65 years of influenza surveillance by a World Health Organization-coordinated global network

Characterizing Emerging Canine H3 Influenza Viruses

The continual emergence of novel influenza A strains from non-human hosts requires constant vigilance and the need for ongoing research to identify strains that may pose a human public health risk. Since 1999, canine H3 influenza A viruses (CIVs) have caused many thousands or millions of respiratory infections in dogs in the United States. While no human infections with CIVs have been reported to date, these viruses could pose a zoonotic risk. In these studies, the National Institutes of Allergy and Infectious Diseases (NIAID) Centers of Excellence for Influenza Research and Surveillance (CEIRS) network collaboratively demonstrated that CIVs replicated in some primary human cells and transmitted effectively in mammalian models. While people born after 1970 had little or no pre-existing humoral immunity against CIVs, the viruses were sensitive to existing antivirals and we identified a panel of H3 cross-reactive human monoclonal antibodies (hmAbs) that could have prophylactic and/or therapeutic value. Our data predict these CIVs posed a low risk to humans. Importantly, we showed that the CEIRS network could work together to provide basic research information important for characterizing emerging influenza viruses, although there were valuable lessons learned.

Recombinant Measles AIK-C Vaccine Strain Expressing Influenza HA Protein

Recombinant measles AIK-C vaccine expressing the hemagglutinin (HA) protein of influenza A/Sapporo/107/2013(H1N1pdm) (MVAIK/PdmHA) was constructed. Measles particle agglutination (PA) and influenza hemagglutinin inhibition (HI) antibodies were induced in cotton rats immunized with MVAIK/PdmHA. Cotton rats immunized with two doses of the HA split vaccine were used as positive controls, and higher HI antibodies were detected 3 weeks after the first dose. Following the challenge of A/California/07/2009(H1N1pdm), higher viral loads (10⁷ TCID50/g) were detected in the lung homogenates of cotton rats immunized with the empty vector (MVAIK) or control groups than those immunized with MVAIK/Pdm HA (10³ TCID50/g) or the group immunized with HA split vaccine (10⁵ TCID50/g). Histopathologically, destruction of the alveolar structure, swelling of broncho-epithelial cells, and thickening of the alveolar wall with infiltration of inflammatory cells and HA antigens were detected in lung tissues obtained from non-immunized rats and those immunized with the empty vector after the challenge, but not in those immunized with the HA spilt or MVAIK/PdmHA vaccine. Lower levels of IFN-α, IL-1β, and TNF-α mRNA, and higher levels of IFN-γ mRNA were found in the lung homogenates of the MVAIK/PdmHA group. Higher levels of IFN-γ mRNA were detected in spleen cell culture from the MVAIK/PdmHA group stimulated with UV-inactivated A/California/07/2009(H1N1pdm). In conclusion, the recombinant MVAIK vaccine expressing influenza HA protein induced protective immune responses in cotton rats.

Fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance (EMARIS) network and first scientific conference on acute respiratory infections in the Eastern Mediterranean Region, 11-14 December, 2017, Amman, Jordan

Influenza causes significant morbidity and mortality worldwide. Owing to its ability to rapidly evolve and spread, the influenza virus is of global public health importance. Information on the burden, seasonality and risk factors of influenza in countries of the World Health Organization Eastern Mediterranean Region is emerging because of collaborative efforts between countries, WHO and its partners over the past 10 years. The fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance network was held in Amman, Jordan on 11–14 December 2017. The meeting reviewed the progress and achievements reported by the countries in the areas of surveillance of and response to seasonal, zoonotic and pandemic influenza. The first scientific conference on acute respiratory infection in the Eastern Mediterranean Region was held at the same time and 38 abstracts from young researchers across the Region were presented on epidemiological and virological surveillance, outbreak detection and response, influenza at the animal-human interface, use and efficacy of new vaccines to control respiratory diseases and pandemic influenza threats. The meeting identified a number of challenges and ways to improve the quality of the surveillance system for influenza, sustain the system so as to address pandemic threats and use the data generated from the surveillance system to inform decision-making, policies and practices to reduce the burden of influenza-associated illnesses in the Region.

