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

SHEA position statement on pandemic preparedness for policymakers: introduction and overview

Throughout history, pandemics and their aftereffects have spurred society to make substantial improvements in healthcare. After the Black Death in 14th century Europe, changes were made to elevate standards of care and nutrition that resulted in improved life expectancy.1 The 1918 influenza pandemic spurred a movement that emphasized public health surveillance and detection of future outbreaks and eventually led to the creation of the World Health Organization Global Influenza Surveillance Network.2 In the present, the COVID-19 pandemic exposed many of the pre-existing problems within the US healthcare system, which included (1) a lack of capacity to manage a large influx of contagious patients while simultaneously maintaining routine and emergency care to non-COVID patients; (2) a "just in time" supply network that led to shortages and competition among hospitals, nursing homes, and other care sites for essential supplies; and (3) longstanding inequities in the distribution of healthcare and the healthcare workforce. The decades-long shift from domestic manufacturing to a reliance on global supply chains has compounded ongoing gaps in preparedness for supplies such as personal protective equipment and ventilators. Inequities in racial and socioeconomic outcomes highlighted during the pandemic have accelerated the call to focus on diversity, equity, and inclusion (DEI) within our communities. The pandemic accelerated cooperation between government entities and the healthcare system, resulting in swift implementation of mitigation measures, new therapies and vaccinations at unprecedented speeds, despite our fragmented healthcare delivery system and political divisions. Still, widespread misinformation or disinformation and political divisions contributed to eroded trust in the public health system and prevented an even uptake of mitigation measures, vaccines and therapeutics, impeding our ability to contain the spread of the virus in this country.3 Ultimately, the lessons of COVID-19 illustrate the need to better prepare for the next pandemic. Rising microbial resistance, emerging and re-emerging pathogens, increased globalization, an aging population, and climate change are all factors that increase the likelihood of another pandemic.4.

Zoonotic spillover and viral mutations from low and middle-income countries: improving prevention strategies and bridging policy gaps

The increasing frequency of zoonotic spillover events and viral mutations in low and middle-income countries presents a critical global health challenge. Contributing factors encompass cultural practices like bushmeat consumption, wildlife trade for traditional medicine, habitat disruption, and the encroachment of impoverished settlements onto natural habitats. The existing "vaccine gap" in many developing countries exacerbates the situation by allowing unchecked viral replication and the emergence of novel mutant viruses. Despite global health policies addressing the root causes of zoonotic disease emergence, there is a significant absence of concrete prevention-oriented initiatives, posing a potential risk to vulnerable populations. This article is targeted at policymakers, public health professionals, researchers, and global health stakeholders, particularly those engaged in zoonotic disease prevention and control in low and middle-income countries. The article underscores the importance of assessing potential zoonotic diseases at the animal-human interface and comprehending historical factors contributing to spillover events. To bridge policy gaps, comprehensive strategies are proposed that include education, collaborations, specialized task forces, environmental sampling, and the establishment of integrated diagnostic laboratories. These strategies advocate simplicity and unity, breaking down barriers, and placing humanity at the forefront of addressing global health challenges. Such a strategic and mental shift is crucial for constructing a more resilient and equitable world in the face of emerging zoonotic threats.

Non-SARS-CoV-2 respiratory viral detection and whole genome sequencing from COVID-19 rapid antigen test devices: a laboratory evaluation study

BACKGROUND

There has been high uptake of rapid antigen test device use for point-of-care COVID-19 diagnosis. Individuals who are symptomatic but test negative on COVID-19 rapid antigen test devices might have a different respiratory viral infection. We aimed to detect and sequence non-SARS-CoV-2 respiratory viruses from rapid antigen test devices, which could assist in the characterisation and surveillance of circulating respiratory viruses in the community.

METHODS

We applied archival clinical nose and throat swabs collected between Jan 1, 2015, and Dec 31, 2022, that previously tested positive for a common respiratory virus (adenovirus, influenza, metapneumovirus, parainfluenza, rhinovirus, respiratory syncytial virus [RSV], or seasonal coronavirus; 132 swabs and 140 viral targets) on PCR to two commercially available COVID-19 rapid antigen test devices, the Panbio COVID-19 Ag Rapid Test Device and Roche SARS-CoV-2 Antigen Self-Test. In addition, we collected 31 COVID-19 rapid antigen test devices used to test patients who were symptomatic at The Royal Melbourne Hospital emergency department in Melbourne, Australia. We extracted total nucleic acid from the device paper test strips and assessed viral recovery using multiplex real-time PCR (rtPCR) and capture-based whole genome sequencing. Sequence and genome data were analysed through custom computational pipelines, including subtyping.

FINDINGS

Of the 140 respiratory viral targets from archival samples, 89 (64%) and 88 (63%) were positive on rtPCR for the relevant taxa following extraction from Panbio or Roche rapid antigen test devices, respectively. Recovery was variable across taxa: we detected influenza A in nine of 18 samples from Panbio and seven of 18 from Roche devices; parainfluenza in 11 of 20 samples from Panbio and 12 of 20 from Roche devices; human metapneumovirus in 11 of 16 from Panbio and 14 of 16 from Roche devices; seasonal coronavirus in eight of 19 from Panbio and two of 19 from Roche devices; rhinovirus in 24 of 28 from Panbio and 27 of 28 from Roche devices; influenza B in four of 15 in both devices; and RSV in 16 of 18 in both devices. Of the 31 COVID-19 devices collected from The Royal Melbourne Hospital emergency department, 11 tested positive for a respiratory virus on rtPCR, including one device positive for influenza A virus, one positive for RSV, four positive for rhinovirus, and five positive for SARS-CoV-2. Sequences of target respiratory viruses from archival samples were detected in 55 (98·2%) of 56 samples from Panbio and 48 (85·7%) of 56 from Roche rapid antigen test devices. 98 (87·5%) of 112 viral genomes were completely assembled from these data, enabling subtyping for RSV and influenza viruses. All 11 samples collected from the emergency department had viral sequences detected, with near-complete genomes assembled for influenza A and RSV.

