Influenza, influenza-like symptoms and their association with cardiovascular risks: a systematic review and meta-analysis of observational studies

Cumulative incidence and mortality rate of cardiovascular complications due to laboratory-confirmed influenza virus infection: A systematic review and meta-analysis

Influenza infection is associated with cardiovascular complications that range significantly in presentation and severity. The cumulative incidence of cardiovascular complications due to laboratory-confirmed influenza, however, is not reported in the literature. We conducted a systematic review and random-effects meta-analysis to evaluate the cumulative incidence and mortality rate of influenza virus-related cardiovascular complications in hospitalized patients. We searched the PubMed and EMBASE databases for studies reporting acute myocardial infarction (AMI), heart failure (HF), arrhythmia of any kind, stroke or transient ischemic attack (TIA), and myocarditis in hospitalized patients with laboratory-confirmed influenza virus infection. Prospective studies, retrospective cohort studies, and randomized controlled trials (RCTs) were included in the analysis. We followed the PRISMA checklist and used 95% confidence intervals (CIs) to report meta-analysis outcomes. This study was registered on PROSPERO (CRD42023427849). After retrieving 2803 studies, we identified 19 studies (18 observational and 1 RCT) with relevant data, and we included 6936 patients in our analysis, of whom 690 (9.9%) developed a cardiovascular outcome of interest. The cumulative incidence of HF was 17.47% (95% CI: 5.06%-34.54%), arrhythmia of any kind 6.12% (95% CI: 0.00%-21.92%), myocarditis 2.56% (95% CI: 0.66%-5.38%), AMI 2.19% (95% CI: 1.03%-3.72%), and stroke or TIA 1.14% (95% CI: 0.00%-4.05%). The in-hospital mortality rate from cardiovascular events was 1.38% (95% CI: 0.00%-4.80%). Cardiovascular complications occur in patients with influenza virus infection, with the cumulative incidence of specific cardiac manifestations varying considerably (1.51%-17.47%). Preventive strategies and close clinical monitoring after infection remain a priority.

Estimated causal effects of common respiratory infections on cardiovascular risk: a meta-analysis

OBJECTIVE

Literature supports associations between common respiratory tract infections (RTIs) and risk of cardiovascular diseases, yet the importance of RTIs for cardiovascular risk management remains less understood. This systematic review and meta-analysis aimed to estimate the causal effects of RTIs on occurrence of cardiovascular diseases in the general population.

METHODS

MEDLINE and EMBASE were systematically searched up to 4 November 2022. Eligible were all aetiological studies evaluating risk of cardiovascular outcomes after exposure to common RTIs within any follow-up duration. Evidence was pooled using random-effects models if data allowed. The ROBINS-E and GRADE approaches were used to rate risk of bias and certainty of evidence, respectively. All assessments were performed in duplicate.

RESULTS

We included 34 studies (65 678 650 individuals). Most studies had a high risk of bias. COVID-19 likely increases relative risk (RR (95% CI)) of myocardial infarction (3.3 (1.0 to 11.0)), stroke (3.5 (1.2 to 10)), pulmonary embolism (24.6 (13.5 to 44.9)) and deep venous thrombosis (7.8 (4.3 to 14.4)) within 30 days after infection (GRADE: moderate) and about twofold within 1 year (GRADE: low to moderate). Other RTIs also likely increase the RR of myocardial infarction (2.9 (95% CI 1.8 to 4.9)) and stroke (2.6 (95% CI 1.1 to 6.4)) within 30 days (GRADE: moderate), and to a lesser extent with longer follow-up.

CONCLUSIONS

RTIs likely increase the risk of cardiovascular diseases about 1.5-5 fold within 1 month after infection. RTIs may, therefore, have clinical relevance as target for cardiovascular risk management, especially in high-risk populations.

PROSPERO REGISTRATION NUMBER

CRD42023416277.

Environmental factors and stroke: Risk and prevention

Stroke is a leading cause of death and adult disability globally. In addition to traditional risk factors, environmental risk factors have emerged over the recent past and are becoming increasingly important. The disproportionate rise of stroke incidence in low- and middle-income countries has been attributed, at least in part, to environmental factors. This narrative review provides details on the interplay between the environment and health generally and stroke specifically, covering topics including air pollution, atmospheric brown clouds, desert dust storms, giant wildfires, chemical contamination, biological aggressors, urbanization, and climate change. It also covers some beneficial environmental effects such as can be harnessed from the exposure to green spaces. It concludes with a summary of pragmatic actions that can be taken to help address some of these challenges at individual, community, and political advocacy levels.

Systematic influenza screening in cardiac intensive care units during the influenza season: A prospective study in Spain

BACKGROUND

Little is known about the incidence of influenza among admissions to the cardiac intensive care unit (C-ICU), accuracy of clinical suspicion, and influenza vaccination uptake. We evaluated the incidence of influenza at C-ICU admission during the influenza season, potential underdiagnosis, and vaccination uptake.

METHODS

Prospective study at five C-ICUs during the 2017-2020 influenza seasons. A nasopharyngeal swab was collected at admission from patients who consented (n = 788). Testing was with Xpert®XpressFlu/RSV.

RESULTS

Influenza was detected in 43 patients (5.5%) (40 FluA; 3 FluB) and clinically suspected in 27 (62.8%). Compared to patients without influenza, patients with influenza more frequently had heart failure (37.2% vs 22.8%, P = 0.031), previous contact with relatives with influenza-like illnesses (23.3% vs 12.5%, P = 0.042), antimicrobial use (67.4% vs 23.2%, P <0.01), and need for mechanical ventilation (25.6% vs 14.5%, P = 0.048). Patients received oseltamivir promptly. We found no differences in mortality (11.6% vs 5.2%, P = 0.076). Patients with influenza more frequently had myocarditis (9.3% vs 0.9%, P <0.01) and pericarditis (7.0% vs 0.8%, P = 0.01). Overall, 43.0% of patients (339/788) were vaccinated (51.9% of those with a clear indication [303/584]).

CONCLUSION

Influenza seems to be a frequently underdiagnosed underlying condition in admissions to the C-ICU. Influenza should be screened for at C-ICU admission during influenza epidemics.

A Rare Association: Non-ST Elevation Myocardial Infarction (NSTEMI) Secondary to Respiratory Syncytial Virus (RSV) Infection

We present a case report on a rare association between non-ST elevation myocardial infarction (NSTEMI) and respiratory syncytial virus (RSV) infection in a patient with no traditional risk factors for cardiovascular disease (CVD) including a family history of premature coronary artery disease (CAD). While RSV is commonly known for its respiratory manifestations, it has been increasingly recognized as a cause of significant morbidity and mortality in adults, particularly those with underlying comorbidities. However, the association between RSV infection and NSTEMI, especially in patients without traditional risk factors, remains relatively unexplored. Our case involves a 31-year-old healthy adult who presented with progressive exertional chest pain and flu-like symptoms. Electrocardiogram (EKG) changes and elevated troponin levels indicated NSTEMI. Laboratory tests confirmed RSV infection. Angiography revealed significant coronary artery disease requiring percutaneous coronary intervention. This case highlights the need for healthcare professionals to be aware of the potential cardiovascular (CV) complications associated with RSV infection, even in patients without traditional risk factors. It expands our understanding of viral respiratory infections as potential triggers for acute coronary syndromes (ACS) and emphasizes the importance of considering RSV infection in the differential diagnosis of NSTEMI, especially in young otherwise healthy individuals. Further research is warranted to explore the underlying mechanisms and develop preventive strategies for RSV-related cardiovascular complications.

