Complications of seasonal and pandemic influenza

Comorbidity of patients with noncommunicable diseases in general practice. Eurasian guidelines

Создание руководства поддержано Советом по терапевтическим наукам отделения клинической медицины Российской академии наук.

Forecasting influenza hospital admissions within English sub-regions using hierarchical generalised additive models

BACKGROUND

Seasonal influenza places a substantial burden annually on healthcare services. Policies during the COVID-19 pandemic limited the transmission of seasonal influenza, making the timing and magnitude of a potential resurgence difficult to ascertain and its impact important to forecast.

METHODS

We have developed a hierarchical generalised additive model (GAM) for the short-term forecasting of hospital admissions with a positive test for the influenza virus sub-regionally across England. The model incorporates a multi-level structure of spatio-temporal splines, weekly cycles in admissions, and spatial correlation. Using multiple performance metrics including interval score, coverage, bias, and median absolute error, the predictive performance is evaluated for the 2022-2023 seasonal wave. Performance is measured against autoregressive integrated moving average (ARIMA) and Prophet time series models.

RESULTS

Across the epidemic phases the hierarchical GAM shows improved performance, at all geographic scales relative to the ARIMA and Prophet models. Temporally, the hierarchical GAM has overall an improved performance at 7 and 14 day time horizons. The performance of the GAM is most sensitive to the flexibility of the smoothing function that measures the national epidemic trend.

CONCLUSIONS

This study introduces an approach to short-term forecasting of hospital admissions for the influenza virus using hierarchical, spatial, and temporal components. The methodology was designed for the real time forecasting of epidemics. This modelling framework was used across the 2022-2023 winter for healthcare operational planning by the UK Health Security Agency and the National Health Service in England.

Association of climatic variables with risk of transmission of influenza in Guangzhou, China, 2005-2021

BACKGROUND

Climatic variables constitute important extrinsic determinants of transmission and seasonality of influenza. Yet quantitative evidence of independent associations of viral transmissibility with climatic factors has thus far been scarce and little is known about the potential effects of interactions between climatic factors on transmission.

OBJECTIVE

This study aimed to examine the associations of key climatic factors with risk of influenza transmission in subtropical Guangzhou.

METHODS

Influenza epidemics were identified over a 17-year period using the moving epidemic method (MEM) from a dataset of N = 295,981 clinically- and laboratory-confirmed cases of influenza in Guangzhou. Data on eight key climatic variables were collected from China Meteorological Data Service Centre. Generalized additive model combined with the distributed lag non-linear model (DLNM) were developed to estimate the exposure-lag-response curve showing the trajectory of instantaneous reproduction number (R_t) across the distribution of each climatic variable after adjusting for depletion of susceptible, inter-epidemic effect and school holidays. The potential interaction effects of temperature, humidity and rainfall on influenza transmission were also examined.

RESULTS

Over the study period (2005-21), 21 distinct influenza epidemics with varying peak timings and durations were identified. Increasing air temperature, sunshine, absolute and relative humidity were significantly associated with lower R_t, while the associations were opposite in the case of ambient pressure, wind speed and rainfall. Rainfall, relative humidity, and ambient temperature were the top three climatic contributors to variance in transmissibility. Interaction models found that the detrimental association between high relative humidity and transmissibility was more pronounced at high temperature and rainfall.

CONCLUSION

Our findings are likely to help understand the complex role of climatic factors in influenza transmission, guiding informed climate-related mitigation and adaptation policies to reduce transmission in high density subtropical cities.

Outcomes after surgery in patients with and without recent influenza: a nationwide population-based study

Background

The influence of recent influenza infection on perioperative outcomes is not completely understood.

Method

Using Taiwan's National Health Insurance Research Data from 2008 to 2013, we conducted a surgical cohort study, which included 20,544 matched patients with a recent history of influenza and 10,272 matched patients without. The main outcomes were postoperative complications and mortality. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the complications and for mortality in patients with a history of influenza within 1-14 days or 15-30 days compared with non-influenza controls.

Results

Compared with patients who had no influenza, patients with influenza within preoperative days 1-7 had increased risks of postoperative pneumonia (OR 2.22, 95% CI 1.81-2.73), septicemia (OR 1.98, 95% CI 1.70-2.31), acute renal failure (OR 2.10, 95% CI 1.47-3.00), and urinary tract infection (OR 1.45, 95% CI 1.23-1.70). An increased risk of intensive care admission, prolonged length of stay, and higher medical expenditure was noted in patients with history of influenza within 1-14 days.

Conclusion

We found that there was an association between influenza within 14 days preoperatively and the increased risk of postoperative complications, particularly with the occurrence of influenza within 7 days prior to surgery.

A Retrospective Assessment of Sputum Samples and Antimicrobial Resistance in COVID-19 Patients

Data on bacterial or fungal pathogens and their impact on the mortality rates of Western Romanian COVID-19 patients are scarce. As a result, the purpose of this research was to determine the prevalence of bacterial and fungal co- and superinfections in Western Romanian adults with COVID-19, hospitalized in in-ward settings during the second half of the pandemic, and its distribution according to sociodemographic and clinical conditions. The unicentric retrospective observational study was conducted on 407 eligible patients. Expectorate sputum was selected as the sampling technique followed by routine microbiological investigations. A total of 31.5% of samples tested positive for Pseudomonas aeruginosa, followed by 26.2% having co-infections with Klebsiella pneumoniae among patients admitted with COVID-19. The third most common Pathogenic bacteria identified in the sputum samples was Escherichia coli, followed by Acinetobacter baumannii in 9.3% of samples. Commensal human pathogens caused respiratory infections in 67 patients, the most prevalent being Streptococcus penumoniae, followed by methicillin-sensitive and methicillin-resistant Staphylococcus aureus. A total of 53.4% of sputum samples tested positive for Candida spp., followed by 41.1% of samples with Aspergillus spp. growth. The three groups with positive microbial growth on sputum cultures had an equally proportional distribution of patients admitted to the ICU, with an average of 30%, compared with only 17.3% among hospitalized COVID-19 patients with negative sputum cultures (p = 0.003). More than 80% of all positive samples showed multidrug resistance. The high prevalence of bacterial and fungal co-infections and superinfections in COVID-19 patients mandates for strict and effective antimicrobial stewardship and infection control policies.

Neighborhood environmental factors linked to hospitalizations of older people for viral lower respiratory tract infections in Spain: a case-crossover study

BACKGROUND

Lower respiratory tract viral infection (LRTI) is a significant cause of morbidity-mortality in older people worldwide. We analyzed the association between short-term exposure to environmental factors (climatic factors and outdoor air pollution) and hospital admissions with a viral LRTI diagnosis in older adults.

METHODS

We conducted a bidirectional case-crossover study in 6367 patients over 65 years of age with viral LRTI and residential zip code in the Spanish Minimum Basic Data Set. Spain's State Meteorological Agency was the source of environmental data. Associations were assessed using conditional logistic regression. P-values were corrected for false discovery rate (q-values).

RESULTS

Almost all were hospital emergency admissions (98.13%), 18.64% were admitted to the intensive care unit (ICU), and 7.44% died. The most frequent clinical discharge diagnosis was influenza (90.25%). LRTI hospital admissions were more frequent when there were lower values of temperature and O₃ and higher values of relative humidity and NO₂. The regression analysis adjusted by temperatures and relative humidity showed higher concentrations at the hospital admission for NO₂ [compared to the lag time of 1-week (q-value< 0.001) and 2-weeks (q-value< 0.001)] and O₃ [compared to the lag time of 3-days (q-value< 0.001), 1-week (q-value< 0.001), and 2-weeks (q-value< 0.001)] were related to a higher odds of hospital admissions due to viral LRTI. Moreover, higher concentrations of PM₁₀ at the lag time of 1-week (q-value = 0.023) and 2-weeks (q-value = 0.002), and CO at the lag time of 3-days (q-value = 0.023), 1-week (q-value< 0.001) and 2-weeks (q-value< 0.001)], compared to the day of hospitalization, were related to a higher chances of hospital admissions with viral LRTI.

CONCLUSION

Unfavorable environmental factors (low temperatures, high relative humidity, and high concentrations of NO₂, O₃, PM₁₀, and CO) increased the odds of hospital admissions with viral LRTI among older people, indicating they are potentially vulnerable to these environmental factors.

