An integrative pharmacology-based study on the efficacy and mechanism of essential oil of Chaihu Guizhi Decoction on influenza A virus induced pneumonia in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Chaihu Guizhi Decoction (CGD) has a long history of use in China for the treatment of influenza, which involves the use of a variety of aromatic herbs. Our previous studies have found that the contents of aromatic constituents in CGD affected the efficacy of treatment of influenza-infected mice, suggesting a clue that essential oil from CGD may play a relatively important role in ameliorating influenza induced pneumonia. AIM OF THE STUDY: To evaluate the anti-influenza potential of essential oil derived from Chaihu Guizhi Decoction (CGD-EO), to characterize and predict the key active components in CGD-EO, and to explore the mechanism of action of CGD-EO. MATERIALS AND METHODS: CGD-EO was obtained by steam distillation, and the components of the essential oil were characterized by gas chromatography-mass spectrometry (GC-MS) in conjunction with the retention index. The constituents absorbed into the blood of mice treated with CGD-EO were analyzed by headspace solid phase microextraction gas chromatography/mass spectrometry (HS-SPME-GC/MS). The potential anti-influenza active constituents and their possible action pathway were predicted by simulation using a network pharmacology approach. The protective effect of CGD-EO and its major components on H1N1/PR8-infected cells was determined using the CCK8 assay kit. Mice infected with influenza A virus H1N1/PR8 were administered different doses of CGD-EO orally and the body weights and lung weights were recorded. Mice with varying degrees of H1N1/PR8 infection were administered CGD-EO orally, and their daily weight, water consumption, and clinical indicators were recorded. Necropsies were conducted on days 3 and 5, during which lung weights were measured and lung tissues were preserved. Furthermore, the mRNA expression of the H1N1/PR8 virus and inflammatory factors in lung tissue was analyzed using RT-qPCR. RESULTS: (E)-cinnamaldehyde was the most abundant compound in the CGD-EO. The results of serum medicinal chemistry combined with network pharmacological analysis indicated that (E)-cinnamaldehyde and 3-phenyl-2-propenal may be potential active components of the CGD-EO anti-influenza, and may be involved in the NF-κB signalling pathway. In vitro studies have demonstrated that both CGD-EO and cinnamaldehyde exert a protective effect on MDCK cells infected with H1N1/PR8. In a 0.5 TCID50 H1N1/PR8-induced influenza model, mice treated with CGD-EO at a dose of 63.50 µg/kg exhibited a reduction in lung index, pathological lung lesions, and H1N1/PR8 viral gene levels. In addition, CGD-EO treatment was found to regulate the levels of inflammatory cytokines, including IL-6, TNF-α, and IFN-γ. Moreover, following three days of administration, an upregulation of NF-κB mRNA levels in mouse lung tissue was observed in response to CGD-EO treatment. CONCLUSIONS: The findings of our study indicate CGD-EO exerts a protective effect against H1N1-induced cytopathic lesions in vitro and is capable of alleviating H1N1-induced pneumonitis in mice. Moreover, it appears to be more efficacious in the treatment of mild symptoms of H1N1 infection. Studies have demonstrated that CGD-EO has antiviral potential to attenuate influenza-induced lung injury by modulating inflammatory cytokines and NF-κB signalling pathways during the early stages of influenza infection. It is possible that (E)-cinnamaldehyde is a potential active ingredient in the anti-influenza efficacy of CGD-EO.

[The rs2564978(T) Allele Associated with Severe Influenza A Disrupts the Binding Site for Myeloid Differentiation Factor PU.1 and Reduces CD55/DAF Gene Promoter Activity in Macrophages].

The complement inhibitor CD55/DAF is expressed on many cell types. Dysregulation of CD55 expression is associated with increased disease severity in influenza A infection and vascular complications in pathologies that involve excessive activation of the complement system. A luciferase reporter system was used to functionally analyze the single nucleotide polymorphism rs2564978 in the U937 human promonocytic cell line. The polymorphism is in the promoter of the CD55 gene, and its minor allele T is associated with a severe course of influenza A(H1N1)pdm09. A decreased activity of the CD55 promoter carrying the minor rs2564978(T) allele was observed in activated U937 cells, which provide a cell model of human macrophages. Using bioinformatics resources, PU.1 was identified as a potential transcription factor that may bind to the CD55 promoter at the rs2564978 site in an allele-specific manner. The involvement of PU.1 in modulating CD55 promoter activity was verified by a PU.1 genetic knockdown with small interfering RNAs under specific monocyte activation conditions.