Sex and molecular differences in cardiovascular parameters at peak influenza disease in mice

There is a growing interest in the detection of subtle changes in cardiovascular physiology in response to viral infection to develop better disease surveillance strategies. This is not only important for earlier diagnosis and better prognosis of symptomatic carriers but also useful to diagnose asymptomatic carriers of the virus. Previous studies provide strong evidence of an association between inflammatory biomarker levels and both blood pressure (BP) and heart rate (HR) during infection. The identification of novel biomarkers during an inflammatory event could significantly improve predictions for cardiovascular events. Thus, we evaluated changes in cardiovascular physiology induced in A/Puerto Rico/8/34 (PR8) influenza infections in female and male C57BL/6J mice and compared them with the traditional method of influenza disease detection using body weight (BW). Using radiotelemetry, changes in BP, HR, and activity were studied. Change in BW of infected females was significantly decreased from 5 to 13 days postinfection (dpi), yet alterations in normal physiology including loss of diurnal rhythm and reduced activity was observed starting at about 3 dpi for HR and 4 dpi for activity and BP; continuing until about 13 dpi. In contrast, males had significantly decreased BW 8 to 12 dpi and demonstrated altered physiological measurements for a shorter period compared with females with a reduction starting at 5 dpi for activity, 6 dpi for BP, and 7 dpi for HR until about 12 dpi, 10 dpi, and 9 dpi, respectively. Finally, females and males exhibited different patterns of inflammatory maker expression in lungs at peak disease by analyzing bulk RNA-sequencing data for lungs and Bio-plex cytokine assay for blood collected from influenza-infected and naïve C57BL/6J female and male mice at 7 dpi. In total, this study provides insight into cardiovascular changes and molecular markers to distinguish sex differences in peak disease caused by influenza virus infection.NEW & NOTEWORTHY This study performed longitudinal cardiovascular measurements of influenza viral infection and identified sex difference in both physiological and molecular markers at peak disease.

Comparison of Fragments in Human Hemostatic Proteins That Mimics Fragments in Proteins of A/H1N1 Viruses and Coronaviruses

Objective: To compare the repertoire of proteins of the human hemostatic system and fragments mimicking these proteins in the proteins of influenza A/H1N1 viruses and coronaviruses. Material and methods. Influenza viruses A/H1N1 (A/Brevig Mission/1/18), A/St. Petersburg /RII04/2016 (H1N1)pdm09, coronaviruses SARS-CoV and SARS-CoV-2 (strain Wuhan-Hu-1) were used for comparative computer analysis. The sources of the primary structures of proteins of the analyzed viruses and 41 proteins of the human hemostatic system were publicly available Internet databases, respectively, www.ncbi.nlm.nih.gov and www.nextprot.org. The search for homologous sequences in the structure of viral proteins and hemostatic proteins was carried out by comparing fragments of 12 amino acids in length, taking as related those that showed identity at ≥8 positions. Results. Comparative analysis of the repertoire of cellular proteins of the hemostatic system and fragments mimicking these proteins in the structure of proteins of viruses A/H1N1 1918, A(H1N1)pdm09 isolated in 2016, SARS-CoV and SARS-CoV-2, showed a significant difference between SARS-CoV-2 and analyzed viruses. In the protein structure of the SARS-CoV-2 virus, mimicry was revealed for almost all analyzed hemostasis proteins. As for the comparison of viruses A/H1N1 1918, A(H1N1)pdm09 2016 and SARS-CoV, the influenza virus A/H1N1 1918 and SARS-CoV are the closest in the repertoire of hemostatic proteins. Conclusion. Obtained bioinformatic analysis data can serve as a basis for further study of the role of homologous fragments in the regulation of hemostasis of the host organism.

Influenza Vaccination for Cardiovascular Prevention: Further Insights from the IAMI Trial and an Updated Meta-analysis

Purpose of Review

Influenza infection is a significant, well-established cause of cardiovascular disease (CVD) and CV mortality. Influenza vaccination has been shown to reduce major adverse cardiovascular events (MACE) and CV mortality. Therefore, major society guidelines have given a strong recommendation for its use in patients with established CVD or high risk for CVD. Nevertheless, influenza vaccination remains underutilized. Historically, influenza vaccination is administered to stable outpatients. Until recently, the safety and efficacy of influenza vaccination among patients with acute myocardial infarction (MI) had not been established.

Recent Findings

The recently published Influenza Vaccination after Myocardial Infarction (IAMI) trial showed that influenza vaccination within 72 h of hospitalization for MI led to a significant 28% reduction in MACE and a 41% reduction in CV mortality, without any excess in serious adverse events. Additionally, we newly performed an updated meta-analysis of randomized clinical trials (RCTs) including IAMI and the recent Influenza Vaccine to Prevent Adverse Vascular Events (IVVE) trial. In pooled analysis of 8 RCTs with a total of 14,420 patients, influenza vaccine, as compared with control/placebo, was associated with significantly lower risk of MACE at follow-up [RR 0.75 (95%CI 0.57–0.97), I² 56%].

Summary

The recent IAMI trial showed that influenza vaccination in patients with recent MI is safe and efficacious at reducing CV morbidity and mortality. Our updated meta-analysis confirms a 25% reduction in MACE. The influenza vaccine should be strongly encouraged in all patients with CVD and incorporated as an essential facet of post-MI care and secondary CVD prevention.

Role of Inflammation in Cardiac Remodeling After Acute Myocardial Infarction

Atherosclerosis is defined as an inflammatory disease. Low-grade inflammation is present in all phases of the cardiovascular continuum, since the establishment of cardiovascular risk factors and ischemic heart disease until cardiovascular events, such as myocardial infarction, heart failure and death. Not all inflammatory pathways are linked to cardiovascular outcomes, and thus, not all anti-inflammatory approaches decrease cardiovascular events. The most common cause of ventricular remodeling and heart failure is ischemic heart disease. Biomarkers such as high-sensitivity C-reactive protein can identify individuals at risk of major cardiovascular complications, but this biomarker has no causal effect on cardiovascular disease. On the other hand, interleukin 6 appears to be causally associated with cardiovascular disease. CANTOS was the first proof of concept study showing that anti-inflammatory therapy reduces major cardiovascular outcomes. Based on many anti-inflammatory trials, only therapies acting on the NLRP3 inflammasome, or interleukin 1beta, showed benefits on cardiovascular disease. Ventricular remodeling, particularly after myocardial infarction seems also influenced by the intensity of inflammatory responses, suggesting that anti-inflammatory therapies may reduce the residual cardiovascular risk. Inflammasome (NLRP3) activation, subtypes of lymphocytes, interleukin 6, and some inflammatory biomarkers, are associated with larger infarct size and impaired ventricular function after myocardial infarction. Cardiovascular risk factors commonly present in patients with myocardial infarction, and advanced age are associated with higher inflammatory activity.

