Extreme influenza epidemics and out-of-hospital cardiac arrest

Cost-benefit of influenza vaccination in preventing sudden cardiac arrest amongst Australian adults

OBJECTIVE

The objective of the study was to estimate the economic cost benefit of funding influenza vaccination to all Australian adults 50-64 years and predict its effect on sudden cardiac arrest (SCA) deaths and hospitalisation.

METHODS

We combined SCA hospitalisation data from the Australian Institute of Health and Welfare (AIHW) with survival, vaccination, and cost parameters from published literature to create a model estimating the cost benefit of universally funded influenza vaccinations to prevent SCA deaths and hospitalisation. Costs were considered from a government perspective and included cost of vaccines and GP consultations, whilst averted deaths were estimated through the age-adjusted value of a statistical life.

RESULTS

The target policy was estimated to prevent 278 SCA hospitalisations and 1269 SCA deaths. This would result in cost-savings of almost $4 billion annually, with an incremental benefit-cost ratio (BCR) of 59.94. The majority of savings were associate with averted deaths. When a sensitivity analysis was performed by altering statistical life year values and reducing life years left, the cost-saving remained significant with a minimum BCR of 29.97 derived.

CONCLUSIONS

Reducing SCA through extended vaccination including adults 50-64 years is likely to be a cost beneficial policy from a governmental perspective. SCA deaths account for a significant economic loss due to the high mortality rate, which was far greater than the costs saved through averted hospitalisations. More accurate parameters are needed to improve the reliability of these estimate; however, this model can be used as a basis for further research into the economic impact of SCA.

Prehospital Cardiac Arrest Should be Considered When Evaluating Coronavirus Disease 2019 Mortality in the United States

BACKGROUND

Public health emergencies leave little time to develop novel surveillance efforts. Understanding which preexisting clinical datasets are fit for surveillance use is of high value. Coronavirus disease 2019 (COVID-19) offers a natural applied informatics experiment to understand the fitness of clinical datasets for use in disease surveillance.

OBJECTIVES

This study evaluates the agreement between legacy surveillance time series data and discovers their relative fitness for use in understanding the severity of the COVID-19 emergency. Here fitness for use means the statistical agreement between events across series.

METHODS

Thirteen weekly clinical event series from before and during the COVID-19 era for the United States were collected and integrated into a (multi) time series event data model. The Centers for Disease Control and Prevention (CDC) COVID-19 attributable mortality, CDC's excess mortality model, national Emergency Medical Services (EMS) calls, and Medicare encounter level claims were the data sources considered in this study. Cases were indexed by week from January 2015 through June of 2021 and fit to Distributed Random Forest models. Models returned the variable importance when predicting the series of interest from the remaining time series.

RESULTS

Model r2 statistics ranged from 0.78 to 0.99 for the share of the volumes predicted correctly. Prehospital data were of high value, and cardiac arrest (CA) prior to EMS arrival was on average the best predictor (tied with study week). COVID-19 Medicare claims volumes can predict COVID-19 death certificates (agreement), while viral respiratory Medicare claim volumes cannot predict Medicare COVID-19 claims (disagreement).

CONCLUSION

Prehospital EMS data should be considered when evaluating the severity of COVID-19 because prehospital CA known to EMS was the strongest predictor on average across indices.

Adult Respiratory Syncytial Virus Infection and Hypoxic Cardiac Arrest—Coexistent or Causal? A Hypothesis-Generating Case Report

Respiratory syncytial virus (RSV) is a well-known pathogen in paediatric patients. However, it also causes substantial morbidity and mortality in adults, posing a major healthcare problem. We present a patient with chronic pulmonary conditions and an acute RSV infection, thus leading to cardiac arrest (CA). We speculate that RSV as the causative agent for CA should be considered in post-resuscitation care. From a wider public health perspective, immuno-naivety for RSV caused by the coronavirus disease 2019 pandemic may induce a severe rise in cases, morbidity, and mortality in the future.