Molecular epidemiology and vaccine compatibility analysis of seasonal influenza A viruses in the context of COVID-19 epidemic in Wuhan, China.

The COVID-19 pandemic had a significant impact on the global influenza vaccination and the epidemics of seasonal influenza. To further explore the molecular epidemiology of influenza viruses and assess vaccine effectiveness, we collected influenza cases in Wuhan during the 2022-2023 influenza season. Among 1312 clinical samples, 312 samples tested positive for influenza viruses using reverse transcription polymerase chain reaction. These positive samples included 146A/H1N1 subtypes (46.8%), 164A/H3N2 subtypes (52.6%) and 2 influenza B virus types (0.6%). Based on the whole genome sequence information of hemagglutinin (HA) and neuraminidase (NA) from 27A/H1N1 influenza virus strains and 26A/H3N2 influenza virus strains obtained in this study, a phylogenetic analysis was conducted. The analysis revealed that all A/H1N1 strains belonged to the evolutionary branch 6B.1A.5a.2a, and they exhibited specific substitutions at positions K71Q, Q206E, E241A, and R276K. Similarly, all A/H3N2 strains were classified into the 3C.2a1b.2a.1a subclade and displayed amino acid substitutions at positions S172H, N175Y, I176T, K187N, and S214P. Notably, the A/H3N2 strains also acquired a new potential glycosylation site at position N174. Using an epitope model, the predicted vaccine effectiveness was assessed for the A/H1N1 and A/H3N2 strains. The predicted vaccine effectiveness against the Wuhan influenza epidemic strain was over 85% for the A/H1N1 vaccine strain. However, the effectiveness against the A/H3N2 vaccine strain was only 48.7%. To further verify the protection of influenza vaccine against circulating influenza viruses in the region, we conducted in vivo and in vitro animal studies. The results of in vitro neutralization experiment showed that rabbit serum antibodies inoculated with quadrivalent isolated influenza vaccine had neutralization ability against all 24 isolated influenza viruses. In vivo experiments showed that vaccinated mice had fewer lung lesions when infected with the influenza strain circulating in Wuhan, suggesting that vaccination can effectively reduce the occurrence of severe lung damage. These findings emphasize the importance of accurately predicting seasonal influenza strains for effective influenza prevention and control, especially during the co-circulation of SARS-CoV-2 and influenza viruses. This study provides valuable information on the seasonal influenza virus in Wuhan during the COVID-19 pandemic and serves as a basis for vaccine prediction and updates.

First detection of influenza A virus subtypes H1N1 and H3N8 in the Antarctic region: King George Island, 2023.

RELEVANCE: Influenza A virus is characterized by a segmented single-stranded RNA genome. Such organization of the virus genome determines the possibility of reassortment, which can lead to the emergence of new virus variants. The main natural reservoir of most influenza A virus subtypes are wild waterfowl. Seasonal migrations gather waterfowl from all major migration routes to nesting areas near the northern and southern polar circles. This makes intercontinental spread of influenza A viruses possible. Objective ‒ to conduct molecular genetic monitoring and study the phylogenetic relationships of influenza A virus variants circulating in Antarctica in 2023. MATERIALS AND METHODS: We studied 84 samples of biological material obtained from birds and marine mammals in April‒May 2023 in coastal areas of Antarctica. For 3 samples, sequencing was performed on the Miseq, Illumina platform and phylogenetic analysis of the obtained nucleotide sequences of the influenza A virus genomes was performed. RESULTS: The circulation of avian influenza virus in the Antarctic region was confirmed. Heterogeneity of the pool of circulating variants of the influenza A virus (H3N8, H1N1) was revealed. Full-length genomes of the avian influenza virus were sequenced and posted in the GISAID database (EPI_ISL_19032103, 19174530, 19174467). CONCLUSION: The study of the genetic diversity of influenza A viruses circulating in the polar regions of the Earth and the identification of the conditions for the emergence of new genetic variants is a relevant task for the development of measures to prevent biological threats.