Dynamic changes of emergency visits: a retrospective observational study

BACKGROUND

With more emergency visits, there is increasing pressure to provide emergency medical services globally and locally. This study aimed to investigate the epidemiological characteristics and the disease spectrum of patients presenting in the last three years to the Department of Emergency Medicine of Tianjin Medical University General Hospital, a tertiary hospital in Tianjin, China, to improve the services of the emergency medicine department.

METHODS

A retrospective study was conducted on all patients in the Department of Emergency Medicine of Tianjin Medical University General Hospital from Jan 1, 2017, 00:00:00 to Dec 31, 2020, 23:59:59, including variables like medical record number, gender, age, date of admission, principal diagnosis. The data were analyzed by SPSS statistical software; statistical charts were prepared by GraphPad Prism9.0 and SPSS 20.0; statistical tables were made by Microsoft Excel.

RESULTS

A total of 1,314,916 patients presented to the Department of Emergency Medicine of Tianjin Medical University General Hospital from Jan 1, 2017, 00:00:00 to Dec 31, 2020, 23:59:59. In terms of gender distribution, the male-female ratio was 0.78∶1. As for age distribution, patients aged 60-69 were the most (23.47%), and patients younger than 20 years were the least (2.80%). Concerning monthly data, the number of visits peaked during January and December. The distribution of daily visits showed the feature of three highs and a low. The top three prevalence diseases in the emergency disease spectrum were respiratory, cardiovascular, and digestive diseases. The respiratory system was the most common in patients with infectious diseases (200,912, accounting for 86.97%). Among the patients suffering from infectious diseases, the number of patients with respiratory infections peaked in 2019 (73,530) and was the lowest in 2020 (20,078).

CONCLUSIONS

From 2017 to 2019, the demand for emergency services in Tianjin Medical University General Hospital continued to increase, but it was greatly affected by COVID-19 in 2020. This emergency department is mainly for patients with respiratory system, circulatory system and digestive system diseases, and its treatment time is relatively centralized. The prevention of diseases for people of all ages, especially female patients and the elderly, should be strengthened, and emergency medical resources should be allocated reasonably according to the peak months and crowed periods of patients.

Evaluating the Increased Burden of Cardiorespiratory Illness Visits to Adult Emergency Departments During Flu and Bronchiolitis Outbreaks in the Pediatric Population: Retrospective Multicentric Time Series Analysis

BACKGROUND

Cardiorespiratory decompensation (CRD) visits have a profound effect on adult emergency departments (EDs). Respiratory pathogens like respiratory syncytial virus (RSV) and influenza virus are common reasons for increased activity in pediatric EDs and are associated with CRD in the adult population. Given the seasonal aspects of such challenging pathology, it would be advantageous to predict their variations.

OBJECTIVE

The goal of this study was to evaluate the increased burden of CRD in adult EDs during flu and bronchiolitis outbreaks in the pediatric population.

METHODS

An ecological study was conducted, based on admissions to the adult ED of the Centre Hospitalier Universitaire (CHU) of Grenoble and Saint Etienne from June 29, 2015 to March 22, 2020. The outbreak periods for bronchiolitis and flu in the pediatric population were defined with a decision-making support tool, PREDAFLU, used in the pediatric ED. A Kruskal-Wallis variance analysis and a Spearman monotone dependency were performed in order to study the relationship between the number of adult ED admissions for the International Classification of Diseases (ICD)-10 codes related to cardiorespiratory diagnoses and the presence of an epidemic outbreak as defined with PREDAFLU.

RESULTS

The increase in visits to the adult ED for CRD and the bronchiolitis and flu outbreaks had a similar distribution pattern (CHU Saint Etienne: χ²₃=102.7, P<.001; CHU Grenoble: χ²₃=126.67, P<.001) and were quite dependent in both hospital settings (CHU Saint Etienne: Spearman ρ=0.64; CHU Grenoble: Spearman ρ=0.71). The increase in ED occupancy for these pathologies was also significantly related to the pediatric respiratory infection outbreaks. These 2 criteria gave an idea of the increased workload in the ED due to CRD during the bronchiolitis and flu outbreaks in the pediatric population.

CONCLUSIONS

This study established that CRD visits and bed occupancy for adult EDs were significantly increased during bronchiolitis and pediatric influenza outbreaks. Therefore, a prediction tool for these outbreaks such as PREDAFLU can be used to provide early warnings of increased activity in adult EDs for CRD visits.

Risk of acute respiratory infection and acute cardiovascular events following acute respiratory infection among adults with increased cardiovascular risk in England between 2008 and 2018: a retrospective, population-based cohort study

BACKGROUND

Although acute respiratory infections can lead to cardiovascular complications, the effect of underlying cardiovascular risk on the incidence of acute respiratory infections and cardiovascular complications following acute respiratory infection in individuals without established cardiovascular disease is unknown. We aimed to investigate whether cardiovascular risk is associated with increased risk of acute respiratory infection and acute cardiovascular events after acute respiratory infection using 10 years of linked electronic health record (EHR) data in England.

METHODS

In this retrospective, population-based cohort study we used EHRs from primary care providers registered on the Clinical Practice Research Datalink (CPRD) GOLD and Aurum databases in England. Eligible individuals were aged 40-64 years, did not have established cardiovascular disease or a chronic health condition that would make them eligible for influenza vaccination, were registered at a general practice contributing to the CPRD, and had linked Hospital Episode Statistics Admitted Patient Care data in England from Sept 1, 2008, to Aug 31, 2018. We classified cardiovascular risk on the basis of diagnosed hypertension and overall predicted cardiovascular risk, estimated by use of the QRISK2 risk-prediction tool (comparing a score of ≥10% [increased risk] with a score of <10% [low risk]). Using multivariable Poisson regression models, we calculated incidence rate ratios (IRRs) for systemic acute respiratory infection. Among individuals who had an acute respiratory infection, we used multivariable Cox regression to calculate hazard ratios (HRs) for the risk of acute cardiovascular events within 1 year of infection.

