ABSTRACT
BackgroundAfter mild COVID-19, some outpatients experience persistent symptoms. However, data are scarce and prospective studies are urgently needed. ObjectivesTo characterize the post-COVID-19 syndrome after mild COVID-19 and identify predictors. ParticipantsOutpatients with symptoms suggestive of COVID-19 with (1) PCR-confirmed COVID-19 (COVID-positive) or (2) SARS-CoV-2 negative PCR (COVID-negative). DesignMonocentric cohort study with prospective phone interview between more than three months to ten months after initial visit to the emergency department and outpatient clinics. Main MeasuresData of the initial visits were extracted from the electronic medical file. Predefined persistent symptoms were assessed through a structured phone interview. Associations between long-term symptoms and PCR results, as well as predictors of persistent symptoms among COVID-positive, were evaluated by multivariate logistic regression adjusted for age, gender, smoking, comorbidities, and timing of the survey. Key resultsThe study population consisted of 418 COVID-positive and 89 COVID-negative patients, mostly young adults (median age of 41 versus 36 years in COVID-positive and COVID-negative, respectively; p=0.020) and health care workers (67% versus 82%; p=0.006). Median time between the initial visit and the phone survey was 150 days in COVID-positive and 242 days in COVID-negative patients. Persistent symptoms were reported by 223 (53%) COVID-positive and 33 (37%) COVID-negative patients (p=0.006). Overall, 21% COVID-positive and 15% COVID-negative patients (p=0.182) attended care for this purpose. Four surveyed symptoms were independently associated with COVID-19: fatigue (adjusted odds ratio [or] 2.14, 95%CI 1.04-4.41), smell/taste disorder (26.5, 3.46-202), dyspnea (2.81, 1.10-7.16) and memory impairment (5.71, 1.53-21.3). Among COVID-positive, female gender (1.67, 1.09-2.56) and overweight/obesity (1.67, 1.10-2.56) were predictors of persistent symptoms. ConclusionsMore than half of COVID-positive outpatients report persistent symptoms up to ten months after a mild disease. Only 4 of 14 symptoms were associated with COVID-19 status. The symptoms and predictors of the post-COVID-19 syndrome need further characterization as this condition places a significant burden on society.
ABSTRACT
BackgroundEarly identification of SARS-CoV-2 infection is important to guide quarantine and reduce transmission. This study evaluates the diagnostic performance of lung ultrasound (LUS), an affordable, consumable-free point-of-care tool, for COVID-19 screening. MethodsThis prospective observational cohort included adults presenting with cough and/or dyspnea at a SARS-CoV-2 screening center of Lausanne University Hospital between March 31st and May 8th, 2020. Investigators recorded standardized LUS images and videos in 10 lung zones per subject. Two blinded independent experts reviewed LUS recording and classified abnormal findings according to pre-specified criteria to investigate their predictive value to diagnose SARS-CoV-2 infection according to PCR on nasopharyngeal swabs (COVIDpos vs COVIDneg). We finally combined LUS and clinical findings to derive a multivariate logistic regression diagnostic score. ResultsOf 134 included patients, 23% (n=30/134) were COVIDpos and 77% (n=103/134) were COVIDneg; 85%, (n=114/134) cases were previously healthy healthcare workers presenting within 2 to 5 days of symptom onset (IQR). Abnormal LUS findings were significantly more frequent in COVIDpos compared to COVIDneg (45% versus 26%, p=0.045) and mostly consisted of focal pathologic B-lines. Combining LUS findings in a multivariate logistic regression score had an area under the receiver-operating curve of 63.9% to detect COVID-19, but improved to 84.5% with the addition of clinical features ConclusionsCOVIDpos patients are significantly more likely to have lung pathology by LUS. Our findings have potential diagnostic value for COVID-19 at the point of care. Combination of clinical and LUS features showed promising results, which need confirmation in a larger study population. What is already known on the subjectO_LILung ultrasonography (LUS) is a consumable-free, easy-to-use, portable, non-radiating and non-invasive screening tool that can be performed at the bedside: its diagnostic performance for pneumonia has been established. C_LIO_LIRecent studies conducted in emergency department showed a correlation between LUS findings and COVID-19 diagnosis. C_LI What the study adsO_LIThis is the first study assessing the diagnostic performance of LUS for COVID-19 in outpatients with mild acute respiratory tract infection. C_LIO_LIMild COVID-19 patients are more likely to have lung pathology by LUS compared with COVID-19 negative. C_LIO_LICombination of clinical and LUS features showed promising results with a potential diagnostic value for COVID-19 at the point of care. C_LI