Ventilation does not affect close-range transmission of influenza virus in a ferret playpen setup.

Sustained community spread of influenza viruses relies on efficient person-to-person transmission. Current experimental transmission systems do not mimic environmental conditions (e.g., air exchange rates, flow patterns), host behaviors, or exposure durations relevant to real-world settings. Therefore, results from these traditional systems may not be representative of influenza virus transmission in humans. To address this pitfall, we developed a close-range transmission setup that implements a play-based scenario and used it to investigate the impact of ventilation rates on transmission. In this setup, four immunologically naive recipient ferrets were exposed to a donor ferret infected with a genetically barcoded 2009 H1N1 virus (H1N1pdm09) for 4 h. The ferrets interacted in a shared space that included toys, similar to a childcare setting. Transmission efficiency was assessed under low and high ventilation, with air exchange rates of ~1.3 h-1 and 23 h-1, respectively. Transmission efficiencies observed in three independent replicate studies were similar between ventilation conditions. The presence of infectious virus or viral RNA on surfaces and in air throughout the exposure area was also not impacted by the ventilation rate. While high viral genetic diversity in donor ferret nasal washes was maintained during infection, recipient ferret nasal washes displayed low diversity, revealing a narrow transmission bottleneck regardless of ventilation rate. Examining the frequency and duration of ferret physical touches revealed no link between these interactions and a successful transmission event. Our findings indicate that exposures characterized by frequent, close-range interactions and the presence of fomites can overcome the benefits of increased ventilation.

Effectiveness of influenza vaccines in children aged 6 to 59 months: a test-negative case-control study at primary care and hospital level, Spain 2023/24.

During 2023/24, all children aged 6 to 59 months were targeted for seasonal influenza vaccination in Spain nationally. Using a test-negative case-control design with sentinel surveillance data, we estimated adjusted influenza vaccine effectiveness (IVE) against any influenza type to be 70% (95% confidence interval (CI): 51 to 81%) for primary care patients with acute respiratory illness (ARI) and 77% (95% CI: 21 to 93%) for hospitalised patients with severe ARI. In primary care, where most subtyped viruses (61%; 145/237) were A(H1N1), adjusted IVE was 77% (95% CI: 56 to 88%) against A(H1N1)pdm09.

Evaluation and control strategy analysis of influenza cases in Jiujiang City, Jiangxi Province, China from 2018 to 2022.

According to World Trade Organization (WTO) statistics, the incidence of seasonal influenza in China has been on the rise since 2018. The aim of this study was to identify and investigate the influence of factors related to the incidence of four common types of influenza viruses. Data of patients with common cold and associated virus infections are described, and a logistic regression model based on gender, age and season was established. The relationship between virus type and the above three factors was analyzed in depth and significant (p<0.05) associations noted. We noted a fluctuation trend, with the infection rate of influenza virus showing an upward trend from 2018 to 2019 and from 2021 to 2022 and a downward trend from 2019 to 2021. The total number of cases in adolescents aged 18-30 years was higher than that in the elderly. The impact of different types of influenza virus on the population ranked from large to small, with special roles played by Influenza B/Victoria, H3N2, Influenza A/H1N1 pdm and Influenza B/Yamagata.

Smoking and serological response to influenza vaccine.

Cigarette smoking confers additional risk from influenza. This study assessed the effect of smoking on humoral immune response to influenza vaccine. Adults ≥50 y of age were enrolled during the 2011-2016 influenza vaccination seasons in an observational prospective study. Non-fasting whole blood samples for hemagglutination inhibition (HAI) assays were obtained from participants at pre- and 28 d post-clinically administered, trivalent influenza vaccination. Among 273 participants, 133 subjects self-reported as never smokers, 87 as ex-smokers, and 53 as current smokers. Postvaccination geometric mean HAI titers were significantly higher among smokers for A/H1N1 (p = .031) and A/H3N2 (p = .001). Relative to never smokers, smoking was independently related to seroconversion to A/H1N1, A/H3N2 and B. The adjusted odd ratios (ORs) were 5.2 [95% confidence interval (CI), 2.3, 11.5] for seroconversion to A/H1N1, 5.4 (95% CI, 2.4, 12.1) for A/H3N2, and 2.7 (95% CI, 1.3, 5.7) for B. Smoking was also independently related to seroprotection to A/H1N1, A/H3N2 and B. The ORs were 3.6 (95% CI, 1.6, 8.08) for seroprotection to A/H1N1 in smokers, 2.7 (95% CI, 1.14, 6.5) for A/H3N2, and 2.5 (95% CI, 1.1, 5.7) for B. Although the mechanism is unclear, smokers showed a better immune response to influenza vaccination than never smokers and ex-smokers. The results can be used to emphasize the value of influenza vaccination for smokers.