FINDINGS

We identified 6 075 321 individuals aged 40-64 years with data in the CPRD and linked data in the Hospital Episode Statistics Admitted Patient Care database between Sept 1, 2008, and Aug 31, 2018. Of these individuals, 4 212 930 (including 526 480 [12·5%] with hypertension and 607 087 [14·4%] with a QRISK2 score of ≥10%) were included in the assessment of the incidence of acute respiratory infection. After adjusting for confounders (age, sex, ethnicity, socioeconomic status, body-mass index, alcohol consumption, smoking status, and consultation frequency in the hypertension analysis; and alcohol consumption and consultation frequency in the QRISK2 analysis), the incidence of acute respiratory infection was higher in individuals with hypertension than those without (IRR 1·04 [95% CI 1·03-1·05]) and higher in those with a QRISK2 score of 10% or higher than in those with a QRISK2 score of less than 10% (1·39 [1·37-1·40]). Of the 442 408 individuals who had an acute respiratory infection, 4196 (0·9%) had an acute cardiovascular event within 1 year of infection. After adjustment (for age, sex, ethnicity, socioeconomic status, body-mass index, alcohol consumption, and smoking status in the hypertension analysis; and for alcohol consumption in the QRISK2 analysis), hypertension (HR 1·98 [95% CI 1·83-2·15]) and a QRISK2 score of 10% or higher (3·65 [3·42-3·89]) were associated with a substantially increased risk of acute cardiovascular events after acute respiratory infection.

INTERPRETATION

People with increased cardiovascular risk but without diagnosed cardiovascular disease, measured by diagnosed hypertension or overall predicted cardiovascular risk, could benefit from influenza and pneumococcal vaccine prioritisation to reduce their risk of both acute respiratory infection and cardiovascular complications following an acute respiratory infection.

FUNDING

British Heart Foundation and the Wellcome Trust.

Seasonal Variation in Incidence of Stroke in a General Population of 1.4 Million Japanese: The Shiga Stroke Registry

INTRODUCTION

The purpose of this study was to investigate seasonal variation in stroke incidence using data from a large-scale stroke registry of general population in current Japan.

METHODS

Shiga Stroke Registry (SSR) is an ongoing population-based registry of stroke that occurred in the Shiga Prefecture in central Honshu, Japan. A total 6,688 cases of first-ever stroke, with onset dates ranging from 1 January 2011 to 31 December in 2013 were included in this study. Incidence rates of first-ever stroke in each season were estimated using the person-year approach and adjusted for age and sex using the Poisson regression models.

RESULTS

From 2011 to 2013, we identified a total of 6,688 stroke cases (3,570 men, 3,118 women), of which 4,480 cases had ischemic stroke (2,518 men, 1,962 women), 1,588 had intracerebral hemorrhage (857 men, 731 women) and 563 had subarachnoid hemorrhage (166 men, 397 women). Age- and sex-adjusted incidence rates of total stroke were 151 (95% confidence interval [CI] 144-160, p = <0.001 vs. summer) in spring, 130 (95% CI 122-137) in summer, 141 (95% CI 133-149, p = 0.020 vs. summer) in autumn and 170 (95% CI 161-179, p = <0.001 vs. summer) in winter. Seasonal variation was more pronounced in intracerebral hemorrhage than in ischemic stroke.

CONCLUSION

In the present large-scale stroke registry of general population, incidence rates of stroke were highest in winter and lowest in summer in current Japan.

Influenza Vaccination for the Prevention of Cardiovascular Disease in the Americas: Consensus document of the Inter-American Society of Cardiology and the Word Heart Federation

Background

Cardiovascular mortality is decreasing but remains the leading cause of death world-wide. Respiratory infections such as influenza significantly contribute to morbidity and mortality in patients with cardiovascular disease. Despite of proven benefits, influenza vaccination is not fully implemented, especially in Latin America.

Objective

The aim was to develop a regional consensus with recommendations regarding influenza vaccination and cardiovascular disease.

Methods

A multidisciplinary team composed by experts in the management and prevention of cardiovascular disease from the Americas, convened by the Inter-American Society of Cardiology (IASC) and the World Heart Federation (WHF), participated in the process and the formulation of statements. The modified RAND/UCLA methodology was used. This document was supported by a grant from the WHF.

Results

An extensive literature search was divided into seven questions, and a total of 23 conclusions and 29 recommendations were achieved. There was no disagreement among experts in the conclusions or recommendations.

Conclusions

There is a strong correlation between influenza and cardiovascular events. Influenza vaccination is not only safe and a proven strategy to reduce cardiovascular events, but it is also cost saving. We found several barriers for its global implementation and potential strategies to overcome them.

The cytokine storms of COVID-19, H1N1 influenza, CRS and MAS compared. Can one sized treatment fit all?

An analysis of published data appertaining to the cytokine storms of COVID-19, H1N1 influenza, cytokine release syndrome (CRS), and macrophage activation syndrome (MAS) reveals many common immunological and biochemical abnormalities. These include evidence of a hyperactive coagulation system with elevated D-dimer and ferritin levels, disseminated intravascular coagulopathy (DIC) and microthrombi coupled with an activated and highly permeable vascular endothelium. Common immune abnormalities include progressive hypercytokinemia with elevated levels of TNF-α, interleukin (IL)-6, and IL-1β, proinflammatory chemokines, activated macrophages and increased levels of nuclear factor kappa beta (NFκB). Inflammasome activation and release of damage associated molecular patterns (DAMPs) is common to COVID-19, H1N1, and MAS but does not appear to be a feature of CRS. Elevated levels of IL-18 are detected in patients with COVID-19 and MAS but have not been reported in patients with H1N1 influenza and CRS. Elevated interferon-γ is common to H1N1, MAS, and CRS but levels of this molecule appear to be depressed in patients with COVID-19. CD4+ T, CD8+ and NK lymphocytes are involved in the pathophysiology of CRS, MAS, and possibly H1N1 but are reduced in number and dysfunctional in COVID-19. Additional elements underpinning the pathophysiology of cytokine storms include Inflammasome activity and DAMPs. Treatment with anakinra may theoretically offer an avenue to positively manipulate the range of biochemical and immune abnormalities reported in COVID-19 and thought to underpin the pathophysiology of cytokine storms beyond those manipulated via the use of, canakinumab, Jak inhibitors or tocilizumab. Thus, despite the relative success of tocilizumab in reducing mortality in COVID-19 patients already on dexamethasone and promising results with Baricitinib, the combination of anakinra in combination with dexamethasone offers the theoretical prospect of further improvements in patient survival. However, there is currently an absence of trial of evidence in favour or contravening this proposition. Accordingly, a large well powered blinded prospective randomised controlled trial (RCT) to test this hypothesis is recommended.

[Modulation of endothelial factors activity in human endothelial cells in influenza A(H1N1)pdm09 virus infection]

INTRODUCTION

Influenza A virus infection can lead to endothelial dysfunction (ED), including apoptosis of endothelial cells and modulation of endothelial factor activities. Affected biochemical factors may include those playing important roles in vascular homeostasis. However, the effect of this pathogen on the expression pattern of key endothelial factors is still unknown.The aim of this work was to study the expression of endothelial nitric oxide synthase (eNOS) and plasminogen activator inhibitor-1 (PAI-1, serpin E1) in the EA.hy926 endothelial cells.

RESEARCH OBJECTIVES

to assess expression of eNOS and PAI-1 in endothelial cells infected with influenza virus A(H1N1)pdm09, and to identify homologous fragments in structure of viral proteins and endothelial factors.