Influenza vaccines: the potential benefits of cell-culture isolation and manufacturing

Influenza continues to cause severe illness in millions and deaths in hundreds of thousands annually. Vaccines are used to prevent influenza outbreaks, however, the influenza virus mutates and annual vaccination is required for optimal protection. Vaccine effectiveness is also affected by other potential factors such as the human immune system, a mismatch with the chosen candidate virus, and egg adaptation associated with egg-based vaccine production. This article reviews the influenza vaccine development process and describes the implications of the changes to the cell-culture process and vaccine strain recommendations by the World Health Organization since the 2017 season. The traditional manufacturing process for influenza vaccines relies on fertilized chicken eggs that are used for vaccine production. Vaccines must be produced in large volumes and the complete process requires approximately 6 months for the egg-based process. In addition, egg adaptation of seed viruses occurs when viruses adapt to avian receptors found within eggs to allow for growth in eggs. These changes to key viral antigens may result in antigenic mismatch and thereby reduce vaccine effectiveness. By contrast, cell-derived seed viruses do not require fertilized eggs and eliminate the potential for egg-adapted changes. As a result, cell-culture technology improves the match between the vaccine virus strain and the vaccine selected strain, and has been associated with increased vaccine effectiveness during a predominantly H3N2 season. During the 2017–2018 influenza season, a small number of studies conducted in the United States compared the effectiveness of egg-based and cell-culture vaccines and are described here. These observational and retrospective studies demonstrate that inactivated cell-culture vaccines were more effective than egg-based vaccines. Adoption of cell-culture technology for influenza vaccine manufacturing has been reported to improve manufacturing efficiency and the additional benefit of improving vaccine effectiveness is a key factor for future policy making considerations.

Genetic Characterization of Avian Influenza A (H11N9) Virus Isolated from Mandarin Ducks in South Korea in 2018

In July 2018, a novel avian influenza virus (A/Mandarin duck/South Korea/KNU18-12/2018(H11N9)) was isolated from Mandarin ducks in South Korea. Phylogenetic and molecular analyses were conducted to characterize the genetic origins of the H11N9 strain. Phylogenetic analysis indicated that eight gene segments of strain H11N9 belonged to the Eurasian lineages. Analysis of nucleotide sequence similarity of both the hemagglutinin (HA) and neuraminidase (NA) genes revealed the highest homology with A/duck/Kagoshima/KU57/2014 (H11N9), showing 97.70% and 98.00% nucleotide identities, respectively. Additionally, internal genes showed homology higher than 98% compared to those of other isolates derived from duck and wild birds. Both the polymerase acidic (PA) and polymerase basic 1 (PB1) genes were close to the H5N3 strain isolated in China; whereas, other internal genes were closely related to that of avian influenza virus in Japan. A single basic amino acid at the HA cleavage site (PAIASR↓GLF), the lack of a five-amino acid deletion (residue 69–73) in the stalk region of the NA gene, and E627 in the polymerase basic 2 (PB2) gene indicated that the A/Mandarin duck/South Korea/KNU18-12/2018(H11N9) isolate was a typical low-pathogenicity avian influenza. In vitro viral replication of H11N9 showed a lower titer than H1N1 and higher than H9N2. In mice, H11N9 showed lower adaptation than H1N1. The novel A/Mandarin duck/South Korea/KNU18-12/2018(H11N9) isolate may have resulted from an unknown reassortment through the import of multiple wild birds in Japan and Korea in approximately 2016–2017, evolving to produce a different H11N9 compared to the previous H11N9 in Korea (2016). Further reassortment events of this virus occurred in PB1 and PA in China-derived strains. These results indicate that Japanese- and Chinese-derived avian influenza contributes to the genetic diversity of A/Mandarin duck/South Korea/KNU18-12/2018(H11N9) in Korea.