Occurrence and Temporal Variability of Out-of-Hospital Cardiac Arrest during COVID-19 Pandemic in Comparison to the Pre-Pandemic Period in Poland-Observational Analysis of OSCAR-POL Registry

An investigation of the chronobiology of out-of-hospital cardiac arrest (OHCA) during the coronavirus disease 2019 (COVID-19) pandemic and the differences in comparison to the 6-year pre-pandemic period. A retrospective analysis of the dispatch cards from the Emergency Medical Service between January 2014 and December 2020 was performed within the OSCAR-POL registry. The circadian, weekly, monthly, and seasonal variabilities of OHCA were investigated. A comparison of OHCA occurrence between the year 2020 and the 6-year pre-pandemic period was made. A total of 416 OHCAs were reported in 2020 and the median of OHCAs during the pre-pandemic period was 379 (interquartile range 337−407) cases per year. Nighttime was associated with a decreased number of OHCAs (16.6%) in comparison to afternoon (31.5%, p < 0.001) and morning (30.0%, p < 0.001). A higher occurrence at night was observed in 2020 compared to 2014−2019 (16.6% vs. 11.7%, p = 0.001). Monthly and seasonal variabilities were observed in 2020. The months with the highest OHCA occurrence in 2020 were November (13.2%) and October (11.1%) and were significantly higher compared to the same months during the pre-pandemic period (9.1%, p = 0.002 and 7.9%, p = 0.009, respectively). Autumn was the season with the highest rate of OHCA, which was also higher compared to the pre-pandemic period (30.5% vs. 25.1%, p = 0.003). The COVID-19 pandemic was related to a higher occurrence of OHCA. The circadian, monthly, and seasonal variabilities of OHCA occurrence were confirmed. In 2020, the highest occurrence of OHCA was observed in October and November, which coincided with the highest occurrence of COVID-19 infections in Poland.

Adult influenza epidemic is associated with out-of-hospital cardiac arrest: From the All-Japan Utstein Registry, a prospective, nationwide, population-based, observational registry

It has been reported that influenza infection is associated with out-of-hospital cardiac arrest of cardiac origin (OHCA-CA). However, the association between OHCA-CA and influenza epidemics in adults has not been well investigated.We analyzed data from the All-Japan Utstein Registry, a prospective, nationwide, population-based, observational study, regarding OHCA-CA cases and the Infectious Diseases Weekly Report for influenza cases: 17,710 OHCA-CA cases and 764,808 influenza cases were recorded between 2005 and 2015 in Fukuoka, Japan. The weekly average number of OHCA-CA cases was positively associated with the number of patients with influenza infection (r = 0.70, P < .0001). To eliminate the effects of season and age, we investigated only adults in winter. The weekly number of OHCA-CA cases was positively associated with the number of patients with influenza infection in weeks when there was a high frequency of influenza infection in adults (r = 0.36, P = .006), but not in weeks with a medium (r = 0.26, P = .05) or low frequency of influenza infection (r = 0.003, P = 1.0). In weeks during which there was a high frequency of influenza infection, the weekly number of OHCA-CA cases was positively associated with the number of influenza infections in males (r = 0.37, P = .006), but not females (r = 0.18, P = .2).The number of OHCA-CA cases was positively associated with the number of influenza infections in adult males during weeks in which there was a high frequency of influenza infections. To help prevent OHCA-CA in males, it might be beneficial to announce influenza epidemics specifically in adults, in addition to all ages.

Circulating virome and inflammatory proteome in patients with ST-elevation myocardial infarction and primary ventricular fibrillation

Primary ventricular fibrillation (PVF) is a life-threatening complication of ST-segment elevation myocardial infarction (STEMI). It is unclear what roles viral infection and/or systemic inflammation may play as underlying triggers of PVF, as a second hit in the context of acute ischaemia. Here we aimed to evaluate whether the circulating virome and inflammatory proteome were associated with PVF development in patients with STEMI. Blood samples were obtained from non-PVF and PVF STEMI patients at the time of primary PCI, and from non-STEMI healthy controls. The virome profile was analysed using VirCapSeq-VERT (Virome Capture Sequencing Platform for Vertebrate Viruses), a sequencing platform targeting viral taxa of 342,438 representative sequences, spanning all virus sequence records. The inflammatory proteome was explored with the Olink inflammation panel, using the Proximity Extension Assay technology. After analysing all viral taxa known to infect vertebrates, including humans, we found that non-PVF and PVF patients only significantly differed in the frequencies of viruses in the Gamma-herpesvirinae and Anelloviridae families. In particular, most showed a significantly higher relative frequency in non-PVF STEMI controls. Analysis of systemic inflammation revealed no significant differences between the inflammatory profiles of non-PVF and PVF STEMI patients. Inflammatory proteins associated with cell adhesion, chemotaxis, cellular response to cytokine stimulus, and cell activation proteins involved in immune response (IL6, IL8 CXCL-11, CCL-11, MCP3, MCP4, and ENRAGE) were significantly higher in STEMI patients than non-STEMI controls. CDCP1 and IL18-R1 were significantly higher in PVF patients compared to healthy subjects, but not compared to non-PVF patients. The circulating virome and systemic inflammation were not associated with increased risk of PVF development in acute STEMI. Accordingly, novel strategies are needed to elucidate putative triggers of PVF in the setting of acute ischaemia, in order to reduce STEMI-driven sudden death burden.

