The association of influenza infection and vaccine with myocardial infarction: systematic review and meta-analysis of self-controlled case series

Respiratory Syncytial Virus Sequelae Among Adults in High-Income Countries: A Systematic Literature Review and Meta-analysis

INTRODUCTION

Respiratory syncytial virus (RSV) can cause severe respiratory infections in adults; however, information on associated sequelae is limited. This systematic literature review aimed to identify sequelae in adults within 1 year following RSV-related hospitalization or resolution of acute infection.

METHODS

Studies were identified from Embase, MEDLINE, LILACS, SciELO, and grey literature. Random-effects meta-analyses using restricted maximum likelihood were used to calculate the proportions and relative risks of sequelae in patients with RSV compared with controls (patients with RSV-negative influenza-like illness, influenza, and parainfluenza) per follow-up period, population, and treatment setting, where possible.

RESULTS

Twenty-one relevant studies covering the period from 1990 to 2019 were included. Among the general population, the most frequent clinical sequela was sustained function loss (33.5% [95% CI 27.6-39.9]). Decline in lung function and cardiovascular event or congestive heart failure were also identified. Utilization sequelae were readmission (highest at > 6 months after discharge) and placement in a skilled nursing facility. The only subpopulation with data regarding sequelae was transplant patients. Among lung transplant patients, the most frequently reported clinical sequelae were decline in lung function, followed by graft dysfunction and bronchiolitis obliterans syndrome. Pooled relative risks were calculated for the following sequela with controls (primarily influenza-positive patients): cardiovascular event (general population) and pulmonary impairment (hematogenic-transplant patients) both 1.4 (95% CI 1.0-2.0) and for readmission (general population) 1.2 (95% CI 1.1-1.3).

CONCLUSIONS

Although less data are available for RSV than for influenza or other lower respiratory tract infections, RSV infection among adults is associated with medically important sequelae, with a prevalence similar to other respiratory pathogens. RSV sequelae should be included in disease burden estimates.

Prevalence of influenza and other acute respiratory illnesses in patients with acute myocardial infarction in Bangladesh: A cross-sectional study

Background and Aims

Several studies imply that influenza and other respiratory illnesses could lead to acute myocardial infarction (AMI), but data from low-income countries are scarce. We investigated the prevalence of recent respiratory illnesses and confirmed influenza in AMI patients, while also exploring their relationship with infarction severity as defined by ST-elevation MI (STEMI) or high troponin levels.

Methods

This cross-sectional study, held at a Dhaka tertiary hospital from May 2017 to October 2018, involved AMI inpatients. The study examined self-reported clinical respiratory illnesses (CRI) in the week before AMI onset and confirmed influenza using baseline real-time reverse transcription polymerase chain reaction (qRT-PCR).

Results

Of 744 patients, 11.3% reported a recent CRI, most prominently during the 2017 influenza season (35.7%). qRT-PCR testing found evidence of influenza in 1.5% of 546 patients, with all positives among STEMI cases. Frequencies of CRI were higher in patients with STEMI and in those with high troponin levels, although these relationships were not statistically significant after adjusting for other variables. The risk of STEMI was significantly greater during influenza seasons in the unadjusted analysis (relative risk: 1.09, 95% confidence interval [CI]: 1.02-1.18), however, this relationship was not significant in the adjusted analysis (adjusted relative risk: 1.03, 95% CI: 0.91-1.16).

Conclusion

In Bangladesh, many AMI patients had a recent respiratory illness history, with some showing evidence of influenza. However, these illnesses showed no significant relationship to AMI severity. Further research is needed to understand these relationships better and to investigate the potential benefits of infection control measures and influenza vaccinations in reducing AMI incidence.

RNAseq of INOCA patients identifies innate, invariant, and acquired immune changes: potential autoimmune microvascular dysfunction

Background

Ischemia with non-obstructive coronary arteries (INOCA) is a major clinical entity that involves potentially 20%-30% of patients with chest pain. INOCA is typically attributed either to coronary microvascular disease and/or vasospasm, but is likely distinct from classical coronary artery disease (CAD).

Objectives

To gain insights into the etiology of INOCA and CAD, RNA sequencing of whole blood from patients undergoing both stress testing and elective invasive coronary angiography (ICA) was conducted.

Methods

Stress testing and ICA of 177 patients identified 40 patients (23%) with INOCA compared to 39 controls (stress-, ICA-). ICA+ patients divided into 38 stress- and 60 stress+. RNAseq was performed by Illumina with ribosomal RNA depletion. Transcriptome changes were analyzed by DeSeq2 and curated by manual and automated methods.