Pathogen Genomics in Public Health

Rapid advances in DNA sequencing technology ("next-generation sequencing") have inspired optimism about the potential of human genomics for "precision medicine." Meanwhile, pathogen genomics is already delivering "precision public health" through more effective investigations of outbreaks of foodborne illnesses, better-targeted tuberculosis control, and more timely and granular influenza surveillance to inform the selection of vaccine strains. In this article, we describe how public health agencies have been adopting pathogen genomics to improve their effectiveness in almost all domains of infectious disease. This momentum is likely to continue, given the ongoing development in sequencing and sequencing-related technologies.

Predicting Seasonal Influenza Based on SARIMA Model, in Mainland China from 2005 to 2018

Seasonal influenza is one of the mandatorily monitored infectious diseases, in China. Making full use of the influenza surveillance data helps to predict seasonal influenza. In this study, a seasonal autoregressive integrated moving average (SARIMA) model was used to predict the influenza changes by analyzing monthly data of influenza incidence from January 2005 to December 2018, in China. The inter-annual incidence rate fluctuated from 2.76 to 55.07 per 100,000 individuals. The SARIMA (1, 0, 0) × (0, 1, 1) 12 model predicted that the influenza incidence in 2018 was similar to that of previous years, and it fitted the seasonal fluctuation. The relative errors between actual values and predicted values fluctuated from 0.0010 to 0.0137, which indicated that the predicted values matched the actual values well. This study demonstrated that the SARIMA model could effectively make short-term predictions of seasonal influenza.

New York State Emergency Preparedness and Response to Influenza Pandemics 1918-2018

Emergency health preparedness and response efforts are a necessity in order to safeguard the public against major events, such as influenza pandemics. Since posting warnings of the epidemic influenza in 1918, to the mass media communications available a century later, state, national and global public health agencies have developed sophisticated networks, tools, detection methods, and preparedness plans. These progressive measures guide health departments and clinical providers, track patient specimens and test reports, monitor the spread of disease, and evaluate the most threatening influenza strains by means of risk assessment, to be able to respond readily to a pandemic. Surge drills and staff training were key aspects for New York State preparedness and response to the 2009 influenza pandemic, and the re-evaluation of preparedness plans is recommended to ensure readiness to address the emergence and spread of a future novel virulent influenza strain.

Influenza Infections and Emergent Viral Infections in Intensive Care Unit

Critically ill patients are admitted to an intensive care unit (ICU) for multiple reasons. In this study, we aim to analyze the current evidence and findings associated with influenza and other emergent viral infections, namely, herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV), and cytomegalovirus (CMV).

Among medical conditions, community-acquired respiratory infections are the most frequent reason for ventilatory support in ICUs. Community-acquired pneumonia in a severe form including the need of invasive mechanical ventilation and/or vasopressors is associated with high mortality rates. However, after the pandemic that occurred in 2009 by H1N1 influenza, the number of cases being admitted to ICUs with viral infections is on the rise. Patients in whom an etiology would not have been identified in the past are currently being tested with more sensitive viral molecular diagnostic tools, and patients being admitted to ICUs have more preexisting medical conditions that can predispose to viral infections. Viral infections can trigger the dysregulation of the immune system by inducing a massive cytokine response. This cytokine storm can cause endothelial damage and dysfunction, deregulation of coagulation, and, consequently, alteration of microvascular permeability, tissue edema, and shock. In severe influenza, this vascular hyperpermeability can lead to acute lung injury, multiorgan failure, and encephalopathy. In immunocompetent patients, the most common viral infections are respiratory, and influenza should be considered in patients with severe respiratory failure being admitted to ICU. Seasonality and coinfection are two important features when considering influenza as a pathogen in critically ill patients.

Herpesviridae (HSV, CMV, and EBV) may reactivate in ICU patients, and their reactivation is associated with morbidity/mortality. However, whether a specific treatment may impact on outcome remains to be determined.