Dually-amplified electrochemical aptasensor based on the self-linking AuPt nanoflowers for ultrasensitive determination of hemagglutinin.

BACKGROUND: Influenza virus can spread from person to person and cause epidemics. Therefore, rapid and sensitive diagnosis of virus is essential in controlling influenza outbreaks. Conventional virus diagnostic techniques are time-consuming, labor-intensive and requires large instruments. In this work, a sandwich electrochemical assay by a pair of aptamers was developed for ultrasensitive determination of hemagglutinin (HA) protein, which is one of the two surface glycoproteins of influenza A (H1N1) virus, using dual signal amplification techniques. RESULTS: HA was captured and magnetically separated by Fe3O4@SiO2-NH2@Au attached to aptamer 1 (Apt1), creating a sandwich structure with AuPt nanoflowers (AuPtNFs) connected to aptamer 2 (Apt2). Herein, AuPtNFs could catalyze H2O2/hydroquinone (HQ) to generate 1,4-benzoquinone (BQ), and achieved amplification of electrochemical signal detection through differential pulse voltammetry (DPV). The constructed aptasensor expressed a wide linear range (10 pg/mL-100 ng/mL) with limit of detection (LOD) of 2.4 pg/mL. Moreover, a novel strategy for dual signal amplification was developed to further enhance sensitivity. The innovative electrochemical aptasensor could achieve secondary amplification of the detection signal with LOD of 0.3 pg/mL and linear concentration range from 0.5 pg/mL to 100 ng/mL. The secondary amplification could be achieved only through the self-linking process, which allowed for the retention of numerous AuPtNFs by simple complementary base pairing to connect more AuPtNFs onto the above-mentioned sandwich structure. SIGNIFICANCE: Overall, the constructed aptasensor exhibited favorable sensitivity and accuracy, indicating the potential expanded application for the clinical detection of numerous viruses.

Interim Effectiveness Estimates of 2024 Southern Hemisphere Influenza Vaccines in Preventing Influenza-Associated Hospitalization - REVELAC-i Network, Five South American Countries, March-July 2024.

To reduce influenza-associated morbidity and mortality, countries in South America recommend annual influenza vaccination for persons at high risk for severe influenza illness, including young children, persons with preexisting health conditions, and older adults. Interim estimates of influenza vaccine effectiveness (VE) from Southern Hemisphere countries can provide early information about the protective effects of vaccination and help guide Northern Hemisphere countries in advance of their season. Using data from a multicountry network, investigators estimated interim VE against influenza-associated severe acute respiratory illness (SARI) hospitalization using a test-negative case-control design. During March 13-July 19, 2024, Argentina, Brazil, Chile, Paraguay, and Uruguay identified 11,751 influenza-associated SARI cases; on average, 21.3% of patients were vaccinated against influenza, and the adjusted VE against hospitalization was 34.5%. The adjusted VE against the predominating subtype A(H3N2) was 36.5% and against A(H1N1)pdm09 was 37.1%. These interim VE estimates suggest that although the proportion of hospitalized patients who were vaccinated was modest, vaccination with the Southern Hemisphere influenza vaccine significantly lowered the risk for hospitalization. Northern Hemisphere countries should, therefore, anticipate the need for robust influenza vaccination campaigns and early antiviral treatment to achieve optimal protection against influenza-associated complications.

Evaluating hand hygiene knowledge, attitudes, and practices among healthcare workers in post-pandemic H1N1 influenza control: a cross-sectional study from China.

