Influenza 2019

Multiple factors can affect and impact infection dynamics and virulence produced by influenza virus (IV) infections. Susceptibility factors and host responses can also have major effects in disease severity. It has become apparent that innate and adaptive immune responses can modulate clinical evolution to infection, which is directly and indirectly modulated by factors such as pre-existing conditions and host and virus genetic background. Thus, a major leap forward lies in understanding and integrating global virus-host interactions. To identify viral and host molecular markers of disease severity and outcome we investigated IV diversity and evolution and host responses to infection. Hence, we evaluated the status of the innate and adaptive immune responses, and established clinical parameters associated with poor outcome. A comprehensive multiscale analysis of clinical metadata and cytokine profiling, revealed that comorbidities such as arterial hypertension, chronic cardiovascular disease and obesity, together with early increased expression of pro-inflammatory cytokines, including of IL-6, 8 and the anti-inflammatory IL-10, were associated with severity. Additionally, we used next generation sequencing and developed bioinformatics tools to investigate viral diversity and to evaluate different IV variants obtained from severe individuals. We identified a number of transitional amino acid changes over time in functional sites. Notably, we found two novel mutations of epidemiological relevance in the viral glycoproteins. The I223M mutation on the Neuraminidase was found to confer resistance to the antiviral oseltamivir, whereas a K180Q residue change in a major antigenic site of the Hemagglutinin was found to contribute to the evasion of preexisting immunity (antibody responses). These changes occurred independently in severe subjects and were detected as mixed populations in sequential samples, indicating a dynamic change in the IV genome over time. Overall, our systematic approach suggests that early aberrant immune responses and increased viral diversity in susceptible individuals can play a crucial role in disease outcome. This translational virology approach allows us to interrogate complex biological systems in depth, to define and dissect the global molecular processes involved in viral infection and disease.
FUNDING: FONDECYT 1121172, 1161791 and PIA-ACT 1408 from CONICYT, the Chilean Ministry of Economy, Development and Tourism, P09/016-F, the Center for Research in Influenza Pathogenesis (CRIP) HHSN272201400008C and grant U19AI135972 both from NIH-NIAID

Learning Objectives:
1. To identify what factors can contribute to disease severity during Influenza virus infection.
2. To describe novel techniques and methodologies used to study viral-host interactions.

Since the establishment of reverse genetics techniques to manipulate the influenza virus genome, it has been possible to study viral molecular signatures responsible for virulence, and the generation of novel and improved vaccine strains. Moreover, high throughput screen technologies combined with functional genomics, transcriptomics and proteomics are now been used to identify novel mechanisms associated with virus replication and pathogenicity, as well as novel antivirals. Finally recombinant technologies can now be applied for the generation of broadly neutralizing influenza virus vaccines that could eliminate the need for annual vaccination and prevent pandemics by inducing protective immunity against conserved epitope shared by all influenza virus strains.
 
Learning objectives:

1. Current influenza vaccines and antivirals are useful, but not optimal
2. New technologies allow the discovery of improved influenza antivirals and vaccines

To prepare for the 2019 flu season it is important to get immunized. In 2019 a tetravalent (four-virus) vaccine is available in a number of forms including an egg-free formulation that is for people who have egg allergies. The talk delineates populations who are highest priority for flu vaccine as well as age-appropriate guidelines for the general population.  It also is important to understand the symptoms and signs of flu – and how flu is transmitted – in order to take appropriate action to prevent spread of flu virus should one become infected

We must also be prepared for a possible flu pandemic, which occurs infrequently but can happen in any year when a new strain of flu emerges. Since flu pandemics are unpredictable it is important to have in place global capacity to monitor and investigate “novel” flu cases. The talk describes the stages of a flu pandemic and actions that are taken at each stage. Vaccines would not initially be available and in the case of a major pandemic transmission might be controlled via measures such as closing schools and workplaces and reducing travel.