In silico method for predicting infectious strains of influenza A virus from its genome and protein sequences

Influenza A is a contagious viral disease responsible for four pandemics in the past and a major public health concern. Being zoonotic in nature, the virus can cross the species barrier and transmit from wild aquatic bird reservoirs to humans via intermediate hosts. In this study, we have developed a computational method for the prediction of human-associated and non-human-associated influenza A virus sequences. The models were trained and validated on proteins and genome sequences of influenza A virus. Firstly, we have developed prediction models for 15 types of influenza A proteins using composition-based and one-hot-encoding features. We have achieved a highest AUC of 0.98 for HA protein on a validation dataset using dipeptide composition-based features. Of note, we obtained a maximum AUC of 0.99 using one-hot-encoding features for protein-based models on a validation dataset. Secondly, we built models using whole genome sequences which achieved an AUC of 0.98 on a validation dataset. In addition, we showed that our method outperforms a similarity-based approach (i.e., blast) on the same validation dataset. Finally, we integrated our best models into a user-friendly web server 'FluSPred' (https://webs.iiitd.edu.in/raghava/fluspred/index.html) and a standalone version (https://github.com/raghavagps/FluSPred) for the prediction of human-associated/non-human-associated influenza A virus strains.

Extreme obesity is a strong predictor for in-hospital mortality and the prevalence of long-COVID in severe COVID-19 patients with acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) is common in COVID-19 patients and is associated with high mortality. The aim of this observational study was to describe patients' characteristics and outcome, identifying potential risk factors for in-hospital mortality and for developing Long-COVID symptoms. This retrospective study included all patients with COVID-19 associated ARDS (cARDS) in the period from March 2020 to March 2021 who were invasively ventilated at the intensive care unit (ICU) of the University Hospital Dresden, Germany. Between October 2021 and December 2021 patients discharged alive (at minimum 6 months after hospital discharge-midterm survival) were contacted and interviewed about persistent symptoms possibly associated with COVID-19 as well as the quality of their lives using the EQ-5D-5L-questionnaire. Long-COVID was defined as the occurrence of one of the symptoms at least 6 months after discharge. Risk factors for mortality were assessed with Cox regression models and risk factors for developing Long-COVID symptoms by using relative risk (RR) regression. 184 Patients were included in this study (male: n = 134 (73%), median age 67 (range 25-92). All patients were diagnosed with ARDS according to the Berlin Definition. 89% of patients (n = 164) had severe ARDS (Horovitz-index < 100 mmHg). In 27% (n = 49) extracorporeal membrane oxygenation was necessary to maintain gas exchange. The median length of in-hospital stay was 19 days (range 1-60). ICU mortality was 51%, hospital mortality 59%. Midterm survival (median 11 months) was 83% (n = 55) and 78% (n = 43) of these patients presented Long-COVID symptoms with fatigue as the most common symptom (70%). Extreme obesity (BMI > 40 kg/m2) was the strongest predictor for in-hospital mortality (hazard ratio: 3.147, confidence interval 1.000-9.897) and for developing Long-COVID symptoms (RR 1.61, confidence interval 1.26-2.06). In-hospital mortality in severe cARDS patients was high, but > 80% of patients discharged alive survived the midterm observation period. Nonetheless, most patients developed Long-COVID symptoms. Extreme obesity with BMI > 40 kg/m2 was identified as independent risk factor for in-hospital mortality and for developing Long-COVID symptoms.Trial registration DRKS-ID DRKS00027856.

Predictive ability of viscoelastic testing using ClotPro® for short-term outcome in patients with severe Covid-19 ARDS with or without ECMO therapy: a retrospective study

BACKGROUND

SARS-CoV-2 infections are suspected to trigger the coagulation system through various pathways leading to a high incidence of thromboembolic complications, hypercoagulation and impaired fibrinolytic capacity were previously identified as potentially mechanisms. A reliable diagnostic tool for detecting both is still under discussion. This retrospective study is aimed to examine the prognostic relevance of early viscoelastic testing compared to conventional laboratory tests in COVID-19 patients with acute respiratory distress syndrome (ARDS).

METHODS

All mechanically ventilated patients with COVID-19 related ARDS treated in our intensive care unit (ICU) between January and March 2021 were included in this study. Viscoelastic testing (VET) was performed using the ClotPro® system after admission to our ICU. Prevalence of thromboembolic events was observed by standardized screening for venous and pulmonary thromboembolism using complete compression ultrasound and thoracic computed tomography pulmonary angiography at ICU admission, respectively. We examined associations between the severity of ARDS at admission to our ICU, in-hospital mortality and the incidence of thromboembolic events comparing conventional laboratory analysis and VET. ECMO related coagulopathy was investigated in a subgroup analysis. The data were analyzed using the Mann-Whitney U test.

RESULTS

Of 55 patients enrolled in this study, 22 patients required treatment with ECMO. Thromboembolic complications occurred in 51% of all patients. Overall hospital mortality was 55%. In patients with thromboembolic complications, signs of reduced fibrinolytic capacity could be detected in the TPA assay with prolonged lysis time, median 460 s (IQR 350-560) vs 359 s (IQR 287-521, p = 0.073). Patients with moderate to severe ARDS at admission to our ICU showed increased maximum clot firmness as a sign of hypercoagulation in the EX-test (70 vs 67 mm, p < 0.05), FIB-test (35 vs 24 mm, p < 0.05) and TPA-test (52 vs 36 mm, p < 0.05) as well as higher values of inflammatory markers (CRP, PCT and IL6). ECMO patients suffered more frequently from bleeding complications (32% vs 15%).

CONCLUSION

Although, the predictive value for thromboembolic complications or mortality seems limited, point-of-care viscoelastic coagulation testing might be useful in detecting hypercoagulable states and impaired fibrinolysis in critically ill COVID-19 ARDS patients and could be helpful in identifying patients with a potentially very severe course of the disease.

Global variation in early epidemic growth rates and reproduction number of seasonal influenza

INTRODUCTION

Little is known about global variation in early epidemic growth rates and effective reproduction numbers (R_e) of seasonal influenza. We aimed to estimate global variation in R_e of influenza type A and B during a single period.

METHODS

Country influenza detection time series from September 2017 through January 2019 were obtained from an international database. Type A and B epidemics by country were selected based on R_e estimates for a five-week moving window advanced by week. Associations of R_e with absolute latitude, Human Development Index, percent of the population aged <15 years and percent living rurally in each country were assessed.

RESULTS

Time series were included for 119 of 169 available countries. There were 100 countries with influenza A and 79 with B epidemics. Median R_e for both influenza A and B epidemics was 1.23 (ranges: A 1.10, 1.60; B 1.06, 1.58). R_e of influenza B, but not A, was independently associated with absolute latitude, increasing by 0.022 (95% CI 0.002, 0.043) per 10 degrees.

CONCLUSIONS

R_e of influenza A and B were similar. Only R_e of influenza B was associated with country characteristics; increasing with distance from the equator. The approach may be suitable for continuous R_e surveillance.

In vitro anti-influenza assessment of anionic compounds ascorbate, acetate and citrate

BACKGROUND

Influenza A virus (IAV) infection remains a serious public health threat. Due to drug resistance and side effects of the conventional antiviral drugs, repurposing the available natural compounds with high tolerability and fewer side effects has attracted researchers' attention. The aim of this study was to screen in vitro anti-influenza activity of three anionic compounds ascorbate, acetate, and citrate.

METHODS

The non-cytotoxic concentration of the compounds was determined by MTT assay and examined for the activity against IAV in simultaneous, pre-, and post-penetration combination treatments over 1 h incubation on Madin-Darby Canine Kidney (MDCK) cell line. The virus titer and viral load were determined using hemagglutination assay (HA) and qPCR, respectively. Few pro-inflammatory and anti-inflammatory cytokines were evaluated at RNA and protein levels by qPCR and ELISA, respectively.

RESULTS

The non-cytotoxic concentrations of the ascorbate (200 mg/ml), acetate and citrate (both 3 mg/ml) reduced the viral titer by 6.5, 4.5, and 1.5 logs in the simultaneous combination treatment. The M protein gene copy number decreased significantly in simultaneous treatment (P < 0.01). The expression of cytokines was also affected by the treatment of these compounds.

CONCLUSIONS

These anionic compounds could affect the influenza virus load, thereby reducing pro-inflammatory cytokines and increasing anti-inflammatory cytokines levels.

A tool for early estimation of influenza vaccination coverage in Spanish general population and healthcare workers in the 2018-19 season: the Gripómetro

ASBTRACT

BACKGROUND: Electronic vaccine registries are not yet widely established. There is a need to real-time monitor influenza vaccine coverage, which may raise awareness to risk groups and professionals, and eventually allow to adopt tailored measures during the vaccination campaign. To evaluate the utility of the "Gripómetro", a demographic study designed to monitor national and regional influenza vaccine coverage on a weekly basis in Spain.

METHODS

Quantitative study based on surveys of the Spanish population between 18-80 years and a sample of primary care doctors and nurses randomly selected. Pre-proportional fixation has been established by Autonomous Communities and age group to guarantee the representativeness of all the autonomies.