Background: This study evaluates the knowledge, attitudes, and practices (KAP) of hand hygiene among healthcare workers, crucial for preventing healthcare-associated infections (HAIs) in medical facilities. Methodology: This cross-sectional study assessed hand hygiene KAP among healthcare workers across various settings in Hubei, China utilizing a stratified random sampling approach from, December 25, 2023-to-April 25, 2024. A bilingual electronic survey, adapted from validated tools, was disseminated via email and social media to ensure a broad reach. Participants included diverse healthcare professionals who met specific inclusion criteria. Responses were analyzed using R software, employing descriptive and inferential statistics to identify key predictors of hand hygiene behavior and to confirm the reliability of the survey instrument. Results: The survey of 2,265 healthcare workers revealed that 77% demonstrated comprehensive knowledge of hand hygiene, 80% exhibited positive attitudes, and 94% practiced effective hand hygiene. Notable findings include a significant understanding of hand hygiene's role in preventing respiratory illnesses (58%) and HAIs (41% agreed, 39% unsure). High compliance in practices like washing hands for at least 20 s was evident (84%), though gaps in confidence about hand hygiene techniques were noted (33% confident, 56% unsure). Binary logistic regression analysis indicated that younger healthcare workers (21-30 years) were more likely to exhibit both knowledge (OR = 7.4, 95% CI = 1.44-136, p = 0.059) and positive attitudes (OR = 4.48, 95% CI = 1.73-11.8, p < 0.001) compared to other age groups. Significant associations were found between higher income levels and positive attitudes toward hand hygiene (OR for ≥80,000 = 3.19, 95% CI = 2.05-5.02, p < 0.001), and between knowledge and practices, suggesting that well-informed individuals are more likely to adhere to recommended practices. Conclusion: The findings reveal robust hand hygiene knowledge but uncover critical confidence gaps among healthcare workers, urging immediate, targeted educational interventions to fortify adherence and prevent infection outbreaks.

Evaluation of antibacterial and antiviral efficacy of volatile organic compounds.

This study searched for volatile organic compounds (VOCs）having antibacterial and antiviral efficacy. The antibacterial efficacy of volatilized components was evaluated and (2E,4E）-2,4-hexadienal, α- angelica lactone, 2-cyclohexen-1-one and 2-cyclopenten-1-one were found to inhibit the formation of colonies of Staphylococcus aureus and Escherichia coli. Evaluating the antimicrobial efficacy of the surfaces to which each VOC adhered to, these four compounds were revealed to have antibacterial efficacy (antibacterial activity value (A-value）against S. aureus; ≧2.63, A-value against Klebsiella pneumoniae; >5.07, A-value against E. coli; ≧2.17）. Furthermore, (2E,4E）-2,4-hexadienal and α-angelica lactone were found to have antiviral efficacy against Influenza A virus (H1N1）and Feline calicivirus on the cotton cloths to which it adheres to (antiviral activity value (R-value）against Influenza A virus; >2.94, R-value against Feline calicivirus; ≧2.31）. Using these components, it might be possible to develop antimicrobial products that exhibit antibacterial and antiviral efficacy.

PEG-SeNPs as therapeutic agents inhibiting apoptosis and inflammation of cells infected with H1N1 influenza A virus.

The rapid variation of influenza challenges vaccines and treatments, which makes an urgent task to develop the high-efficiency and low-toxicity new anti-influenza virus drugs. Selenium is one of the essential trace elements for the human body that possesses a good antiviral activity. In this study, we assessed anti-influenza A virus (H1N1) activity of polyethylene glycol (PEG)-modified gray selenium nanoparticles (PEG-SeNPs) on Madin-Darby Canine Kidney (MDCK) cells in vitro. CCK-8 assay showed that PEG-SeNPs had a protective effect on H1N1-infected MDCK cells. Moreover, PEG-SeNPs significantly reduced the mRNA level of H1N1. TUNEL-DAPI test showed that DNA damage reached a high level but effectively prevented after PEG-SeNPs treatment. Meanwhile, JC-1, Annexin V-FITC and cell cycle assay demonstrated the apoptosis induced by H1N1 was reduced greatly when treated with PEG-SeNPs. Furthermore, the downregulation of p-ATM, p-ATR and P53 protein, along with the upregualation of AKT protein indicated that PEG-SeNPs could inhibit H1N1-induced cell apoptosis through reactive oxygen species (ROS)-mediated related signaling pathways. Finally, Cytokine detection demonstrated PEG-SeNPs inhibited the production of pro-inflammatory factors after infection, including IL-1ß, IL-5, IL-6, and TNF-α. To sum up, PEG-SeNPs might become a new potential anti-H1N1 influenza virus drug due to its antiviral and anti-inflammatory activity.

