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We construct text-based measures of the primary concerns listed firms associated with the spread of COVID-19 and other epidemic diseases. We identify which firms perceive to lose or gain from a given epidemic and textually decompose the epidemic's effect on the firm's demand and supply. We find that the effects of COVID-19 manifest as a simultaneous shock to demand and supply, with both shocks affecting firms' market valuations in equal measure on average. By contrast, demand-related impacts appear more important in accounting for the observed collapse in firm-level investment during the COVID-19 crisis. Authors have furnished an Internet Appendix , which is available on the Oxford University Press Web site next to the link to the final published paper online [ABSTRACT FROM AUTHOR]

This article explores the potential drawbacks of increased regulation of laboratory-developed tests (LDTs) and challenges the assumption that more regulation automatically leads to better quality. It argues that excessive regulation could actually pose a greater risk to the quality of LDTs and highlights instances where LDTs have performed favorably compared to FDA-cleared tests. The article emphasizes the advantages of LDTs, such as their ability to quickly adapt to changing needs. It concludes that increased regulation may have negative effects on test quality, innovation, and access to tests for uncommon conditions or limited markets. The article also references three other articles that discuss topics related to laboratory testing, including the use of quantitative hCG immunoassays as tumor markers, the laboratory diagnosis of the 2009 H1N1 influenza A virus, and the interference of biotin in laboratory tests. These additional articles may be of interest to library patrons researching these specific topics. [Extracted from the article]

Despite its increasing role in the understanding of infectious disease transmission at the applied and theoretical levels, phylodynamics lacks a well-defined notion of ideal data and optimal sampling. We introduce a method to visualize and quantify the relative impact of pathogen genome sequence and sampling times—two fundamental sources of data for phylodynamics under birth–death-sampling models—to understand how each drives phylodynamic inference. Applying our method to simulated data and real-world SARS-CoV-2 and H1N1 Influenza data, we use this insight to elucidate fundamental trade-offs and guidelines for phylodynamic analyses to draw the most from sequence data. Phylodynamics promises to be a staple of future responses to infectious disease threats globally. Continuing research into the inherent requirements and trade-offs of phylodynamic data and inference will help ensure phylodynamic tools are wielded in ever more targeted and efficient ways. [ABSTRACT FROM AUTHOR]

Background Obesity dysregulates immunity to influenza infection. Therefore, there is a critical need to investigate how obesity impairs immunity and to establish therapeutic approaches that mitigate the impact of increased adiposity. One mechanism by which obesity may alter immune responses is through changes in cellular metabolism. Methods We studied inflammation and cellular metabolism of peripheral blood mononuclear cells (PBMCs) isolated from individuals with obesity relative to lean controls. We also investigated if impairments to PBMC metabolism were reversible upon short-term weight loss following bariatric surgery. Results Obesity was associated with systemic inflammation and poor inflammation resolution. Unstimulated PBMCs from participants with obesity had lower oxidative metabolism and adenosine triphosphate (ATP) production compared to PBMCs from lean controls. PBMC secretome analyses showed that ex vivo stimulation with A/Cal/7/2009 H1N1 influenza led to a notable increase in IL-6 with obesity. Short-term weight loss via bariatric surgery improved biomarkers of systemic metabolism but did not improve markers of inflammation resolution, PBMC metabolism, or the PBMC secretome. Conclusions These results show that obesity drives a signature of impaired PBMC metabolism, which may be due to persistent inflammation. PBMC metabolism was not reversed after short-term weight loss despite improvements in measures of systemic metabolism. [ABSTRACT FROM AUTHOR]

There have been numerous reports of patients initially misdiagnosed in the 2009 H1N1 influenza and coronavirus disease 2019 (COVID-19) pandemics within the literature. A systematic review was undertaken to collate misdiagnoses during the H1N1 and COVID-19 pandemics and identify which cognitive biases may contribute to this. MEDLINE, Embase, Cochrane and MedRxiv databases were searched for misdiagnoses or cognitive biases resulting in misdiagnosis, occurring during the H1N1 or COVID-19 virus pandemics. Eligible studies were assessed for quality using JBI criteria; primary outcome was the final diagnosis. Sixty-nine studies involving 2551 participants were included. We identified 686 cases of misdiagnosis, categorized as viral respiratory infection, other respiratory infection, non-respiratory infection, and non-infective. Misdiagnoses are listed and relevant investigations are offered. No article described prospective assessment of decision making in the pandemic setting or debiasing diagnostic thinking. Further research is required to understand why misdiagnoses occur and harm arises and how clinicians can be assisted in their decision making in a pandemic context. [ABSTRACT FROM AUTHOR]

This study aims to review articles reporting the perspectives and experiences of pandemic-related discrimination among racially minoritized peoples in high-income contexts. We searched online databases (Medline, EMBASE, PsycINFO, Web of Science, and ProQuest) for peer-reviewed articles published between January 2002 and October 2020. Eligible studies reported either quantitative or qualitative accounts of pandemic-related discrimination from the perspectives of racially minoritized peoples in high-income contexts. Two authors screened 30% of titles/abstracts, and all full-text articles. Each article included for extraction underwent a quality assessment by two reviewers. Data were extracted and categorized thematically using NVivo 12, followed by a secondary analysis informed by critical race theory. Of the 1289 articles screened, 16 articles from five countries met the inclusion criteria. Racial discrimination is heightened during pandemic periods, due to the social association of specific racial groups with pandemic diseases including COVID-19, SARS (Asian), H1N1 (Hispanic) and Ebola (African). Fear based responses to racially minoritized peoples during pandemic periods included verbal/physical abuse, hypersurveillance, and avoidance, often occurring in public spaces. Pandemic-related racism had subsequent impacts on mental health and health care accessibility. Various coping strategies, including community support, avoidance, and problem solving, were documented in response to racial discrimination. Racialized discrimination and violence is a serious threat to the health and wellbeing of racially minoritized peoples, particularly due to its increase during pandemic periods. Racism must be recognized as a public health issue, and efforts to address its increased impact in pandemic contexts should be made, including ensuring that adequate representation of racially minoritized groups is present in policy, planning, and implementation. [ABSTRACT FROM AUTHOR]

High-throughput sequencing enables rapid genome sequencing during infectious disease outbreaks and provides an opportunity to quantify the evolutionary dynamics of pathogens in near real-time. One difficulty of undertaking evolutionary analyses over short timescales is the dependency of the inferred evolutionary parameters on the timespan of observation. Crucially, there are an increasing number of molecular clock analyses using external evolutionary rate priors to infer evolutionary parameters. However, it is not clear which rate prior is appropriate for a given time window of observation due to the time-dependent nature of evolutionary rate estimates. Here, we characterize the molecular evolutionary dynamics of SARS-CoV-2 and 2009 pandemic H1N1 (pH1N1) influenza during the first 12 months of their respective pandemics. We use Bayesian phylogenetic methods to estimate the dates of emergence, evolutionary rates, and growth rates of SARS-CoV-2 and pH1N1 over time and investigate how varying sampling window and data set sizes affect the accuracy of parameter estimation. We further use a generalized McDonald–Kreitman test to estimate the number of segregating nonneutral sites over time. We find that the inferred evolutionary parameters for both pandemics are time dependent, and that the inferred rates of SARS-CoV-2 and pH1N1 decline by ∼50% and ∼100%, respectively, over the course of 1 year. After at least 4 months since the start of sequence sampling, inferred growth rates and emergence dates remain relatively stable and can be inferred reliably using a logistic growth coalescent model. We show that the time dependency of the mean substitution rate is due to elevated substitution rates at terminal branches which are 2–4 times higher than those of internal branches for both viruses. The elevated rate at terminal branches is strongly correlated with an increasing number of segregating nonneutral sites, demonstrating the role of purifying selection in generating the time dependency of evolutionary parameters during pandemics. [ABSTRACT FROM AUTHOR]