Future Pandemic Influenza Virus Detection Relies on the Existing Influenza Surveillance Systems: A Perspective from Australia and New Zealand

The anniversary of the 1918–1919 influenza pandemic has allowed a refocusing on the global burden of influenza and the importance of co-ordinated international surveillance for both seasonal influenza and the identification of control strategies for future pandemics. Since the introduction of the International Health Regulations (IHR), progress had been slow, until the emergence of the novel influenza A(H1N1)2009 virus and its global spread, which has led to the World Health Organization (WHO) developing a series of guidance documents on global influenza surveillance procedures, severity and risk assessments, and essential measurements for the determination of national pandemic responses. However, the greatest burden of disease from influenza occurs between pandemics during seasonal influenza outbreaks and epidemics. Both Australia and New Zealand utilise seasonal influenza surveillance to support national influenza awareness programs focused on seasonal influenza vaccination education and promotion. These programs also serve to promote the importance of pandemic preparedness.

Public Health-Driven Research and Innovation for Next-Generation Influenza Vaccines, European Union

Influenza virus infections are a major public health threat. Vaccination is available, but unpredictable antigenic changes in circulating strains require annual modification of seasonal influenza vaccines. Vaccine effectiveness has proven limited, particularly in certain groups, such as the elderly. Moreover, preparedness for upcoming pandemics is challenging because we can predict neither the strain that will cause the next pandemic nor the severity of the pandemic. The European Union fosters research and innovation to develop novel vaccines that evoke broadly protective and long-lasting immune responses against both seasonal and pandemic influenza, underpinned by a political commitment to global public health.

Identification of Broad-Spectrum Antiviral Compounds by Targeting Viral Entry

Viruses are a major threat to human health and economic well-being. In recent years Ebola, Zika, influenza, and chikungunya virus epidemics have raised awareness that infections can spread rapidly before vaccines or specific antagonists can be made available. Broad-spectrum antivirals are drugs with the potential to inhibit infection by viruses from different groups or families, which may be deployed during outbreaks when specific diagnostics, vaccines or directly acting antivirals are not available. While pathogen-directed approaches are generally effective against a few closely related viruses, targeting cellular pathways used by multiple viral agents can have broad-spectrum efficacy. Virus entry, particularly clathrin-mediated endocytosis, constitutes an attractive target as it is used by many viruses. Using a phenotypic screening strategy where the inhibitory activity of small molecules was sequentially tested against different viruses, we identified 12 compounds with broad-spectrum activity, and found a subset blocking viral internalisation and/or fusion. Importantly, we show that compounds identified with this approach can reduce viral replication in a mouse model of Zika infection. This work provides proof of concept that it is possible to identify broad-spectrum inhibitors by iterative phenotypic screenings, and that inhibition of host-pathways critical for viral life cycles can be an effective antiviral strategy.

Fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance (EMARIS) network and first scientific conference on acute respiratory infections in the Eastern Mediterranean Region, 11-14 December, 2017, Amman, Jordan

Influenza causes significant morbidity and mortality worldwide. Owing to its ability to rapidly evolve and spread, the influenza virus is of global public health importance. Information on the burden, seasonality and risk factors of influenza in countries of the World Health Organization Eastern Mediterranean Region is emerging because of collaborative efforts between countries, WHO and its partners over the past 10 years. The fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance network was held in Amman, Jordan on 11–14 December 2017. The meeting reviewed the progress and achievements reported by the countries in the areas of surveillance of and response to seasonal, zoonotic and pandemic influenza. The first scientific conference on acute respiratory infection in the Eastern Mediterranean Region was held at the same time and 38 abstracts from young researchers across the Region were presented on epidemiological and virological surveillance, outbreak detection and response, influenza at the animal-human interface, use and efficacy of new vaccines to control respiratory diseases and pandemic influenza threats. The meeting identified a number of challenges and ways to improve the quality of the surveillance system for influenza, sustain the system so as to address pandemic threats and use the data generated from the surveillance system to inform decision-making, policies and practices to reduce the burden of influenza-associated illnesses in the Region.

The National Influenza Surveillance System of Korea

Influenza is a very important respiratory infectious disease that causes seasonal epidemics and pandemics. A well-organized surveillance system is necessary to monitor and respond effectively to the epidemiologic features of influenza. Korea currently operates a national influenza surveillance system based on the clinical sentinel surveillance system, laboratory sentinel surveillance system, and hospitalization and mortality surveillance system. However, there is a need for a better national surveillance system due to a demand for various pieces of information related to influenza. This article discusses the general aspects of influenza surveillance systems and the future direction of the national influenza surveillance system of Korea.