INTERPRETATION

Non-SARS-CoV-2 respiratory viruses can be detected and sequenced from COVID-19 rapid antigen devices. Recovery of near full-length viral sequences from these devices provides a valuable opportunity to expand genomic surveillance programmes for public health monitoring of circulating respiratory viruses.

FUNDING

Australian Government Medical Research Future Fund and Australian National Health and Medical Research Council.

Integrating single-cell RNA sequencing data to genome-wide association analysis data identifies significant cell types in influenza A virus infection and COVID-19

With the global pandemic of COVID-19, the research on influenza virus has entered a new stage, but it is difficult to elucidate the pathogenesis of influenza disease. Genome-wide association studies (GWASs) have greatly shed light on the role of host genetic background in influenza pathogenesis and prognosis, whereas single-cell RNA sequencing (scRNA-seq) has enabled unprecedented resolution of cellular diversity and in vivo following influenza disease. Here, we performed a comprehensive analysis of influenza GWAS and scRNA-seq data to reveal cell types associated with influenza disease and provide clues to understanding pathogenesis. We downloaded two GWAS summary data, two scRNA-seq data on influenza disease. After defining cell types for each scRNA-seq data, we used RolyPoly and LDSC-cts to integrate GWAS and scRNA-seq. Furthermore, we analyzed scRNA-seq data from the peripheral blood mononuclear cells (PBMCs) of a healthy population to validate and compare our results. After processing the scRNA-seq data, we obtained approximately 70 000 cells and identified up to 13 cell types. For the European population analysis, we determined an association between neutrophils and influenza disease. For the East Asian population analysis, we identified an association between monocytes and influenza disease. In addition, we also identified monocytes as a significantly related cell type in a dataset of healthy human PBMCs. In this comprehensive analysis, we identified neutrophils and monocytes as influenza disease-associated cell types. More attention and validation should be given in future studies.

A phased strengthening of laboratory capacity in the Eastern Mediterranean Region during the COVID-19 pandemic

The Eastern Mediterranean Region (EMR) faces ongoing challenges in its public health system due to limited resources, logistical issues, and political disruptions. The COVID-19 pandemic accelerated the need for stronger laboratory capacities to handle the increased demand for testing. In a phased response, EMR countries utilized the National Influenza Centers to rapidly establish and scale molecular testing for SARS-CoV-2, the causative agent of COVID-19. The expansion of capacity included strong collaborations between public health bodies and private and academic sectors to decentralize and expand testing to the subnational level. To ensure that the quality of testing was not impacted by rapid expansion, national and subnational laboratories were enrolled in external quality assurance programs for the duration of the response. Implementation of genomic surveillance was prioritized for variant tracking, leading to the establishment of regional sequencing reference laboratories and the distribution of MinION sequencing platforms to complex emergency countries who previously had limited experience with pathogen sequencing. Challenges included a lack of technical expertise, including in implementing novel diagnostic assays and sequencing, a lack of bioinformatics expertise in the region, and significant logistical and procurement challenges. The collaborative approach, coordinated through the WHO Eastern Mediterranean Regional Office, enabled all 22 countries to achieve SARS-CoV-2 diagnostic capabilities, highlighting the pivotal role of laboratories in global health security.

Permanent Complete Heart Block: A Rare Complication of Influenza Infection

The cardiovascular complications of viral illnesses are often underestimated in clinical practice. The influenza virus, one of the most prevalent viral infections, has been associated with a wide spectrum of arrhythmias that are typically transient and self-resolving. We present the case of a 60-year-old female with no prior cardiac comorbidities who developed a complete heart block after an influenza infection. She presented to the clinic with flu-like symptoms and was found to have a complete heart block with a junctional escape rhythm. Polymerase chain reaction testing subsequently confirmed an influenza A infection. She was initially placed on a temporary pacemaker. However, a permanent dual-chamber pacemaker was implanted as bradycardia persisted. Later follow-ups in the cardiology clinic showed that the patient remained dependent on the pacemaker. While there are a few descriptions of influenza-induced transient atrioventricular block, cases of influenza-induced permanent complete heart block are extremely rare, particularly in the absence of severe myocardial inflammation.

Infectious disease control: from health security strengthening to health systems improvement at global level

Since the twenty first century, the outbreaks of global infectious diseases have caused several public health emergencies of international concern, imposing an enormous impact on population health, the economy, and social development. The COVID-19 pandemic has once again exposed deficiencies in existing global health systems, emergency management, and disease surveillance, and highlighted the importance of developing effective evaluation tools. This article outlines current challenges emerging from infectious disease control from the perspective of global health, elucidated through influenza, malaria, tuberculosis, and neglected tropical diseases. The discordance among government actors and absent data sharing platforms or tools has led to unfulfilled targets in health system resilience and a capacity gap in infectious disease response. The current situation calls for urgent action to tackle these threats of global infectious diseases with joined forces through more in-depth international cooperation and breaking governance barriers from the purview of global health. Overall, a systematic redesign should be considered to enhance the resilience of health systems, which warrants a great need to sustain capacity-building efforts in emergency preparedness and response and raises an emerging concern of data integration in the concept of One Health that aims to address shared health threats at the human-animal-environment interface.