5-azacytidine-induced protein 2 (AZI2) is known to have a crucial role in antiviral innate immunity. This study aims to explore the roles of AZI2 in influenza-trigger pediatric pneumonia and its molecular mechanism. qPCR and immunoblotting assays were used to determine the levels of target genes and proteins. The lung infection mouse model was established by using PR8 H1N1 virus in AZI2 germline knockout (AZI2−/−) and wild-type (WT) mice. In addition, HEK293T cell-based luciferase reporter assays were used to investigate the regulatory effects of AZI2 on type I interferon. Immune precipitation and immunofluorescence staining were used to evaluate the interactions between AZI2 and TANK binding kinase 1 (TBK1). We observed an elevation in the expressions of IFN-I and AZI2 in peripheral blood mononuclear cells from the pneumonia patients with mild symptoms. Interestingly, AZI2 deficiency deteriorated the influenza-induced pathological symptoms in the lung as well as reduced the survival rate. It was further showed that AZI2 positively regulated the expressions of type I interferon, inflammatory cytokines, and IFN production-related genes. The molecular mechanism data revealed that AZI2 regulated the interactions between TBK1 and TANK. In summary, AZI2 positively regulates type I interferon production in influenza-induced pediatric pneumonia by promoting the interactions between TBK1 and TANK. [ABSTRACT FROM AUTHOR]

This study estimates the overall effect of two influenza vaccination programs consecutively administered in a cluster‐randomized trial in western Senegal over the course of two influenza seasons from 2009 to 2011. We apply cutting‐edge methodology combining social contact data with infection data to reduce bias in estimation arising from contamination between clusters. Our time‐varying estimates reveal a reduction in seasonal influenza from the intervention and a non‐significant increase in H1N1 pandemic influenza. We estimate an additive change in overall cumulative incidence (which was 6.13% in the control arm) of ‐0.68 percentage points during Year 1 of the study (95% CI: −2.53, 1.18). When H1N1 pandemic infections were excluded from analysis, the estimated change was −1.45 percentage points and was significant (95% CI, −2.81, −0.08). Because cross‐cluster contamination was low (0–3% of contacts for most villages), an estimator assuming no contamination was only slightly attenuated (−0.65 percentage points). These findings are encouraging for studies carefully designed to minimize spillover. Further work is needed to estimate contamination – and its effect on estimation – in a variety of settings. [ABSTRACT FROM AUTHOR]

Influenza type-A viruses (IAVs) present a global burden of human respiratory infections and mortality. Genome reassortment is an important mechanism through which epidemiologically novel influenza viruses emerge and a core step in the safe reassortment-incompetent live-attenuated influenza vaccine development. Currently, there are no data on the rate, spatial and temporal distribution, and role of reassortment in the evolution and diversification of IAVs circulating in Africa. We aimed to detect intra-subtype reassortment among Africa pandemic H1N1pdm09 (2009–10), seasonal H1N1pdm09 (2011–20), and seasonal H3N2 viruses and characterize the genomic architecture and temporal and spatial distribution patterns of the resulting reassortants. Our study was nested within the Uganda National Influenza Surveillance Programme. Next-generation sequencing was used to generate whole genomes (WGs) from 234 H1N1pdm09 (n  = 116) and H3N2 (n  = 118) viruses sampled between 2010 and 2018 from seven districts in Uganda. We combined our newly generated WGs with 658 H1N1pdm09 and 1131 H3N2 WGs sampled between 1994 and 2020 across Africa and identified reassortants using an automated Graph Incompatibility Based Reassortment Finder software. Viral reassortment rates were estimated using a coalescent reassortant constant population model. Phylogenetic analysis was used to assess the effect of reassortment on viral genetic evolution. We observed a high frequency of intra-subtype reassortment events, 12 · 4 per cent (94/758) and 20 · 9 per cent (256/1,224), and reassortants, 13 · 3 per cent (101/758) and 38 · 6 per cent (472/1,224), among Africa H1N1pdm09 and H3N2 viruses, respectively. H1N1pdm09 reassorted at higher rates (0.1237–0.4255) than H3N2 viruses (0 · 00912–0.0355 events/lineage/year), a case unique to Uganda. Viral reassortants were sampled in 2009 through 2020, except in 2012. 78 · 2 per cent (79/101) of H1N1pdm09 reassortants acquired new non-structural, while 57 · 8 per cent (273/472) of the H3N2 reassortants had new hemagglutinin (H3) genes. Africa H3N2 viruses underwent more reassortment events involving larger reassortant sets than H1N1pdm09 viruses. Viruses with a specific reassortment architecture circulated for up to five consecutive years in specific countries and regions. The Eastern (Uganda and Kenya) and Western Africa harboured 84 · 2 per cent (85/101) and 55 · 9 per cent (264/472) of the continent's H1N1pdm09 and H3N2 reassortants, respectively. The frequent reassortment involving multi-genes observed among Africa IAVs showed the intracontinental viral evolution and diversification possibly sustained by viral importation from outside Africa and/or local viral genomic mixing and transmission. Novel reassortant viruses emerged every year, and some persisted in different countries and regions, thereby presenting a risk of influenza outbreaks in Africa. Our findings highlight Africa as part of the global influenza ecology and the advantage of implementing routine whole-over partial genome sequencing and analyses to monitor circulating and detect emerging viruses. Furthermore, this study provides evidence and heightens our knowledge on IAV evolution, which is integral in directing vaccine strain selection and the update of master donor viruses used in recombinant vaccine development. [ABSTRACT FROM AUTHOR]

The pandemic influenza A (H1N1) virus spread globally and posed one of the most serious global public health challenges. The traditional Chinese medicine is served as a complementary treatment strategy with vaccine immunization. Here, we demonstrated that the mixed polysaccharides (MPs) derived from shiitake mushroom, poriacocos, ginger, and tyangerine peel prevent the H1N1 virus infections in mice. MP pretreatment attenuated H1N1 virus-induced weight loss, clinical symptoms, and death. The lymphocytes detection results showed that the CD3+, CD19+, and CD25+ cell proportions were upregulated in thymus under MP pretreatment. Besides, MP pretreatment reduced the inflammatory cell infiltration and increased the cell proportions of CD19+, CD25+, and CD278+ in lung. However, MP treatment have no effective therapeutic effect after H1N1 virus challenge. The current study suggested that pretreatment with MPs could attenuate H1N1 virus-induced lung injury and upregulate humoral and cellular immune responses in nonimmunized mice. [ABSTRACT FROM AUTHOR]

Viruses are often cultured in cell lines for research and vaccine development, and those often differ from the natural hosts or tissues. Cell lines can also differ in the presence of virus receptors, such as the sialic acid (Sia) receptors used by influenza A viruses (IAV), which can vary in linkage (α2,3‐ or α2,6‐linkage) and form (N‐glycolylneuraminic acid [Neu5Gc] or N‐acetylneuraminic acid [Neu5Ac]). The selective pressures resulting from passaging viruses in cell types with host‐specific variations in viral receptors are still only partially understood. IAV are commonly cultured in MDCK cells which are both derived from canine kidney tubule epithelium and inherently heterogeneous. MDCK cells naturally present Neu5Ac and α2,3‐linked Sia forms. Here, we examine natural MDCK variant lineages, as well as engineered variants that synthesize Neu5Gc and/or α2,6‐linkages. We determined how viral genetic variation occurred within human H3N2, H1N1 pandemic and canine H3N2 IAV populations when serially passaged in MDCK cell lines that vary in cell type (MDCK‐Type I or MDCK‐Type II clones) and in Sia display. Deep sequencing of viral genomes showed small numbers of consensus‐level mutations, mostly within the hemagglutinin (HA) gene. Both human IAV showed variants in the HA stem and the HA receptor‐binding site of populations passaged in cells displaying Neu5Gc. Canine H3N2 showed variants near the receptor‐binding site when passaged in cells displaying Neu5Gc or α2,6‐linkages. Viruses replicated to low titres in MDCK‐Type II cells, suggesting that not all cell types in heterogeneous MDCK cell populations are equally permissive to infection. [ABSTRACT FROM AUTHOR]