RESULTS

Interviews were conducted in 3400 households of general population and 807 respondents among health care professionals. We found that the results of influenza vaccination coverage in the population ≥ 65 years obtained by the Gripómetro for 2018-2019 season were mostly comparable with the official data presented by the Ministry of Health after the end of the vaccination campaign.

CONCLUSIONS

The Gripómetro is a robust research method that provides real-time data and trends for influenza vaccine coverage along with other useful information related to vaccination such as intention to vaccinate, motivation and barriers to vaccination.

The time to advocate for influenza vaccines in patients with cirrhosis is now

BACKGROUND AND AIM

The effect of an influenza infection on patients with cirrhosis remains unclear. This study aimed to compare the rate of influenza hospitalizations, influenza associated complications, and healthcare outcomes in patients with and without cirrhosis.

METHODS

Utilizing the Nationwide Inpatient Sample between 2005 and 2013, hospitalized patients with a diagnosis of influenza were identified. Patients with cirrhosis were classified as compensated or decompensated based on the Baveno criteria. Multivariable analyses were performed to evaluate complications of influenza, inpatient mortality and healthcare utilization including length of stay and cost of admission.

RESULTS

In total, 236,513 patients with a diagnosis of influenza were admitted during the study period, including 1,553 (0.66%) with cirrhosis. Of those with cirrhosis, 1,176 (75.7%) were compensated and 377 (24.3%) were decompensated. On multivariable analysis, influenza patients with cirrhosis had a higher total cost of admission [$1,030; CI: $710-$1,351] compared to the general population. Influenza patients with decompensated cirrhosis had a longer length of stay [1.92 days; CI:1.63-2.21], higher total cost of admission [$5,005; CI: $4,459-$5,551] and increased rates of influenza complications [OR: 2.56; CI:1.32-4.93] compared to patients with compensated cirrhosis.

CONCLUSIONS

Patients with cirrhosis have increased healthcare utilization when admitted with influenza compared to the general population. Providers must advocate for patients with cirrhosis to obtain the influenza vaccine.

The impact of antimicrobial stewardship program designed to shorten antibiotics use on the incidence of resistant bacterial infections and mortality

Reassessing the continuing need for and choice of antibiotics by using an antibiotic "time out'' program may reduce unnecessary treatment. This study aimed to explore the effect of an antibiotic stewardship program (ASP) on the antibiotics consumption, incidence of resistant bacterial infections and overall hospital mortality in a tertiary medical center during the study period 2012-2014. An ASP composed of multidisciplinary strategies including pre-prescription approval and post-approval feedback and audit, and a major "time out'' intervention (shorten the default antibiotic prescription duration) usage was introduced in year 2013. Consumption of antibiotics was quantified by calculating defined daily doses (DDDs). Interrupted time series (ITS) analysis was used to explore the changes of antibiotics consumption before and after intervention, accounting for temporal trends that may be unrelated to intervention. Our results showed that following the intervention, DDDs showed a decreased trend in overall (in particular the major consumed penicillins and cephalosporins), in both intensive care unit (ICU) and non-ICU, and in non-restrictive versus restrictive antibiotics. Importantly, ITS analysis showed a significantly slope change since intervention (slope change p value 0.007), whereas the incidence of carbapenem-resistant and vancomycin-resistant pathogens did not change significantly. Moreover, annual overall mortality rates were 3.0%, 3.1% and 3.1% from 2012 to 2014, respectively. This study indicates that implementing a multi-disciplinary strategy to shorten the default duration of antibiotic prescription can be an effective manner to reduce antibiotic consumption while not compromising resistant infection incidence or mortality rates.

Advanced Point-of-Care Testing Technologies for Human Acute Respiratory Virus Detection

The ever-growing global threats to human life caused by the human acute respiratory virus (RV) infections have cost billions of lives, created a significant economic burden, and shaped society for centuries. The timely response to emerging RVs could save human lives and reduce the medical care burden. The development of RV detection technologies is essential for potentially preventing RV pandemic and epidemics. However, commonly used detection technologies lack sensitivity, specificity, and speed, thus often failing to provide the rapid turnaround times. To address this problem, new technologies are devised to address the performance inadequacies of the traditional methods. These emerging technologies offer improvements in convenience, speed, flexibility, and portability of point-of-care test (POCT). Herein, recent developments in POCT are comprehensively reviewed for eight typical acute respiratory viruses. This review discusses the challenges and opportunities of various recognition and detection strategies and discusses these according to their detection principles, including nucleic acid amplification, optical POCT, electrochemistry, lateral flow assays, microfluidics, enzyme-linked immunosorbent assays, and microarrays. The importance of limits of detection, throughput, portability, and specificity when testing clinical samples in resource-limited settings is emphasized. Finally, the evaluation of commercial POCT kits for both essential RV diagnosis and clinical-oriented practices is included.

The Impact of Obesity on Critical Illnesses

ABSTRACT

In the last few decades, obesity became one of the world's greatest health challenges reaching a size of global epidemic in virtually all socioeconomic statuses and all age groups. Obesity is a risk factor for many health problems and as its prevalence gradually increases is becoming a significant economic and health burden. In this manuscript we describe how normal respiratory and cardiovascular physiology is altered by obesity. We review past and current literature to describe how obesity affects outcomes of patients facing critical illnesses and discuss some controversies related to this topic.

Positron emission tomography in the COVID-19 pandemic era

Coronavirus disease 2019 (COVID-19) has become a major public health problem worldwide since its outbreak in 2019. Currently, the spread of COVID-19 is far from over, and various complications have roused increasing awareness of the public, calling for novel techniques to aid at diagnosis and treatment. Based on the principle of molecular imaging, positron emission tomography (PET) is expected to offer pathophysiological alternations of COVID-19 in the molecular/cellular perspectives and facilitate the clinical management of patients. A number of PET-related cases and research have been reported on COVID-19 over the past one year. This article reviews the current studies of PET in the diagnosis and treatment of COVID-19, and discusses potential applications of PET in the development of management strategy for COVID-19 patients in the pandemic era.

A study on catalytic and non-catalytic sites of H5N1 and H1N1 neuraminidase as the target for chalcone inhibitors

The H1N1 pandemic in 2009 and the H5N1 outbreak in 2005 have shocked the world as millions of people were infected and hundreds of thousands died due to the infections by the influenza virus. Oseltamivir, the most common drug to block the viral life cycle by inhibiting neuraminidase (NA) enzyme, has been less effective in some resistant cases due to the virus mutation. Presently, the binding of 10 chalcone derivatives towards H5N1 and H1N1 NAs in the non-catalytic and catalytic sites was studied using molecular docking. The in silico study was also conducted for its drug-like likeness such as Lipinski Rule, mutagenicity, toxicity and pharmacokinetic profiles. The result demonstrates that two chalcones (1c and 2b) have the potential for future NA inhibitor development. Compound 1c inhibits H5N1 NA and H1N1 NA with IC₅₀ of 27.63 µM and 28.11 µM, respectively, whereas compound 2b inhibits NAs with IC₅₀ of 87.54 µM and 73.17 µM for H5N1 and H1N1, respectively. The in silico drug-like likeness prediction reveals that 1c is 62% better than 2b (58%) in meeting the criteria. The results suggested that 1c and 2b have potencies to be developed as non-competitive inhibitors of neuraminidase for the future development of anti-influenza drugs.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s13765-021-00639-w.

Signatures of COVID-19 Severity and Immune Response in the Respiratory Tract Microbiome

Viral infection of the respiratory tract can be associated with propagating effects on the airway microbiome, and microbiome dysbiosis may influence viral disease. Here, we investigated the respiratory tract microbiome in coronavirus disease 2019 (COVID-19) and its relationship to disease severity, systemic immunologic features, and outcomes. We examined 507 oropharyngeal, nasopharyngeal, and endotracheal samples from 83 hospitalized COVID-19 patients as well as non-COVID patients and healthy controls. Bacterial communities were interrogated using 16S rRNA gene sequencing, and the commensal DNA viruses Anelloviridae and Redondoviridae were quantified by qPCR. We found that COVID-19 patients had upper respiratory microbiome dysbiosis and greater change over time than critically ill patients without COVID-19. Oropharyngeal microbiome diversity at the first time point correlated inversely with disease severity during hospitalization. Microbiome composition was also associated with systemic immune parameters in blood, as measured by lymphocyte/neutrophil ratios and immune profiling of peripheral blood mononuclear cells. Intubated patients showed patient-specific lung microbiome communities that were frequently highly dynamic, with prominence of Staphylococcus. Anelloviridae and Redondoviridae showed more frequent colonization and higher titers in severe disease. Machine learning analysis demonstrated that integrated features of the microbiome at early sampling points had high power to discriminate ultimate level of COVID-19 severity. Thus, the respiratory tract microbiome and commensal viruses are disturbed in COVID-19 and correlate with systemic immune parameters, and early microbiome features discriminate disease severity. Future studies should address clinical consequences of airway dysbiosis in COVID-19, its possible use as biomarkers, and the role of bacterial and viral taxa identified here in COVID-19 pathogenesis. IMPORTANCE COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of the respiratory tract, results in highly variable outcomes ranging from minimal illness to death, but the reasons for this are not well understood. We investigated the respiratory tract bacterial microbiome and small commensal DNA viruses in hospitalized COVID-19 patients and found that each was markedly abnormal compared to that in healthy people and differed from that in critically ill patients without COVID-19. Early airway samples tracked with the level of COVID-19 illness reached during hospitalization, and the airway microbiome also correlated with immune parameters in blood. These findings raise questions about the mechanisms linking SARS-CoV-2 infection and other microbial inhabitants of the airway, including whether the microbiome might regulate severity of COVID-19 disease and/or whether early microbiome features might serve as biomarkers to discriminate disease severity.