Burden of influenza in adults with cardiac arrest admissions in Australia

BACKGROUND

Cardiac arrest is the least preventable burden of cardiovascular disease, as treatment depends on timely resuscitation. The incidence of sudden cardiac arrest (SCA) is high, contributing 10-20% of cardiovascular mortality globally. The influenza vaccine reduces the risk of acute cardiovascular events. Little is known about the relationship of influenza infection to cardiac arrest.

METHODS

This study aimed to determine the estimated rate of SCA hospitalisations attributable to influenza in Australian adults. A generalised-additive statistical model was applied in the study. Weekly counts of laboratory-confirmed influenza notifications were used as independent variables in the model.

RESULTS

Our estimates showed that the yearly rate of SCA hospitalisations varied, and a significant association with influenza was observed in some years in older adults aged 65 years and over. On average, the annual estimated SCA hospitalisations rate due to influenza in adults aged 50-64 years and ≥ 65 years were 0.7 (95%CI: 0.4, 1.1) and 5.3 (95%CI: 4.4, 6.2) per 100,000 population, respectively.

CONCLUSION

The association between influenza and SCA is evident in adults and the disease burden is significant in older people. Prevention of influenza by vaccination may reduce SCA.

COVID-19 Disease, Women's Predominant Non-Heparin Vaccine-Induced Thrombotic Thrombocytopenia and Kounis Syndrome: A Passepartout Cytokine Storm Interplay

Coronavirus disease 2019 (COVID-19) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constitute one of the deadliest pandemics in modern history demonstrating cardiovascular, gastrointestinal, hematologic, mucocutaneous, respiratory, neurological, renal and testicular manifestations and further complications. COVID-19-induced excessive immune response accompanied with uncontrolled release of cytokines culminating in cytokine storm seem to be the common pathogenetic mechanism of these complications. The aim of this narrative review is to elucidate the relation between anaphylaxis associated with profound hypotension or hypoxemia with pro-inflammatory cytokine release. COVID-19 relation with Kounis syndrome and post-COVID-19 vaccination correlation with heparin-induced thrombocytopenia with thrombosis (HITT), especially serious cerebral venous sinus thrombosis, were also reviewed. Methods: A current literature search in PubMed, Embase and Google databases was performed to reveal the pathophysiology, prevalence, clinical manifestation, correlation and treatment of COVID-19, anaphylaxis with profuse hypotension, Kounis acute coronary syndrome and thrombotic events post vaccination. Results: The same key immunological pathophysiology mechanisms and cells seem to underlie COVID-19 cardiovascular complications and the anaphylaxis-associated Kounis syndrome. The myocardial injury in patients with COVID-19 has been attributed to coronary spasm, plaque rupture and microthrombi formation, hypoxic injury or cytokine storm disposing the same pathophysiology with the three clinical variants of Kounis syndrome. COVID-19-interrelated vaccine excipients as polysorbate, polyethelene glycol (PEG) and trometamol constitute potential allergenic substances. Conclusion: Better acknowledgement of the pathophysiological mechanisms, clinical similarities, multiorgan complications of COVID-19 or other viral infections as dengue and human immunodeficiency viruses along with the action of inflammatory cells inducing the Kounis syndrome could identify better immunological approaches for prevention, treatment of the COVID-19 pandemic as well as post-COVID-19 vaccine adverse reactions.

The effect of COVID-19 on emergency medical service call volumes and patient acuity: a cross-sectional study in Niagara, Ontario

Background

The COVID-19 pandemic is a major public health problem. Subsequently, emergency medical services (EMS) have anecdotally experienced fluctuations in demand, with reports across Canada of both increased and decreased demand. Our primary objective was to assess the effect of the COVID-19 pandemic on call volumes for several determinants in Niagara Region EMS. Our secondary objective was to assess changes in paramedic-assigned patient acuity scores as determined using the Canadian Triage and Acuity Scale (CTAS).

Methods

We analyzed data from a regional EMS database related to call type, volume, and patient acuity for January to May 2016–2020. We used statistical methods to assess differences in EMS calls between 2016 and 2019 and 2020.