Results

Differentially expressed genes for INOCA were associated with elevated levels of transcripts related to mucosal-associated invariant T (MAIT) cells, plasmacytoid dendritic cells (pcDC), and memory B cells, and were associated with autoimmune diseases such as rheumatoid arthritis. Decreased transcripts were associated with neutrophils, but neutrophil transcripts, per se, were not less abundant in INOCA. CAD transcripts were more related to T cell functions.

Conclusions

Elevated transcripts related to pcDC, MAIT, and memory B cells suggest an autoimmune component to INOCA. Reduced neutrophil transcripts are likely attributed to chronic activation leading to increased translation and degradation. Thus, INOCA could result from stimulation of B cell, pcDC, invariant T cell, and neutrophil activation that compromises cardiac microvascular function.

Tree-temporal scan statistics for safety signal detection in vaccine clinical trials

The evaluation of safety is critical in all clinical trials. However, the quantitative analysis of safety data in clinical trials poses statistical difficulties because of multiple potentially overlapping endpoints. Tree-temporal scan statistic approaches address this issue and have been widely employed in other data sources, but not to date in clinical trials. We evaluated the performance of three complementary scan statistical methods for routine quantitative safety signal detection: the self-controlled tree-temporal scan (SCTTS), a tree-temporal scan based on group comparison (BGTTS), and a log-rank based tree-temporal scan (LgRTTS). Each method was evaluated using data from two phase III clinical trials, and simulated data (simulation study). In the case study, the reference set was adverse events (AEs) in the Reference Safety Information of the evaluated vaccine. The SCTTS method had higher sensitivity than other methods, and after dose 1 detected 80 true positives (TP) with a positive predictive value (PPV) of 60%. The LgRTTS detected 49 TPs with 69% PPV. The BGTTS had 90% of PPV with 38 TPs. In the simulation study, with simulated reference sets of AEs, the SCTTS method had good sensitivity to detect transient effects. The LgRTTS method showed the best performance for the detection of persistent effects, with high sensitivity and expected probability of type I error. These three methods provide complementary approaches to safety signal detection in clinical trials or across clinical development programmes. All three methods formally adjust for multiple testing of large numbers of overlapping endpoints without being excessively conservative.

Influenza vaccination in older adults and patients with chronic disorders: A position paper from the Portuguese Society of Pulmonology, the Portuguese Society of Diabetology, the Portuguese Society of Cardiology, the Portuguese Society of Geriatrics and Gerontology, the Study Group of Geriatrics of the Portuguese Society of Internal Medicine, and the Portuguese Society of Infectious Diseases and Clinical Microbiology

Influenza affects millions of people worldwide each year and can lead to severe complications, hospitalizations, and even death, especially among vulnerable populations such as older adults and those with chronic medical conditions. Annual vaccination is considered the most effective measure for preventing influenza and its complications. Despite the widespread availability of influenza vaccines, however, vaccination coverage rates remain suboptimal in several countries. Based on the latest scientific evidence and expert opinions on influenza vaccination in older people and patients with chronic disease, the Portuguese Society of Pulmonology (SPP), the Portuguese Society of Diabetology (SPD), the Portuguese Society of Cardiology (SPC), the Portuguese Society of Geriatrics and Gerontology (SPGG), the Study Group of Geriatrics of the Portuguese Society of Internal Medicine (NEGERMI-SPMI), and the Portuguese Society of Infectious Diseases and Clinical Microbiology (SPDIMC) discussed best practices for promoting vaccination uptake and coverage and drew up several recommendations to mitigate the impact of influenza. These recommendations focus on the efficacy and safety of available vaccines; the impact of influenza vaccination on older adults; patients with chronic medical conditions, namely cardiac and respiratory conditions, diabetes, and immunosuppressive diseases; and health care professionals, optimal vaccination timing, and strategies to increase vaccination uptake and coverage. The resulting position paper highlights the critical role that vaccinations play in promoting public health, raising awareness, and encouraging more people to get vaccinated.

Association of recent respiratory illness and influenza with acute myocardial infarction among the Bangladeshi population: A case-control study

Current evidence suggests that recent acute respiratory infections and seasonal influenza may precipitate acute myocardial infarction (AMI). This study examined the potential link between recent clinical respiratory illness (CRI) and influenza, and AMI in Bangladesh. Conducted during the 2018 influenza season at a Dhaka tertiary-level cardiovascular (CV) hospital, it included 150 AMI cases and two control groups: 44 hospitalized cardiac patients without AMI and 90 healthy individuals. Participants were matched by gender and age groups. The study focused on self-reported CRI and laboratory-confirmed influenza ascertained via quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) within the preceding week, analyzed using multivariable logistic regression. Results showed that cases reported CRI, significantly more frequently than healthy controls (27.3% vs. 13.3%, adjusted odds ratio (aOR): 2.21; 95% confidence interval (CI): 1.05-4.06), although this was not significantly different from all controls (27.3% vs. 22.4%; aOR: 1.19; 95% CI: 0.65-2.18). Influenza rates were insignificantly higher among cases than controls. The study suggests that recent respiratory illnesses may precede AMI onset among Bangladeshi patients. Infection prevention and control practices, as well as the uptake of the influenza vaccine, may be advocated for patients at high risk of acute CV events.