Understanding the divergent evolution and epidemiology of H3N8 influenza viruses in dogs and horses

Cross-species virus transmission events can lead to dire public health emergencies in the form of epidemics and pandemics. One example in animals is the emergence of the H3N8 equine influenza virus (EIV), first isolated in 1963 in Miami, FL, USA, after emerging among horses in South America. In the early 21st century, the American lineage of EIV diverged into two 'Florida' clades that persist today, while an EIV transferred to dogs around 1999 and gave rise to the H3N8 canine influenza virus (CIV), first reported in 2004. Here, we compare CIV in dogs and EIV in horses to reveal their host-specific evolution, to determine the sources and connections between significant outbreaks, and to gain insight into the factors controlling their different evolutionary fates. H3N8 CIV only circulated in North America, was geographically restricted after the first few years, and went extinct in 2016. Of the two EIV Florida clades, clade 1 circulates widely and shows frequent transfers between the USA and South America, Europe and elsewhere, while clade 2 was globally distributed early after it emerged, but since about 2018 has only been detected in Central Asia. Any potential zoonotic threat of these viruses to humans can only be determined with an understanding of its natural history and evolution. Our comparative analysis of these three viral lineages reveals distinct patterns and rates of sequence variation yet with similar overall evolution between clades, suggesting epidemiological intervention strategies for possible eradication of H3N8 EIV.

Impact analysis of COVID-19 on Nigerian workers' productivity using multiple correspondence analysis

As the COVID-19 pandemic became a global health concern, many business activities have had to adjust to the protocols required to keep people safe, thereby altering the work structures of many professionals. With data gathered from 466 respondents in Nigeria, of which approximately 70% are from the South-West, this study shows how the factors associated with the health crisis have affected work productivity during this period. The snowball survey research design techniques with the two-way interaction model were employed. Multiple Correspondence Analysis was used to analyse and understand multiple and pairwise qualitative factors that influence productivity. The first part of the analysis identified boredom, remuneration, internet availability, fear of COVID-19 and depressing news of COVID-19 as the factors that had significant impacts on workers' productivity. The second part of the analysis shows how the categories of the five significant factors were either associated or not with productivity. An analysis of each of these factors showed that fear of the disease was associated with slight productivity but access to internet facilities and remuneration were strongly associated with improved work productivity, while boredom and depressing news about COVID-19 were associated with non-productivity during this period. Further evidence also showed that training and new skills acquisition might improve workers' productivity much more. We, therefore, recommend dynamic skills acquisition, training, and investment in tools and services that will enhance flexibility with the changing work structure that comes because of global crises.

A framework for seroepidemiologic investigations in future pandemics: insights from an evaluation of WHO's Unity Studies initiative

BACKGROUND

The WHO Unity Studies initiative supports countries, especially low- and middle-income countries (LMICs), in conducting seroepidemiologic studies for rapidly informing responses to the COVID-19 pandemic. Ten generic study protocols were developed which standardized epidemiologic and laboratory methods. WHO provided technical support, serological assays and funding for study implementation. An external evaluation was conducted to assess (1) the usefulness of study findings in guiding response strategies, (2) management and support to conduct studies and (3) capacity built from engagement with the initiative.

METHODS

The evaluation focused on the three most frequently used protocols, namely first few cases, household transmission and population-based serosurvey, 66% of 339 studies tracked by WHO. All 158 principal investigators (PIs) with contact information were invited to complete an online survey. A total of 19 PIs (randomly selected within WHO regions), 14 WHO Unity focal points at the country, regional and global levels, 12 WHO global-level stakeholders and eight external partners were invited to be interviewed. Interviews were coded in MAXQDA™, synthesized into findings and cross-verified by a second reviewer.

RESULTS

Among 69 (44%) survey respondents, 61 (88%) were from LMICs. Ninety-five percent gave positive feedback on technical support, 87% reported that findings contributed to COVID-19 understanding, 65% to guiding public health and social measures, and 58% to guiding vaccination policy. Survey and interview group responses showed that the main technical barriers to using study findings were study quality, variations in study methods (challenge for meta-analysis), completeness of reporting study details and clarity of communicating findings. Untimely study findings were another barrier, caused by delays in ethical clearance, receipt of serological assays and approval to share findings. There was strong agreement that the initiative created equitable research opportunities, connected expertise and facilitated study implementation. Around 90% of respondents agreed the initiative should continue in the future.

CONCLUSIONS

The Unity Studies initiative created a highly valued community of practice, contributed to study implementation and research equity, and serves as a valuable framework for future pandemics. To strengthen this platform, WHO should establish emergency-mode procedures to facilitate timeliness and continue to build capacity to rapidly conduct high-quality studies and communicate findings in a format friendly to decision-makers.