MATERIAL AND METHODS

Cells were infected with influenza virus A/St. Petersburg/48/16 (H1N1)pdm09 and analyzed in dynamics in 6, 12, 18, 24, 48, and 72 hrs post infection (hpi). Detection of endothelial factors expression levels was performed by immunocytochemical method (ICC) using antibodies for eNOS and PAI-1 while quantitative assessment of expression levels was carried out by program Nis-Elements F3.2 («Nikon», Japan). The search for homologous sequences between viral proteins and eNOS and PAI-1 was performed by computer comparison. Sequences were analyzed as fragments 12 amino acid residues (aar) in length.

RESULTS AND DISCUSSION

eNOS expression in infected cells had decreased to 7.9% by 6 hpi (control was taken as 100%) to 3.3% at 72 hpi. PAI-1 expression varied significantly over the course of the experiment: by 6 hpi it had decreased to 49.6%, and to 43.2% by 12 hpi. Later PAI-1 levels were: 116.3% (18 hpi); 18.9% (24 hpi); 23.5% (48 hpi), and 35% (72 hpi).

CONCLUSION

These results indicate that influenza A infection of endothelial cells causes a significant decrease in eNOS expression, while modulating PAI-1 one. The described phenomenon can be used in the further development of directions of pathogenetic therapy of vascular complications of infection caused by this pathogen.

The impact of influenza vaccination on cardiovascular disease

Influenza infection has been identified as a triggering or exacerbating factor for cardiovascular events. To analyse the effect of influenza vaccination on cardiovascular disease, a systematic search of studies published between 2009-2019 was conducted. All the studies that evaluated the effect of vaccination against influenza on cardiovascular events and their outcome were considered. Finally, 30 of the 1147 identified studies were included. These studies show a protective effect of the influenza vaccine on the development of cardiovascular events (myocardial infarction, cerebrovascular accidents, atrial fibrillation, and heart failure) and on the worsening of these conditions. Furthermore, the data showed that vaccinated patients have a lower risk of death from cardiovascular pathologies. Influenza vaccination is therefore an effective measure in the prevention of cardiovascular diseases both in patients with established cardiovascular disease and in the population without previous coronary pathology.

Location of death among patients presenting with cardiovascular disease to the emergency department in the United states

BACKGROUND

In-hospital deaths are an important outcome and little is known about deaths in the emergency department (ED). Among patients who died of cardiovascular diseases (CVD), we assessed causes of death, temporal trends and the relative distribution of deaths in the ED versus hospital.

METHODS

Using the United States Nationwide Emergency Department Sample, we conducted a retrospective study of patients presenting to the ED with a primary diagnosis of CVD between 2006 and 2014. We used descriptive statistics to describe causes of deaths, temporal trends and location of death.

RESULTS

During the study period, there were 27 144 508 visits to the ED with CVD diagnoses (~2% of all ED visits,). The most common CVD diagnoses were heart failure (n = 8 571 598), acute myocardial infarction (n = 4 827 518) and atrial fibrillation/flutter (n = 4 713 241). There were a total of 2.2 million deaths caused by the CVD, with the majority (57.6%) occurring in the ED. Cardiac arrest was the most common cause of in-hospital death (n = 1 225 095, 55.3%), followed by acute myocardial infarction (n = 279 310, 12.6%), heart failure (n = 217 367, 9.8%), intracranial hemorrhage (n = 168 009, 7.6%) and ischemic stroke (n = 151 615, 6.8%). The proportion of deaths in the ED for these causes were 91.9% cardiac arrest (n = 1 173 471), 3.6% acute myocardial infarction (n = 46 909), 1.0% heart failure (n = 12 599) and 1.1% intracranial hemorrhage (n = 13 579). There was a decrease in death for most CVDs over time.

CONCLUSIONS

Inpatient CVD admissions and their associated death may not be a robust measure of the national burden of CVD since ED death-which are common for some conditions-are not captured.

Influenza and Pneumococcal Vaccination in Non-Infected Cardiometabolic Patients from the Americas during the COVID-19 Pandemic. A Sub-Analysis of the CorCOVID-LATAM Study

BACKGROUND

Influenza vaccination (IV) and Pneumococcus vaccination (PV) are recommended for patients with cardiometabolic diseases. This study aimed to evaluate the immunization rate of ambulatory cardiometabolic patients during the COVID-19 pandemic in the Americas.

METHODS

Electronic surveys were collected from 13 Spanish speaking countries between 15 June and 15 July 2020.

RESULTS

4216 patients were analyzed. Mean age 60 (±15) years and 49% females. Global IV rate was 46.5% and PV 24.6%. Vaccinated patients were older (IV = 63 vs. 58 years; PV = 68 vs. 59, p < 0.01) but without gender difference. Vaccination rates were greater in higher-risk groups (65+, diabetics, heart failure), but not in coronary artery disease patients. In the Southern cone, the rate of IV and PV was approximately double that in the tropical regions of the Americas. In a multivariate model, geographic zone (IV = OR 2.02, PV = OR 2.42, p < 0.001), age (IV = OR 1.023, PV = OR 1.035, p < 0.001), and incomes (IV = OR 1.28, PV = OR 1.58, p < 0.001) were predictors for vaccination.

CONCLUSIONS

During the COVID-19 pandemic, ambulatory patients with cardiometabolic diseases from the Americas with no evidence of COVID-19 infection had lower-than-expected rates of IV and PV. Geographic, social, and cultural differences were found, and they should be explored in depth.

Economic evaluation of high-dose inactivated influenza vaccine in adults aged ≥65 years: A systematic literature review

INTRODUCTION

Due to waning immunity, adults aged ≥65 years are at increased risk of seasonal influenza infection and its complications. Adding to this risk, older adults have reduced responses to influenza vaccines. A high-dose trivalent inactivated influenza vaccine (Fluzone High-Dose, Sanofi Pasteur) (IIV3-HD) was developed to improve protection against influenza in adults aged ≥65 years and has been licensed in the US since 2009 and in Canada since 2015. Post-licensure studies have shown that IIV3-HD is more effective than standard-dose trivalent inactivated influenza vaccine (IIV3-SD) at protecting against influenza infection in this population. Here, we performed a systematic review of economic analyses of IIV3-HD in adults aged ≥65 years.

METHODS

On June 9, 2019, using the Ovid search platform, we searched Econlit, Embase, and Ovid MEDLINE® for original studies published in peer-reviewed journals examining the economics or cost-effectiveness of IIV3-HD in adults aged ≥65 years. Two reviewers independently selected studies and assessed their quality.

RESULTS

Seven studies were selected, all performed in the US or Canada. Five studies were funded by IIV3-HD manufacturer, and the remaining two by the US National Institute of General Medical Sciences. In all studies, IIV3-HD reduces healthcare resource utilization and is cost-effective or cost-saving compared to IIV3-SD. The main driver is reduced hospitalizations for cardiorespiratory events.

CONCLUSION

IIV3-HD is cost-saving or cost-effective versus IIV3-SD in adults aged ≥65 years. Reduced cardiorespiratory complications are an important driver of these economic benefits. A video summary of the article can be accessed via the Supplementary data link at the end of this article.