Back to the Future: Lessons Learned From the 1918 Influenza Pandemic

2018 marks the 100-year anniversary of the 1918 influenza pandemic, which killed ~50 million people worldwide. The severity of this pandemic resulted from a complex interplay between viral, host, and societal factors. Here, we review the viral, genetic and immune factors that contributed to the severity of the 1918 pandemic and discuss the implications for modern pandemic preparedness. We address unresolved questions of why the 1918 influenza H1N1 virus was more virulent than other influenza pandemics and why some people survived the 1918 pandemic and others succumbed to the infection. While current studies suggest that viral factors such as haemagglutinin and polymerase gene segments most likely contributed to a potent, dysregulated pro-inflammatory cytokine storm in victims of the pandemic, a shift in case-fatality for the 1918 pandemic toward young adults was most likely associated with the host's immune status. Lack of pre-existing virus-specific and/or cross-reactive antibodies and cellular immunity in children and young adults likely contributed to the high attack rate and rapid spread of the 1918 H1N1 virus. In contrast, lower mortality rate in in the older (>30 years) adult population points toward the beneficial effects of pre-existing cross-reactive immunity. In addition to the role of humoral and cellular immunity, there is a growing body of evidence to suggest that individual genetic differences, especially involving single-nucleotide polymorphisms (SNPs), contribute to differences in the severity of influenza virus infections. Co-infections with bacterial pathogens, and possibly measles and malaria, co-morbidities, malnutrition or obesity are also known to affect the severity of influenza disease, and likely influenced 1918 H1N1 disease severity and outcomes. Additionally, we also discuss the new challenges, such as changing population demographics, antibiotic resistance and climate change, which we will face in the context of any future influenza virus pandemic. In the last decade there has been a dramatic increase in the number of severe influenza virus strains entering the human population from animal reservoirs (including highly pathogenic H7N9 and H5N1 viruses). An understanding of past influenza virus pandemics and the lessons that we have learnt from them has therefore never been more pertinent.

65 years of influenza surveillance by a World Health Organization-coordinated global network

The 1918 devastating influenza pandemic left a lasting impact on influenza experts and the public, and the importance of global influenza surveillance was soon recognized. The World Health Organization (WHO) Global Influenza Surveillance Network (GISN) was founded in 1952 and renamed to Global Influenza Surveillance and Response System in 2011 upon the adoption by the World Health Assembly, of the Pandemic Influenza Preparedness Framework for the Sharing of Influenza Viruses and Access to Vaccines and Other Benefits ("PIP Framework"). The importance of influenza surveillance had been recognized and promoted by experts prior to the years leading up to the establishment of WHO. In the 65 years of its existence, the Network has grown to comprise 143 National Influenza Centers recognized by WHO, 6 WHO Collaborating Centers, 4 Essential Regulatory Laboratories, and 13 H5 Reference Laboratories. The Network has proven its excellence throughout these 65 years, providing detailed information on circulating seasonal influenza viruses, as well as immediate response to the influenza pandemics in 1957, 1968, and 2009, and to threats caused by animal influenza viruses and by zoonotic transmission of coronaviruses. For its central role in global public health, the Network has been highly recognized by its many partners and by international bodies. Several generations of world-renowned influenza scientists have brought the Network to where it is now and they will take it forward to the future, as influenza will remain a preeminent threat to humans and to animals.

The WHO global influenza surveillance and response system (GISRS)-A future perspective

In the centenary year of the devastating 1918-19 pandemic, it seems opportune to reflect on the success of the WHO Global Influenza Surveillance and Response System (GISRS) initiated 70 years ago to provide early warning of changes in influenza viruses circulating in the global population to help mitigate the consequences of such a pandemic and maintain the efficacy of seasonal influenza vaccines. Three pandemics later and in the face of pandemic threats from highly pathogenic zoonotic infections by different influenza A subtypes, it continues to represent a model platform for global collaboration and timely sharing of viruses, reagents and information to forestall and respond to public health emergencies.