An appraisal of peer-reviewed published literature on Influenza, 2000-2021 from countries in South-East Asia Region

Background

Influenza poses a major public health challenge in South-East Asia Region (SEAR). To address the challenge, there is a need to generate contextual evidence that could inform policy makers and program managers for response preparedness and impact mitigation. The World Health Organization has identified priority areas across five streams for research evidence generation at a global level (WHO Public Health Research Agenda). Stream 1 focuses on research for reducing the risk of emergence, Stream 2 on limiting the spread, Stream 3 on minimizing the impact, Stream 4 on optimizing the treatment and Stream 5 on promoting public health tools and technologies for Influenza. However, evidence generation from SEAR has been arguably low and needs a relook for alignment with priorities. This study aimed to undertake a bibliometric analysis of medical literature on Influenza over the past 21 years to identify gaps in research evidence and for identifying major areas for focusing with a view to provide recommendations to member states and SEAR office for prioritizing avenues for future research.

Methods

We searched Scopus, PubMed, Embase, and Cochrane databases in August 2021. We identified studies on influenza published from the 11 countries in WHO SEAR in the date range of 1 January 2000-31 December 2021. Data was retrieved, tagged and analyzed based on the WHO priority streams for Influenza, member states, study design and type of research. Bibliometric analysis was done on Vosviewer.

Findings

We included a total of 1,641 articles (Stream 1: n = 307; Stream 2: n = 516; Stream 3: n = 470; Stream 4: n = 309; Stream 5: n = 227). Maximum number of publications were seen in Stream 2, i.e., limiting the spread of pandemic, zoonotic, and seasonal epidemic influenza which majorly included transmission, spread of virus at global and local levels and public health measures to limit the transmission. The highest number of publications was from India (n = 524) followed by Thailand (n = 407), Indonesia (n = 214) and Bangladesh (n = 158). Bhutan (n = 10), Maldives (n = 1), Democratic People's Republic of Korea (n = 1), and Timor-Leste (n = 3) had the least contribution in Influenza research. The top-most journal was PloS One which had the maximum number of influenza articles (n = 94) published from SEAR countries. Research that generated actionable evidence, i.e., implementation and intervention related topics were less common. Similarly, research on pharmaceutical interventions and on innovations was low. SEAR member states had inconsistent output across the five priority research streams, and there was a much higher scope and need for collaborative research. Basic science research showed declining trends and needed reprioritization.

Interpretation

While a priority research agenda has been set for influenza at the global level through the WHO Global Influenza Program since 2009, and subsequently revisited in 2011 and again in 2016-2017, a structured contextualized approach to guide actionable evidence generation activities in SEAR has been lacking. In the backset of the Global Influenza Strategy 2019-2030 and the COVID-19 pandemic, attuning research endeavors in SEAR could help in improved pandemic influenza preparedness planning. There is a need to prioritize contextually relevant research themes within priority streams. Member states must inculcate a culture of within and inter-country collaboration to produce evidence that has regional as well as global value.

The global region-specific epidemiologic characteristics of influenza: World Health Organization FluNet data from 1996 to 2021

OBJECTIVES

This study aimed to investigate region-specific epidemiologic characteristics of influenza and influenza transmission zones (ITZs).

METHODS

Weekly influenza surveillance data of 156 countries from 1996 to 2021 were obtained using FluNet. Joinpoint regression was used to describe global influenza virus trends, and clustering analyses were used to classify the ITZs.

RESULTS

The global median average positive rate for total influenza virus was 16.19% (interquartile range: 11.62-25.70%). Overall, three major subtypes (influenza H1, H3, and B viruses) showed alternating epidemics. Notably, the proportion of influenza B viruses increased significantly from July 2020 to June 2021, reaching 62.66%. The primary peaks of influenza virus circulation in the north were earlier than those in the south. Global influenza virus circulation was significantly characterized by seven ITZs, including "Northern America" (primary peak: week 10), "Eastern & Southern-Asia" (primary peak: week 10), "Europe" (primary peak: week 11), "Asia-Europe" (primary peak: week 12), "Southern-America" (primary peak: week 30), "Oceania-Melanesia-Polynesia" (primary peak: week 39), and "Africa" (primary peak: week 46).

CONCLUSION

Global influenza virus circulation was significantly characterized by seven ITZs that could be applied to influenza surveillance and warning.

An Old Acquaintance: Could Adenoviruses Be Our Next Pandemic Threat?

Human adenoviruses (HAdV) are one of the most important pathogens detected in acute respiratory diseases in pediatrics and immunocompromised patients. In 1953, Wallace Rowe described it for the first time in oropharyngeal lymphatic tissue. To date, more than 110 types of HAdV have been described, with different cellular tropisms. They can cause respiratory and gastrointestinal symptoms, even urinary tract inflammation, although most infections are asymptomatic. However, there is a population at risk that can develop serious and even lethal conditions. These viruses have a double-stranded DNA genome, 25-48 kbp, 90 nm in diameter, without a mantle, are stable in the environment, and resistant to fat-soluble detergents. Currently the diagnosis is made with lateral flow immunochromatography or molecular biology through a polymerase chain reaction. This review aimed to highlight the HAdV variability and the pandemic potential that a HAdV3 and 7 recombinant could have considering the aggressive outbreaks produced in health facilities. Herein, we described the characteristics of HAdV, from the infection to treatment, vaccine development, and the evaluation of the social determinants of health associated with HAdV, suggesting the necessary measures for future sanitary control to prevent disasters such as the SARS-CoV-2 pandemic, with an emphasis on the use of recombinant AdV vaccines to control other potential pandemics.