Burden of Pneumonia Among Hospitalized Patients with Influenza: Real-World Evidence from a US Managed Care Population

Introduction

Pneumonia is among the most prevalent complications of influenza. The purpose of this study is to quantify the burden of pneumonia among hospitalized patients with influenza.

Methods

Real-world retrospective data from 01JAN2014-30JUN2019 (study period) were obtained from Optum’s de-identified Clinformatics® Data Mart Database (2007–2020) for patients who had ≥ 1 diagnosis for influenza during the identification period and ≥ 1 all-cause inpatient visit within 1 day of diagnosis. Cases had ≥ 1 diagnosis claim for an influenza-related pneumonia within the 30 days after the initial influenza diagnosis date. Controls had no evidence of influenza-related pneumonia in the 30 days following the initial influenza diagnosis. Final 1:1 matching was determined using propensity score matching (PSM). Statistical significance between the cohorts was tested.

Results

After PSM, there were 4878 hospitalized patients with influenza in each of the case and control groups. During the index hospitalization, cases vs. controls had longer length of stay [Mean (standard deviation): 6.5 (8.3) vs. 1.9 (3.7)], greater intensive care unit (ICU) use (38.4 vs. 16.8%), and greater mechanical ventilation use (invasive: 11.4 vs. 2.3%; non-invasive: 6.8 vs. 2.6%) (all p < 0.001). Cases also had higher readmission rates than controls (12.3 vs. 3.5% within 30 days; 20.0 vs. 6.1% within 90 days; p < 0.001 for both). Post-index date direct all-cause healthcare costs were higher for cases than for controls (median total cost: $18,428 vs. $621 for 30 days; $21,774 vs. $3312 for 90 days; $25,960 vs. $8699 for 6 months; $35,875 vs. $21,619 for 1 year; all p < 0.001).

Conclusions

Pneumonia as a complication of influenza increases risk of mortality and leads to greater healthcare resource use and direct medical costs among patients hospitalized with influenza. These effects are seen early during the index hospitalization and within the first 30 days after diagnosis, but their impact continues throughout a year of follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41030-021-00169-2.

Untreated obstructive sleep apnea is associated with increased hospitalization from influenza infection

STUDY OBJECTIVES

There is evidence that sleep deprivation or diseases such as obstructive sleep apnea (OSA) that lead to sleep disruption may adversely impact immune system functioning. We hypothesized that individuals who have OSA who did not use continuous positive airway pressure (CPAP) would have higher rates of hospitalization and complications from influenza infection than patients with OSA who were adherent to treatment.

METHODS

Medical records of patients at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire who had both OSA and a new, laboratory-confirmed influenza infection between 2016 and 2018 were reviewed for results of polysomnography, CPAP usage, influenza vaccination records, confirmation of influenza infection, and influenza-related hospitalizations and complications.

RESULTS

Compared to the patients who were adherent to CPAP, patients who were either conservatively treated without CPAP or who were nonadherent to CPAP therapy had higher odds of hospitalization from influenza infections (odds ratio = 4.7, 95% confidence interval 1.3 to 19.5, P = .01) but no higher odds of complications from influenza. The patients who had untreated sleep apnea had a higher percentage of influenza vaccination for their season of illness (75% of patients) compared to patients who were adherent to CPAP (56% of patients), although the difference in vaccination was not statistically significant.

CONCLUSIONS

Patients with OSA who did not use CPAP appear to have greater rates of hospitalization from acute influenza infection, despite having a higher trend of influenza vaccination compared to patients who were adherent to CPAP.

Signatures of COVID-19 severity and immune response in the respiratory tract microbiome

Rationale

Viral infection of the respiratory tract can be associated with propagating effects on the airway microbiome, and microbiome dysbiosis may influence viral disease.

Objective

To define the respiratory tract microbiome in COVID-19 and relationship disease severity, systemic immunologic features, and outcomes.

Methods and Measurements

We examined 507 oropharyngeal, nasopharyngeal and endotracheal samples from 83 hospitalized COVID-19 patients, along with non-COVID patients and healthy controls. Bacterial communities were interrogated using 16S rRNA gene sequencing, commensal DNA viruses Anelloviridae and Redondoviridae were quantified by qPCR, and immune features were characterized by lymphocyte/neutrophil (L/N) ratios and deep immune profiling of peripheral blood mononuclear cells (PBMC).

Main Results

COVID-19 patients had upper respiratory microbiome dysbiosis, and greater change over time than critically ill patients without COVID-19. Diversity at the first time point correlated inversely with disease severity during hospitalization, and microbiome composition was associated with L/N ratios and PBMC profiles in blood. Intubated patients showed patient-specific and dynamic lung microbiome communities, with prominence of Staphylococcus. Anelloviridae and Redondoviridae showed more frequent colonization and higher titers in severe disease. Machine learning analysis demonstrated that integrated features of the microbiome at early sampling points had high power to discriminate ultimate level of COVID-19 severity.

Conclusions

The respiratory tract microbiome and commensal virome are disturbed in COVID-19, correlate with systemic immune parameters, and early microbiome features discriminate disease severity. Future studies should address clinical consequences of airway dysbiosis in COVID-19, possible use as biomarkers, and role of bacterial and viral taxa identified here in COVID-19 pathogenesis.

Effectiveness of the Cell-Derived Inactivated Quadrivalent Influenza Vaccine in Individuals at High Risk of Influenza Complications in the 2018-2019 United States Influenza Season

Background

Higher rates of influenza-related morbidity and mortality occur in individuals with underlying medical conditions. To improve vaccine effectiveness, cell-based technology for influenza vaccine manufacturing has been developed. Cell-derived inactivated quadrivalent influenza vaccines (cIIV4) may improve protection in seasons in which egg-propagated influenza viruses undergo mutations that affect antigenicity. This study aimed to estimate the relative vaccine effectiveness (rVE) of cIIV4 versus egg-derived inactivated quadrivalent influenza vaccines (eIIV4) in preventing influenza-related medical encounters in individuals with underlying medical conditions putting them at high risk of influenza complications during the 2018-2019 US influenza season.

Methods

An integrated dataset, linking primary care electronic medical records with claims data, was used to conduct a retrospective cohort study among individuals aged ≥4 years, with ≥1 health condition, vaccinated with cIIV4 or eIIV4 during the 2018-2019 season. Adjusted odds ratios (ORs) were derived using a doubly robust inverse probability of treatment-weighting (IPTW) model, adjusting for age, sex, race, ethnicity, geographic region, vaccination week, and health status. Relative vaccine effectiveness was estimated by (1 - OR) × 100 and presented with 95% confidence intervals (CIs).

Results

The study cohort included 471 301 cIIV4 and 1 641 915 eIIV4 recipients. Compared with eIIV4, cIIV4 prevented significantly more influenza-related medical encounters among individuals with ≥1 health condition (rVE, 13.4% [95% CI, 11.4%-15.4%]), chronic pulmonary disease (rVE, 18.7% [95% CI, 16.0%-21.3%]), and rheumatic disease (rVE, 11.8% [95% CI, 3.6%-19.3%]).

Conclusions

Our findings support the use of cIIV4 in individuals ≥4 years of age at high risk of influenza complications and provide further evidence supporting improved effectiveness of cIIV4 compared with eIIV4.

Social Media Engagement and Influenza Vaccination During the COVID-19 Pandemic: Cross-sectional Survey Study

Background

Vaccines are one of the most important achievements of modern medicine. However, their acceptance is only partial, with vaccine hesitancy and refusal representing a major health threat. Influenza vaccines have low compliance since repeated, annual vaccination is required. Influenza vaccines stimulate discussions both in the real world and online. Social media is currently a significant source of health and medical information. Elucidating the association between social media engagement and influenza vaccination is important and may be applicable to other vaccines, including ones against COVID-19.