The burden of influenza and the role of influenza vaccination in adults aged 50-64 years: A summary of available evidence

Influenza is a vaccine-preventable disease and a global public health problem. Although most national influenza vaccination recommendations focus on subjects aged ≥65 years, an extensive burden of influenza has also been reported in those aged ≥50 years and is exacerbated by immune system aging. The main purpose of this review is to provide an overview of the burden of influenza and its potential prevention within the 50-64 age-group. These subjects account for a large proportion of the workforce, and play a central economic and social role. Individuals aged 50-64 years had a 3-times higher rate of hospitalization and a 9-fold higher mortality rate attributable to influenza than those aged 18-49-years, generating higher influenza-related hospitalization costs. Available data suggest that including healthy subjects aged 50-64 years in influenza vaccination recommendations would allow a broader population to be reached, reducing the economic and social burden of influenza.

Awareness and Knowledge of Pneumococcal Vaccination in Cardiology Outpatient Clinics and the Impact of Physicians’ Recommendations on Vaccination Rates

Aim: We aimed to evaluate the awareness of pneumococcal vaccination (PCV13, PPSV23) in general cardiology outpatient clinics and impact of physicians’ recommendations on vaccination rates. Methods: This was a multicenter, observational, prospective cohort study. Patients over the age of 18 from 40 hospitals in different regions of Turkey who applied to the cardiology outpatient clinic between September 2022 and August 2021 participated. The vaccination rates were calculated within three months of follow-up from the admitting of the patient to cardiology clinics. Results: The 403 (18.2%) patients with previous pneumococcal vaccination were excluded from the study. The mean age of study population (n = 1808) was 61.9 ± 12.1 years and 55.4% were male. The 58.7% had coronary artery disease, hypertension (74.1%) was the most common risk factor, and 32.7% of the patients had never been vaccinated although they had information about vaccination before. The main differences between vaccinated and unvaccinated patients were related to education level and ejection fraction. The physicians’ recommendations were positively correlated with vaccination intention and behavior in our participants. Multivariate logistic regression analysis showed a significant correlation between vaccination and female sex [OR = 1.55 (95% CI = 1.25–1.92), p < 0.001], higher education level [OR = 1.49 (95% CI = 1.15–1.92), p = 0.002] patients’ knowledge [OR = 1.93 (95% CI = 1.56–2.40), p < 0.001], and their physician’s recommendation [OR = 5.12 (95% CI = 1.92–13.68), p = 0.001]. Conclusion: To increase adult immunization rates, especially among those with or at risk of cardiovascular disease (CVD), it is essential to understand each of these factors. Even if during COVID-19 pandemic, there is an increased awareness about vaccination, the vaccine acceptance level is not enough, still. Further studies and interventions are needed to improve public vaccination rates.

Myocardial infarction and viral triggers: what do we know by now?

Myocardial infarction (MI) is an acute clinical manifestation ischaemic heart disease, which is the leading cause of death worldwide. Infections also have an important burden worldwide, with lower respiratory infections being the worldwide leading cause of death due to communicable diseases. The relationship of MI with viral respiratory infections (including influenza and SARS-CoV-2) as a trigger has been well documented with significant associations. These infections can lead to Type 1 MI, where inflammation and vascular dysfunction, as well as the increased prothrombotic environment lead to atherothrombosis. Type 2 MI may also occur due to an imbalance of oxygen/blood supply and myocardial demand (hypoxaemia, fever, and tachycardia). The data from randomized controlled trials showing a potential benefit of influenza vaccination in coronary artery disease patients should not be ignored. This can be considered a further argument for the association of viral infections (influenza in particular) and MI.