Impact of the Swine flu pandemic on General Practitioner (GP) visits in Finland: sex and age differences.

BACKGROUND: Swine flu might serve as a model for challenges that primary care faces during pandemics. This study examined changes in the numbers and diagnoses of general practitioner (GP) visits during and after the Swine flu pandemic in Vantaa, a Finnish city, and how GP activities recovered after the pandemic. Putative sex and age group differences were also evaluated. METHODS: The study was an observational retrospective study. The monthly number of patient visits to primary care GPs by women and men in age groups 0-19, 20-64 and 65 + years was recorded before, during and two years after the Swine flu pandemic. The recorded diagnoses were also examined. The investigation period was from 2008 to 2012. RESULTS: The numbers of monthly visits to primary care decreased from 12 324 (mean) to 10 817 in women and from 8563 to 7612 in men during the first six months of the Swine flu, returning to the original level afterwards. This decrease was thus slightly more prominent in women. However, as the size of the population increased during the follow-up period, the actual number of GP visits adjusted for the size of population remained at a decreased level for two years after the Swine flu. This decrease was observed especially in office-hours visits of men (from 3692 to 3260) and women (from 6301 to 5428) of 20-64 years. Swine flu did not alter the number of visits to the primary care Emergency Department. The proportion of visits with diagnostic recordings of common infectious diseases mostly decreased during the Swine flu. Only a minor impact on the distribution of recordings of chronic diagnoses was found. CONCLUSION: A pandemic, such as Swine flu, may decrease office-hours visits to primary care GPs. This in turn may lead to activities of primary care being adjusted downward for a long time following the pandemic. Especially the age group 20-64 years may be affected. This risk should be considered when recovery from the COVID-19 pandemic begins. Swine flu did not affect the proportion of consultations of chronic diseases, but the number of diagnoses of common infectious diseases had diminished.

Yeast Surface-Displayed Quenchbody as a Novel Whole-Cell Biosensor for One-Step Detection of Influenza A (H1N1) Virus.

Timely surveillance of airborne pathogens is essential to preventing the spread of infectious diseases and safeguard human health. Methods for sensitive, efficient, and cost-effective detection of airborne viruses are needed. With advances in synthetic biology, whole-cell biosensors have emerged as promising platforms for environmental monitoring and medical diagnostics. However, the current design paradigm of whole-cell biosensors is mostly based on intracellular detection of analytes that can transport across the cell membrane, which presents a critical challenge for viral pathogens and large biomolecules. To address this challenge, we developed a new type of whole-cell biosensor by expressing and displaying VHH-based quenchbody (Q-body) on the surface of the yeast Saccharomyces cerevisiae for simple one-step detection of influenza A (H1N1) virus. Seventeen VHH antibody fragments targeting the hemagglutinin protein H1N1-HA were displayed on the yeast cells and screened for the H1N1-HA binding affinity. The functionally displayed VHHs were selected to create surface-displayed Q-body biosensors. The surface-displayed Q-body exhibiting the highest quenching and dequenching efficiency was identified. The biosensor quantitatively detected H1N1-HA in a range from 0.5 to 16 µg/mL, with a half-maximal concentration of 2.60 µg/mL. The biosensor exhibited high specificity for H1N1-HA over other hemagglutinin proteins from various influenza A virus subtypes. Moreover, the biosensor succeeded in detecting the H1N1 virus at concentrations from 2.4 × 104 to 1.5 × 107 PFU/mL. The results from this study demonstrated a new whole-cell biosensor design that circumvents the need for transport of analytes into biosensor cells, enabling efficient detection of the target virus particles.