Objective

The goal of this study is to characterize profiles of social media engagement regarding the influenza vaccine and their association with knowledge and compliance in order to support improvement of future web-associated vaccination campaigns.

Methods

A weblink to an online survey in Hebrew was disseminated over social media and messaging platforms. The survey answers were collected during April 2020. Anonymous and volunteer participants aged 21 years and over answered 30 questions related to sociodemographics; social media usage; influenza- and vaccine-related knowledge and behavior; health-related information searching, its reliability, and its influence; and COVID-19-related information searching. A univariate descriptive data analysis was performed, followed by multivariate analysis via building a decision tree to define the most important attributes associated with vaccination compliance.

Results

A total of 213 subjects responded to the survey, of whom 207 were included in the analysis; the majority of the respondents were female, were aged 21 to 40 years, had 1 to 2 children, lived in central Israel, were secular Israeli natives, had higher education, and had a salary close to the national average. Most respondents (128/207, 61.8%) were not vaccinated against influenza in 2019 and used social media. Participants that used social media were younger, secular, and living in high-density agglomerations and had lower influenza vaccination rates. The perceived influence and reliability of the information on social media about COVID-19 were generally similar to those perceptions about influenza.

Conclusions

Using social media is negatively linked to compliance with seasonal influenza vaccination in this study. A high proportion of noncompliant individuals can lead to increased consumption of health care services and can, therefore, overload these health services. This is particularly crucial with a concomitant outbreak, such as COVID-19. Health care professionals should use improved and targeted health communication campaigns with the aid of experts in social media. Targeted communication, based on sociodemographic factors and personalized social media usage, might increase influenza vaccination rates and compliance with other vaccines as well.

A High-Fat Diet Increases Influenza A Virus-Associated Cardiovascular Damage

BACKGROUND

Influenza A virus (IAV) causes a wide range of extrarespiratory complications. However, the role of host factors in these complications of influenza virus infection remains to be defined.

METHODS

Here, we sought to use transcriptional profiling, virology, histology, and echocardiograms to investigate the role of a high-fat diet in IAV-associated cardiac damage.

RESULTS

Transcriptional profiling showed that, compared to their low-fat counterparts (LF mice), mice fed a high-fat diet (HF mice) had impairments in inflammatory signaling in the lung and heart after IAV infection. This was associated with increased viral titers in the heart, increased left ventricular mass, and thickening of the left ventricular wall in IAV-infected HF mice compared to both IAV-infected LF mice and uninfected HF mice. Retrospective analysis of clinical data revealed that cardiac complications were more common in patients with excess weight, an association which was significant in 2 out of 4 studies.

CONCLUSIONS

Together, these data provide the first evidence that a high-fat diet may be a risk factor for the development of IAV-associated cardiovascular damage and emphasizes the need for further clinical research in this area.

Predictors and Outcomes of Hospitalization for Influenza: Real-World Evidence from the United States Medicare Population

INTRODUCTION

The purpose of this study was to identify predictors of initial hospitalization and describe the outcomes of high-risk patients hospitalized with influenza.

METHODS

Data were taken from the 5% national US Medicare database from 2012 to 2015. Patients (aged at least 13 years) were required to have at least one diagnosis for influenza and have continuous health plan enrollment for 6 months before (baseline) and 3 months (follow-up) after the date of influenza diagnosis. Patients who died during follow-up were included. Patients were categorized as initially hospitalized if hospitalized within 0-1 day of diagnosis. High-risk initially hospitalized patients were defined as patients aged at least 65 years or those that had a diagnostic code for chronic lung disease, cardiovascular or cerebrovascular disease, or weakened immune system during baseline period. Logistic regression models were developed to determine predictors of initial hospitalization.

RESULTS

The study population included 8127 high-risk patients who were initially hospitalized and 16,784 who were not hospitalized. Among high-risk patients, 89.3% were diagnosed in the emergency room, whereas 7.5% and 3.2% were diagnosed in a physician's office or other Medicare settings, respectively. Chronic obstructive pulmonary disorder, congestive heart failure, chronic kidney disease, older age, being male, other comorbidities, number of comorbidities, and baseline healthcare resource use were the predictors of hospitalization. Median length of stay for the hospitalization was 5.0 days, and the 30-day readmission rate was 14%. All-cause mortality rate was 5.1% during the inpatient stay and 9.2% within 30 days of diagnosis. Hospitalized patients with influenza incurred an increase of $16,568 per patient in total all-cause healthcare costs from pre-influenza to post-influenza diagnosis.

CONCLUSION

The study characterized the burden of hospitalization for influenza and found that hospitalized high-risk patients experience greater comorbidity burden, higher likelihood of multiple inpatient admissions, and costly medical interventions compared to patients who were not hospitalized.

Perceptions of Seasonal Influenza Vaccine Among U.S. Army Civilians and Dependents in the Kaiserslautern Military Community: A Mixed-Methods Survey

Introduction

Influenza is a globally occurring viral respiratory infection that can lead to hospitalizations and death. An influenza outbreak can interfere with combat readiness in a military setting, as the infection can incapacitate soldiers. Vaccination remains the most effective tool to prevent and mitigate seasonal influenza. Although influenza vaccinations for U.S. Army soldiers can be monitored through military health systems, those systems cannot capture DoD civilians and Army dependents who may not use military health services. This study aims to gauge flu vaccine uptake and perceptions in U.S. Army civilians and dependents.

Materials and Methods

An online survey was e-mailed to civilian and dependent enrollees of Landstuhl Regional Medical Center. The survey contained 24 questions pertaining to demographics, vaccine history, history of the flu, and beliefs toward vaccines. Chi-square tests, t-tests, and logistic regressions were performed to investigate the association between demographic, behavior, and belief factors with vaccine uptake. Free-text answers were coded and categorized by themes.

Results

Over 70% of respondents were vaccinated for the flu. There were differences between vaccinated and unvaccinated respondents regarding their perceptions of barriers to vaccination, benefits of the flu vaccine, severity of flu symptoms, and personal risk of getting ill with the flu. After controlling for confounders, flu vaccination in the previous season and healthcare worker status were associated with increased vaccine uptake, while perceived barriers to influenza vaccination were associated with decreased vaccine uptake.

Conclusions

Flu vaccine uptake may be increased by increasing access to vaccination, promoting vaccination and addressing concerns at the provider level, and engaging positively framed public messaging. Increasing flu vaccine uptake is of particular importance as the flu season approaches during the COVID-19 (Coronavirus disease 2019) pandemic.

Neurological complications of pandemic A(H1N1)2009pdm, postpandemic A(H1N1)v, and seasonal influenza A

OBJECTIVES

Not much is known about influenza-associated neurological complications. We aimed to describe the case series of hospitalized patients who were confirmed with influenza A and presented with neurological symptoms in order to capture the broad spectrum of influenza clinical manifestation and suggest including influenza diagnostic in some neurological conditions.

MATERIALS AND METHODS

The inclusion criteria were age ≥ 18 and laboratory-confirmed influenza presenting with neurological symptoms. Influenza-associated neurological complication was described as a development of neurological symptom with no other origin. The outcomes were classified into 5 categories: 1. recovery with no significant disability; 2. minor disability (able to manage on their own); 3. moderate disability (requiring some help but able to walk without assistance); 4. severe disability (unable to walk without assistance and perform daily activities); 5. death.

RESULTS

In total, 12 patients (five women and seven men) were enrolled, with age range 18-71 years old. Neurological complications of pandemic A(H₁ N₁ )2009pdm influenza developed in seven out of 69 (10.1%) hospitalized patients. The most common neurological complication was encephalopathy. Neurological complications developed in two out of 24 (8.3%) hospitalized patients during postpandemic (H₁ N₁ )_V period. One patient presented with encephalopathy, another with meningoencephalitis. During the 2018 influenza season, there was one patient who has developed influenza A neurological complications. Overall, two out of 104 (1.9%) influenza A patients developed influenza-associated neurological complications in 2019.

CONCLUSIONS

Every patient with unexplained neurological symptoms and signs similar to aseptic and septic meningitis/encephalitis has to be tested for influenza virus during epidemics and pandemics.

Linear ubiquitin assembly complex regulates lung epithelial-driven responses during influenza infection

Influenza A virus (IAV) is among the most common causes of pneumonia-related death worldwide. Pulmonary epithelial cells are the primary target for viral infection and replication and respond by releasing inflammatory mediators that recruit immune cells to mount the host response. Severe lung injury and death during IAV infection result from an exuberant host inflammatory response. The linear ubiquitin assembly complex (LUBAC), composed of SHARPIN, HOIL-1L, and HOIP, is a critical regulator of NF-κB-dependent inflammation. Using mice with lung epithelial-specific deletions of HOIL-1L or HOIP in a model of IAV infection, we provided evidence that, while a reduction in the inflammatory response was beneficial, ablation of the LUBAC-dependent lung epithelial-driven response worsened lung injury and increased mortality. Moreover, we described a mechanism for the upregulation of HOIL-1L in infected and noninfected cells triggered by the activation of type I IFN receptor and mediated by IRF1, which was maladaptive and contributed to hyperinflammation. Thus, we propose that lung epithelial LUBAC acts as a molecular rheostat that could be selectively targeted to modulate the immune response in patients with severe IAV-induced pneumonia.