Impact of the presence of heart disease, cardiovascular medications and cardiac events on outcome in COVID-19

BACKGROUND

Cardiovascular risk factors and usage of cardiovascular medication are prevalent among coronavirus disease 2019 (COVID-19) patients. Little is known about the cardiovascular implications of COVID-19. The goal herein, was to evaluate the prognostic impact of having heart disease (HD) and taking cardiovascular medications in a population diagnosed of COVID-19 who required hospitalization. Also, we studied the development of cardiovascular events during hospitalization.

METHODS

Consecutive patients with definitive diagnosis of COVID-19 made by a positive real time- -polymerase chain reaction of nasopharyngeal swabs who were admitted to the hospital from March 15 to April 14 were included in a retrospective registry. The association of HD with mortality and with mortality or respiratory failure were the primary and secondary objectives, respectively.

RESULTS

A total of 859 patients were included in the present analysis. Cardiovascular risk factors were related to death, particularly diabetes mellitus (hazard ratio in the multivariate analysis: 1.810 [1.159- -2.827], p = 0.009). A total of 113 (13.1%) patients had HD. The presence of HD identified a group of patients with higher mortality (35.4% vs. 18.2%, p < 0.001) but HD was not independently related to prognosis; renin-angiotensin-aldosterone system inhibitors, calcium channel blockers, diuretics and beta-blockers did not worsen prognosis. Statins were independently associated with decreased mortality (0.551 [0.329-0.921], p = 0.023). Cardiovascular events during hospitalization identified a group of patients with poor outcome (mortality 31.8% vs. 19.3% without cardiovascular events, p = 0.007).

CONCLUSIONS

The presence of HD is related to higher mortality. Cardiovascular medications taken before admission are not harmful, statins being protective. The development of cardiovascular events during the course of the disease is related to poor outcome.

Cardiovascular implications of COVID-19 versus influenza infection: a review

BACKGROUND

Due to the overlapping clinical features of coronavirus disease 2019 (COVID-19) and influenza, parallels are often drawn between the two diseases. Patients with pre-existing cardiovascular diseases (CVD) are at a higher risk for severe manifestations of both illnesses. Considering the high transmission rate of COVID-19 and with the seasonal influenza approaching in late 2020, the dual epidemics of COVID-19 and influenza pose serious cardiovascular implications. This review highlights the similarities and differences between influenza and COVID-19 and the potential risks associated with coincident pandemics.

MAIN BODY

COVID-19 has a higher mortality compared to influenza with case fatality rate almost 15 times more than that of influenza. Additionally, a significantly increased risk of adverse outcomes has been noted in patients with CVD, with ~ 15 to 70% of COVID-19 related deaths having an underlying CVD. The critical care need have ranged from 5 to 79% of patients hospitalized due to COVID-19, a proportion substantially higher than with influenza. Similarly, the frequency of vascular thrombosis including deep venous thrombosis and pulmonary embolism is markedly higher in COVID-19 patients compared with influenza in which vascular complications are rarely seen. Unexpectedly, while peak influenza season is associated with increased cardiovascular hospitalizations, a decrease of ~ 50% in cardiovascular hospitalizations has been observed since the first diagnosed case of COVID-19, owing in part to deferred care.

CONCLUSION

In the coming months, increasing efforts towards evaluating new interventions will be vital to curb COVID-19, especially as peak influenza season approaches. Currently, not enough data exist regarding co-infection of COVID-19 with influenza or how it would progress clinically, though it may cause a significant burden on an already struggling health care system. Until an effective COVID-19 vaccination is available, high coverage of influenza vaccination should be of utmost priority.

Delicate Role of PD-L1/PD-1 Axis in Blood Vessel Inflammatory Diseases: Current Insight and Future Significance

Immune checkpoint molecules are the antigen-independent generator of secondary signals that aid in maintaining the homeostasis of the immune system. The programmed death ligand-1 (PD-L1)/PD-1 axis is one among the most extensively studied immune-inhibitory checkpoint molecules, which delivers a negative signal for T cell activation by binding to the PD-1 receptor. The general attributes of PD-L1's immune-suppressive qualities and novel mechanisms on the barrier functions of vascular endothelium to regulate blood vessel-related inflammatory diseases are concisely reviewed. Though targeting the PD-1/PD-L1 axis has received immense recognition-the Nobel Prize in clinical oncology was awarded in the year 2018 for this discovery-the use of therapeutic modulating strategies for the PD-L1/PD-1 pathway in chronic inflammatory blood vessel diseases is still limited to experimental models. However, studies using clinical specimens that support the role of PD-1 and PD-L1 in patients with underlying atherosclerosis are also detailed. Of note, delicate balances in the expression levels of PD-L1 that are needed to preserve T cell immunity and to curtail acute as well as chronic infections in underlying blood vessel diseases are discussed. A significant link exists between altered lipid and glucose metabolism in different cells and the expression of PD-1/PD-L1 molecules, and its possible implications on vascular inflammation are justified. This review summarizes the most recent insights concerning the role of the PD-L1/PD-1 axis in vascular inflammation and, in addition, provides an overview exploring the novel therapeutic approaches and challenges of manipulating these immune checkpoint proteins, PD-1 and PD-L1, for suppressing blood vessel inflammation.

Association of Influenza-like Illness Activity With Hospitalizations for Heart Failure: The Atherosclerosis Risk in Communities Study

Importance

Influenza is associated with an increased risk of cardiovascular events, but to our knowledge, few studies have explored the temporal association between influenza activity and hospitalizations, especially those caused by heart failure (HF).

Objective

To explore the temporal association between influenza activity and hospitalizations due to HF and myocardial infarction (MI). We hypothesized that increased influenza activity would be associated with an increase in hospitalizations for HF and MI among adults in the community.

Design, Setting, and Participants

As part of the community surveillance component of the Atherosclerosis Risk in Communities (ARIC) study, a population-based study with hospitalizations sampled from 4 US communities, data were collected from 451 588 adults aged 35 to 84 years residing in the ARIC communities from annual cross-sectional stratified random samples of hospitalizations during October 2010 to September 2014.

Exposures

Monthly influenza activity, defined as the percentage of patient visits to sentinel clinicians for influenza-like illness by state, as reported by the Centers for Disease Control and Prevention Surveillance Network.

Main Outcomes and Measures

The monthly frequency of MI hospitalizations (n = 3541) and HF hospitalizations (n = 4321), collected through community surveillance and adjudicated as part of the ARIC Study.

Results

Between October 2010 and September 2014, 2042 (47.3%) and 1599 (45.1%) of the sampled patients who were hospitalized for HF and MI, respectively, were women and 2391 (53.3%) and 2013 (57.4%) were white, respectively. A 5% monthly absolute increase in influenza activity was associated with a 24% increase in HF hospitalization rates, standardized to the total population in each community, within the same month after adjusting for region, season, race/ethnicity, sex, age, and number of MI/HF hospitalizations from the month before (incidence rate ratio, 1.24; 95% CI, 1.11-1.38; P < .001), while overall influenza activity was not significantly associated with MI hospitalizations (incidence rate ratio, 1.02; 95% CI, 0.90-1.17; P = .72). Influenza activity in the months before hospitalization was not associated with either outcome. Our model suggests that in a month with high influenza activity, approximately 19% of HF hospitalizations (95% CI, 10%-28%) could be attributable to influenza.