Leveraging International Influenza Surveillance Systems and Programs during the COVID-19 Pandemic

A network of global respiratory disease surveillance systems and partnerships has been built over decades as a direct response to the persistent threat of seasonal, zoonotic, and pandemic influenza. These efforts have been spearheaded by the World Health Organization, country ministries of health, the US Centers for Disease Control and Prevention, nongovernmental organizations, academic groups, and others. During the COVID-19 pandemic, the US Centers for Disease Control and Prevention worked closely with ministries of health in partner countries and the World Health Organization to leverage influenza surveillance systems and programs to respond to SARS-CoV-2 transmission. Countries used existing surveillance systems for severe acute respiratory infection and influenza-like illness, respiratory virus laboratory resources, pandemic influenza preparedness plans, and ongoing population-based influenza studies to track, study, and respond to SARS-CoV-2 infections. The incorporation of COVID-19 surveillance into existing influenza sentinel surveillance systems can support continued global surveillance for respiratory viruses with pandemic potential.

In silico characterization of aryl benzoyl hydrazide derivatives as potential inhibitors of RdRp enzyme of H5N1 influenza virus

RNA-dependent RNA polymerase (RdRp) is a potential therapeutic target for the discovery of novel antiviral agents for the treatment of life-threatening infections caused by newly emerged strains of the influenza virus. Being one of the most conserved enzymes among RNA viruses, RdRp and its inhibitors require further investigations to design novel antiviral agents. In this work, we systematically investigated the structural requirements for antiviral properties of some recently reported aryl benzoyl hydrazide derivatives through a range of in silico tools such as 2D-quantitative structure-activity relationship (2D-QSAR), 3D-QSAR, structure-based pharmacophore modeling, molecular docking and molecular dynamics simulations. The 2D-QSAR models developed in the current work achieved high statistical reliability and simultaneously afforded in-depth mechanistic interpretability towards structural requirements. The structure-based pharmacophore model developed with the docked conformation of one of the most potent compounds with the RdRp protein of H5N1 influenza strain was utilized for developing a 3D-QSAR model with satisfactory statistical quality validating both the docking and the pharmacophore modeling methodologies performed in this work. However, it is the atom-based alignment of the compounds that afforded the most statistically reliable 3D-QSAR model, the results of which provided mechanistic interpretations consistent with the 2D-QSAR results. Additionally, molecular dynamics simulations performed with the apoprotein as well as the docked complex of RdRp revealed the dynamic stability of the ligand at the proposed binding site of the receptor. At the same time, it also supported the mechanistic interpretations drawn from 2D-, 3D-QSAR and pharmacophore modeling. The present study, performed mostly with open-source tools and webservers, returns important guidelines for research aimed at the future design and development of novel anti-viral agents against various RNA viruses like influenza virus, human immunodeficiency virus-1, hepatitis C virus, corona virus, and so forth.

Influenza Myopericarditis and Pericarditis: A Literature Review

Myopericarditis is a rare complication of influenza infection. The presentation may range from mild and frequently unrecognized, to fulminant and potentially complicated by cardiogenic and/or obstructive shock (tamponade), which is associated with high mortality. We performed a review of literature on all influenza pericarditis and myopericarditis cases according to PRISMA guidelines using the PubMed search engine of the Medline database. Seventy-five cases of influenza myopericarditis and isolated pericarditis were identified from 1951 to 2021. Influenza A was reported twice as often as influenza B; however, influenza type did not correlate with outcome. Men and elderly patients were more likely to have isolated pericarditis, while women and younger patients were more likely to have myopericarditis. All included patients had pericardial effusion, while 36% had tamponade. Tamponade was more common in those with isolated pericarditis (41.2%) than myopericarditis (13.8%). Cardiogenic shock was more common in patients with myopericarditis (64%), with an overall mortality rate of 14.7%. Nearly 88% of the recovered patients remained without long-term complications reported. Conclusion: Influenza A appears a more common cause of pericarditis and myopericarditis. Isolated pericarditis was more commonly associated with tamponade but without reported deaths, whereas myopericarditis was more commonly associated with cardiogenic shock and death (19%).

Trends in Influenza Infections in Three States of India from 2015-2021: Has There Been a Change during COVID-19 Pandemic?

The COVID-19 pandemic and public health response to the pandemic has caused huge setbacks in the management of other infectious diseases. In the present study, we aimed to (i) assess the trends in numbers of samples from patients with influenza-like illness and severe acute respiratory syndrome tested for influenza and the number and proportion of cases detected from 2015−2021 and (ii) examine if there were changes during the COVID-19 period (2020−2021) compared to the pre-COVID-19 period (2015−2019) in three states of India. The median (IQR) number of samples tested per month during the pre-COVID-19 period was 653 (395−1245), compared to 27 (11−98) during the COVID-19 period (p value < 0.001). The median (IQR) number of influenza cases detected per month during the pre-COVID-19 period was 190 (113−372), compared to 29 (27−30) during the COVID-19 period (p value < 0.001). Interrupted time series analysis (adjusting for seasonality and testing charges) confirmed a significant reduction in the total number of samples tested and influenza cases detected during the COVID-19 period. However, there was no change in the influenza positivity rate between pre-COVID-19 (29%) and COVID-19 (30%) period. These findings suggest that COVID-19-related disruptions, poor health-seeking behavior, and overburdened health systems might have led to a reduction in reported influenza cases rather than a true reduction in disease transmission.

