influencing the delay in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA negative conversion. METHODS: A cohort study was conducted that included patients with coronavirus disease 2019 (COVID-19) admitted to the Tunisian national containment center. Follow-up consisted of a weekly RT-PCR test. Multivariate Cox regression analysis was performed to determine independent predictors associated with negative RNA conversion. RESULTS: Among the 264 patients included, the median duration of viral clearance was 20 days (interquartile range (IQR) 17-32 days). The shortest duration was 9 days and the longest was 58 days. Factors associated with negative conversion of viral RNA were symptoms such as fatigue, fever, and shortness of breath (hazard ratio (HR) 0.600, 95% confidence interval (CI) 0.401-0.897) and face mask use when exposed to COVID-19 cases (HR 2.006, 95% CI 1.247-3.228). The median time to RNA viral conversion was 18 days (IQR 16-21 days) when using masks versus 23 days (IQR 17-36 days) without wearing masks, and 24 days (IQR 18-36 days) for symptomatic patients versus 20 days (IQR 16-30 days) for asymptomatic patients. CONCLUSIONS: The results of this study revealed that during SARS-CoV-2 infection, having symptoms delayed viral clearance, while wearing masks accelerated this conversion. These factors should be taken into consideration for the strategy of isolating infected patients.

“Evaluation of a COVID-19 IgM and IgG Rapid Test and Assessment of Specific Antibody Response in COVID-19 patients, Tunisia 2020” (preprint)

Background COVID-19 pandemic is a massive global health emergency. Although RT-PCR is the gold standard for diagnosing suspected cases, there is a need of serological tests to investigate antibody responses. Many serologic immunoassays have been developed to detect antibodies to SARS-CoV2, including rapid tests. This study assessed the clinical performance of the SARS-CoV-2 antibody test (colloidal gold immunochromatography, LEPU TECHNOLOGY) and evaluated the kinetic antibody response in COVID-19 patients.Methods:  Samples collected by finger stick; obtained from RT-PCR confirmed cases and samples of negative controls were tested with the IgM/IgG Detection Kit . Results: The kit shows a clinical sensitivity of 65.7 % [59.7%-71.3%] and a specificity of 96.3% [93.0%-98.3%]. The predictive positive value and negative predictive value were respectively 95.2% [91.0%-97.8%] and 71.4% [66.1%-76.2%]. The seroconversion of specific IgM and IgG antibodies were observed as early as the 2nd day after symptom onset.Conclusions: This test is quite useful for assessing previous virus exposure, although negative results may be unreliable during the first weeks after infection. Longitudinal studies on antibody responses during and post infection are needed.

Identification of Transmission Chains and Clusters Associated with COVID-19 in Tunisia (preprint)

Background: The aim of this study was to characterize the transmission chains and clusters of COVID-19 infection in TunisiaMethods: All cases were confirmed by RT-PCR of a nasopharyngeal specimen. Contact tracing is undertaken for all confirmed cases in order to identify close contacts that will be systematically screened and quarantined. Transmission chains were identified based on field investigation, contact tracing, results of screening tests and by assessing all probable mode of transmission and interactions.Results: As of May 18, 2020, 656 cases out of a total of 1043 confirmed cases of COVID-19 belong to 127 transmission chains identified during the epidemic (mean age 42.36 years, Standard deviation 19.56 and sex ratio 0.86). The virus transmission is the most concentrated in the governorate of Tunis (31.5%), Ariana (10.2%) and Ben Arous (10.2%). Virus transmission occurred 50 times (9.72% of secondary transmission events) between two different governorates. A maximum of seven generations of secondary infection was identified, whereas 62% of these secondary infections belong the first generation. A total of 11 “superspreader” cases were identified in this investigation. Four large clusters have been identified. The evolution of secondary cases highlighted two peaks: one in 2nd April and a second in 16 th April whereas imported cases caused local transmission of virus during the early phase of the epidemic.Conclusion: Correct contact tracing and early active case finding is useful to identify transmission chains and source of infection in order to contain the widespread transmission in the community.