Background Pneumonia is a leading cause of mortality worldwide. Influenza may result in primary pneumonia or be associated with secondary bacterial pneumonia. While the association with secondary pneumonia has been established ecologically, individual-level evidence remains sparse and the risk period for pneumonia following influenza poorly defined. Methods We conducted a matched case-control study and a prospective cohort study among Nicaraguan children aged 0–14 years from 2011 through 2018. Physicians diagnosed pneumonia cases based on Integrated Management for Childhood Illness guidelines. Cases were matched with up to 4 controls on age (months) and study week. We fit conditional logistic regression models to assess the association between influenza subtype and subsequent pneumonia development, and a Bayesian nonlinear survival model to estimate pneumonia hazard following influenza. Results Participants with influenza had greater risk of developing pneumonia in the 30 days following onset compared to those without influenza (matched odds ratio [mOR], 2.7 [95% confidence interval {CI}, 1.9–3.9]). Odds of developing pneumonia were highest for participants following A(H1N1)pdm09 illness (mOR, 3.7 [95% CI, 2.0–6.9]), followed by influenza B and A(H3N2). Participants' odds of pneumonia following influenza were not constant, showing distinct peaks 0–6 days (mOR, 8.3 [95% CI, 4.8–14.5] days) and 14–20 (mOR, 2.5 [95% CI, 1.1–5.5] days) after influenza infection. Conclusions Influenza is a significant driver of both primary and secondary pneumonia among children. The presence of distinct periods of elevated pneumonia risk in the 30 days following influenza supports multiple etiological pathways. [ABSTRACT FROM AUTHOR]

Background: Respiratory viral infections are common and potentially devastating to patients with underlying lung disease. Diagnosing viral infections often requires invasive sampling, and interpretation often requires specialized laboratory equipment. Here, we test the hypothesis that a breath test could diagnose influenza and rhinovirus infections using an in vitro model of the human airway.Methods: Cultured primary human tracheobronchial epithelial cells were infected with either influenza A H1N1 or rhinovirus 1B and compared with healthy control cells. Headspace volatile metabolite measurements of cell cultures were made at 12-hour time points postinfection using a thermal desorption-gas chromatography-mass spectrometry method.Results: Based on 54 compounds, statistical models distinguished volatile organic compound profiles of influenza- and rhinovirus-infected cells from healthy counterparts. Area under the curve values were 0.94 for influenza, 0.90 for rhinovirus, and 0.75 for controls. Regression analysis predicted how many hours prior cells became infected with a root mean square error of 6.35 hours for influenza- and 3.32 hours for rhinovirus-infected cells.Conclusions: Volatile biomarkers released by bronchial epithelial cells could not only be used to diagnose whether cells were infected, but also the timing of infection. Our model supports the hypothesis that a breath test could serve to diagnose viral infections. [ABSTRACT FROM AUTHOR]

Influenza A virus (H1N1), a swine-origin influenza A virus, causes seasonal epidemics that result in severe illnesses and deaths. Leonurine has been reported to function as an anti-inflammatory agent with protective effects on nervous, urinary and cardiovascular systems. However, the therapeutic effects of leonurine on the pneumonia caused by H1N1 infection remain unclear. Hematoxylin and eosin staining was performed to evaluate the lung injuries of mice infected by H1N1. The amount of immune cells was analyzed by flow cytometry. Enzyme-linked immunosorbent assay was used to evaluate the alteration of multiple cytokines in lung tissues. Real-time quantitative polymerase chain reaction assay was performed to investigate the ribonucleic acid (RNA) levels of certain genes. The protein levels in toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B cells (TLR4/NF-κB) signaling were estimated by western blot assay. Leonurine treatment significantly inhibited the mortality caused by H1N1 infection. Leonurine treatment (60 mg/kg) alleviated the lung injuries caused by virus infection. The inflammatory cell accumulation and cytokine expression were inhibited by the leonurine administration. Leonurine inhibited the mRNA expression of pro-inflammatory cytokines in the lung homogenates at day 5 postinfection. Leonurine regulated the TLR4/NF-κB signaling in the lung homogenates of H1N1-infected mice at day 5 postinfection. Leonurine protects against H1N1 infection-induced pneumonia in mice. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides (OCPs) are persistent pollutants linked to diverse adverse health outcomes. Environmental exposure to OCPs has been suggested to negatively impact the immune system but their effects on cellular antiviral responses remain unknown. Transcriptomic analysis of N27 rat dopaminergic neuronal cells unexpectedly detected high level expression of genes in the interferon (IFN)-related antiviral response pathways including the IFN-induced protein with tetratricopeptide repeats 1 and 2 (Ifit1/2) and the MX Dynamin Like GTPases Mx1 and Mx2. Interestingly, treatment of N27 cells with dieldrin markedly downregulated the expression of many of these genes. Dieldrin exterted a similar effect in inhibiting IFIT2 and MX1 gene expression in human SH-SY5Y neuronal cells induced by an RNA viral mimic, polyinosinic: polycytidylic acid (poly I:C) and IFIT2/3 gene expression in human pulmonary epithelial cells exposed to human influenza H1N1 virus. Mechanistically, dieldrin induced a rapid rise in levels of intracellular reactive oxygen species (iROS) and a decrease in intracellular glutathione (GSH) levels in SH-SY5Y cells. Treatment with N-acetylcysteine, an antioxidant and GSH biosynthesis precursor, effectively blocked both dieldrin-induced increases in iROS and its inhibition of poly I:C-induced upregulation of IFIT and MX gene expression, suggesting a role for intracellular oxidative status in dieldrin's modulation of antiviral gene expression. This study demonstrates that dieldrin modulates key genes of the cellular innate immune responses that are normally involved in the host's cellular defense against viral infections. Our findings have potential relevance to understanding the organismal effects of environmentally persistent organochlorine contaminants on the mammalian cellular immune system. [ABSTRACT FROM AUTHOR]

To identify key gene expression pathways altered with infection of the novel coronavirus SARS-CoV-2, we performed the largest comparative genomic and transcriptomic analysis to date. We compared the novel pandemic coronavirus SARS-CoV-2 with SARS-CoV and MERS-CoV, as well as influenza A strains H1N1, H3N2 and H5N1. Phylogenetic analysis confirms that SARS-CoV-2 is closely related to SARS-CoV at the level of the viral genome. RNAseq analyses demonstrate that human lung epithelial cell responses to SARS-CoV-2 infection are distinct. Extensive Gene Expression Omnibus literature screening and drug predictive analyses show that SARS-CoV-2 infection response pathways are closely related to those of SARS-CoV and respiratory syncytial virus infections. We validated SARS-CoV-2 infection response genes as disease-associated using Kaplan–Meier survival estimates in lung disease patient data. We also analysed COVID-19 patient peripheral blood samples, which identified signalling pathway concordance between the primary lung cell and blood cell infection responses. [ABSTRACT FROM AUTHOR]

Coronavirus Disease 2019 (COVID-19) is a sudden viral contagion that appeared at the end of last year in Wuhan city, the Chinese province of Hubei, China. The fast spread of COVID-19 has led to a dangerous threat to worldwide health. Also in the last two decades, several viral epidemics have been listed like the severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002/2003, the influenza H1N1 in 2009 and recently the Middle East respiratory syndrome coronavirus (MERS-CoV) which appeared in Saudi Arabia in 2012. In this research, an automated system is created to differentiate between the COVID-19, SARS-CoV and MERS-CoV epidemics by using their genomic sequences recorded in the NCBI GenBank in order to facilitate the diagnosis process and increase the accuracy of disease detection in less time. The selected database contains 76 genes for each epidemic. Then, some features are extracted like a discrete Fourier transform (DFT), discrete cosine transform (DCT) and the seven moment invariants to two different classifiers. These classifiers are the k -nearest neighbor (KNN) algorithm and the trainable cascade-forward back propagation neural network where they give satisfying results to compare. To evaluate the performance of classifiers, there are some effective parameters calculated. They are accuracy (ACC), F1 score, error rate and Matthews correlation coefficient (MCC) that are 100%, 100%, 0 and 1, respectively, for the KNN algorithm and 98.89%, 98.34%, 0.0111 and 0.9754, respectively, for the cascade-forward network. [ABSTRACT FROM AUTHOR]