A Review on Equine Influenza from a Human Influenza Perspective

Influenza A viruses (IAVs) have a main natural reservoir in wild birds. IAVs are highly contagious, continually evolve, and have a wide host range that includes various mammalian species including horses, pigs, and humans. Furthering our understanding of host-pathogen interactions and cross-species transmissions is therefore essential. This review focuses on what is known regarding equine influenza virus (EIV) virology, pathogenesis, immune responses, clinical aspects, epidemiology (including factors contributing to local, national, and international transmission), surveillance, and preventive measures such as vaccines. We compare EIV and human influenza viruses and discuss parallels that can be drawn between them. We highlight differences in evolutionary rates between EIV and human IAVs, their impact on antigenic drift, and vaccine strain updates. We also describe the approaches used for the control of equine influenza (EI), which originated from those used in the human field, including surveillance networks and virological analysis methods. Finally, as vaccination in both species remains the cornerstone of disease mitigation, vaccine technologies and vaccination strategies against influenza in horses and humans are compared and discussed.

Global respiratory virus surveillance: strengths, gaps, and way forward

Current situation

The global influenza surveillance and response system (GISRS), coordinated by the World Health Organization (WHO), is a global framework for surveillance of influenza and other respiratory viruses, data collection, laboratory capacity building, genomic data submission and archival, standardization, and calibration of reagents and vaccine strains, production of seasonal influenza vaccines and creating a facilitatory regulatory environment for the same.

Gaps

WHO-designated national influenza centers (NICs) are entrusted with establishing surveillance in their respective countries. National and subnational surveillance remains weak in most parts of the world because of varying capacities of the NICs, lack of funds, poor human and veterinary surveillance mechanisms, lack of intersectoral coordination, and varying commitments of the local government.

Way forward

As influenza viruses have a wide variety of nonhuman hosts, it is critical to strengthen surveillance at local levels for timely detection of untypable or novel strains with potential to cause epidemics or pandemics. In this article, we have proposed possible strategies to strengthen and expand local capacities for respiratory virus surveillance through the designated NICs of the WHO.

The Most Common Location of Schools with Viral Upper Respiratory Tract Infection Clusters in Taiwan, 2011-2019

Clusters of acute upper respiratory tract infections are mainly caused by type A or B influenza virus. Numerous factors modify the risk of upper respiratory tract infection (URTI) cluster transmission. The purpose of this study was to investigate the epidemiological characteristics, differences, and epidemic trends in influenza viruses and in non-influenza respiratory pathogens, and the distribution of the sites of URTI cluster events in Taiwan from 2011 to 2019. We examined the publicly available annual summary data on 1864 confirmed URTI clusters in the Taiwan Centers for Disease Control (Taiwan CDC) from 2011 to 2019. URTI clusters were mainly divided into 1295 clusters of influenza virus infections, 149 clusters of non-influenza respiratory pathogen infections, 341 clusters of pathogens not detected by routine tests, and 79 clusters of unchecked samples. There were statistically significant differences (p < 0.001) in the event numbers of URTI clusters among influenza and non-influenza respiratory pathogens between 2011 and 2019. There were statistically significant differences (p = 0.01) in instances of URTI clusters among non-influenza respiratory pathogens between 2011 and 2019. There were also statistically significant differences (p < 0.001) in instances of URTI clusters in different locations between 2011 and 2019. In all the pathogens of URTI clusters (odds ratio (OR) = 1.89−2.25, p = 0.002−0.004), most single infections were influenza A viruses (64.9%, 937/1444). Respiratory syncytial virus single infections were most numerous (43.0%, 64/149) among the non-influenza respiratory pathogens of URTI clusters. Of the institutions where URTI clusters occurred, schools had the most cases (50.1%, 933/1864) (OR = 1.41−3.02, p < 0.001−0.04). After the categorization of isolated virus strains by gene sequencing, it was found that, of the seasonal influenza A viruses, the H1N1 subtype viruses were predominantly A/California/07/2009, A/Michigan/45/2015, and A/Brisbane/02/2018, and the H3N2 subtype viruses were predominantly A/Hong Kong/4801/2014, A/Singapore/INFIMH-16−0019/2016, and A/Switzerland/8060/2017, during 2017−2019. Of the influenza B viruses, B/Brisbane/60/2008 (B/Vic) was the dominant type, and some were B/Massachusetts/02/2012 (B/Yam) and B/PHUKET/3073/2013 (B/Yam). This study is the first report of confirmed events of URTI clusters from surveillance data provided by the Taiwan CDC (2011−2019). This study highlights the importance of long-term, geographically extended studies, particularly for highly fluctuating pathogens, for understanding the implications of the transmission of URTI clusters in Taiwanese populations. Knowledge gaps and important data have been identified to inform future surveillance and research efforts in Taiwan.

Identification of Neutrophil-Related Factor LCN2 for Predicting Severity of Patients With Influenza A Virus and SARS-CoV-2 Infection

Background

Influenza and COVID-19 are respiratory infectious diseases that are characterized by high contagiousness and high mutation and pose a serious threat to global health. After Influenza A virus (IAV) and SARS-CoV-2 infection, severe cases may develop into acute lung injury. Immune factors act as an important role during infection and inflammation. However, the molecular immune mechanisms still remain unclear. We aimed to explore immune-related host factors and core biomarker for severe infection, to provide a new therapeutic target of host factor in patients.