High-dose influenza vaccines for the prevention of hospitalization due to cardiovascular events in older adults in the nursing home: Post-hoc analysis of a cluster-randomized trial

Older adults are at high risk of major acute cardiovascular events (MACE) linked to influenza illness andpreventable by influenza vaccination. It is unknown whether high-dose vaccine might incrementally reduce the risk of MACE.We conducted a post-hoc analysis of data collected from a pragmatic cluster randomized study of 823 nursing homes (NH) randomized to standard-dose (SD) or high-dose (HD) influenza vaccine in the 2013-14 season. Adults age 65 year or older who are Medicare-enrolled long-stay residents were included in the analysis.There were no statistically significant differences in hospitalization for MACE, acute coronary syndromes (ACS), stroke or heart failure between the HD and SD arms. However, in the fee-for-service group, participants in the HD arm had significantly decreased risk of hospitalization for respiratory problems, which was not observed in the Medicare Advantage group.High-dose influenza vaccine was not shown to be incrementally protective against MACE relative to standard-dose vaccine.

Influenza vaccination reduced myocardial infarctions in United Kingdom older adults: a prior event rate ratio study

OBJECTIVES

We aimed to estimate the real-world effectiveness of the influenza vaccine against myocardial infarction (MI) and influenza in the decade since adults aged ≥ 65 years were first recommended the vaccine.

STUDY DESIGN AND SETTING

We identified annual cohorts, 1997 to 2011, of adults aged ≥ 65 years, without previous influenza vaccination, from UK general practices, registered with the Clinical Practice Research Datalink. Using a quasi-experimental study design to control for confounding bias, we estimated influenza vaccine effectiveness on hospitalization for MI, influenza, and antibiotic prescriptions for lower respiratory tract infections.

RESULTS

Vaccination was moderately effective against influenza, the prior event rate ratio-adjusted hazard ratios ranging from 0.70 in 1999 to 0.99 in 2001. Prior event rate ratio-adjusted hazard ratios demonstrated a protective effect against MIs, varying between 0.40 in 2010 and 0.89 in 2001. Aggregated across the cohorts, influenza vaccination reduced the risk of MIs by 39% (95% confidence interval: 34%, 44%).

CONCLUSION

Effectiveness of the flu vaccine in preventing MIs in older UK adults is consistent with the limited evidence from clinical trials. Similar trends in effectiveness against influenza and against MIs suggest the risk of influenza mediates the effectiveness against MIs, although divergence in some years implies the mechanism may be complex.

Effectiveness of influenza vaccination on in-hospital death and recurrent hospitalization in older adults with cardiovascular diseases

OBJECTIVES

There is limited evidence on the effectiveness of influenza vaccination on hospitalization outcomes by cardiovascular disease (CVD) subtypes or comorbidities.

METHODS

This study involved 713,488 records of hospitalization of adults ≥60 years with CVD from the Beijing Urban Employee Basic Medical Insurance database. Logistic regression with generalized estimating equations was conducted to estimate the effectiveness of influenza vaccination on in-hospital death and recurrent hospitalization, adjusting for unmeasured confounders.

RESULTS

The coverage of influenza vaccination was only 13.3% among older adults hospitalized for CVD. Influenza vaccination was associated with 15% (odds ratios 0.85 [0.74, 0.99]) lower risk of in-hospital death among patients with CVD, with stronger associations in patients with stroke. Influenza vaccination was associated with 6% (0.94 [0.88, 0.99]) and 28% (0.72 [0.56, 0.93]) lower risks of recurrent hospitalization for ischemic heart disease (IHD) and respiratory disease in patients with IHD, but there were no clear associations in patients with stroke. For in-hospital death, the protective association of influenza vaccination was stronger in patients with fewer comorbidities and was similar to that of joint vaccinations of influenza and pneumococcal vaccinations.

CONCLUSION

The protective association of influenza vaccination on CVD hospitalization outcomes serves as the evidence base to increase the uptake of influenza vaccination among older adults in China.

Impact of industry sponsorship on the quality of systematic reviews of vaccines: a cross-sectional analysis of studies published from 2016 to 2019

BACKGROUND

Systematic reviews (SRs) provide the highest level of evidence and inform evidence-based decision making in health care. Earlier studies found association with industry to be negatively associated with methodological quality of SRs. However, this has not been investigated in SRs on vaccines.

METHODS

We performed a systematic literature search using MEDLINE and EMBASE in March 2020. The results were restricted to those published between 2016 and 2019 with no language restrictions. Study characteristics were extracted by one person and checked by an experienced reviewer. The methodological quality of the SRs was assessed with the AMSTAR 2 tool by multiple reviewers after a calibration exercise was performed. A summary score for each SR was calculated. The Mann-Whitney U test and Fisher's exact test were performed to compare both groups.