Motivation Influenza viruses are a cause of large outbreaks and pandemics with high death tolls. A key obstacle is that flu vaccines have inconsistent performance, in the best cases up to 60% effectiveness, but it can be as low as 10%. Uncovering the hidden pathways of how antibodies (Abs) induced by one influenza strain are effective against another, cross-reaction, is a central vexation for the design of universal flu vaccines. Results We conceive a stochastic model that successfully represents the antibody cross-reactive data from mice infected with H3N2 influenza strains and further validation with cross-reaction data of H1N1 strains. Using a High-Performance Computing cluster, several aspects and parameters in the model were tested. Computational simulations highlight that changes in time of infection and the B-cells population are relevant, however, the affinity threshold of B-cells between consecutive infections is a necessary condition for the successful Abs cross-reaction. Our results suggest a 3-D reformulation of the current influenza antibody landscape for the representation and modeling of cross-reactive data. Availability and implementation The full code as a testing/simulation platform is freely available here: https://github.com/systemsmedicine/Antibody%5fcross-reaction%5fdynamics. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Background: Baloxavir acid, the active form of the orally available prodrug baloxavir marboxil, is a novel cap-dependent endonuclease inhibitor of influenza virus. Baloxavir marboxil has been shown to rapidly reduce virus titres compared with oseltamivir in clinical studies.Objectives: We investigated the relationship between pharmacokinetic (PK) parameters and antiviral activity of baloxavir acid based on virus titre reduction in lungs of infected mice.Methods: BALB/c mice infected with a sub-lethal dose of influenza A(H1N1), A(H1N1)pdm09, A(H3N2) or type B virus were treated on day 5 with oral baloxavir marboxil (0.5-50 mg/kg q12h), subcutaneous baloxavir acid (0.25-8 mg/kg/day), oseltamivir phosphate (5 or 50 eq mg/kg q12h) or other antivirals for 1 day. Lung virus titres were assessed 24 h after initial antiviral dosing. PK testing was performed at up to 24 h post-dosing of baloxavir marboxil or baloxavir acid in A/WSN/33-infected mice and the PK/pharmacodynamic (PD) relationship was evaluated for baloxavir acid.Results: Oral baloxavir marboxil administration showed dose-dependent virus titre reductions in lungs of mice infected with the different types/subtypes of influenza viruses 24 h post-dosing. Baloxavir marboxil at 15 mg/kg q12h resulted in ≥100-fold and ≥10-fold reductions in influenza A and B virus titres, respectively, compared with oseltamivir phosphate. PK/PD analysis showed that the plasma concentration at the end of the dosing interval (Cτ) or the plasma concentration at 24 h after initial dosing (C24) was the PK parameter predicting the virus titres at 24 h post-dosing of baloxavir acid.Conclusions: PK/PD analysis of baloxavir acid based on virus titre reduction in this mouse model could be helpful in predicting and maximizing virological outcomes in clinical settings. [ABSTRACT FROM AUTHOR]

Rationale: The International Health Regulations (IHR) have been the governing framework for global health security since 2007. Declaring public health emergencies of international concern (PHEIC) is a cornerstone of the IHR. Here we review how PHEIC are formally declared, the diseases for which such declarations have been made from 2007 to 2020 and justifications for such declarations.Key Findings: Six events were declared PHEIC between 2007 and 2020: the 2009 H1N1 influenza pandemic, Ebola (West African outbreak 2013-2015, outbreak in Democratic Republic of Congo 2018-2020), poliomyelitis (2014 to present), Zika (2016) and COVID-19 (2020 to present). Poliomyelitis is the longest PHEIC. Zika was the first PHEIC for an arboviral disease. For several other emerging diseases a PHEIC was not declared despite the fact that the public health impact of the event was considered serious and associated with potential for international spread.Recommendations: The binary nature of a PHEIC declaration is often not helpful for events where a tiered or graded approach is needed. The strength of PHEIC declarations is the ability to rapidly mobilize international coordination, streamline funding and accelerate the advancement of the development of vaccines, therapeutics and diagnostics under emergency use authorization. The ultimate purpose of such declaration is to catalyse timely evidence-based action, to limit the public health and societal impacts of emerging and re-emerging disease risks while preventing unwarranted travel and trade restrictions. [ABSTRACT FROM AUTHOR]

Human infection with influenza A/Hong Kong/156/97 (H5N1) avian influenza virus is associated with a high mortality rate of 60%. This virus is originated from influenza A/Quail/Hong Kong/G1/97 (H9N2/G1) avian influenza virus. Since the 1990s, four lineages of H9N2 viruses have been circulating in poultry and cause occasional infection in humans in different countries. Due to its zoonotic and genetic reassortment potential, H9N2/G1 and H5N1 viruses are believed to be the next pandemic candidates. Previous reports, including ours, showed that the virulence of avian virus strains correlates with their ability to dysregulate cytokine expression, including TNF‐α, CXCL10, and related chemokines in the virus‐infected cells. However, the transcriptional factors required for this cytokine dysregulation remains undefined. In light of our previous report showing the unconventional role of MYC, an onco‐transcriptional factor, for regulating the antibacterial responses, we hypothesize that the influenza virus–induced cytokine productions may be governed by MYC/MAX/MXD1 network members. Here, we demonstrated that the influenza A/Hong Kong/54/98 (H1N1)‐ or H9N2/G1 virus–induced CXCL10 expressions can be significantly attenuated by knocking down the MXD1 expression in primary human blood macrophages. Indeed, only the MXD1 expression was up‐regulated by both H1N1 and H9N2/G1 viruses, but not other MYC/MAX/MXD1 members. The MXD1 expression and the CXCL10 hyperinduction were dependent on MEK1/2 activation. By using EMSAs, we revealed that MXD1 directly binds to the CXCL10 promoter–derived oligonucleotides upon infection of both viruses. Furthermore, silencing of MXD1 decreased the replication of H9N2 but not H1N1 viruses. Our results provide a new insight into the role of MXD1 for the pathogenicity of avian influenza viruses. [ABSTRACT FROM AUTHOR]

Background: High levels of circulating neutrophil extracellular traps (NETs) are associated with a poor prognosis in influenza A infection. It remains unclear whether NETs in the plasma or bronchoalveolar lavage fluid (BALF) can predict clinical outcomes in influenza.Methods: One hundred eighteen patients who were diagnosed with H1N1 influenza in 2017-2018 were recruited. The NETs were assessed in plasma and BALF samples by quantifying cell-free deoxyribonucleic acid (cfDNA) and protein-DNA complexes. Predictions of severe illness and 60-day mortality were analyzed with receiver operating characteristic curves.Results: The NET levels were significantly elevated in the BALF and contributed to the pathology of lungs, yet it was not associated with disease severity or mortality in patients severely infected with H1N1. Plasma NET levels were significantly increased in the patients with severe influenza and positively correlated with the oxygen index and sequential organ failure assessment scores. High levels of plasma cfDNA (>286.6 ng/mL) or histone-bound DNA (>9.4 ng/mL) discriminated severe influenza from mild, and even higher levels of cfDNA (>306.3 ng/mL) or histone-bound DNA (>23.1 ng/mL) predicted fatal outcomes in severely ill patients.Conclusions: The cfDNA and histone-bound DNA in plasma represent early predictive biomarkers for the prognosis of influenza. [ABSTRACT FROM AUTHOR]

Background China is thought to be a hotspot for zoonotic influenza virus emergence, yet there have been few prospective studies examining the occupational risks of such infections. Methods We present the first 2 years of data collected from a 5-year, prospective, cohort study of swine-exposed and -unexposed participants at 6 swine farms in China. We conducted serological and virological surveillance to examine evidence for swine influenza A virus infection in humans. Results Of the 658 participants (521 swine-exposed and 137 swine-unexposed), 207 (31.5%) seroconverted against at least 1 swine influenza virus subtype (swine H1N1 or H3N2). Swine-exposed participants' microneutralization titers, especially those enrolled at confined animal feeding operations (CAFOs), were higher against the swine H1N1 virus than were other participants at 12 and 24 months. Despite elevated titers, among the 187 study subjects for whom we had complete follow-up, participants working at swine CAFOs had significantly greater odds of seroconverting against both the swine H1N1 (odds ratio [OR] 19.16, 95% confidence interval [CI] 3.55–358.65) and swine H3N2 (OR 2.97, 95% CI 1.16–8.01) viruses, compared to unexposed and non-CAFO swine workers with less intense swine exposure. Conclusions While some of the observed increased risk against swine viruses may have been explained by exposure to human influenza strains, study data suggest that even with elevated preexisting antibodies, swine-exposed workers were at high risk of infection with enzootic swine influenza A viruses. [ABSTRACT FROM AUTHOR]