Results

A total of 114,507 EMS calls were made for the period of January 1 to May 26 between 2016 and 2020, inclusive. Overall, the incidence rate of EMS calls significantly decreased in 2020 compared to the total EMS calls in 2016–2019. Motor vehicle collisions decreased in 2020 relative to 2016–2019 (17%), while overdoses relatively increased (70%) in 2020 compared to 2016–2019. Calls for patients assigned a higher acuity score increased (CTAS 1) (4.1% vs. 2.9%).

Conclusion

We confirmed that overall, EMS calls have decreased since the emergence of COVID-19. However, this effect on call volume was not consistent across all call determinants, as some call types rose while others decreased. These findings indicate that COVID-19 may have led to actual changes in emergency medical service demand and will be of interest to other services planning for future pandemics or further waves of COVID-19.

Public health impact of daily life triggers of sudden cardiac death: A systematic review and comparative risk assessment

BACKGROUND

Sudden cardiac death (SCD) may be triggered by daily circumstances and activities such as stressful psycho-emotional events, physical exertion or substance misuse. We calculated population attributable fractions (PAFs) to estimate the public health relevance of daily life triggers of SCD and to compare their population impacts.

METHODS

We searched PubMed, Scopus and the Web of Science citation databases to retrieve studies of triggers of SCD and cardiac arrest that would enable a computation of PAFs. When more studies investigated the same trigger, a meta-analytical pooled risk random-effect estimate was used.

RESULTS

Of the retrieved studies, eight provided data enabling computation of PAFs. The prevalence of exposure within population for SCD triggers in the control periods ranged from 1.06% for influenza infection to 8.73% for recent use of cannabis. Triggers ordered from the highest to the lowest risk increase were: physical exertion, recent cocaine use, episodic alcohol consumption, recent amphetamine use, episodic coffee consumption, psycho-emotional stress within the previous month, influenza infection, and recent cannabis use. The relative risk increase ranged from 1.10 to 4.98. By accounting for both the magnitude of the risk increase and the prevalence in the population, the present estimates of PAF assign 14.5% (95% confidence interval [CI] 4.9-28.5) of all SCDs to episodic alcohol consumption, 9.4% (95% CI 1.2-29.3) to physical exertion, 6.9% (95% CI 0.3-25.0) to cocaine, 6% (95% CI 1.2-14.6) to episodic coffee consumption, 3% (95% CI 0.4-6.8) to psycho-emotional stress in the previous month, 1.7% (95% CI -0.9 to 12.9) to amphetamines, 0.9% (95% CI -4.9 to 12.5) to cannabis, and 0.3% (95% CI 0.2-0.4) to influenza infections.

CONCLUSIONS

In addition to episodic alcohol consumption, a trigger with the greatest public health importance for SCD, episodic physical exertion, cocaine use and coffee consumption also show a considerable population impact.

A cost-effectiveness analysis of South Africa's seasonal influenza vaccination programme

BACKGROUND

Seasonal influenza imposes a significant health and economic burden in South Africa, particularly in populations vulnerable to severe consequences of influenza. This study assesses the cost-effectiveness of South Africa's seasonal influenza vaccination strategy, which involves vaccinating vulnerable populations with trivalent inactivated influenza vaccine (TIV) during routine facility visits. Vulnerable populations included in our analysis are persons aged ≥ 65 years; pregnant women; persons living with HIV/AIDS (PLWHA), persons of any age with underlying medical conditions (UMC) and children aged 6-59 months.

METHOD

We employed the World Health Organisation's (WHO) Cost Effectiveness Tool for Seasonal Influenza Vaccination (CETSIV), a decision tree model, to evaluate the 2018 seasonal influenza vaccination campaign from a public healthcare provider and societal perspective. CETSIV was populated with existing country-specific demographic, epidemiologic and coverage data to estimate incremental cost-effectiveness ratios (ICERs) by comparing costs and benefits of the influenza vaccination programme to no vaccination.

RESULTS

The highest number of clinical events (influenza cases, outpatient visits, hospitalisation and deaths) were averted in PLWHA and persons with other UMCs. Using a cost-effectiveness threshold of US$ 3400 per quality-adjusted life year (QALY), our findings suggest that the vaccination programme is cost-effective for all vulnerable populations except for children aged 6-59 months. ICERs ranged from ~US$ 1 750 /QALY in PLWHA to ~US$ 7500/QALY in children. In probabilistic sensitivity analyses, the vaccination programme was cost-effective in pregnant women, PLWHA, persons with UMCs and persons aged ≥65 years in >80% of simulations. These findings were robust to changes in many model inputs but were most sensitive to uncertainty in estimates of influenza-associated illness burden.