RESULTS

Out of 185 SRs that met all inclusion criteria, 27 SRs were industry funded. Those were matched with 30 non-industry funded SRs resulting in a total sample size of 57. The mean AMSTAR 2 summary score across all SRs was 0.49. Overall, the median AMSTAR 2 summary score was higher for the non-industry funded SRs than for the industry-funded SRs (0.62 vs. 0.36; p < .00001). Lower ratings for industry funded SRs were consistent across all but one AMSTAR 2 item, though significantly lower only for three specific items.

CONCLUSION

The methodological quality of SRs in vaccination is comparable to SRs in other fields, while it is still suboptimal. We are not able to provide a satisfactory explanation why industry funded SRs had a lower methodological quality than non-industry funded SRs over recent years. Industry funding is an important indicator of methodological quality for vaccine SRs and should be carefully considered when appraising SR quality.

Early risk of acute myocardial infarction following hospitalization for severe influenza infection in the middle-aged population of Hong Kong

Introduction

Despite evidence suggesting an association between influenza infection and increased risk of acute myocardial infarction (AMI) in the older adult population (aged 65 years or above), little is known about its near-term risks in middle-aged adults (aged 45 to 64 years). This study aims to estimate the risks of and association between severe influenza infection requiring hospitalization and subsequent AMI within 12 months in middle-aged adults.

Method

This is a retrospective case-control analysis of territorywide registry data of people aged 45 to 64 years admitting from up to 43 public hospitals in Hong Kong during a 20-year period from January 1997 to December 2017. The exposure was defined as severe influenza infection documented as the principal diagnosis using International Classification of Diseases codes and non-exposure as hospitalization for orthopedic surgery. Logistic regression was used to analyze the risk of subsequent hospitalization for AMI within 12 months following the exposure.

Results

Among 30,657 middle-aged adults with an indexed hospitalization, 8,840 (28.8%) had an influenza-associated hospitalization. 81 (0.92%) were subsequently rehospitalized with AMI within 12 months after the indexed hospitalization. Compared with the control group, the risk of subsequent hospitalization for AMI was significantly increased (odds ratio [OR]: 2.54, 95% confidence interval [CI]: 1.64–3.92, p<0.001). The association remained significant even after adjusting for potential confounders (adjusted OR: 1.81, 95% CI: 1.11–2.95, p = 0.02). Patients with a history of hypertension, but not those with diabetes mellitus, dyslipidemia or atrial fibrillation/flutter, were at increased risk (adjusted OR: 5.01, 95% CI: 2.93–8.56, p<0.001).

Conclusion

Subsequent hospitalization for AMI within 12 months following an indexed respiratory hospitalization for severe influenza increased nearly two-fold compared with the non-cardiopulmonary, non-exposure control. Recommendation of influenza vaccination extending to middle-aged adult population may be justified for the small but significant increased near-term risk of AMI.

Looking back on 50 years of literature to understand the potential impact of influenza on extrapulmonary medical outcomes

We conducted a scoping review of the epidemiological literature from the past 50 years to document the contribution of influenza virus infection to extrapulmonary clinical outcomes. We identified 99 publications reporting 243 associations using many study designs, exposure and outcome definitions, and methods. Laboratory confirmation of influenza was used in only 28 (12%) estimates, mostly in case-control and self-controlled case series study designs. We identified 50 individual clinical conditions associated with influenza. The most numerous estimates were of cardiocirculatory diseases, neurological/neuromuscular diseases, and fetal/newborn disorders, with myocardial infarction the most common individual outcome. Due to heterogeneity, we could not generate summary estimates of effect size, but of 130 relative effect estimates, 105 (81%) indicated an elevated risk of extrapulmonary outcome with influenza exposure. The literature is indicative of systemic complications of influenza virus infection, the requirement for more effective influenza control, and a need for robust confirmatory studies.

Impact of SARS-CoV-2 Outbreak on Emergency Department Presentation and Prognosis of Patients with Acute Myocardial Infarction: A Systematic Review and Updated Meta-Analysis