Background Study characteristics influence vaccine effectiveness (VE) estimation. We examined the influence of some of these on seasonal influenza VE estimates from test-negative design (TND) studies. Methods We systematically searched bibliographic databases and websites for full-text publications of TND studies on VE against laboratory-confirmed seasonal influenza in outpatients after the 2009 pandemic influenza. We followed the Cochrane Handbook for Systematic Reviews of Interventions guidelines. We examined influence of source of vaccination information, respiratory specimen swab time, and covariate adjustment on VE. We calculated pooled adjusted VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza using an inverse-variance random-effects model. Results We included 70 full-text articles. Pooled VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza was higher for studies that used self-reported vaccination than for those that used medical records. Pooled VE was higher with respiratory specimen collection within ≤7 days vs ≤4 days of symptom onset, but the opposite was observed for H1N1. Pooled VE was higher for studies that adjusted for age but not for medical conditions compared with those that adjusted for both. There was, however, a lack of statistical significance in almost all differences in pooled VE between compared groups. Conclusions The available evidence is not strong enough to conclude that influenza VE from TND studies varies by source of vaccination information, respiratory specimen swab time, or adjustment for age/medical conditions. The evidence is, however, indicative that these factors ought to be considered while designing or evaluating TND studies of influenza VE. [ABSTRACT FROM AUTHOR]

The H1N1 influenza infection usually coincides with the typical scrub typhus season in North India. This leads to diagnostic difficulties due to their similar and non-specific symptoms. We describe three patients with confirmed co-infection of pandemic (H1N1) influenza and scrub typhus who had presented with acute respiratory distress syndrome. A systematic review of database yielded one case of scrub typhus and H1N1 influenza co-infection reported from South Korea. Co-infection of influenza with tropical infections may not be uncommon in endemic countries and hence a high index of suspicion on the part of physicians coupled with appropriate investigations are needed. The true burden of co-infections needs to be evaluated during outbreaks of influenza in a systematic manner. [ABSTRACT FROM AUTHOR]

Background The (H1N1)pdm09 live attenuated influenza vaccine (LAIV) strain was changed for the 2017–2018 influenza season to improve viral fitness, following poor protection against (H1N1)pdm09 viruses in 2015–2016. We conducted LAIV virus shedding studies to assess the effect of this change. Methods Children aged 2–18 years were recruited to receive LAIV in the 2016–2017 (n = 641) and 2017–2018 (n = 362) influenza seasons. Viruses from nasal swabs taken 1, 3, and 6 days postvaccination were quantified by reverse-transcription polymerase chain reaction and area under the curve titers were determined. Presence and quantity of shedding were compared between strains and seasons with adjustment for age and prior LAIV (n = 436), inactivated seasonal vaccine (n = 100), or (H1N1)pdm09 vaccine (n = 166) receipt. Results (H1N1)pdm09 detection (positivity) in 2016–2017 and 2017–2018 (11.2% and 3.9%, respectively) was lower than that of H3N2 (19.7% and 18.7%, respectively) and B/Victoria (28.9% and 33.9%, respectively). (H1N1)pdm09 positivity was higher in 2016–2017 than 2017–2018 (P =.005), but within shedding-positive participants, the (H1N1)pdm09 titer increased in 2017–2018 (P =.02). H3N2 and influenza B titers were similar between seasons. Positivity declined with age, and prior vaccination reduced the likelihood of shedding influenza B but not (H1N1)pdm09. Conclusions The (H1N1)pdm09 titer increased in 2017–2018, indicating more efficient virus replication in shedding-positive children than the 2016–2017 strain, although overall positivity was reduced. Age and vaccination history require consideration when correlating virus shedding and protection. Clinical Trials Registration NCT02143882, NCT02866942, and NCT03104790. [ABSTRACT FROM AUTHOR]

Background Although high-dose (HD) vaccines have been reported to stimulate higher antibody responses compared with standard-dose (SD) influenza vaccines, there have been limited studies on the impact of frailty on such responses. Methods We conducted a randomized, double-blind trial (2014/2015 to 2017/2018) of SD versus HD trivalent split-virus vaccine (Fluzone) in 612 study participants aged 65+ over 4 influenza seasons. Hemagglutination inhibition antibody titers for influenza H1N1, H3N2, and B vaccine subtypes were measured at baseline and at 4, 10, and 20 weeks postvaccination and frailty was measured using a validated frailty index. Results Geometric mean antibody titers were significantly higher in HD compared with SD vaccine recipients for all influenza subtypes at all time points postvaccination. However, frailty was positively correlated with 4-week titers and was associated with increased odds of being a vaccine responder. For influenza A subtypes, this was mostly limited to HD recipients. Conclusions Frailty was associated with higher titers and increased antibody responses at 4 weeks after influenza vaccination, which was partially dependent on vaccine dosage. Chronic inflammation or dysregulated immunity, both of which are commonly observed with frailty, may be responsible, but it requires further investigation. [ABSTRACT FROM AUTHOR]

Introduction: This study evaluates a large cohort of college students after the 2009-2010 pandemic H1N1 influenza season. The objective was to assess influenza vaccination status, influenzalike illnesses (ILIs), and other characteristics associated with attaining immunizations.Methods: This study was conducted during the summer 2010 the Reserve Officer Training Corps Leadership Development and Assessment Course involving 6272 college students. A voluntary, anonymous questionnaire was administered to assess study objectives.Results: Vaccination rates were 39.9% for pandemic H1N1, 40.6% for seasonal influenza, and 32.6% for receiving both vaccinations. Age less than 25 and having a Reserve Officer Training Corps scholarship were associated with lower odds of receiving vaccinations, whereas entering the nursing field and simultaneous membership in the Army reserve forces were associated with higher odds of vaccination. There are 11.2% of respondents reported having an ILI, including 4.3% with severe ILI. There were 4184 reasons indicated for not attaining influenza vaccinations, which are listed in categorical groupings.Conclusions: A historical anchor for vaccination rates and ILI is provided in a large cohort of college students following the 2009 H1N1 influenza pandemic. Influenza immunization locations were determined, as was self-reported obstacles to receiving vaccinations. These are important results for public health leaders seeking to increase vaccination rates during future influenza seasons. [ABSTRACT FROM AUTHOR]

Double-stranded RNA (dsRNA) is well characterized as an inducer of anti-viral interferon responses. We previously reported that dsRNA extracted from a specific edible plant possesses an immune-modulating capacity to confer, in mice, resistance against respiratory viruses, including the H1N1 strain of the influenza A virus (IAV). We report here that the systemic immune-activating capacity of the plant-derived dsRNA protected mice from infection by a highly virulent H5N1 strain of the IAV. In addition, subcutaneous inoculation of the dsRNA together with the inactivated virion of the H5N1 strain of the IAV suppressed the lethality of the viral infection as compared with individual inoculation of either dsRNA or HA protein, suggesting its potential usage as a vaccination adjuvant. Moreover, intra-peritoneal inoculation of the dsRNA limited the growth of B16-F10 melanoma cells through the activation of NK cells in murine models. Taken together, this study demonstrated the systemic immune-modulating capacity of a plant-derived dsRNA and its potential for nucleic acid-based clinical applications. [ABSTRACT FROM AUTHOR]