Conclusions and Relevance

Influenza activity was temporally associated with an increase in HF hospitalizations across 4 influenza seasons. These data suggest that influenza may contribute to the risk of HF hospitalization in the general population.

Influenza Infections and Emergent Viral Infections in Intensive Care Unit

Critically ill patients are admitted to an intensive care unit (ICU) for multiple reasons. In this study, we aim to analyze the current evidence and findings associated with influenza and other emergent viral infections, namely, herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and cytomegalovirus (CMV).

Among medical conditions, community-acquired respiratory infections are the most frequent reason for ventilatory support in ICUs. Community-acquired pneumonia in a severe form including the need of invasive mechanical ventilation and/or vasopressors is associated with high mortality rates. However, after the pandemic that occurred in 2009 by H1N1 influenza, the number of cases being admitted to ICUs with viral infections is on the rise. Patients in whom an etiology would not have been identified in the past are currently being tested with more sensitive viral molecular diagnostic tools, and patients being admitted to ICUs have more preexisting medical conditions that can predispose to viral infections. Viral infections can trigger the dysregulation of the immune system by inducing a massive cytokine response. This cytokine storm can cause endothelial damage and dysfunction, deregulation of coagulation, and, consequently, alteration of microvascular permeability, tissue edema, and shock. In severe influenza, this vascular hyperpermeability can lead to acute lung injury, multiorgan failure, and encephalopathy. In immunocompetent patients, the most common viral infections are respiratory, and influenza should be considered in patients with severe respiratory failure being admitted to ICU. Seasonality and coinfection are two important features when considering influenza as a pathogen in critically ill patients.

Herpesviridae (HSV, CMV, and EBV) may reactivate in ICU patients, and their reactivation is associated with morbidity/mortality. However, whether a specific treatment may impact on outcome remains to be determined.

The challenges of influenza for public health

Influenza, an infectious disease of the respiratory system, represents a major burden for public health. This disease affects all age groups with different prognosis, being life threatening for vulnerable individuals. Despite influenza being a vaccine-preventable disease, the control of the infection needs annual vaccination campaigns and constant improvements. Herein, the main challenges of influenza in relation to the pathogenic agent, the available vaccines and the health impact identified during the Light on Vax event, an expert meeting organized by the Asociación Española de Vacunología [Spanish Vaccinology Association] (AEV), are reported. Further possible steps in the control of influenza are also suggested. Ideally, the development of innovative and universal vaccines that would confer life-lasting and broader-spectrum immunity is highly desirable.

Respiratory Syncytial Virus and Associations With Cardiovascular Disease in Adults

Respiratory syncytial virus (RSV) is historically known for causing respiratory illness in young children, but the appreciation of its impact on older adults is growing. Studies have shown that hospitalization for respiratory illness due to RSV is complicated by cardiovascular events in 14% to 22% of adult patients, including worsening congestive heart failure, acute coronary syndrome, and arrhythmias. Additionally, underlying cardiovascular disease is associated with hospitalization in 45% to 63% of adults with confirmed RSV. In summary, patients with cardiopulmonary disease have higher rates of health care utilization for RSV-related illness and worse outcomes. Patients with cardiovascular disease likely represent an important target population for the rapidly developing field of RSV vaccines.

Excess Deaths Attributable to Influenza-Like Illness in the ESRD Population

BACKGROUND

Morbidity and mortality vary seasonally. Timing and severity of influenza seasons contribute to those patterns, especially among vulnerable populations such as patients with ESRD. However, the extent to which influenza-like illness (ILI), a syndrome comprising a range of potentially serious respiratory tract infections, contributes to mortality in patients with ESRD has not been quantified.

METHODS

We used data from the Centers for Disease Control and Prevention (CDC) Outpatient Influenza-like Illness Surveillance Network and Centers for Medicare and Medicaid Services ESRD death data from 2000 to 2013. After addressing the increasing trend in deaths due to the growing prevalent ESRD population, we calculated quarterly relative mortality compared with average third-quarter (summer) death counts. We used linear regression models to assess the relationship between ILI data and mortality, separately for quarters 4 and 1 for each influenza season, and model parameter estimates to predict seasonal mortality counts and calculate excess ILI-associated deaths.

RESULTS

An estimated 1% absolute increase in quarterly ILI was associated with a 1.5% increase in relative mortality for quarter 4 and a 2.0% increase for quarter 1. The average number of annual deaths potentially attributable to ILI was substantial, about 1100 deaths per year.

CONCLUSIONS

We found an association between community ILI activity and seasonal variation in all-cause mortality in patients with ESRD, with ILI likely contributing to >1000 deaths annually. Surveillance efforts, such as timely reporting to the CDC of ILI activity within dialysis units during influenza season, may help focus attention on high-risk periods for this vulnerable population.

Herpes Zoster: Epidemiological Links With Stroke and Myocardial Infarction

Routine data from electronic health records (EHRs) provide insights into links between herpes zoster (HZ) and cardiovascular complications such as stroke or myocardial infarction (MI) in different populations worldwide. Evidence from large EHR studies using both self-controlled case series and traditional cohort designs suggests that there is a transient increase in the risk of stroke after HZ, which gradually resolves over 6-12 months. In these studies, herpes zoster ophthalmicus was associated with a higher risk of stroke than HZ at other sites. A larger effect size was seen in people aged under 40 years. Existing studies also suggest that HZ may have a triggering effect on MI, although fewer studies examined this outcome. Further evidence is needed on the effectiveness and cost-effectiveness of vaccine and antiviral drugs to reduce cardiovascular complications after HZ from studies that are designed to minimize selection biases and confounding by indication.

Inhibition of influenza A virus by mixed siRNAs, targeting the PA, NP, and NS genes, delivered by hybrid microcarriers

In the present study, a highly effective carrier system has been developed for the delivery of antiviral siRNA mixtures. The developed hybrid microcarriers, made of biodegradable polymers and SiO₂ nanostructures, more efficiently mediate cellular uptake of siRNA than commercially available liposome-based reagents and polyethyleneimine (PEI); they also demonstrate low in vitro toxicity and protection of siRNA from RNase degradation. A series of siRNA designs (targeting the most conserved regions of three influenza A virus (IAV) genes: NP, NS, and PA) were screened in vitro using RT-qPCR, ELISA analysis, and hemagglutination assay. Based on the results of screening, the three most effective siRNAs (PA-1630, NP-717, and NS-777) were selected for in situ encapsulation into hybrid microcarriers. It was revealed that pre-treatment of cells with a mixture of PA-1630, NP-717, and NS-777 siRNAs, delivered by hybrid microcarriers, provided stronger inhibition of viral M1 mRNA expression and control of NP protein level, after viral infection, than single pre-treatment by any of three encapsulated siRNAs used in the study. Moreover, the effective inhibition of replication in several IAV subtypes (H1N1, H1N1pdm, H5N2, and H7N9) using a cocktail of the three selected siRNAs, delivered by our hybrid capsules to the cells, was achieved. In conclusion, we have developed a proof-of-principle which shows that our hybrid microcarrier technology (utilizing a therapeutic siRNA cocktail) may represent a promising approach in anti-influenza therapy.