CONCLUSION

South Africa's seasonal influenza vaccination strategy of opportunistically targeting vulnerable populations during routine visits is cost-effective. A budget impact analysis will be useful for supporting future expansions of the programme.

Association Between Cardiac Injury and Mortality in Hospitalized Patients Infected With Avian Influenza A (H7N9) Virus

OBJECTIVES

To evaluate the prevalence of cardiac injury and its association with mortality in hospitalized patients infected with avian influenza A (H7N9) virus.

DESIGN

Retrospective cohort study.

SETTING

A total of 133 hospitals in 17 provinces, autonomous regions, and municipalities of mainland China that admitted influenza A (H7N9) virus-infected patients between January 22, 2015, and June 16, 2017.

PATIENTS

A total of 321 patients with influenza A (H7N9) virus infection were included in the final analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographics and clinical characteristics were collected from medical records. Cardiac injury was defined according to cardiac biomarkers, electrocardiography, or echocardiography. Among the 321 patients, 203 (63.2%) showed evidence of cardiac injury. Compared with the uninjured group, the cardiac injury group had lower PaO2/FIO2 (median, 102.0 vs 148.4 mm Hg; p < 0.001), higher Acute Physiology and Chronic Health Evaluation II score (median, 17.0 vs 11.0; p < 0.001), longer stay in the ICU (10.0 vs 9.0 d; p = 0.029), and higher proportion of in-hospital death (64.0% vs 20.3%; p < 0.001). The proportion of virus clearance until discharge or death was lower in the cardiac injury group than in the uninjured group (58.6% vs 86.4%; p < 0.001). Multivariable-adjusted Cox proportional hazards regression analysis showed that cardiac injury was associated with higher mortality (hazards ratio, 2.06; 95% CI, 1.31-3.24) during hospitalization.

CONCLUSIONS

Cardiac injury is a frequent condition among hospitalized patients infected with influenza A (H7N9) virus, and it is associated with higher risk of mortality.

Seasonality of ventricular fibrillation at first myocardial infarction and association with viral exposure

AIMS

To investigate seasonality and association of increased enterovirus and influenza activity in the community with ventricular fibrillation (VF) risk during first ST-elevation myocardial infarction (STEMI).

METHODS

This study comprised all consecutive patients with first STEMI (n = 4,659; aged 18-80 years) admitted to the invasive catheterization laboratory between 2010-2016, at Copenhagen University Hospital, Rigshospitalet, covering eastern Denmark (2.6 million inhabitants, 45% of the Danish population). Hospital admission, prescription, and vital status data were assessed using Danish nationwide registries. We utilized monthly/weekly surveillance data for enterovirus and influenza from the Danish National Microbiology Database (2010-2016) that receives copies of laboratory tests from all Danish departments of clinical microbiology.

RESULTS

Of the 4,659 consecutively enrolled STEMI patients, 581 (12%) had VF before primary percutaneous coronary intervention. In a subset (n = 807), we found that VF patients experienced more generalized fatigue and flu-like symptoms within 7 days before STEMI compared with the patients without VF (OR 3.39, 95% CI 1.76-6.54). During the study period, 2,704 individuals were diagnosed with enterovirus and 19,742 with influenza. No significant association between enterovirus and VF (OR 1.00, 95% CI 0.99-1.02), influenza and VF (OR 1.00, 95% CI 1.00-1.00), or week number and VF (p-value 0.94 for enterovirus and 0.89 for influenza) was found.

CONCLUSION

We found no clear seasonality of VF during first STEMI. Even though VF patients had experienced more generalized fatigue and flu-like symptoms within 7 days before STEMI compared with patients without VF, no relationship was found between enterovirus or influenza exposure and occurrence of VF.

Influenza and sudden unexpected death: the possible role of peptide cross-reactivity

This study investigates the hypothesis that cross-reactions may occur between human cardiac proteins and influenza antigens, thus possibly representing the molecular mechanism underlying influenzaassociated sudden unexpected death (SUD). Using titin protein as a research model, data were obtained on (1) the occurrence of the titin octapeptide AELLVLLE or its mimic AELLVALE in influenza A virus hemagglutinin (HA) sequences; (2) the immunological potential of AELLVLLE and its mimic AELLVALE; (3) the possible role of the flanking amino acid aa) context of the two octapeptide determinants in eliciting cross-reactivity between the human cardiac titin protein and HA antigens.