Patients with influenza admitted to a tertiary-care hospital in Riyadh between 2018 and 2022: characteristics, outcomes and factors associated with ICU admission and mortality.

BACKGROUND: Influenza is a common cause of hospital admissions globally with regional variations in epidemiology and clinical profile. We evaluated the characteristics and outcomes of patients with influenza admitted to a tertiary-care center in Riyadh, Saudi Arabia. METHODS: This was a retrospective cohort of adult patients admitted with polymerase chain reaction-confirmed influenza to King Abdulaziz Medical City-Riyadh between January 1, 2018, and May 31, 2022. We compared patients who required intensive care unit (ICU) admission to those who did not and performed multivariable logistic regression to assess the predictors of ICU admission and hospital mortality. RESULTS: During the study period, 675 adult patients were hospitalized with influenza (median age 68.0 years, females 53.8%, hypertension 59.9%, diabetes 55.1%, and chronic respiratory disease 31.1%). Most admissions (83.0%) were in the colder months (October to March) in Riyadh with inter-seasonal cases even in the summertime (June to August). Influenza A was responsible for 79.0% of cases, with H3N2 and H1N1 subtypes commonly circulating in the study period. Respiratory viral coinfection occurred in 12 patients (1.8%) and bacterial coinfection in 42 patients (17.4%). 151 patients (22.4%) required ICU admission, of which 62.3% received vasopressors and 48.0% mechanical ventilation. Risk factors for ICU admission were younger age, hypertension, bilateral lung infiltrates on chest X-ray, and Pneumonia Severity Index. The overall hospital mortality was 7.4% (22.5% for ICU patients, p < 0.0001). Mortality was 45.0% in patients with bacterial coinfection, 30.9% in those requiring vasopressors, and 29.2% in those who received mechanical ventilation. Female sex (odds ratio [OR], 2.096; 95% confidence interval [CI] 1.070, 4.104), ischemic heart disease (OR, 3.053; 95% CI 1.457, 6.394), immunosuppressed state (OR, 7.102; 95% CI 1.803, 27.975), Pneumonia Severity Index (OR, 1.029; 95% CI, 1.017, 1.041), leukocyte count and serum lactate level (OR, 1.394; 95% CI, 1.163, 1.671) were independently associated with hospital mortality. CONCLUSIONS: Influenza followed a seasonal pattern in Saudi Arabia, with H3N2 and H1N1 being the predominant circulating strains during the study period. ICU admission was required for > 20%. Female sex, high Pneumonia Severity Index, ischemic heart disease, and immunosuppressed state were associated with increased mortality.

Epidemiology and genetic characterization of influenza viruses circulating in Bhutan in 2022.

INTRODUCTION: Influenza (Flu) causes considerable morbidity and mortality globally, and in Bhutan, Flu viruses are a leading cause of acute respiratory infection and cause outbreaks during Flu seasons. In this study, we aim to analyze the epidemiology and the genetic characterization of Flu viruses circulated in Bhutan in 2022. METHOD: Respiratory specimens were collected from patients who meet the case definition for influenza-like illness (ILI) and severe acute respiratory infection (SARI) from sentinel sites. Specimens were tested for Flu and SARS-CoV-2 viruses by RT-PCR using the Multiplex Assay. Selected positive specimens were utilized for Flu viral genome sequencing by next-generation sequencing. Descriptive analysis was performed on patient demographics to see the proportion of Flu-associated ILI and SARI. All data were analyzed using Epi Info7 and QGIS 3.16 software. RESULT: A weekly average of 16.2 ILI cases per 1000 outpatient visits and 18 SARI cases per 1000 admitted cases were reported in 2022. The median age among ILI was 12 years (IQR: 5-28) and SARI was 6.2 (IQR: 2.5-15) years. Flu A(H3N2) (70.2%) subtype was the most predominant circulating strain. Flu A(H1N1)pdm09 and Flu B viruses belonged to subclades that were mismatched to the vaccine strains recommended for the 2021-2022 season but matched the vaccine strain for the 2022-2023 season with vaccine efficacy 85.14% and 88.07% respectively. Flu A(H3N2) virus belonged to two subclades which differed from the vaccine strains recommended in both the 2021-2022 and 2022-2023 seasons with vaccine efficacy 68.28%. CONCLUSION: Flu virus positivity rates were substantially elevated during the Flu season in 2022 compared to 2021. Flu A(H3N2) subtype was the most predominant circulating strain in the country and globally. Genetic characterization of the Flu viruses in Bhutan showed a close relatedness of high vaccine efficacy with the vaccine strain that WHO recommended for the 2022-23 season.

