Mechanically ventilated patients shed high titre live SARS-CoV2 for extended periods from both the upper and lower respiratory tract

BackgroundSARS-CoV-2 infection can lead to severe acute respiratory distress syndrome needing intensive care admission and may lead to death. As a virus that transmits by respiratory droplets and aerosols, determining the duration of viable virus shedding from the respiratory tract is critical for patient prognosis, and informs infection control measures both within healthcare settings and the public domain. MethodsWe examined upper and lower airway respiratory secretions for both viral RNA and infectious virions in mechanically ventilated patients admitted to the intensive care unit of the University Hospital of Wales. Samples were taken from the oral cavity (saliva), oropharynx (sub-glottic aspirate), or lower respiratory tract (non-directed bronchoalveolar lavage (NBL) or bronchoalveolar lavage (BAL)) and analyzed by both qPCR and plaque assay. Results117 samples were obtained from 25 patients. qPCR showed extremely high rates of positivity across all sample types, however live virus was far more common in saliva (68%) than in BAL/NBAL (32%). Average titres of live virus were higher in subglottic aspirates (4.5x107) than in saliva (2.2x106) or BAL/NBAL (8.5x106), and reached >108 PFU/ml in some samples. The longest duration of shedding was 98 days, while the majority of patients (14/25) shed live virus for 20 days or longer. ConclusionsIntensive care unit patients infected with SARS-CoV-2 can shed high titres of virus both in the upper and lower respiratory tract, and tend to be prolonged shedders. This information is important for decision making around cohorting patients, de-escalation of PPE, and undertaking potential aerosol generating procedures. SummaryPatients on intensive therapy infected with SARS-CoV-2 tend to be prolonged shedders, excreting virus for far beyond the time periods specified in current guidelines, and live virus titres can be extremely high in both the upper and lower respiratory tracts.

Extended laboratory panel testing in the Emergency Department for risk-stratification of patients with COVID-19: a single centre retrospective service evaluation

BackgroundThe role of specific blood tests to predict poor prognosis in patients admitted with infection from SARS-CoV2 virus remains uncertain. During the first wave of the global pandemic, an extended laboratory testing panel was integrated into the local pathway to guide triage and healthcare resource utilisation for emergency admissions. We conducted a retrospective service evaluation to determine the utility of extended tests (D-dimer, ferritin, high-sensitivity troponin I, lactate dehydrogenase, procalcitonin) compared to the core panel (full blood count, urea & electrolytes, liver function tests, C-reactive protein). MethodsClinical outcomes for adult patients with laboratory-confirmed COVID-19 admitted between 17th March to 30st June 2020 were extracted, alongside costs estimates for individual tests. Prognostic performance was assessed using multivariable logistic regression analysis with 28-day mortality used as the primary endpoint, and a composite of 28-day intensive care escalation or mortality for secondary analysis. ResultsFrom 13,500 emergency attendances we identified 391 unique adults admitted with COVID-19. Of these, 113 died (29%) and 151 (39%) reached the composite endpoint. "Core" test variables adjusted for age, gender and index of deprivation had a prognostic AUC of 0.79 (95% Confidence Interval, CI: 0.67 to 0.91) for mortality and 0.70 (95% CI: 0.56 to 0.84) for the composite endpoint. Addition of "extended" test components did not improve upon this. ConclusionOur findings suggest use of the extended laboratory testing panel to risk stratify community-acquired COVID-19-positive patients on admission adds limited prognostic value. We suggest laboratory requesting should be targeted to patients with specific clinical indications.

Early osmotic, antioxidant, ionic, and redox responses to salinity in leaves and roots of Indian mustard (Brassica juncea L.).

Salt-stress-induced alterations in osmotic, ionic, and redox responses were studied in the early period of treatment (30 min to 5 days) in seedlings of Brassica juncea L. Roots and shoots under mild (50 mM) and severe (250 mM) NaCl stress were analyzed for growth, oxidative stress, osmolyte accumulation, antioxidant defense, and redox state. Growth reduction was less pronounced in the early time period of salt stress while oxidative damage increased linearly and in a sustained manner under severe stress up to 6 h. An early and transient reactive oxygen species (ROS) burst, as evidenced by superoxide and hydrogen peroxide level was observed, followed by activation of enzymatic antioxidant system (GPX, SOD, CAT, and GR) in both root and shoot. The enzymatic activity was not affected much under mild stress particularly at early phase; however, severe stress induced a significant increase in the activity of antioxidant enzymes. Root ascorbate was progressively accumulated, and its redox state maintained in the early time phase of treatment under mild stress while increase in root and shoot glutathione content was recorded under mild stress at 5 days when the active ascorbate pool decreased. While early period of salt stress showed significant Na(+) accumulation over control, plants subjected to mild stress measured less Na(+) accumulation up to 5 days compared to severely stressed plants. The results showed an early induction of differential responses to salt stress in roots and shoots of Brassica which include growth limitations, reduced relative water content, increased osmolytes, redox state, and antioxidant system, and a significant Na(+) increase. The results also indicate that roots and shoots may have distinct mechanisms of responses to salt stress.