Predictors of H1N1 influenza in the emergency department: proposition for a modified H1N1 case definition

Quality over quantity; eosinophil activation status will deepen the insight into eosinophilic diseases

Eosinophil associated diseases have gained much attention recently because of the introduction of specific eosinophil targeted therapies. These diseases range from acute parasitic infections to chronic inflammatory diseases such as eosinophilic asthma. In eosinophilic asthma an increased eosinophil cell count in peripheral blood is the gold standard for determination of the pheno-/endotype and severity of disease. Despite a broad consensus there is concern on validity of this simple measurement, because the eosinophil compartment is far from homogenous. Multiple tissues harbour non-activated cells under homeostatic conditions and other tissues, normally devoid of eosinophils, become infested with these cells under inflammatory conditions. It will, therefore, be clear that eosinophils become differentially (pre)-activated at different tissue sites in homeostatic and inflammatory conditions. This complexity should be investigated in detail as it is 1) far from clear what the long-term side effects are that are caused by application of eosinophil targeted therapies in a "one size fits all" concept and 2) real-world data of eosinophil targeted therapies in asthma shows a broad variety in the treatment response. This review will focus on complex mechanisms of eosinophil activation in vivo to create a better view on the dynamics of the eosinophil compartment in health and disease both to prevent collateral damage caused by aberrant activation of eosinophils ánd to improve effectiveness of eosinophil targeted treatments.

[Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers]

Introduction and objectives The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection.Methods We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria.Results Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P < .001) and increased cytotoxic T cell numbers (17.3%; P < .001). Clinically suspected pericarditis was associated (P < .005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P < .05) neutrophil counts, natural killer-cells, and plasma cells.Conclusions Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.

Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers

Introduction and objectives

The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection.

Methods

We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria.

Results

Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P < .001) and increased cytotoxic T cell numbers (17.3%; P < .001). Clinically suspected pericarditis was associated (P < .005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P < .05) neutrophil counts, natural killer-cells, and plasma cells.

Conclusions

Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.

Performance of case definitions and clinical predictors for influenza surveillance among patients followed in a rural cohort in Senegal

Background

Influenza is a major cause of morbidity and mortality in Africa. However, a lack of epidemiological data remains for this pathology, and the performances of the influenza-like illness (ILI) case definitions used for sentinel surveillance have never been evaluated in Senegal. This study aimed to i) assess the performance of three different ILI case definitions, adopted by the WHO, USA-CDC (CDC) and European-CDC (ECDC) and ii) identify clinical factors associated with a positive diagnosis for Influenza in order to develop an algorithm fitted for the Senegalese context.

Methods

All 657 patients with a febrile pathological episode (FPE) between January 2013 and December 2016 were followed in a cohort study in two rural villages in Senegal, accounting for 1653 FPE observations with nasopharyngeal sampling and influenza virus screening by rRT-PCR. For each FPE, general characteristics and clinical signs presented by patients were collected. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for the three ILI case definitions were assessed using PCR result as the reference test. Associations between clinical signs and influenza infection were analyzed using logistic regression with generalized estimating equations. Sore throat, arthralgia or myalgia were missing for children under 5 years.

Results

WHO, CDC and ECDC case definitions had similar sensitivity (81.0%; 95%CI: 77.0–85.0) and NPV (91.0%; 95%CI: 89.0–93.1) while the WHO and CDC ILI case definitions had the highest specificity (52.0%; 95%CI: 49.1–54.5) and PPV (32.0%; 95%CI: 30.0–35.0). These performances varied by age groups. In children < 5 years, the significant predictors of influenza virus infection were cough and nasal discharge. In patients from 5 years, cough, nasal discharge, sore throat and asthenia grade 3 best predicted influenza infection. The addition of “nasal discharge” as a symptom to the WHO case definition decreased sensitivity but increased specificity, particularly in the pediatric population.

Conclusion

In summary, all three definitions studies (WHO, ECDC & CDC) have similar performance, even by age group. The revised WHO ILI definition could be chosen for surveillance purposes for its simplicity. Symptomatic predictors of influenza virus infection vary according the age group.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05724-x.

Butler C, van der Velden AW, J. Verheij T, Sundvall PD. Is C-reactive protein associated with influenza A or B in primary care patients with influenza-like illness? A cross-sectional study

OBJECTIVE

Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. An accurate, cheap and easy to use biomarker might enhance targeting influenza-specific management in primary care. The aim of this study was to investigate if C-reactive protein (CRP) is associated with influenza A or B, confirmed with PCR testing, in patients presenting with ILI.

DESIGN

Cross-sectional study.

SETTING

Primary care in Lithuania, Norway and Sweden.

SUBJECTS

A total of 277 patients at least 1 year of age consulting primary care with ILI during seasonal influenza epidemics.

MAIN OUTCOME MEASURES

Capillary blood CRP analysed as a point-of-care test and detection of influenza A or B on nasopharyngeal swabs in adults, and nasal and pharyngeal swabs in children using PCR.

RESULTS

The prevalence of positive tests for influenza A among patients was 44% (121/277) and the prevalence of influenza B was 21% (58/277). Patients with influenza A infection could not be identified based on CRP concentration. However, increasing CRP concentration in steps of 10 mg/L was associated with a significantly lower risk for influenza B with an adjusted odds ratio of 0.42 (0.25-0.70; p<.001). Signs of more severe symptoms like shortness of breath, sweats or chills and dizziness were associated with higher CRP.

CONCLUSIONS

There was no association between CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. Hence, CRP testing should be avoided in ILI, unless bacterial pneumonia is suspected. Key points Identifying influenza A or B as cause of influenza-like illness (ILI) is a challenge due to non-specific symptoms. There was no association between concentration of CRP and influenza A. Increased concentration of CRP was associated with a lower risk for having influenza B, a finding that lacks clinical usefulness. A consequence is that CRP testing should be avoided in ILI, unless bacterial pneumonia or similar is suspected.

Pitfalls in studies of eosinopenia and neutrophil-to-lymphocyte count ratio

There is a number of publications evaluating the eosinophil count and the neutrophil-to-lymphocyte count ratio for diagnosis, prognosis or monitoring of patients. Of special interest is the use of these parameters for discrimination between the different causes of fever (e.g. bacterial versus viral vs. non-infectious causes of fever) and for monitoring the efficacy of therapy and predict the course of the patient. However, pitfalls in previous study designs prevent applicability to clinical practice. Here, we provide a short review of the relevant literature and summarize important factors that should be taken into account when designing studies, with special attention to the selection of a proper and clinically meaningful study population and the effects of the stress response and of corticosteroids.