We performed an updated meta-analysis to robustly quantify admission trends of patients with ST-segment elevation MI (STEMI) and non-ST-segment elevation MI (NSTEMI) during the first wave of the pandemic and to characterize on a large basis the risk profile and early prognosis. Studies having the same observation period for the comparison between SARS-CoV-2 outbreak in 2020 versus control period in 2019 were included. Primary endpoints were the relative variation of hospital admissions, the difference of in-hospital mortality for STEMI and NSTEMI. Secondary were: mortality according to countries, income levels and data quality; cardiogenic shock, mechanical complications, door-to-balloon time, time from symptom onset to first medical contact, left ventricular ejection fraction (LVEF) and troponin. In total, 61 observational studies with 125,346 patients were included. Compared with 2019, during the pandemic for STEMI were observed: a 24% reduction of hospitalizations with an impact on early survival (OR = 1.33 in-hospital mortality); the time from symptom onset to first medical contact was 91.31 min longer, whereas door-to-balloon time was increased (+5.44 min); after STEMI, the rate of cardiogenic shock was 33% higher; LVEF at discharge was decreased (−3.46); elevated high-sensitivity troponin levels (1.52) on admission. For NSTEMI, in the COVID-19 period, we observed a 31% reduction of hospitalizations and higher in-hospital deaths (OR = 1.34). The highest mortality rates among countries were: Italy OR = 3.71 (high income), Serbia OR = 2.15 (upper middle) and Pakistan OR = 1.69 (lower middle). Later hospital presentation was associated with larger infarctions, as well as with increased cardiogenic shock and in-hospital mortality.

Modelling the influenza disease burden in people aged 50-64 and ≥65 years in Australia

BACKGROUND

Estimation of influenza disease burden is necessary to monitor the impact of intervention programmes. This study aims to estimate the attributable fraction of respiratory and circulatory disease due to influenza among Australian adults 50-64 and ≥65 years of age.

METHODS

A semi-parametric generalised-additive model was used to estimate annual and average rate of influenza-attributable hospitalisation and death per 100,000 population under the principal diagnosis of influenza/pneumonia, respiratory, circulatory and myocardial infarction (MI) from 2001 through 2017.

RESULTS

Over the study period, seasonal influenza accounted for an estimated annual average respiratory hospitalisation rate of 78.9 (95%CI: 76.3, 81.4) and 287.5 (95%CI: 279.8, 295.3) per 100,000 population in adults aged 50-64 and ≥65 years, respectively. The corresponding respiratory mortality rates were 0.9 (95%CI: 0.7, 1.2) and 18.2 (95%CI: 16.9, 19.4) per 100,000 population. The 2017 season had the highest influenza-attributable respiratory hospitalisations in both age groups, and respiratory complications were estimated approximately 2.5 times higher than the average annual estimate in adults aged ≥65 years in 2017. For mortality, on average, influenza attributed 1,080 circulatory and 361 MI deaths in adults aged ≥65 years per year. Influenza accounted for 1% and 2.8% of total MI deaths in adults aged 50-64 and ≥65 years, respectively.

CONCLUSION

Rates of cardiorespiratory morbidity and mortality were high in older adults, whilst the younger age group contributed a lower disease burden. Extension of influenza vaccination programme beyond the targeted population could be an alternative strategy to reduce the burden of influenza.

Cardiovascular disease and COVID-19: a consensus paper from the ESC Working Group on Coronary Pathophysiology & Microcirculation, ESC Working Group on Thrombosis and the Association for Acute CardioVascular Care (ACVC), in collaboration with the European Heart Rhythm Association (EHRA)

The cardiovascular system is significantly affected in coronavirus disease-19 (COVID-19). Microvascular injury, endothelial dysfunction, and thrombosis resulting from viral infection or indirectly related to the intense systemic inflammatory and immune responses are characteristic features of severe COVID-19. Pre-existing cardiovascular disease and viral load are linked to myocardial injury and worse outcomes. The vascular response to cytokine production and the interaction between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and angiotensin-converting enzyme 2 receptor may lead to a significant reduction in cardiac contractility and subsequent myocardial dysfunction. In addition, a considerable proportion of patients who have been infected with SARS-CoV-2 do not fully recover and continue to experience a large number of symptoms and post-acute complications in the absence of a detectable viral infection. This conditions often referred to as 'post-acute COVID-19' may have multiple causes. Viral reservoirs or lingering fragments of viral RNA or proteins contribute to the condition. Systemic inflammatory response to COVID-19 has the potential to increase myocardial fibrosis which in turn may impair cardiac remodelling. Here, we summarize the current knowledge of cardiovascular injury and post-acute sequelae of COVID-19. As the pandemic continues and new variants emerge, we can advance our knowledge of the underlying mechanisms only by integrating our understanding of the pathophysiology with the corresponding clinical findings. Identification of new biomarkers of cardiovascular complications, and development of effective treatments for COVID-19 infection are of crucial importance.