Background: In addition to vaccines' specific effects, vaccines may have non-specific effects (NSEs) altering the susceptibility to unrelated infections. Non-live vaccines have been associated with negative NSEs. In 2010, a campaign with the non-live H1N1-influenza vaccine targeted children 6-59 months in Guinea-Bissau.Methods: Bandim Health Project runs a health and demographic surveillance system site in Guinea-Bissau. Using a Cox proportional hazards model, we compared all-cause consultation rates after vs. before the campaign, stratified by participation status.Results: Among 10 290 children eligible for the campaign, 60% had participated, 18% had not and for 22% no information was obtained. After the H1N1 campaign, the consultation rates tended to decline less for participants [HR = 0.80 (95% confidence interval, CI: 0.75; 0.85)] than for non-participants [HR = 0.68 (95% CI: 0.58; 0.79)], p = 0.06 for same effect.Conclusion: The decline in the vaccinated group may have been smaller than the decline in the non-vaccinated group consistent with H1N1-vaccine increasing susceptibility to unrelated infections. [ABSTRACT FROM AUTHOR]

Background: We sought to determine the role of host interleukin 17A (IL-17A) response against colonizing Streptococcus pneumoniae, and its transition to a pathogen during coinfection with an influenza virus, influenza A H1N1 A/Puerto Rico/8/1934 (PR8).Method: Wild-type (WT) C57BL/6 mice were intranasally inoculated with S. pneumoniae serotype 6A to establish colonization and later infected with the influenza strain, PR8, resulting in invasive S. pneumoniae disease. The role of the IL-17A response in colonization and coinfection was investigated in WT, RoRγt-/- and RAG1-/- mice with antibody-mediated depletion of IL-17A (WT) and CD90 cells (RAG1-/-).Results: RAG1-/- mice did not clear colonization and IL-17A neutralization impaired 6A clearance in WT mice. RoRγt-/- mice also had reduced clearance. S. pneumoniae-PR8 coinfection elicited a robust IL-17A response in the nasopharynx; IL-17A neutralization reduced S. pneumoniae invasive disease. RoRγt-/- mice also had reduced S. pneumoniae disease in a coinfection model. Depletion of CD90+ cells suppressed the IL-17A response and reduced S. pneumoniae invasion in RAG1-/- mice.Conclusion: Our data show that although IL-17A reduces S. pneumoniae colonization, coinfection with influenza virus elicits a robust innate IL-17A response that promotes inflammation and S. pneumoniae disease in the nasopharynx. [ABSTRACT FROM AUTHOR]

Background Prior influenza immunity influences the homologous neutralizing antibody responses elicited by inactivated influenza vaccines (IIV), but neutralizing antibody responses to heterologous strains have not been extensively characterized. Methods We analyzed neutralizing antibody titers in individuals aged 1–88 who received the 2009–2010 season IIV before infection by or vaccination against the 2009 pandemic H1N1 virus. Neutralization titers to homologous and heterologous past, recent, and advanced H1 and H3 strains, as well as H2, H5, and H7 strains, were measured using influenza hemagglutinin pseudoviruses. We performed exploratory analyses based on age, prior-year IIV, and prevaccination titer, without controlling for Type I errors. Results IIV elicited neutralizing antibodies to past and advanced H1 and H3 strains, as well as to an H2 strain in individuals who were likely infected early in life. The neutralization of avian subtype viruses was rare, and there was no imprinting of neutralization responses to novel avian subtype viruses based on the influenza group. Compared to adults, children had higher seroresponse rates to homologous and heterologous strains, and their sera generated larger antigenic distances among strains. Seroresponse rates to homologous and heterologous strains were lower in subjects vaccinated with prior-year IIV, though postimmunization titers were generally high. Conclusions IIV elicited neutralizing antibodies to heterologous H1 and H3 strains in all ages groups, but titers and seroresponse rates were usually higher in children. Prior-year vaccination with the same strains tended to blunt IIV neutralization responses to all strains in young and old age groups, yet postimmunization titers were high. [ABSTRACT FROM AUTHOR]

Background Registration of interventional trials of Food and Drug Administration–regulated drug and biological products and devices became a legal requirement in 2007; the vast majority of these trials are registered in ClinicalTrials.gov. An analysis of ClinicalTrials.gov offers an opportunity to define the clinical research landscape; here we analyze 10 years of infectious disease (ID) clinical trial research. Methods Beginning with 166 415 interventional trials registered in ClinicalTrials.gov from 2007–2017, ID trials were selected by study conditions and interventions. Relevance to ID was confirmed through manual review, resulting in 13 707 ID trials and 152 708 non-ID trials. Results ID-related trials represented 6.9%–9.9% of all trials with no significant trend over time. ID trials tended to be more focused on treatment and prevention, with a focus on testing drugs, biologics, and vaccines. ID trials tended to be large, randomized, and nonblinded with a greater degree of international enrollment. Industry was the primary funding source for 45.2% of ID trials. Compared with the global burden of disease, human immunodeficiency virus/AIDS and hepatitis C trials were overrepresented, and lower respiratory tract infection trials were underrepresented. Hepatitis C trials fluctuated, keeping with a wave of new drug development. Influenza vaccine trials peaked during the 2009 H1N1 swine influenza outbreak. Conclusions This study presents the most comprehensive characterization of ID clinical trials over the past decade. These results help define how clinical research aligns with clinical need. Temporal trends reflect changes in disease epidemiology and the impact of scientific discovery and market forces. Periodic review of ID clinical trials can help identify gaps and serve as a mechanism to realign resources. [ABSTRACT FROM AUTHOR]

Background In 2009, a novel influenza A (pH1N1) was identified, resulting in a pandemic with significant morbidity and mortality. A monovalent pH1N1 vaccine was separately produced in addition to the seasonal trivalent influenza vaccine. Formulation of the seasonal influenza vaccine (injectable trivalent inactivated influenza vaccine [TIV] vs. intranasal live, attenuated influenza vaccine [LAIV]) was postulated to have impacted the efficacy of the pH1N1 vaccination. Methods We reviewed electronic health and databases, which included vaccination records, and healthcare encounters for influenza-like illness (ILI), influenza, and pneumonia among US military members. We examined rates by vaccination type to identify factors associated with the risk for study outcomes. Results Compared with those receiving the seasonal influenza vaccine alone, subjects receiving the pH1N1 vaccine, either alone (RR, 0.49) or in addition to the seasonal vaccine (RR, 0.51), had an approximately 50% reduction in ILI, 88% reduction in influenza (RR, 0.11 and 0.12, respectively), and 63% reduction in pneumonia (RR, 0.37 and 0.35, respectively). There was no clinically significant difference in ILI, influenza, or pneumonia attack rates among those receiving the pH1N1 vaccine with or without presence of the seasonal vaccine. Similarly, there was no clinically relevant difference in pH1N1 effectiveness between seasonal TIV and LAIV recipients. Conclusions During the 2009–2010 pandemic, the pH1N1 vaccination was effective in reducing rates of ILI, influenza, and pneumonia. Administration of the seasonal vaccine should continue without concern of potential interference with a novel pandemic vaccine, though more studies are needed to determine if this is applicable to other influenza seasons. [ABSTRACT FROM AUTHOR]

Background: Influenza virus infection during pregnancy is associated with enhanced disease severity. However, the underlying mechanisms are still not fully understood. We hypothesized that normal alveolar macrophage (AM) functions, which are central to maintaining lung immune homeostasis, are altered during pregnancy and that this dysregulation contributes to the increased inflammatory response to influenza virus infection.Methods: Time-mated BALB/c mice were infected with a low dose of H1N1 influenza A virus at gestation day 9.5. Inflammatory cells in bronchoalveolar lavage (BAL) fluid were assessed by flow cytometry.Results: Our findings confirm previous reports of increased severity of influenza virus infection in pregnant mice. The heightened inflammatory response detected in BAL fluid from infected pregnant mice was characterized by neutrophil-rich inflammation with concomitantly reduced numbers of AM, which were slower to return to baseline counts, compared with nonpregnant infected mice. The increased infection severity and inflammatory responses to influenza during pregnancy were associated with a pregnancy-induced shift in AM phenotype at homeostatic baseline, from the M1 (ie, classical activation) state toward the M2 (ie, alternative activation) state, as evidence by increased expression of CD301 and reduced levels of CCR7.Conclusion: These results show that pregnancy is associated with an alternatively activated phenotype of AM before infection, which may contribute to heightened disease severity. [ABSTRACT FROM AUTHOR]