Laboratory-Confirmed Respiratory Infections as Predictors of Hospital Admission for Myocardial Infarction and Stroke: Time-Series Analysis of English Data for 2004-2015

Background

Acute respiratory infections are associated with increased risk of myocardial infarction (MI) and stroke; however, the role of different organisms is poorly characterized.

Methods

Time-series analysis of English hospital admissions for MI and stroke (age-stratified: 45-64, 65-74, ≥75 years), laboratory-confirmed viral respiratory infections, and environmental data for 2004-2015. Weekly counts of admissions were modeled using multivariable Poisson regression with weekly counts of respiratory viruses (influenza, parainfluenza, rhinovirus, respiratory syncytial virus [RSV], adenovirus, or human metapneumovirus [HMPV]) investigated as predictors. We controlled for seasonality, long-term trends, and environmental factors.

Results

Weekly hospital admissions in adults aged ≥45 years averaged 1347 (interquartile range [IQR], 1217-1541) for MI and 1175 (IQR, 1023-1395) for stroke. Respiratory infections ranged from 11 cases per week (IQR, 5-53) for influenza to 55 (IQR, 7-127) for rhinovirus. In the adjusted models, all viruses except parainfluenza were significantly associated with MI and ischemic stroke admissions in those aged ≥75. Among 65- to 74-year-olds, adenovirus, rhinovirus, and RSV were associated with MI but not ischemic stroke admissions. Respiratory infections were not associated with MI or ischemic stroke in people aged 45-64 years, nor with hemorrhagic stroke in any age group. An estimated 0.4%-5.7% of MI and ischemic stroke admissions may be attributable to respiratory infection.

Conclusions

We identified small but strongly significant associations in the timing of respiratory infection (with HMPV, RSV, influenza, rhinovirus, and adenovirus) and MI or ischemic stroke hospitalizations in the elderly.

Clinical Trials Registration

NCT02984280.

Pleiotropic Meta-Analyses of Longitudinal Studies Discover Novel Genetic Variants Associated with Age-Related Diseases

Age-related diseases may result from shared biological mechanisms in intrinsic processes of aging. Genetic effects on age-related diseases are often modulated by environmental factors due to their little contribution to fitness or are mediated through certain endophenotypes. Identification of genetic variants with pleiotropic effects on both common complex diseases and endophenotypes may reveal potential conflicting evolutionary pressures and deliver new insights into shared genetic contribution to healthspan and lifespan. Here, we performed pleiotropic meta-analyses of genetic variants using five NIH-funded datasets by integrating univariate summary statistics for age-related diseases and endophenotypes. We investigated three groups of traits: (1) endophenotypes such as blood glucose, blood pressure, lipids, hematocrit, and body mass index, (2) time-to-event outcomes such as the age-at-onset of diabetes mellitus (DM), cancer, cardiovascular diseases (CVDs) and neurodegenerative diseases (NDs), and (3) both combined. In addition to replicating previous findings, we identify seven novel genome-wide significant loci (< 5e-08), out of which five are low-frequency variants. Specifically, from Group 2, we find rs7632505 on 3q21.1 in SEMA5B, rs460976 on 21q22.3 (1 kb from TMPRSS2) and rs12420422 on 11q24.1 predominantly associated with a variety of CVDs, rs4905014 in ITPK1 associated with stroke and heart failure, rs7081476 on 10p12.1 in ANKRD26 associated with multiple diseases including DM, CVDs, and NDs. From Group 3, we find rs8082812 on 18p11.22 and rs1869717 on 4q31.3 associated with both endophenotypes and CVDs. Our follow-up analyses show that rs7632505, rs4905014, and rs8082812 have age-dependent effects on coronary heart disease or stroke. Functional annotation suggests that most of these SNPs are within regulatory regions or DNase clusters and in linkage disequilibrium with expression quantitative trait loci, implying their potential regulatory influence on the expression of nearby genes. Our mediation analyses suggest that the effects of some SNPs are mediated by specific endophenotypes. In conclusion, these findings indicate that loci with pleiotropic effects on age-related disorders tend to be enriched in genes involved in underlying mechanisms potentially related to nervous, cardiovascular and immune system functions, stress resistance, inflammation, ion channels and hematopoiesis, supporting the hypothesis of shared pathological role of infection, and inflammation in chronic age-related diseases.

Aberrant coagulation causes a hyper-inflammatory response in severe influenza pneumonia

Influenza A virus (IAV) infects the respiratory tract in humans and causes significant morbidity and mortality worldwide each year. Aggressive inflammation, known as a cytokine storm, is thought to cause most of the damage in the lungs during IAV infection. Dysfunctional coagulation is a common complication in pathogenic influenza, manifested by lung endothelial activation, vascular leak, disseminated intravascular coagulation and pulmonary microembolism. Importantly, emerging evidence shows that an uncontrolled coagulation system, including both the cellular (endothelial cells and platelets) and protein (coagulation factors, anticoagulants and fibrinolysis proteases) components, contributes to the pathogenesis of influenza by augmenting viral replication and immune pathogenesis. In this review, we focus on the underlying mechanisms of the dysfunctional coagulatory response in the pathogenesis of IAV.

Point-of-care testing for respiratory viruses in adults: The current landscape and future potential

Respiratory viruses are responsible for a large proportion of acute respiratory illness in adults as well as children, and are associated with a huge socio-economic burden worldwide. Development of accurate point-of-care tests (POCT) for respiratory viruses has been listed as a priority by the World Health Organisation and replacing the current paradigm of empirical antimicrobial use with directed use is a listed goal of the movement for reduction in antimicrobial resistance. POCTs for respiratory viruses have previously been limited by the poor sensitivity of antigen detection based tests and by a limited range of detectable viruses. Highly accurate molecular platforms are now able to test for a comprehensive range of viruses, can be operated by non-laboratory staff and can generate a result in approximately 1 h, making them potentially deployable as POCTs. The potential clinical benefits of POC testing for respiratory viruses in adults include a reduction in unnecessary antibiotic use, improved antiviral prescribing for influenza and rationalisation of isolation facilities. We review here the burden of disease, the currently available molecular platforms with potential for POCT use and the existing evidence for clinical and economic benefits of testing for respiratory viruses in adults.

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There is a large burden of respiratory virus infection in hospitalised adults.

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Replacing empirical antimicrobials with pathogen directed use is a global priority.

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Molecular platforms now exist with potential for use as point-of-care tests (POCT).

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Potential benefits of POCT include a reduction in unnecessary antibiotic use.

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High quality trials evaluating clinically relevant outcomes are urgently needed.