Learning Objectives:
1. Understand the basics of influenza virus infection in terms of virus types; signs and symptoms indicative of flu infection; and the differences between seasonal and pandemic flu.
2. Understand the steps that can be taken to prevent seasonal influenza via immunization and other actions, and the availability of age-specific as well as egg-free flu vaccines in 2019.
3. Understand how flu pandemics arise, pandemic stages and measures that are taken to control pandemics at various stages.

The efficacy of current influenza antiviral drugs is compromised by emerging drug resistance. To address this unmet medical need, we have made progress in developing novel influenza antivirals by targeting the drug-resistant mutants of M2 and the viral polymerase. In this presentation, I will introduce our work in designing inhibitors targeting the viral M2-S31N mutant proton channel and the viral polymerase PA-PB1 interactions. The designed M2-S31N inhibitors and the PA-PB1 inhibitors have been shown to inhibit drug resistant influenza viruses with potent antiviral efficacy and a high selectivity index. 

Influenza viruses are transmitted by membrane-bound virus particles, or virions. Unlike some viruses, which produce near-identical virions from a well-defined set of viral components, influenza virions are assembled from shifting mixtures of viral and host components and vary markedly in their size, shape and composition. In this talk we will show how a variety of advanced methods can be combined to explore the complex structure of influenza virions. We will examine sources of variation in influenza virions and discuss the challenges this variation creates for understanding how influenza viruses infect new cells.

Learning Objectives:
1. Gain a detailed understanding of the structure and composition of the virus particles that transmit influenza infections.
2. Understand that the idea of a single type of influenza virus particle is a simplification, and that in fact influenza infections involve interactions between a highly variable mixture of different particles.

Despite FDA-approved vaccines and antivirals, seasonal and pandemic influenza remains a serious threat associated with substantial morbidity and mortality.  The present modalities and vaccine approaches will be discussed and the difficulties one faces with the presently available formulations will be addressed. While annual seasonal influenza virus vaccination is frequently effective – albeit underutilized in most countries – a safe universal influenza virus vaccine providing broad and long-lasting immunity would represent a major breakthrough.  We have developed vaccine constructs which express chimeric hemagglutinins resulting in the redirection of the immune response away from the immunodominant (variant) head domain of the hemagglutinin toward the much more conserved stalk of the hemagglutinin and the highly conserved neuraminidase.  Such vaccine constructs work well in animal challenge models and await extensive clinical trials in humans.

Respiratory viral infections remain a leading cause of medical visits and can contribute significantly to morbidity and mortality. Influenza, together with pneumonia, is the leading infectious cause of death in Canada and the United States, and is of particular concern especially in individuals with secondary risk factors. As "influenza season" approaches each year, hospitals and healthcare organizations review and update testing algorithms in attempts to maximize clinical useful testing, staffing issues, sensitivity, and rising health care costs. Despite decades of diagnostic research into laboratory and clinic based influenza testing, no one single diagnostic algorithm has emerged as a one size-fits-all strategy. Clinical decision making and subsequent patient management for patients who present to busy emergency departments during flu season is not always straight forward. Recently the COBAS LIAT Influenza assay was recently approved by the FDA for diagnosis of Influenza A/B virus. The test represents among the first truly rapid multiplex molecular PCR-based assays that can simultaneously detect and discriminate influenza A and influenza B RNA in nasopharyngeal specimens. While the prospects of reliable rapid influenza diagnostics have been examined before, few studies have attempted to correlate in real time the immediate impact of influenza assays, and no study assessing the clinical utility of LIAT during influenza season has been performed to date. Objectives: 1. Introduce the historical challenges of test options for influenza testing in hospital settings 2. Describe the performance and test characteristics of the Cobas® Liat influenza A/B assay on emergency department patients who presented with influenza-like-illness during the 2015 influenza season 3. Demonstrate the impact that rapid reliable influenza testing within emergency department settings have on patient management