Targeting the Linear Ubiquitin Assembly Complex to Modulate the Host Response and Improve Influenza A Virus Induced Lung Injury

Influenza virus infection is characterized by symptoms ranging from mild congestion and body aches to severe pulmonary edema and respiratory failure. While the majority of those exposed have minor symptoms and recover with little morbidity, an estimated 500,000 people succumb to IAV-related complications each year worldwide. In these severe cases, an exaggerated inflammatory response, known as "cytokine storm", occurs which results in damage to the respiratory epithelial barrier and development of acute respiratory distress syndrome (ARDS). Data from retrospective human studies as well as experimental animal models of influenza virus infection highlight the fine line between an excessive and an inadequate immune response, where the host response must balance viral clearance with exuberant inflammation. Current pharmacological modulators of inflammation, including corticosteroids and statins, have not been successful in improving outcomes during influenza virus infection. We have reported that the amplitude of the inflammatory response is regulated by Linear Ubiquitin Assembly Complex (LUBAC) activity and that dampening of LUBAC activity is protective during severe influenza virus infection. Therapeutic modulation of LUBAC activity may be crucial to improve outcomes during severe influenza virus infection, as it functions as a molecular rheostat of the host response. Here we review the evidence for modulating inflammation to ameliorate influenza virus infection-induced lung injury, data on current anti-inflammatory strategies, and potential new avenues to target viral inflammation and improve outcomes.

Review of influenza-associated pulmonary aspergillosis in ICU patients and proposal for a case definition: an expert opinion

PURPOSE

Invasive pulmonary aspergillosis is increasingly reported in patients with influenza admitted to the intensive care unit (ICU). Classification of patients with influenza-associated pulmonary aspergillosis (IAPA) using the current definitions for invasive fungal diseases has proven difficult, and our aim was to develop case definitions for IAPA that can facilitate clinical studies.

METHODS

A group of 29 international experts reviewed current insights into the epidemiology, diagnosis and management of IAPA and proposed a case definition of IAPA through a process of informal consensus.

RESULTS

Since IAPA may develop in a wide range of hosts, an entry criterion was proposed and not host factors. The entry criterion was defined as a patient requiring ICU admission for respiratory distress with a positive influenza test temporally related to ICU admission. In addition, proven IAPA required histological evidence of invasive septate hyphae and mycological evidence for Aspergillus. Probable IAPA required the detection of galactomannan or positive Aspergillus culture in bronchoalveolar lavage (BAL) or serum with pulmonary infiltrates or a positive culture in upper respiratory samples with bronchoscopic evidence for tracheobronchitis or cavitating pulmonary infiltrates of recent onset. The IAPA case definitions may be useful to classify patients with COVID-19-associated pulmonary aspergillosis (CAPA), while awaiting further studies that provide more insight into the interaction between Aspergillus and the SARS-CoV-2-infected lung.

CONCLUSION

A consensus case definition of IAPA is proposed, which will facilitate research into the epidemiology, diagnosis and management of this emerging acute and severe Aspergillus disease, and may be of use to study CAPA.

Attitudes Toward Influenza Vaccination Administration in the Emergency Department Among Health Care Providers: A Cross-Sectional Survey

INTRODUCTION

Influenza is a burdensome and vaccine-preventable infectious disease. Lack of time was reported as a common barrier by Canadians who did not receive their influenza vaccine. Increasing convenient access to vaccination increases uptake, and a potential setting for vaccine administration is the emergency department, where long wait times are common.

METHODS

A cross-sectional survey to gauge health care provider support and perceived barriers and facilitators to delivering influenza vaccine was conducted at 1 emergency and trauma center in Halifax, Nova Scotia. Anonymous questionnaires were completed by a convenience sample of emergency nurses, physicians, and paramedics (n = 82).

RESULTS

In total, 86% (n = 68) of health care providers supported vaccination in the emergency department when sufficient staffing and resources were available. When asked to consider implementation of influenza vaccination in the emergency department based on current staffing and resources, only 59% (n = 48) supported making vaccination available. Most surveyed health care providers preferred screening for vaccination at triage (57%) and supported a nurse-initiated protocol for vaccine administration (74%). After Bonferroni correction, there was no significant association between preference for when to vaccinate and being a nurse or physician (χ²(2) = 6.208, P = 0.05). The highest risk patient groups with the lowest provider endorsement of vaccination were people involved in poultry culling (77%) and pregnant women (83%).

DISCUSSION

Surveyed health care providers were supportive of ED influenza vaccination. However, this study revealed additional barriers that need to be addressed to effectively launch such a program.

Vaccine Effectiveness Against Influenza-Associated Lower Respiratory Tract Infections in Hospitalized Adults, Louisville, Kentucky, 2010-2013

Background

Preventing severe complications of influenza such as hospitalization is a public health priority; however, estimates of influenza vaccine effectiveness (VE) against influenza-associated acute lower respiratory tract infection (LRTI) hospitalizations are limited. We examined influenza VE against influenza-associated LRTIs in hospitalized adult patients.

Methods

We retrospectively analyzed data from a randomized trial of oseltamivir treatment in adults hospitalized with LRTI in Louisville, Kentucky, from 2010 to 2013. Patients were systematically tested for influenza at the time of enrollment. We estimated VE as 1 - the adjusted odds ratio (aOR) of antecedent vaccination in influenza-positives vs negatives × 100%. Vaccination status was obtained by patient self-report. Using logistic regression adjusting for age, sex, season, timing of illness, history of chronic lung disease, and activities of daily living, we estimated VE against hospitalized influenza-associated LRTIs and community-acquired pneumonia (CAP) with radiographic findings of infiltrate.

Results

Of 810 patients with LRTI (median age, 62 years), 184 (23%) were influenza-positive and 57% had radiographically confirmed CAP. Among influenza-positives and -negatives, respectively, 61% and 69% were vaccinated. Overall, 29% were hospitalized in the prior 90 days and >80% had comorbidities. Influenza-negatives were more likely to have a history of chronic obstructive pulmonary disease than influenza-positives (59% vs 48%; P = .01), but baseline medical conditions were otherwise similar. Overall, VE was 35% (95% CI, 4% to 56%) against influenza-associated LRTI and 51% (95% CI, 13% to 72%) against influenza-associated radiographically confirmed CAP.

Conclusions

Vaccination reduced the risk of hospitalization for influenza-associated LRTI and radiographically confirmed CAP. Clinicians should maintain high rates of influenza vaccination to prevent severe influenza-associated complications.

High-Grade Atrioventricular Block Associated With Acute Influenza

Influenza causes cardiac and pulmonary complications that can lead to death. Its effect on the conduction system, first described a century ago, has long been thought to be fairly benign. We report 2 cases of high-grade atrioventricular block associated with acute influenza infection. Both patients-a 50-year-old woman with no history of cardiac disease or conduction abnormalities and a 20-year-old man with a history of complex congenital heart disease and conduction abnormalities-received a permanent pacemaker. In the first case, pacemaker interrogation at 4 months revealed persistent atrioventricular block. In the second case, pacemaker interrogation at 3 months suggested resolution. Whether such influenza-associated changes are transient or permanent remains unknown. We recommend keeping a careful watch on influenza patients with cardiac rhythm abnormalities and monitoring them closely to see if the problem resolves.

Targeting the Linear Ubiquitin Assembly Complex to Modulate the Host Response and Improve Influenza A Virus Induced Lung Injury

Influenza virus infection is characterized by symptoms ranging from mild congestion and body aches to severe pulmonary edema and respiratory failure. While the majority of those exposed have minor symptoms and recover with little morbidity, an estimated 500,000 people succumb to IAV-related complications each year worldwide. In these severe cases, an exaggerated inflammatory response, known as "cytokine storm", occurs which results in damage to the respiratory epithelial barrier and development of acute respiratory distress syndrome (ARDS). Data from retrospective human studies as well as experimental animal models of influenza virus infection highlight the fine line between an excessive and an inadequate immune response, where the host response must balance viral clearance with exuberant inflammation. Current pharmacological modulators of inflammation, including corticosteroids and statins, have not been successful in improving outcomes during influenza virus infection. We have reported that the amplitude of the inflammatory response is regulated by Linear Ubiquitin Assembly Complex (LUBAC) activity and that dampening of LUBAC activity is protective during severe influenza virus infection. Therapeutic modulation of LUBAC activity may be crucial to improve outcomes during severe influenza virus infection, as it functions as a molecular rheostat of the host response. Here we review the evidence for modulating inflammation to ameliorate influenza virus infection-induced lung injury, data on current anti-inflammatory strategies, and potential new avenues to target viral inflammation and improve outcomes.

