Outcome of Patients Admitted to Intensive Care Units due to Influenza-Related Severe Acute Respiratory Illness in 2017-2018 Flu Season: A Multicenter Study from Turkey

Influenza A virus replicates productively in primary human kidney cells and induces factors and mechanisms related to regulated cell death and renal pathology observed in virus-infected patients

Introduction

Influenza A virus (IAV) infection can cause the often-lethal acute respiratory distress syndrome (ARDS) of the lung. Concomitantly, acute kidney injury (AKI) is frequently noticed during IAV infection, correlating with an increased mortality. The aim of this study was to elucidate the interaction of IAV with human kidney cells and, thereby, to assess the mechanisms underlying IAV-mediated AKI.

Methods

To investigate IAV effects on nephron cells we performed infectivity assays with human IAV, as well as with human isolates of either low or highly pathogenic avian IAV. Also, transcriptome and proteome analysis of IAV-infected primary human distal tubular kidney cells (DTC) was performed. Furthermore, the DTC transcriptome was compared to existing transcriptomic data from IAV-infected lung and trachea cells.

Results

We demonstrate productive replication of all tested IAV strains on primary and immortalized nephron cells. Comparison of our transcriptome and proteome analysis of H1N1-type IAV-infected human primary distal tubular cells (DTC) with existing data from H1N1-type IAV-infected lung and primary trachea cells revealed enrichment of specific factors responsible for regulated cell death in primary DTC, which could be targeted by specific inhibitors.

Discussion

IAV not only infects, but also productively replicates on different human nephron cells. Importantly, multi-omics analysis revealed regulated cell death as potential contributing factor for the clinically observed kidney pathology in influenza.

Characterizing deaths among adult patients with severe acute respiratory infection: during the pre- and COVID-19 pandemic periods in Bangladesh, 2018-2022

BACKGROUND

Severe acute respiratory infection (SARI) is a leading cause of mortality globally, peaking during the COVID-19 pandemic. We analyzed SARI-associated deaths during the pre-and-pandemic periods in Bangladesh to identify the contributing factors.

METHODS

We analyzed data from hospital-based influenza surveillance at nine tertiary-level hospitals in Bangladesh. We considered March 2018-February 2020 as the pre-pandemic period and March 2020-February 2022 as the pandemic period and included adult (≥ 18 years) participants in our study. Surveillance physicians identified WHO-SARI case definition meeting inpatients and collected demographics, clinical characteristics, and outcomes at hospital discharge and 30 days post-discharge. We performed rRT-PCR for influenza and SARS-CoV-2 viruses on collected nasopharyngeal and oropharyngeal swabs. We used multivariable Cox's regression models to calculate the hazard ratio (HR) for factors associated with SARI deaths in these adult patients.

RESULTS

We enrolled 4392 SARI patients during the pre-pandemic and 3824 SARI patients during the pandemic period. Case fatality ratio was higher during the pandemic: 13.62% (521) [in-hospital: 6.45% (247); post-discharge: 7.17% (274)] compared to pre-pandemic, 6.01% (264) [in-hospital: 2.01% (89), post-discharge: 4% (175)] (p < 0.001). Pre-pandemic, influenza was detected in 14% (37/264) of SARI deaths. Influenza was detected during the pandemic in 2.3% (12/521), SARS-CoV-2 in 41.8% (218/521), and both viruses in only one SARI death. History of smoking and the presence of 1 or more co-morbid conditions independently attributed to SARI deaths in adults in the pre-pandemic period. SARI deaths in such patients were also associated with respiratory difficulties on admission in both pre-pandemic (aHR 2.36; 95% CI:1.65-3.36) and pandemic period (aHR 2.30; 95% CI: 1.57-3.35) after accounting for age, sex, smoking status, presence of 1 or more co-morbid conditions, and detection of influenza and SARS-CoV-2 viruses.

CONCLUSIONS

During the pandemic, SARI mortality increased; influenza-associated mortality declined, and SARS-CoV-2 caused over a third of SARI deaths. Post-discharge mortality was higher than in-hospital mortality during both periods. Limiting premature discharge and strengthening post-discharge monitoring and nursing services could reduce unexpected deaths. Formative research to better understand post-discharge mortality is essential to reduce SARI deaths.

Age Differences in Comorbidities, Presenting Symptoms, and Outcomes of Influenza Illness Requiring Hospitalization: A Worldwide Perspective From the Global Influenza Hospital Surveillance Network

Background

The Global Influenza Hospital Surveillance Network (GIHSN) was established in 2012 to conduct coordinated worldwide influenza surveillance. In this study, we describe underlying comorbidities, symptoms, and outcomes in patients hospitalized with influenza.

Methods

Between November 2018 and October 2019, GIHSN included 19 sites in 18 countries using a standardized surveillance protocol. Influenza infection was laboratory-confirmed with reverse-transcription polymerase chain reaction. A multivariate logistic regression model was utilized to analyze the extent to which various risk factors predict severe outcomes.

Results

Of 16 022 enrolled patients, 21.9% had laboratory-confirmed influenza; 49.2% of influenza cases were A/H1N1pdm09. Fever and cough were the most common symptoms, although they decreased with age (P < .001). Shortness of breath was uncommon among those <50 years but increased with age (P < .001). Middle and older age and history of underlying diabetes or chronic obstructive pulmonary disease were associated with increased odds of death and intensive care unit (ICU) admission, and male sex and influenza vaccination were associated with lower odds. The ICU admissions and mortality occurred across the age spectrum.

Conclusions

Both virus and host factors contributed to influenza burden. We identified age differences in comorbidities, presenting symptoms, and adverse clinical outcomes among those hospitalized with influenza and benefit from influenza vaccination in protecting against adverse clinical outcomes. The GIHSN provides an ongoing platform for global understanding of hospitalized influenza illness.

Comparison of critically ill COVID-19 and influenza patients with acute respiratory failure

Background

Coronavirus disease 2019 (COVID-19) is one of the biggest pandemic causing acute respiratory failure (ARF) in the last century. Seasonal influenza carries high mortality, as well. The aim of this study was to compare features and outcomes of critically-ill COVID-19 and influenza patients with ARF.

Methods

Patients with COVID-19 and influenza admitted to intensive care unit with ARF were retrospectively analyzed.

Results

Fifty-four COVID-19 and 55 influenza patients with ARF were studied. Patients with COVID-19 had 32% of hospital mortality, while those with influenza had 47% (P=0.09). Patients with influenza had higher Eastern Cooperative Oncology Group, Clinical Frailty Scale, Acute Physiology and Chronic Health Evaluation II and admission Sequential Organ Failure Assessment (SOFA) scores than COVID-19 patients (P<0.01). Secondary bacterial infection, admission acute kidney injury, procalcitonin level above 0.2 ng/ml were the independent factors distinguishing influenza from COVID-19 while prone positioning differentiated COVID-19 from influenza. Invasive mechanical ventilation (odds ratio [OR], 42.16; 95% confidence interval [CI], 9.45–187.97), admission SOFA score more than 4 (OR, 5.92; 95% CI, 1.85–18.92), malignancy (OR, 4.95; 95% CI, 1.13–21.60), and age more than 65 years (OR, 3.31; 95% CI, 0.99–11.03) were found to be independent risk factors for hospital mortality.

Conclusions

There were few differences in clinical features of critically-ill COVID-19 and influenza patients. Influenza cases had worse performance status and disease severity. There was no significant difference in hospital mortality rates between COVID-19 and influenza patients.