Background Many countries have acquired antiviral stockpiles for pandemic influenza mitigation and a significant part of the stockpile may be focussed towards community-based treatment. Methods We developed a spreadsheet-based, decision tree model to assess outcomes averted and cost-effectiveness of antiviral treatment for outpatient use from the perspective of the healthcare payer in the UK. We defined five pandemic scenarios—one based on the 2009 A(H1N1) pandemic and four hypothetical scenarios varying in measures of transmissibility and severity. Results Community-based antiviral treatment was estimated to avert 14–23% of hospitalizations in an overall population of 62.28 million. Higher proportions of averted outcomes were seen in patients with high-risk conditions, when compared to non-high-risk patients. We found that antiviral treatment was cost-saving across pandemic scenarios for high-risk population groups, and cost-saving for the overall population in higher severity influenza pandemics. Antiviral effectiveness had the greatest influence on both the number of hospitalizations averted and on cost-effectiveness. Conclusions This analysis shows that across pandemic scenarios, antiviral treatment can be cost-saving for population groups at high risk of influenza-related complications. [ABSTRACT FROM AUTHOR]

We analyzed the virulence of pandemic H1N1 2009 influenza A viruses in vivo and in vitro. Selected viruses isolated in 2009, 2010, 2014, and 2015 were assessed using an aerosol-mediated high-dose infection model for pigs as well as air-liquid interface cultures of differentiated airway epithelial cells. Using a dyspnea score, rectal temperature, lung lesions, and viral load in the lung as parameters, the strains from 2014-2015 were significantly less virulent than the strains isolated in 2009-2010. In vitro, the viruses from 2009-2010 also differed from the 2014-2015 viruses by increased release of infectious virus, a more pronounced loss of ciliated cells, and a reduced thickness of the epithelial cell layer. Our in vivo and in vitro results reveal an evolution of A(H1N1)pdm09 viruses toward lower virulence. Our in vitro culture system can be used to predict the virulence of influenza viruses. [ABSTRACT FROM AUTHOR]

Despite the emphasis placed on agility in uncertain situations such as extreme events, no comparative data exist to look into the determinants that drive agility. For crisis response managers, the failure to develop agility threatens organizations’ survival amid uncertainties. This paper investigates the development of agility and explains the emergence of agility against the fight of influenza A/H1N1 pandemics in Singapore and Taiwan in 2009. This paper further provides empirically grounded evidence to identify prerequisites for agility development in response to public health crises in East Asia. [ABSTRACT FROM AUTHOR]

Four-year old boy was admitted with acute onset of fever with seizures and altered sensorium. His mother had history of contact with influenza A H1N1 virus (H1N1) infection. Blood counts, electrolytes, blood sugar and ammonia were normal. Liver enzymes were mildly elevated. CSF study showed elevated protein, normal sugar and no pleocytosis. Cerebrospinal fluid (CSF) viral panel was negative. Magnetic resonance imaging brain was suggestive of acute necrotizing encephalopathy. His throat swab and sputum polymerase chain reaction was positive for H1N1. He was managed with ventilation, intravenous steroids and other supportive measures. At discharge his sensorium improved but had neurological sequelae. We are presenting this case as this is a very rare complication of H1N1 infection with high rate of mortality. Early supportive measures and steroids/intravenous immunoglobulin may save the patient. [ABSTRACT FROM AUTHOR]

Background: Although ferret antisera used in influenza surveillance did not detect antigenic drift of A(H1N1)pdm09 viruses during the 2015-2016 season, low vaccine effectiveness was reported in adults. We investigated the immune basis of low responses to circulating A(H1N1)pdm09 viruses after vaccination.Methods: Prevaccination and postvaccination serum samples collected from >300 adults (aged 18-49 years) in 6 seasons (2010-2011 to 2015-2016) were analyzed using hemagglutination inhibition assays to evaluate the antibody responses to 13 A(H1N1) viruses circulated from 1977 to 2016. Microneutralization and serum adsorption assays were used to verify the 163K and 223R specificity of antibodies.Results: Individual antibody profiles to A(H1N1) viruses revealed 3 priming patterns: USSR/77, TW/86, or NC/99 priming. More than 20% of adults had reduced titers to cell-propagated circulating 6B.1 and 6B.2 A(H1N1)pdm09 viruses compared with the A/California/07/2009 vaccine virus X-179A. Significantly reduced antibody reactivity to circulating viruses bearing K163Q was observed only in the USSR/77-primed cohort, whereas significantly lower reactivity caused by egg-adapted Q223R change was detected across all 3 cohorts.Conclusion: Both 163K specificity driven by immune priming and 223R specificity from egg-adapted changes in the vaccine contributed to low responses to circulating A(H1N1)pdm09 viruses after vaccination. Our study highlights the need to incorporate human serology in influenza surveillance and vaccine strain selection. [ABSTRACT FROM AUTHOR]

Objective To assess the possible effect of therapy, disease subtype and severity on H1N1 immunogenicity in patients with SSc. Methods Ninety-two patients and 92 age- and gender-matched healthy controls received adjuvant-free influenza A/California/7/2009 (pH1N1) vaccine. Blood samples were collected immediately before and 3 weeks after vaccination to evaluate antibody responses to the H1N1 virus. Efficacy was assessed by seroprotection (SP) and seroconversion (SC) rates and the factor increase in geometric mean antibody titre. Participants received a 21-day symptom diary card and were instructed to report local and systemic adverse events. Results SSc patients were predominantly females (91%) and 61% had limited SSc, 12% had severe skin involvement and 57.6% were on immunosuppressive (IS) therapy. SSc patients and controls presented comparable overall SP (P = 0.20) and SC (P = 0.61) rates. Further evaluation of the possible effect of disease and therapy revealed similar rates of SP and SC in patients with dcSSc vs lcSSc (SP P = 0.62 and SC P = 0.66), severe vs mild/moderate skin involvement (SP P = 1 and SC P = 0.45) and with vs without IS (SP P = 0.26 and SC P = 0.10). The frequency of mild local and minor systemic reactions was similar in patients with dcSSC vs lcSSc (P = 0.70 vs 0.32) and in those with and without severe skin involvement (P = 0.59 vs 0.28). Conclusion The non-adjuvanted influenza H1N1 virus vaccine proved to be safe and effective, independent of SSc clinical subtype, disease severity or therapy. These latter factors do not seem to contribute to mild adverse events observed in SSc. Our data support the annual influenza vaccination recommendation for these patients. Trial registration ClinicalTrials.gov (http://clinicaltrials.gov), NCT01151644 [ABSTRACT FROM AUTHOR]

Background Little is known about how pharmaceutical companies lobby authorities or experts regarding procurement or the use of vaccines and antivirals. This paper investigates how members of Denmark's pandemic planning committee experienced lobbying efforts by Roche, manufacturer of Tamiflu, the antiviral that was stockpiled before the 2009 A(H1N1) pandemic. Methods Analysis of interviews with six of seven members of the Danish core pandemic committee, supplemented with documentary analysis. We sought to identify (1) arguments and (2) tactics used in lobbying, and to characterize interviewees' views on the impact of (3) lobbying and (4) scientific evidence on the decision to stockpile Tamiflu. Results Roche lobbied directly (in its own name) and through a seemingly independent third party. Roche used two arguments: (1) the procurement agreement had to be signed quickly because the drug would be delivered on a first-come, first-served basis and (2) Denmark was especially vulnerable to an influenza crisis because it had smaller Tamiflu stocks than other countries. Most interviewees suspected that lobbying had an impact on Tamiflu procurement. Conclusions Our study highlights risks posed by pharmaceutical lobbying. Arguments and tactics deployed by Roche are likely to be repeated whenever many countries are negotiating drug procurements in a monopolistic market. [ABSTRACT FROM AUTHOR]