Call to action: cardiologists should promote influenza vaccination

The COVID-19 pandemic has spurred clinical and scientific interest in the cardiology community because of the significantly enhanced vulnerability of patients with underlying cardiac diseases. COVID-19 vaccination is therefore of vital importance to the patients we see in our clinics and hospitals every day and should be promoted by the medical community, especially cardiologists. In view of vaccine-preventable diseases, the association between influenza and cardiovascular complications has been widely investigated. Several studies have found a substantially elevated risk of hospital admission for acute myocardial infarction in the first 7 days after laboratory-confirmed influenza, with incidence ratios ranging from 6.05-8.89. The effectiveness of the influenza vaccine to protect against acute myocardial infarction is about 29%. This effectiveness is comparable to or even better than that of existing secondary preventive therapies, such as statins (prevention rate approximately 36%), antihypertensives (prevention rate approximately 15-18%), and smoking cessation (prevention rate approximately 26%). As the influenza season is rapidly approaching, this Point of View article serves as a call to action: Cardiologists should promote influenza vaccination and actively advice their patients to get the seasonal influenza vaccination.

Influenza vaccine and risk of acute myocardial infarction in a population-based case-control study

OBJECTIVE

To assess the relationship between influenza vaccination and risk of a first acute myocardial infarction (AMI) in the general population by different epidemic periods.

METHODS

This is a population-based case-control study carried out in BIFAP (Base de datos para la investigación farmacoepidemiológica en atención primaria), over 2001-2015, in patients aged 40-99 years. Per each incident AMI case, five controls were randomly selected, individually matched for exact age, sex and index date (AMI diagnosis). A patient was considered vaccinated when he/she had a recorded influenza vaccination at least 14 days before the index date within the same season. The association between influenza vaccination and AMI risk was assessed through a conditional logistic regression, computing adjusted ORs (AOR) and their respective 95% CIs. The analysis was performed overall and by each of the three time epidemic periods per study year (pre-epidemic, epidemic and postepidemic).

RESULTS

We identified 24 155 AMI cases and 120 775 matched controls. Of them, 31.4% and 31.2%, respectively, were vaccinated, yielding an AOR of 0.85 (95% CI 0.82 to 0.88). No effect modification by sex, age and background cardiovascular risk was observed. The reduced risk of AMI was observed shortly after vaccination and persisted over time. Similar results were obtained during the pre-epidemic (AOR=0.87; 95% CI 0.79 to 0.95), epidemic (AOR=0.89; 95% CI 0.82 to 0.96) and postepidemic (AOR=0.83; 95% CI 0.79 to 0.87) periods. No association was found with pneumococcal vaccine (AOR=1.10; 95% CI 1.06 to 1.15).

CONCLUSIONS

Results are compatible with a moderate protective effect of influenza vaccine on AMI in the general population, mostly in primary prevention, although bias due to unmeasured confounders may partly account for the results.

Effect of oxygen supply on mortality in acute ST-elevation myocardial infarction: systematic review and meta-analysis

Previous studies stated that high oxygen supply in patients with myocardial infarction (MI) was not associated with improved outcomes. However, the particularities of ST-elevation myocardial infarction (STEMI) and the results of a recent trial raised the question if this subgroup of patients benefits from high oxygen supply. This study aims to evaluate the clinical effect of high oxygen supply in patients with STEMI using a systematic review of the available literature. All randomized controlled trials (RCTs) evaluating the systematic use of high oxygen (6 L/min or higher) versus room air or lower oxygen supply in STEMI patients were included. Systematic review with meta-analysis of trials retrieved in July 2020. Six databases were searched. The confidence in the pooled estimates was ascertained through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Risk of bias was evaluated using the Cochrane risk of bias tool. There were five eligible RCTs (7703 patients). High oxygen supply was associated with a significant risk reduction of short-term mortality [risk ratio (RR) 0.83; 95% confidence interval (CI), 0.70-0.98; I2 = 0%]. Mortality (longest follow-up) (RR 0.83; 95% CI, 0.71-0.97; I2 = 0%) and heart failure (RR 0.84; 95% CI, 0.60-1.18; I2 = 0%) did not present a risk reduction. Recurrent MI presented a contradictory result, favouring the lower oxygen protocol (RR 1.47; 95% CI, 0.84-2.56; I2 = 0%). The GRADE analysis was very low. High oxygen supply may be associated with a decrease in short-term mortality in STEMI patients, but the pooled data are not robust enough to allow definitive conclusions.

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.