Methods

Gene expression profiles were obtained from Gene Expression Omnibus and the Seurat R package was used for data process of single-cell transcriptome. Differentially expressed gene analysis and cell cluster were used to explore core host genes and source cells of genes. We performed Gene Ontology enrichment, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis to explore potential biological functions of genes. Gene set variation analysis was used to evaluate the important gene set variation score for different samples. We conduct Enzyme-linked immunosorbent assay (ELISA) to test plasma concentrations of Lipocalin 2 (LCN2).

Results

Multiple virus-related, cytokine-related, and chemokine-related pathways involved in process of IAV infection and inflammatory response mainly derive from macrophages and neutrophils. LCN2 mainly in neutrophils was significantly upregulated after either IAV or SARS-CoV-2 infection and positively correlated with disease severity. The plasma LCN2 of influenza patients were elevated significantly compared with healthy controls by ELISA and positively correlated with disease severity of influenza patients. Further bioinformatics analysis revealed that LCN2 involved in functions of neutrophils, including neutrophil degranulation, neutrophil activation involved in immune response, and neutrophil extracellular trap formation.

Conclusion

The neutrophil-related LCN2 could be a promising biomarker for predicting severity of patients with IAV and SARS-CoV-2 infection and may as a new treatment target in severe patients.

Discovery of Aryl Benzoyl Hydrazide Derivatives as Novel Potent Broad-Spectrum Inhibitors of Influenza A Virus RNA-Dependent RNA Polymerase (RdRp)

Influenza A viruses possess a high antigenic shift, and the approved anti-influenza drugs are extremely limited, which makes the development of novel anti-influenza drugs for the clinical treatment and prevention of influenza outbreaks imperative. Herein, we report a series of novel aryl benzoyl hydrazide analogs as potent anti-influenza agents. Particularly, analogs 10b, 10c, 10g, 11p, and 11q exhibited potent inhibitory activity against the avian H5N1 flu strain with EC₅₀ values ranging from 0.009 to 0.034 μM. Moreover, compound 11q exhibited nanomolar antiviral effects against both the H1N1 virus and Flu B virus and possessed good oral bioavailability and inhibitory activity against influenza A virus in a mouse model. Preliminary mechanistic studies suggested that these compounds exert anti-influenza virus effects mainly by interacting with the PB1 subunit of RNA-dependent RNA polymerase (RdRp). These results revealed that 11q has the potential to become a potent clinical candidate to combat seasonal influenza and influenza pandemics.

Applying the Moving Epidemic Method to Establish the Influenza Epidemic Thresholds and Intensity Levels for Age-Specific Groups in Hubei Province, China

BACKGROUND

School-aged children were reported to act as the main transmitter during influenza epidemic seasons. It is vital to set up an early detection method to help with the vaccination program in such a high-risk population. However, most relative studies only focused on the general population. Our study aims to describe the influenza epidemiology characteristics in Hubei Province and to introduce the moving epidemic method to establish the epidemic thresholds for age-specific groups.

METHODS

We divided the whole population into pre-school, school-aged and adult groups. The virology data from 2010/2011 to 2017/2018 were applied to the moving epidemic method to establish the epidemic thresholds for the general population and age-specific groups for the detection of influenza in 2018/2019. The performances of the model were compared by the cross-validation process.

RESULTS

The epidemic threshold for school-aged children in the 2018/2019 season was 15.42%. The epidemic thresholds for influenza A virus subtypes H1N1 and H3N2 and influenza B were determined as 5.68%, 6.12% and 10.48%, respectively. The median start weeks of the school-aged children were similar to the general population. The cross-validation process showed that the sensitivity of the model established with school-aged children was higher than those established with the other age groups in total influenza, H1N1 and influenza B, while it was only lower than the general population group in H3N2.

CONCLUSIONS

This study proved the feasibility of applying the moving epidemic method in Hubei Province. Additional influenza surveillance and vaccination strategies should be well-organized for school-aged children to reduce the disease burden of influenza in China.

Influenza Virus: Tracking, Predicting, and Forecasting

Influenza is a common respiratory infection that causes considerable morbidity and mortality worldwide each year. In recent years, along with the improvement in computational resources, there have been a number of important developments in the science of influenza surveillance and forecasting. Influenza surveillance systems have been improved by synthesizing multiple sources of information. Influenza forecasting has developed into an active field, with annual challenges in the United States that have stimulated improved methodologies. Work continues on the optimal approaches to assimilating surveillance data and information on relevant driving factors to improve estimates of the current situation (nowcasting) and to forecast future dynamics.