Influenza A (H1N1) in Hospitalized Children.

BACKGROUND: Influenza A (H1N1) is a contagious respiratory infection caused by the influenza A virus. In the majority of cases, H1N1 influenza is benign. However, it can be dangerous for infants and children with underlying chronic diseases. The severity of influenza depends on various factors, including the virulence of the virus strain, preexisting immunity level, and individual health conditions. The aim of this study is to describe the clinical profile of H1N1 influenza in hospitalized infants and children. METHODS: This is a prospective and descriptive study conducted from November 1, 2018, to January 31, 2024. In this study, we included all children under 14 years old hospitalized for suspected severe lower respiratory infection who had gone through virological testing. We used a multiplex polymerase chain reaction (PCR) kit: the Film Array-Respiratory Panel. Due to the depletion of multiplex PCR kits, this study continued using rapid influenza diagnostic tests based on immunochromatographic technique. RESULTS: We report 45 confirmed cases of H1N1 influenza, collected during the period from November 1, 2018, to January 31, 2024. The average age was 2 years and 4 months. The main reason for admission was respiratory distress found in all patients. In 53% of the cases, there was an associated comorbidity, including asthma (17 cases), prematurity (2 cases), congenital adrenal hyperplasia (2 cases), cystic fibrosis (1 case), undetermined etiology bronchial dilation (1 case), and Basedow's disease (1 case). The clinical presentation included viral bronchiolitis (17 cases), moderate asthma exacerbation (10 cases), severe asthma exacerbation (7 cases), pneumonia (9 cases), bronchial dilation exacerbation (1 case), and flu-like syndrome with adrenal insufficiency (1 case). Fever was present in 31 patients. Gastrointestinal symptoms such as diarrhea and vomiting were present in 20 cases. Three patients required intensive care, with 2 children being intubated and ventilated (one severe acute asthma and one severe viral bronchiolitis). Two cases were treated with oseltamivir. The average length of hospital stay was 7.5 days, ranging from 3 to 20 days. All cases showed favorable evolution. CONCLUSIONS: We conclude that preventive measures remain crucial, and influenza vaccination is highly recommended in cases of underlying morbidity.

Clinical presentations and diagnostic approaches of pediatric necrotizing tracheobronchitis with influenza A virus and Staphylococcus aureus co-infections.

In March 2023, our pediatric intensive care unit (PICU) retrospectively examined six cases of pediatric necrotizing tracheobronchitis (NTB), focusing on co-infections with influenza A virus (IAV) and Staphylococcus aureus (S. aureus). This study aimed to elucidate NTB's clinical characteristics, diagnostics, and therapeutic approaches. Diagnostics included symptom assessment, microbiological testing that confirmed all patients were positive for IAV H1N1 with a predominant S. aureus co-infection, and bronchoscopy. The patients predominantly exhibited fever, cough, and dyspnea. Laboratory analysis revealed decreased lymphocyte counts and elevated infection markers like C-reactive protein and procalcitonin. Chest computed tomography (CT) scans detected tracheobronchial obstructions in half of the cases, while bronchoscopy showed severe mucosal congestion, edema, necrosis, and purulent-hemorrhagic exudates. Treatments encompassed comprehensive strategies like oxygen therapy, intubation, bronchoscopic interventions, thoracentesis, oseltamivir, and a regimen of antibiotics. Our findings suggested potential correlations between clinical markers, notably lymphocyte count and procalcitonin, and clinical interventions such as the number of rescues and intensive care unit (ICU) duration. This research highlights the importance of early detection and the role of bronchoscopy and specific markers in assessing NTB, advocating for continued research in larger cohorts to better understand its clinical trajectory and refine treatment approaches for this challenging pediatric disease.