Protective effect of influenza vaccination on cardiovascular diseases: a systematic review and meta-analysis

Cardiovascular diseases (CVDs) are among the leading causes of mortality and morbidity worldwide. There are many contrasting ideas on the effectiveness of influenza vaccination on CVDs. This study aimed to investigate the association between influenza vaccination and the risk of CVDs. We systematically searched all PubMed/Medline, EMBASE, and the Cochrane library entries up to November 2019 for studies of influenza vs. the CVDs outcomes. We conducted a random-effects meta‐analysis using the inverse variance method for pooled risk ratios (RR) or odds ratios (OR) and evaluated statistical heterogeneity using the I² statistic. We identified 17 studies (6 randomized controlled trial [RCT], 5 cohorts, and 6 case–control) with a total of 180,043 cases and 276,898 control participants. The pooled RR of developing CVDs after influenza vaccination in RCT studies was 0.55 (95% CI 0.41–0.73), which was significant (P-value = 0.00). The pooled OR of decreasing CVDs after influenza vaccination in cohort studies was 0.89 (95% CI 0.77–1.04). The pooled OR of developing CVDs after influenza vaccination by pooling case–control studies was 0.70 (95% CI 0.57–0.86, (P-value = 0.00). All of these studies suggest decreased risks of CVDs with influenza vaccination. The current study does support the protective role of influenza vaccination on CVDs events. Health authorities may develop evidence-based preventive strategies to offer influenza vaccination in patients with CVDs.

The impact of influenza vaccination in patients with cardiovascular disease: An overview of systematic reviews

Whether influenza vaccination can play a prognostic role in patients with cardiovascular (CV) disease (coronary artery disease (CAD), heart failure, stroke, peripheral artery disease (PAD)) is still not completely well-established. We conducted this overview of systematic reviews (SR) evaluating the effects of influenza vaccination in secondary prevention of CV disease. An electronic search was performed in the MEDLINE (to November 2019). Eligibility criteria included SR evaluating the effect of influenza vaccination in patients with CV disease. The risk of bias of the included systematic reviews was evaluated using the ROBIS tool. All-cause mortality, CV mortality, major adverse cardiovascular events (MACE) and hospitalizations were evaluated. Whenever required, data were recalculated through a random-effects meta-analysis to obtain pooled data for the patients at secondary CV prevention. The search process yielded four SR: two in CAD, one in heart failure and one in stroke. There were no SR evaluating the vaccine in PAD. The risk of bias was unclear (2 SR) and high (2 SR). Influenza vaccination in patients with CAD showed a risk reduction in all-cause mortality (data recalculated), cardiovascular mortality and MACE, particularly in patients with recent acute coronary syndrome. In patients with heart failure, vaccination was associated with a decreased risk of all-cause mortality. There was a non-significant trend in recurrent stroke risk reduction in patients with previous stroke. The available evidence suggests that influenza vaccination was associated with a protective effect in CAD and HF patients. However, these results need to be clarified with higher quality evidence studies.

Impact of COVID-19 on the Cardiovascular System: A Review

The recent outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has been declared a public health emergency of international concern. COVID-19 may present as acute respiratory distress syndrome in severe cases, and patients with pre-existing cardiovascular comorbidities are reported to be the most vulnerable. Notably, acute myocardial injury, determined by elevated high-sensitivity troponin levels, is commonly observed in severe cases, and is strongly associated with mortality. Therefore, understanding the effects of COVID-19 on the cardiovascular system is essential for providing comprehensive medical care for critically ill patients. In this review, we summarize the rapidly evolving data and highlight the cardiovascular considerations related to COVID-19.

Pneumococcal vaccination in adults at very high risk or with established cardiovascular disease: systematic review and meta-analysis

AIMS

There are several guidelines that recommend pneumococcal vaccination (PPSV23 and/or PCV13) in adults with a history of cardiovascular disease (established heart failure, coronary disease, and cerebrovascular disease) or at a very high risk of cardiovascular disease. However, there is no randomized controlled trial (RCT) systematic review that evaluates the impact of vaccination on all-cause mortality compared to no vaccination in this particular population. Our objective is to conduct a systematic review and meta-analysis of the impact of pneumococcal vaccination in the referred population.

METHODS AND RESULTS

We searched CENTRAL and MEDLINE for relevant RCTs and observational studies. Data were screened, extracted, and appraised by two independent reviewers. We pooled results using a random effects model, and used hazard ratios (HRs) with 95% confidence intervals (CIs) to assess measure of effect. The primary outcome was all-cause mortality and we assessed the confidence in the evidence using the GRADE framework. No RCTs were found. Seven observational studies were included for analyses. Pooled results from five studies enrolling a total of 163 756 participants showed a significant decrease in all-cause mortality (HR 0.78, 95% CI 0.73-0.83, very low confidence), without statistically significant heterogeneity (χ2 test P = 0.21; I2 = 32%).

CONCLUSIONS

Pneumococcal vaccination was associated with a 22% decrease of all-cause mortality in patients with cardiovascular disease or at a very high cardiovascular risk. However, limitations due to study design and the serious risk of bias in three of the included studies leads to a decreased level of result confidence.