Respiratory and Nonrespiratory Diagnoses Associated With Influenza in Hospitalized Adults

IMPORTANCE

Seasonal influenza virus infection is a major cause of morbidity and mortality and may be associated with respiratory and nonrespiratory diagnoses.

OBJECTIVE

To examine the respiratory and nonrespiratory diagnoses reported for adults hospitalized with laboratory-confirmed influenza between 2010 and 2018 in the United States.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the US Influenza Hospitalization Surveillance Network (FluSurv-NET) from October 1 through April 30 of the 2010-2011 through 2017-2018 influenza seasons. FluSurv-NET is a population-based, multicenter surveillance network with a catchment area that represents approximately 9% of the US population. Patients are identified by practitioner-ordered influenza testing. Adults (aged ≥18 years) hospitalized with laboratory-confirmed influenza were included in the study.

EXPOSURES

FluSurv-NET defines laboratory-confirmed influenza as a positive influenza test result by rapid antigen assay, reverse transcription-polymerase chain reaction, direct or indirect fluorescent staining, or viral culture.

MAIN OUTCOMES AND MEASURES

Acute respiratory or nonrespiratory diagnoses were defined using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) discharge diagnosis codes. The analysis included calculation of the frequency of acute respiratory and nonrespiratory diagnoses with a descriptive analysis of patient demographic characteristics, underlying medical conditions, and in-hospital outcomes by respiratory and nonrespiratory diagnoses.

RESULTS

Of 89 999 adult patients hospitalized with laboratory-confirmed influenza, 76 649 (median age, 69 years; interquartile range, 55-82 years; 55% female) had full medical record abstraction and at least 1 ICD code for an acute diagnosis. In this study, 94.9% of patients had a respiratory diagnosis and 46.5% had a nonrespiratory diagnosis, including 5.1% with only nonrespiratory diagnoses. Pneumonia (36.3%), sepsis (23.3%), and acute kidney injury (20.2%) were the most common acute diagnoses. Fewer patients with only nonrespiratory diagnoses received antiviral therapy for influenza compared with those with respiratory diagnoses (81.4% vs 88.9%; P < .001).

CONCLUSIONS AND RELEVANCE

Nonrespiratory diagnoses occurred frequently among adults hospitalized with influenza, further contributing to the burden of infection in the United States. The findings suggest that during the influenza season, practitioners should consider influenza in their differential diagnosis for patients who present to the hospital with less frequently recognized manifestations and initiate early antiviral treatment for patients with suspected or confirmed infection.

Influenza A-associated severe pneumonia in hospitalized patients: Risk factors and NAI treatments

OBJECTIVE

The risk factors and the impact of NAI treatments in patients with severe influenza A-associated pneumonia remain unclear.

METHODS

A multicenter, retrospective, observational study was conducted in Zhejiang, China during a severe influenza epidemic in August 2017-May 2018. Clinical records of patients (>14 y) hospitalized with laboratory-confirmed influenza A virus infection and who developed severe pneumonia were compared to those with mild-to-moderate pneumonia. Risk factors related to pneumonia severity and effects of NAI treatments (monotherapy and combination of peramivir and oseltamivir) were analyzed.

RESULTS

202 patients with influenza A-associated severe pneumonia were enrolled, of whom 84 (41.6%) had died. Male gender (OR = 1.782; 95% CI: 1.089-2.917; P = 0.022), chronic pulmonary disease (OR = 2.581; 95% CI: 1.447-4.603; P = 0.001) and diabetes mellitus (OR = 2.042; 95% CI: 1.135-3.673; P = 0.017) were risk factors related to influenza A pneumonia severity. In cox proportional hazards model, severe pneumonia patients treated with double dose oseltamivir (300mg/d) had a better survival rate compared to those receiving a single dose (150 mg/d) (HR = 0.475; 95%CI: 0.254-0.887; P = 0.019). However, different doses of peramivir (300 mg/d vs. 600 mg/d) and combination therapy (oseltamivir-peramivir vs. monotherapy) showed no differences in 60-day mortality (P = 0.392 and P = 0.658, respectively).

CONCLUSIONS

Patients with male gender, chronic pulmonary disease, or diabetes mellitus were at high risk of developing severe pneumonia after influenza A infection. Double dose oseltamivir might be considered in treating influenza A-associated severe pneumonia.

Experimental validation and computational modeling of anti-influenza effects of quercetin-3-O-α-L-rhamnopyranoside from indigenous south African medicinal plant Rapanea melanophloeos

BACKGROUND

Influenza A virus (IAV) is still a major health threat. The clinical manifestations of this infection are related to immune dysregulation, which causes morbidity and mortality. The usage of traditional medication with immunomodulatory properties against influenza infection has been increased recently. Our previous study showed antiviral activity of quercetin-3-O-α-L-rhamnopyranoside (Q3R) isolated from Rapanea melanophloeos (RM) (L.) Mez (family Myrsinaceae) against H1N1 (A/PR/8/34) infection. This study aimed to confirm the wider range of immunomodulatory effect of Q3R on selective pro- and anti-inflammatory cytokines against IAV in vitro, to evaluate the effect of Q3R on apoptosis pathway in combination with H1N1, also to assess the physical interaction of Q3R with virus glycoproteins and RhoA protein using computational docking.

METHODS

MDCK cells were exposed to Q3R and 100CCID50/100 μl of H1N1 in combined treatments (co-, pre- and post-penetration treatments). The treatments were tested for the cytokines evaluation at RNA and protein levels by qPCR and ELISA, respectively. In another set of treatment, apoptosis was examined by detecting RhoA GTPase protein and caspase-3 activity. Molecular docking was used as a tool for evaluation of the potential anti-influenza activity of Q3R.

RESULTS

The expressions of cytokines in both genome and protein levels were significantly affected by Q3R treatment. It was shown that Q3R was much more effective against influenza when it was applied in co-penetration treatment. Q3R in combination with H1N1 increased caspase-3 activity while decreasing RhoA activation. The molecular docking results showed strong binding ability of Q3R with M2 transmembrane, Neuraminidase of 2009 pandemic H1N1, N1 and H1 of PR/8/1934 and Human RhoA proteins, with docking energy of - 10.81, - 10.47, - 9.52, - 9.24 and - 8.78 Kcal/mol, respectively.

CONCLUSIONS

Quercetin-3-O-α-L-rhamnopyranoside from RM was significantly effective against influenza infection by immunomodulatory properties, affecting the apoptosis pathway and binding ability to viral receptors M2 transmembrane and Neuraminidase of 2009 pandemic H1N1 and human RhoA cellular protein. Further research will focus on detecting the detailed specific mechanism of Q3R in virus-host interactions.

Diminished immune responses with aging predispose older adults to common and uncommon influenza complications

Influenza (flu) is a serious disease for older adults, with increased severity of infection and greater risk for hospitalization and death. Flu infection is limited to pulmonary epithelial cells, yet there are many systemic symptoms and older adults are more susceptible to flu-related complications. In older adults, flu rarely comes without additional complications and there is a perfect storm for enhanced disease due to multiple factors including existing co-morbidities, plus impaired lung function and dysregulated immune responses that occur with even healthy aging. Commonly, opportunistic secondary bacterial infections prosper in damaged lungs. Intensified systemic inflammation with aging can cause dysfunction in extra-pulmonary organs and tissues such as cardiovascular, musculoskeletal, neuropathologic, hepatic, and renal complications. Often overlooked is the underappreciated connections between many of these conditions, which exacerbate one another when in parallel. This review focuses on flu infection and the numerous complications in older adults associated with diminished immune responses.

Clinical characteristics and outcomes during a severe influenza season in China during 2017-2018

BACKGROUND

A severe seasonal influenza epidemic was observed during 2017-2018 in China, prompting questions on clinical characteristics and outcomes of severe cases with influenza.

METHODS

We retrospectively collected clinical data and outcomes of laboratory-confirmed hospitalized patients (severe to critical) during Jan-2011 to Feb-2018 from five hospitals, followed by a systematic analysis of cases from 2017 to 2018 (n = 289) and all previous epidemics during 2011-2017 (n = 169).

RESULTS

In-hospital fatality was over 5-folds higher during the 2017-2018 (p < 0.01) in which 19 patients died (6.6%), whereas only 2 mortalities (1.2%) were observed during 2011-2017. Of the 289 hospitalized in 2017-2018, 153 were confirmed with influenza B virus, 110 with A/H1N1pdm09, and 26 A/H3N2, whereas A/H1N1pdm09 was the predominant cause of hospitalization in previous seasons combined (45%). Fatal cases in 2017-2018 were exclusively associated with either influenza B or A/H1N1pdm09. Our results show that a significant lower proportion of patients aged 14 or greater were treated with oseltamivir, during the 2017-2018 epidemic, and exhibited higher levels of clinical severity.

