Development and validation of a risk stratification model for screening suspected cases of COVID-19 in China

Eosinophils as potential biomarkers in respiratory viral infections

Eosinophils are bone marrow-derived granulocytes that, under homeostatic conditions, account for as much as 1-3% of peripheral blood leukocytes. During inflammation, eosinophils can rapidly expand and infiltrate inflamed tissues, guided by cytokines and alarmins (such as IL-33), adhesion molecules and chemokines. Eosinophils play a prominent role in allergic asthma and parasitic infections. Nonetheless, they participate in the immune response against respiratory viruses such as respiratory syncytial virus and influenza. Notably, respiratory viruses are associated with asthma exacerbation. Eosinophils release several molecules endowed with antiviral activity, including cationic proteins, RNases and reactive oxygen and nitrogen species. On the other hand, eosinophils release several cytokines involved in homeostasis maintenance and Th2-related inflammation. In the context of SARS-CoV-2 infection, emerging evidence indicates that eosinophils can represent possible blood-based biomarkers for diagnosis, prognosis, and severity prediction of disease. In particular, eosinopenia seems to be an indicator of severity among patients with COVID-19, whereas an increased eosinophil count is associated with a better prognosis, including a lower incidence of complications and mortality. In the present review, we provide an overview of the role and plasticity of eosinophils focusing on various respiratory viral infections and in the context of viral and allergic disease comorbidities. We will discuss the potential utility of eosinophils as prognostic/predictive immune biomarkers in emerging respiratory viral diseases, particularly COVID-19. Finally, we will revisit some of the relevant methods and tools that have contributed to the advances in the dissection of various eosinophil subsets in different pathological settings for future biomarker definition.

Assessment of COVID-19 RT-PCR Positive Symptomatic Patients With Clinical, Hematological, and Radiological Parameters Among Three Groups: A Comparative Study

BACKGROUND

Nearly 70.1 million individuals have been infected by the pandemic viral disease known as coronavirus disease 2019 (COVID-19), which was first discovered in China and is caused by a novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2). This disease is responsible for the deaths of 6 million people. India ranks third in the total number of cases. The purpose of this study was to classify COVID-19 patients according to several criteria and to determine which clinical, hematological, and radiological indicators were most important in their care.

MATERIALS AND METHODS

An analytical cross-sectional study was conducted on a total of 70 symptomatic patients who tested positive for COVID-19 reverse transcription polymerase chain reaction (RT-PCR) and were hospitalized at the Saveetha Medical College and Hospital in Chennai, Tamil Nadu, India, for the duration of the study. Comorbidities and oxygen reliance were taken into consideration while classifying patients into one of three categories. Initial symptoms, as well as hematological (interleukin-6 (IL-6), erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), D-dimer, serum ferritin, and total cell counts) and radiographic (X-ray and computed tomography (CT) of the thorax) characteristics, were taken and analyzed among the different groups.

RESULTS

According to our research, the symptom of fever was the most common, accounting for 84.3% of all cases. This was followed by breathlessness (55.7%), myalgia (31.4%), dry cough (27.1%), sore throat (24.3%), cough with expectoration (20%), loose stools (12.9%), loss of taste (12.9%), and smell (11.4%). Although there was a large amount of variation in D-dimer, with Category C having the highest values, there was only a minor amount of variation in ESR and CRP. The X-ray and CT scans of the chest showed substantial differences between the groups, with CT findings such as COVID-19 Reporting and Data System (CO-RADS) and CT severity score, consolidation, crazy paving pattern, and vascular dilatation showing a wide range of differences between the groups.

CONCLUSIONS

To facilitate easier treatment and place more attention on radiological characteristics using D-dimer, treating physicians are required to categorize COVID-19 patients into several groups. Patients who need oxygen support were included in this category.

Asthma and COVID-19: an update

As the world faces the coronavirus disease 2019 (COVID-19) pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, concerns have been raised that asthma patients could be at increased risk of SARS-CoV-2 infection and disease severity. However, it appears that asthma is not an independent risk factor for both. Furthermore, asthma is not over-represented in hospitalised patients with severe pneumonia due to SARS-CoV-2 infection and there was no increased risk of asthma exacerbations triggered by SARS-CoV-2. There is accumulating evidence that asthma phenotypes and comorbidities are important factors in evaluating the risk for SARS-CoV-2 infection and disease severity, as findings suggest that Th2-high inflammation may reduce the risk of SARS-Cov-2 infection and disease severity in contrast to increased risk in patients with Th2-low asthma. The use of inhaled corticosteroids (ICS) is safe in asthma patients with SARS-CoV-2 infection. Furthermore, it has been proposed that ICS may confer some degree of protection against SARS-CoV-2 infection and the development of severe disease by reducing the expression of angiotensin converting enzyme-2 and transmembrane protease serine in the lung. In contrast, chronic or recurrent use of systemic corticosteroids before SARS-CoV-2 infection is a major risk factor of poor outcomes and worst survival in asthma patients. Conversely, biological therapy for severe allergic and eosinophilic asthma does not increase the risk of being infected with SARS-CoV-2 or having worse COVID-19 severity. In the present review we will summarise the current literature regarding asthma and COVID-19.

Chronic or recurrent use of systemic corticosteroids before SARS-CoV-2 infection is a major risk factor of worst COVID-19 severity and survival in asthmatics as opposed to ICS and biological therapy which seems to be safe.https://bit.ly/3jU0zLR

Decreased eosinophil counts and elevated lactate dehydrogenase predict severe COVID-19 in patients with underlying chronic airway diseases

Background

Several predictors of COVID-19 severity have been reported. However, chronic airway inflammation characterised by accumulated lymphocytes or eosinophils may affect the pathogenesis of COVID-19.