ABSTRACT
To understand the geographical and temporal spread of SARS-CoV-2 during the first wave of infection documented in the canton of Vaud, Switzerland, we analysed clusters of positive cases using the precise place of residence of 33651 individuals tested (RT-PCR) between January 10 and June 30, 2020. We identified both space-time (SaTScan) and transmission (MST-DBSCAN) clusters; we estimated their duration, their transmission behavior (emergence, growth, reduction, etc.) and relative risk. For each cluster, we computed the within number of individuals, their median age and viral load. Among 1684 space-time clusters identified, 457 (27.1%) were significant (p [≤] 0.05), i.e. harboring a higher relative risk of infection, as compared to other regions. They lasted a median of 11 days (IQR 7-13) and included a median of 12 individuals per cluster (IQR 5-20). The majority of significant clusters (n=260; 56.9 %) had at least one person with an extremely high viral load (above 1 billion copies/ml). Those clusters were considerably larger (median of 17 infected individuals, p < 0.001) than clusters with subjects showing a viral load lower than 1 million copies/ml (median of 3 infected individuals). The highest viral loads were found in clusters with the lowest average age, while clusters with the highest average age had low to middle viral load. Interestingly, in 20 significant clusters the viral load of three first cases were all below 100000 copies/ml suggesting that subjects with less than 100000 copies/ml may still have been contagious. Noteworthy, the dynamics of transmission clusters made it possible to identify three diffusion zones, which mainly differentiated rural from urban areas, the latter being more prone to last and spread in a new nearby clusters. The use of geographic information is key for public health decision makers to mitigate the spread of the virus. This study suggests that early localization of clusters help implementing targeted protective measures limiting the spread of the SARS-CoV-2 virus.
ABSTRACT
BackgroundWhile facing a second wave in SARS-CoV-2 pandemic, in November 2020 the Swiss Federal Office of Public Health (FOPH) authorized the use of rapid antigen tests (RATs) in addition to the gold-standard reverse transcription-polymerase chain reaction (RT-PCR). MethodsWe implemented the use of RAT in the emergency ward of our university hospital for rapid patients triaging and compared performances of four different antigen tests. All results were compared to SARS-CoV-2 specific RT-PCR (reference standard). ResultsTriaging patients using RAT in association with RT-PCR allowed us to isolate promptly positive patients and to save resources, in a context of rapid RT-PCR reagents shortage. Among 532 patients with valid results, overall sensitivities were 48.3% for One Step Exdia and 41.2% for Standard Q(R), Panbio-and BD Veritor. All four antigen tests exhibited specificity above 99%. Sensitivity increased up to 74.6%, 66.2%, 66.2% and 64.8% for One Step Exdia, Standard Q, Panbio, and BD Veritor respectively, when considering viral loads above 105copies/ml, up to 100%, 97.8%, 96.6% and 95.6% for viral loads above 106 copies/ml and 100% (for all tests) when considering viral loads above 107 copies/ml. Sensitivity was significantly higher for patients presenting with symptoms onset within 4 days (74.3%, 69.2%, 69.2% and 64%, respectively) versus patients with evolution of symptoms for more than 4 days (36.8%, 21.1%, 21.1% and 23.7%, respectively). Sensitivities of all RAT assays were of only 33% among hospitalized patients without COVID-19 symptoms. ConclusionRAT might represent a useful epidemiological resource in selected clinical settings as a complementary tool to the molecular tests for rapid patients triaging, but the lower sensitivity compared to RT-PCR, especially in late presenters and subjects without COVID-19 symptoms, must be taken into account in order to correctly use RAT for triaging.