Background Early clinical severity assessments during the 2009 influenza A H1N1 pandemic (pH1N1) overestimated clinical severity due to selection bias and other factors. We retrospectively investigated how to use data from the International Network for Strategic Initiatives in Global HIV Trials, a global clinical influenza research network, to make more accurate case fatality ratio (CFR) estimates early in a future pandemic, an essential part of pandemic response. Methods We estimated the CFR of medically attended influenza (CFRMA) as the product of probability of hospitalization given confirmed outpatient influenza and the probability of death given hospitalization with confirmed influenza for the pandemic (2009–2011) and post-pandemic (2012–2015) periods. We used literature survey results on health-seeking behavior to convert that estimate to CFR among all infected persons (CFRAR). Results During the pandemic period, 5.0% (3.1%–6.9%) of 561 pH1N1-positive outpatients were hospitalized. Of 282 pH1N1-positive inpatients, 8.5% (5.7%–12.6%) died. CFRMA for pH1N1 was 0.4% (0.2%–0.6%) in the pandemic period 2009–2011 but declined 5-fold in young adults during the post-pandemic period compared to the level of seasonal influenza in the post-pandemic period 2012–2015. CFR for influenza-negative patients did not change over time. We estimated the 2009 pandemic CFRAR to be 0.025%, 16-fold lower than CFRMA. Conclusions Data from a clinical research network yielded accurate pandemic severity estimates, including increased severity among younger people. Going forward, clinical research networks with a global presence and standardized protocols would substantially aid rapid assessment of clinical severity. Clinical Trials Registration NCT01056354 and NCT010561. [ABSTRACT FROM AUTHOR]

Background: The 1918 Spanish H1N1 influenza pandemic was the most severe recorded influenza pandemic with an estimated 20-50 million deaths worldwide. Even though it is known that influenza viruses can cause extrarespiratory tract complications-which are often severe or even fatal-the potential contribution of extrarespiratory tissues to the pathogenesis of 1918 H1N1 virus infection has not been studied comprehensively.Methods: Here, we performed a time-course study in ferrets inoculated intranasally with 1918 H1N1 influenza virus, with special emphasis on the involvement of extrarespiratory tissues. Respiratory and extrarespiratory tissues were collected after inoculation for virological, histological, and immunological analysis.Results: Infectious virus was detected at high titers in respiratory tissues and, at lower titers in most extrarespiratory tissues. Evidence for active virus replication, as indicated by the detection of nucleoprotein by immunohistochemistry, was observed in the respiratory tract, peripheral and central nervous system, and liver. Proinflammatory cytokines were up-regulated in respiratory tissues, olfactory bulb, spinal cord, liver, heart, and pancreas.Conclusions: 1918 H1N1 virus spread to and induced cytokine responses in tissues outside the respiratory tract, which likely contributed to the severity of infection. Moreover, our data support the suggested link between 1918 H1N1 infection and central nervous system disease. [ABSTRACT FROM AUTHOR]

Background: The kinetics of the antibody response during severe influenza are not well documented.Methods: Critically ill patients infected with 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09), confirmed by reverse-transcription polymerase chain reaction analysis or seroconversion (defined as a ≥4-fold rise in titers), during 2009-2011 in Canada were prospectively studied. Antibody titers in serially collected sera were determined using hemagglutinin inhibition (HAI) and microneutralization assays. Average antibody curves were estimated using linear mixed-effects models and compared by patient outcome, age, and corticosteroid treatment.Results: Of 47 patients with A(H1N1)pdm09 virus infection (median age, 47 years), 59% had baseline HAI titers of <40, and 68% had baseline neutralizing titers of <40. Antibody titers rose quickly after symptom onset, and, by day 14, 83% of patients had HAI titers of ≥40, and 80% had neutralizing titers ≥40. Baseline HAI titers were significantly higher in patients who died compared with patients who survived; however, the antibody kinetics were similar by patient outcome and corticosteroid treatment. Geometric mean titers over time in older patients were lower than those in younger patients.Conclusions: Critically ill patients with influenza A(H1N1)pdm09 virus infection had strong HAI and neutralizing antibody responses during their illness. Antibody kinetics differed by age but were not associated with patient outcome. [ABSTRACT FROM AUTHOR]

Background: Most patients with severe infection with influenza A virus (IAV) progress to acute respiratory distress syndrome and even multiple organ dysfunction syndrome (MODS). Neutrophil extracellular traps (NETs) can be induced by pathogens and are responsible for immune tissue damage. We conducted a prospective study on the production and effects of NETs in H7N9 and H1N1 patients.Methods: We investigated NET production in plasma and supernatant of cultured neutrophils by measuring cell-free deoxyribonucleic acid (DNA) and myeloperoxidase (MPO)-DNA complexes with PicoGreen dye and enzyme-linked immunosorbent assay methods, respectively. We also observed NET structure by immunofluorescence staining.Results: We found that patients with severe influenza showed elevated plasma NET level on the day of admission. Neutrophils from these patients showed higher capacity to release MPO-DNA complex in response to interleukin-8 or lipopolysaccharide stimulation. We also found that NETs from H7N9 and H1N1 patients increased the permeability of alveolar epithelial cells, and, consequently, NET production was positively correlated with acute physiology and chronic health evaluation (APACHE) II score and MODS.Conclusions: These data indicate that high level of NETs contributes to lung injury and is correlated with severity of disease. Thus, NETs might be a key factor to predict the poor prognosis in IAV patients. [ABSTRACT FROM AUTHOR]

Pregnancy has been associated with severe influenza, an association highlighted during the 2009 pandemic of influenza A(H1N1) virus (A[H1N1]pdm09) infection. To assess the underlying mechanism, we infected pregnant and non-pregnant ferrets with A(H1N1) pdm09 virus. A(H1N1)pdm09-infected pregnant ferrets also had higher levels of inflammatory cytokines in their pulmonary tracts. Systemically, total CD8+ T cell counts and A(H1N1)pdm09-specific B-cell responses in blood were significantly lower in pregnant ferrets. This model predicts that the poorer outcome for pregnant women during the A(H1N1)pdm09 pandemic was due to an elevated level of viral replication and to a cytokine imbalance that led to a less effective immune response. [ABSTRACT FROM AUTHOR]

Background: Seasonal influenza vaccines are transitioning to quadrivalent formulations including the hemagglutinins of influenza A subtypes H1N1 and H3N2 and B lineages Yamagata and Victoria.Methods: A new quadrivalent recombinant influenza vaccine (RIV4) was compared directly with a standard-dose, egg-grown, quadrivalent-inactivated influenza vaccine (IIV4) for immunogenicity and safety in adults 18-49 years of age. The coprimary endpoints for noninferiority were hemagglutination inhibition seroconversion rates and postvaccination geometric mean titer ratios for each antigen using US regulatory criteria. Reactogenicity solicited for 7 days, other safety events collected for 28 days, and serious or medically attended adverse events collected for 6 months after vaccination comprised the safety evaluation.Results: The immunogenicity of RIV4 was comparable to that of IIV4; the coprimary noninferiority criteria were met for 3 antigens, and the antibody responses to the fourth antigen, influenza B/Brisbane/60/2008, were low in each group, making comparisons uninterpretable. Systemic and injection site reactions were mild, transient, and similar in each group, whereas none of the spontaneously reported adverse events, serious or nonserious, were considered related to study vaccine.Conclusions: This first head-to-head comparison of recombinant versus inactivated quadrivalent influenza vaccines in 18-49 year old adults showed comparable immunogenicity, safety, and tolerability for both vaccines. [ABSTRACT FROM AUTHOR]

Severe influenza is often associated with disease manifestations outside the respiratory tract. While proinflammatory cytokines can be detected in the lungs and blood of infected patients, the role of extra-respiratory organs in the production of proinflammatory cytokines is unknown. Here, we show that both 2009 pandemic H1N1 influenza A (H1N1) virus and highly pathogenic avian influenza A (H5N1) virus induce expression of tumor necrosis factor α, interleukin-6, and interleukin-8 in the respiratory tract and central nervous system. In addition, H5N1 virus induced cytokines in the heart, pancreas, spleen, liver, and jejunum. Together, these data suggest that extra-respiratory tissues contribute to systemic cytokine responses, which may increase the severity of influenza. [ABSTRACT FROM AUTHOR]