Methods

In this retrospective cohort study, we reviewed the medical records of all patients with laboratory-confirmed COVID-19 with chronic bronchitis, chronic obstructive pulmonary disease (COPD) and asthma admitted to the Sino-French New City Branch of Tongji Hospital, a large regional hospital in Wuhan, China, from 26 January to 3 April. The Tongji Hospital Ethics Committee approved this study.

Results

There were 59 patients with chronic bronchitis, COPD and asthma. When compared with non-severe patients, severe patients were more likely to have decreased lymphocyte counts (0.6×10⁹/L vs 1.1×10⁹/L, p<0.001), eosinopaenia (<0.02×10⁹/L; 73% vs 24%, p<0.001), increased lactate dehydrogenase (LDH) (471.0 U/L vs 230.0 U/L, p<0.001) and elevated interleukin 6 level (47.4 pg/mL vs 5.7 pg/mL, p=0.002) on admission. Eosinopaenia and elevated LDH were significantly associated with disease severity in both univariate and multivariate regression models including the above variables. Moreover, eosinophil count and LDH level tended to return to normal range over time in both groups after treatment and severe patients recovered slower than non-severe patients, especially in eosinophil count.

Conclusions

Eosinopaenia and elevated LDH are potential predictors of disease severity in patients with COVID-19 with underlying chronic airway diseases. In addition, they could indicate disease progression and treatment effectiveness.

Applications of laboratory findings in the prevention, diagnosis, treatment, and monitoring of COVID-19

The worldwide pandemic of coronavirus disease 2019 (COVID-19) presents us with a serious public health crisis. To combat the virus and slow its spread, wider testing is essential. There is a need for more sensitive, specific, and convenient detection methods of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Advanced detection can greatly improve the ability and accuracy of the clinical diagnosis of COVID-19, which is conducive to the early suitable treatment and supports precise prophylaxis. In this article, we combine and present the latest laboratory diagnostic technologies and methods for SARS-CoV-2 to identify the technical characteristics, considerations, biosafety requirements, common problems with testing and interpretation of results, and coping strategies of commonly used testing methods. We highlight the gaps in current diagnostic capacity and propose potential solutions to provide cutting-edge technical support to achieve a more precise diagnosis, treatment, and prevention of COVID-19 and to overcome the difficulties with the normalization of epidemic prevention and control.

Pragmatic Recommendations for Identification and Triage of Patients with COVID-19 Disease in Low- and Middle-Income Countries

Effective identification and prognostication of severe COVID-19 patients presenting to healthcare facilities are essential to reducing morbidity and mortality. Low- and middle-income country (LMIC) facilities often suffer from restrictions in availability of human resources, laboratory testing, medications, and imaging during routine functioning, and such shortages may worsen during times of surge. Low- and middle-income country healthcare providers will need contextually appropriate tools to identify and triage potential COVID-19 patients. We report on a series of LMIC-appropriate recommendations and suggestions for screening and triage of COVID-19 patients in LMICs, based on a pragmatic, experience-based appraisal of existing literature. We recommend that all patients be screened upon first contact with the healthcare system using a locally approved questionnaire to identify individuals who have suspected or confirmed COVID-19. We suggest that primary screening tools used to identify individuals who have suspected or confirmed COVID-19 include a broad range of signs and symptoms based on standard case definitions of COVID-19 disease. We recommend that screening include endemic febrile illness per routine protocols upon presentation to a healthcare facility. We recommend that, following screening and implementation of appropriate universal source control measures, suspected COVID-19 patients be triaged with a triage tool appropriate for the setting. We recommend a standardized severity score based on the WHO COVID-19 disease definitions be assigned to all suspected and confirmed COVID-19 patients before their disposition from the emergency unit. We suggest against using diagnostic imaging to improve triage of reverse transcriptase (RT)-PCR–confirmed COVID-19 patients, unless a patient has worsening respiratory status. We suggest against the use of point-of-care lung ultrasound to improve triage of RT-PCR–confirmed COVID-19 patients. We suggest the use of diagnostic imaging to improve sensitivity of appropriate triage in suspected COVID-19 patients who are RT-PCR negative but have moderate to severe symptoms and are suspected of a false-negative RT-PCR with high risk of disease progression. We suggest the use of diagnostic imaging to improve sensitivity of appropriate triage in suspected COVID-19 patients with moderate or severe clinical features who are without access to RT-PCR testing for SARS-CoV-2.

Eosinophils and COVID-19: diagnosis, prognosis, and vaccination strategies

The unprecedented impact of the coronavirus disease 2019 (COVID-19) pandemic has resulted in global challenges to our health-care systems and our economic security. As such, there has been significant research into all aspects of the disease, including diagnostic biomarkers, associated risk factors, and strategies that might be used for its treatment and prevention. Toward this end, eosinopenia has been identified as one of many factors that might facilitate the diagnosis and prognosis of severe COVID-19. However, this finding is neither definitive nor pathognomonic for COVID-19. While eosinophil-associated conditions have been misdiagnosed as COVID-19 and others are among its reported complications, patients with pre-existing eosinophil-associated disorders (e.g., asthma, eosinophilic gastrointestinal disorders) do not appear to be at increased risk for severe disease; interestingly, several recent studies suggest that a diagnosis of asthma may be associated with some degree of protection. Finally, although vaccine-associated aberrant inflammatory responses, including eosinophil accumulation in the respiratory tract, were observed in preclinical immunization studies targeting the related SARS-CoV and MERS-CoV pathogens, no similar complications have been reported clinically in response to the widespread dissemination of either of the two encapsulated mRNA-based vaccines for COVID-19.