CONCLUSIONS

In-hospital fatality rate might be significantly higher in the 2017-2018 season in China. A sufficient supply of oseltamivir and antiviral therapy within 48 h from onset could reduce fatality rates.

[Influenza infection: An update for clinicians]

Lower respiratory infections remain the deadliest communicable disease in the world. Influenza infections are particularly involved, whether intrinsically, or more frequently, by promoting bacterial infections and superinfections. The flu is also responsible for the decompensation of many comorbidities and could lead to some myocardial infarction and stroke. The effect of antiviral therapies is limited but preventives measures, such as vaccination, remain a major public health issue. The flu is a major challenge at all levels and all times, from vaccine prevention, to the recognition of atypical forms, and the early management of bacterial complications.

Clinical features of Mycoplasma pneumoniae coinfection and need for its testing in influenza pneumonia patients

Background

To investigate the clinical features of coinfection due to Mycoplasma pneumoniae (M. pneumoniae), a common copathogen in influenza, in influenza pneumonia patients.

Methods

We reviewed 4,465 patients with influenza who visited a tertiary care hospital emergency department in Seoul (Korea) from 2010 through 2016, and underwent immunoglobulin M (IgM) serology or polymerase chain reaction (PCR) for M. pneumoniae. Influenza pneumonia was defined as laboratory-confirmed influenza plus radiographic pneumonia. Patients with healthcare-associated pneumonia or non-mycoplasma bacterial coinfection were excluded. Clinical, laboratory, and radiographic findings and outcomes of the influenza pneumonia patients with and without M. pneumoniae coinfection were compared. Multivariable logistic regression analysis was performed to identify factors associated with the coinfection.

Results

Of 244 influenza pneumonia patients, 41 (16.8%) had M. pneumoniae coinfection. These patients were younger with a higher frequency of age of 5-10 years, and had higher white blood cell (WBC) and lymphocyte counts; lower concentration of C-reactive protein (CRP). The coinfection had no association with specific radiographic findings and poor outcome. Multivariable analysis showed the age of 5-10 years (adjusted odds ratio, 18.83; 95% confidence interval, 5.899-60.08; P<0.001) as the factor associated with the coinfection.

Conclusions

M. pneumoniae coinfection in influenza pneumonia may be associated with the age of 5-10 years, and otherwise clinically indistinct from influenza pneumonia without the coinfection. This finding suggests the need for M. pneumoniae testing in patients aged 5-10 years with influenza pneumonia.

STAT2 Signaling Regulates Macrophage Phenotype During Influenza and Bacterial Super-Infection

Influenza is a common respiratory virus that infects between 5 and 20% of the US population and results in 30,000 deaths annually. A primary cause of influenza-associated death is secondary bacterial pneumonia. We have previously shown that influenza induces type I interferon (IFN)-mediated inhibition of Type 17 immune responses, resulting in exacerbation of bacterial burden during influenza and Staphylococcus aureus super-infection. In this study, we investigated the role of STAT2 signaling during influenza and influenza-bacterial super-infection in mice. Influenza-infected STAT2^−/− mice had increased morbidity, viral burden, and inflammation when compared to wild-type mice. Despite an exaggerated inflammatory response to influenza infection, we found increased bacterial control and survival in STAT2 deficient mice during influenza-MRSA super-infection compared to controls. Further, we found that increased bacterial clearance during influenza-MRSA super-infection is not due to rescue of Type 17 immunity. Absence of STAT2 was associated with increased accumulation of M1, M2 and M1/M2 co-expressing macrophages during influenza-bacterial super-infection. Neutralization of IFNγ (M1) and/or Arginase 1 (M2) impaired bacterial clearance in Stat2^−/− mice during super-infection, demonstrating that pulmonary macrophages expressing a mixed M1/M2 phenotype promote bacterial control during influenza-bacterial super-infection. Together, these results suggest that the STAT2 signaling is involved in suppressing macrophage activation and bacterial control during influenza-bacterial super-infection. Further, these studies reveal novel mechanistic insight into the roles of macrophage subpopulations in pulmonary host defense.

Influenza in Asthmatics: For Better or for Worse?

Asthma and influenza are two pathologic conditions of the respiratory tract that affect millions worldwide. Influenza virus of the 2009 pandemic was highly transmissible and caused severe respiratory disease in young and middle-aged individuals. Asthma was discovered to be an underlying co-morbidity that led to hospitalizations during this influenza pandemic albeit with less severe outcomes. However, animal studies that investigated the relationship between allergic inflammation and pandemic (p)H1N1 infection, showed that while characteristics of allergic airways disease were exacerbated by this virus, governing immune responses that cause exacerbations may actually protect the host from severe outcomes associated with influenza. To better understand the relationship between asthma and severe influenza during the last pandemic, we conducted a systematic literature review of reports on hospitalized patients with asthma as a co-morbid condition during the pH1N1 season. Herein, we report that numerous other underlying conditions, such as cardiovascular, neurologic, and metabolic diseases may have been underplayed as major drivers of severe influenza during the 2009 pandemic. This review synopses, (1) asthma and influenza independently, (2) epidemiologic data surrounding asthma during the 2009 influenza pandemic, and (3) recent advances in our understanding of allergic host–pathogen interactions in the context of allergic airways disease and influenza in mouse models. Our goal is to showcase possible immunological benefits of allergic airways inflammation as countermeasures for influenza virus infections as a learning tool to discover novel pathways that can enhance our ability to hinder influenza virus replication and host pathology induced thereof.

Effect of Tea Catechins on Influenza Infection and the Common Cold with a Focus on Epidemiological/Clinical Studies

Influenza and the common cold are acute infectious diseases of the respiratory tract. Influenza is a severe disease that is highly infectious and can progress to life-threating diseases such as pneumonia or encephalitis when aggravated. Due to the fact that influenza infections and common colds spread easily via droplets and contact, public prevention measures, such as hand washing and facial masks, are recommended for influenza prophylaxis. Experimental studies have reported that tea catechins inhibited influenza viral adsorption and suppressed replication and neuraminidase activity. They were also effective against some cold viruses. In addition, tea catechins enhance immunity against viral infection. Although the antiviral activity of tea catechins has been demonstrated, the clinical evidence to support their utility remains inconclusive. Since the late 1990s, several epidemiological studies have suggested that the regular consumption of green tea decreases influenza infection rates and some cold symptoms, and that gargling with tea catechin may protect against the development of influenza infection. This review briefly summarizes the effect of tea catechins on influenza infection and the common cold with a focus on epidemiological/clinical studies, and clarifies the need for further studies to confirm their clinical efficacy.

South African medicinal plant extracts active against influenza A virus

BACKGROUND

Influenza infection remains a major health threat for animals and humans which crucially requires effective antiviral remedies. The usage of herbal medications as readily available alternatives for their compatibility with the body and fewer side effects compared to synthetic chemical treatments has become popular globally. The aim of this study was to investigate and screen in vitro anti-influenza activity of extracts of five South African medicinal plants, namely Tabernaemontana ventricosa, Cussonia spicata, Rapanea melanophloeos, Pittosporum viridiflorum and Clerodendrum glabrum, species which are used traditionally for the treatment of several diseases such as inflammatory and respiratory diseases.

METHODS

Methanol, ethanol (100% and 30%), acetone, hot and cold water extracts of the powdered plants leaves were obtained by standard methods. The cytotoxicity was determined by the MTT colorimetric assay on MDCK cells. The concentrations below CC₅₀ values were tested for antiviral activity against influenza A virus (IAV) in different combination treatments. The effect of extracts on viral surface glycoproteins and viral titer were tested by HI and HA virological assays, respectively.

RESULTS

Based on the applied methods, the most effective results against IAV were obtained from Rapanea melanophloeos methanol leaf extract (EC₅₀ = 113.3 μg/ml) and Pittosporum viridiflorum methanol, 100% and 30% ethanol and acetone leaf extracts (EC₅₀ values = 3.6, 3.4, 19.2, 82.3 μg/ml, respectively) in all types of combined treatments especially in pre- and post-penetration combined treatments with highly significant effects against viral titer (P ≤ 0.01).

CONCLUSION

The outcomes offer for the first time a scientific basis for the use of extracts of Rapanea melanophloeos and Pittosporum viridiflorum against IAV. It is worth focusing on the isolation and identification of effective active compounds and elucidating the mechanism of action from these species. However, Tabernaemontana ventricosa, Cussonia spicata and Clerodendrum glabrum leaf extracts were ineffective in vitro in this study.