Impact of COVID-19 on Primary Care Practice Sites and Their Vulnerable Patients

Purpose: While COVID-19 has upended lives, it has also catalyzed innovation with potential to advance health delivery. Yet, we know little about how the delivery system, and primary care in particular, has responded and how this has impacted vulnerable patients. We aimed to understand the impact of COVID-19 on primary care practice sites and their vulnerable patients and to identify explanations for variation. Approach: We developed and administered a survey to practice managers and physician leaders from 173 primary care practice sites, October-November 2020. We report and graphically depict results from univariate analysis and examine potential explanations for variation in practices' process innovations in response to COVID-19 by assessing bivariate relationships between seven dependent variables and four independent variables. Findings: Among 96 (55.5%) respondents, primary care practice sites on average took more safety (8.5 of 12) than financial (2.5 of 17) precautions in response to COVID-19. Practice sites varied in their efforts to protect patients with vulnerabilities, providing care initially postponed, and experience with virtual visits. Financial risk, practice size, practitioner age, and emergency preparedness explained variation in primary care practices' process innovations. Many practice sites plan to sustain virtual visits, dependent mostly on patient and provider preference and continued reimbursement. Value: While findings indicate rapid and substantial innovation, conditions must enable primary care practice sites to build on and sustain innovations, to support care for vulnerable populations, including those with multiple chronic conditions and socio-economic barriers to health, and to prepare primary care for future emergencies.

Clinical outcomes of adults hospitalized for laboratory confirmed respiratory syncytial virus or influenza virus infection

Objectives

Respiratory syncytial virus (RSV) can cause severe disease in adults, but far less is known than for influenza. The aim of our study was to compare the disease course of RSV infections with influenza infections among hospitalized adults.

Methods

We retrieved clinical data from an ongoing surveillance of adults hospitalized with RSV or influenza virus infection in two acute care hospitals in North-Eastern Switzerland during the winter seasons 2017/2018 and 2018/2019. Our main analysis compared the odds between RSV and influenza patients for admission to an intensive care unit (ICU) or in-hospital death within 7 days after admission.

Results

There were 548 patients, of whom 79 (14.4%) had an RSV and 469 (85.6%) an influenza virus infection. Both groups were similar with respect to age, sex, smoking status, nutritional state, and comorbidities. More RSV patients had an infiltrate on chest radiograph on admission (46.4% vs 29.9%, p = .007). The proportion of patients with RSV who died or were admitted to ICU within seven days after admission was 19.0% compared to 10.2% in influenza patients (p = .024). In multivariable analysis, a higher leukocyte count (adjusted OR 1.07, 95% CI 1.02–1.13, p = .013) and the presence of a pneumonic infiltrate (aOR 3.41, 95% CI 1.93–6.02) significantly increased the risk for experiencing the adverse primary outcome while the effect of the underlying viral pathogen became attenuated (aOR 1.18, 95% CI 0.58–2.41, p = .0.655).

Conclusions

Our results suggest that RSV is responsible for clinical courses at least as severe as influenza in adults. This supports the need for better guidance on diagnostic strategies as well as on preventive and therapeutic measures for hospitalized adults with RSV infection.

Influenza Virus and SARS-CoV-2 Vaccines

Seasonal influenza and the current COVID-19 pandemic represent looming global health challenges. Efficacious and safe vaccines remain the frontline tools for mitigating both influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced diseases. This review will discuss the existing strategies for influenza vaccines and how these strategies have informed SARS-CoV-2 vaccines. It will also discuss new vaccine platforms and potential challenges for both viruses.

Impact of RNA degradation on influenza diagnosis in the surveillance system

BACKGROUND

The continuous evolution of influenza viruses is monitored by the World Health Organization Global Influenza Surveillance and Response System. Sample quality is essential for surveillance quality.

METHODS

To evaluate the RNA degradation of clinical samples, influenza-like illness samples were collected from four sentinel hospitals, and seasonal influenza was tested by real-time reverse transcription polymerase chain reaction and quantified by digital reverse transcription polymerase chain reaction at different time points.

RESULTS

RNA degradation was observed in the majority of samples eight days after sample collection. A significant and faster rate of RNA content reduction was observed in low viral load samples (<10 copies/µl) than in high viral load samples (>10 copies/μl), stored at 2 to 8°C for up to eight days. RNase P (RNP) RNA, which is a key indicator to evaluate sample collection quality, was detected. Sample collection quality was uneven in different hospitals.

CONCLUSION

Low viral load samples increase the risk of false negatives due to RNA degradation to undetectable levels.

Influenza vaccines: Past, present, and future

Globally, infection by seasonal influenza viruses causes 3-5 million cases of severe illness and 290,000-650,000 respiratory deaths each year. Various influenza vaccines, including inactivated split- and subunit-type, recombinant and live attenuated vaccines, have been developed since the 1930s when it was discovered that influenza viruses could be cultivated in embryonated eggs. However, the protection rate offered by these vaccines is rather low, especially in very young children and the elderly. In this review, we describe the history of influenza vaccine development, the immune responses induced by the vaccines and the adjuvants applied. Further, we suggest future directions for improving the effectiveness of influenza vaccines in all age groups. This includes the development of an influenza vaccine that induces a balanced T helper cell type 1 and type 2 immune responses based on the understanding of the immune system, and the development of a broad-spectrum influenza vaccine that can increase effectiveness despite antigen shifts and drifts, which are characteristics of the influenza virus. A brighter future can be envisaged if the development of an adjuvant that is safe and effective is realized.

Interplay between host non-coding RNAs and influenza viruses

Influenza virus infection through seasonal epidemics and occasional pandemics has been a major public health concern for decades. Incomplete protection from vaccination and increased antiviral resistance due to frequent mutations of influenza viruses have led to a continuous need for new therapeutic options. The functional significance of host protein and influenza virus interactions has been established, but relatively less is known about the interaction of host noncoding RNAs, including microRNAs and long noncoding RNAs, with influenza viruses. In this review, we summarize host noncoding RNA profiles during influenza virus infection and the regulation of influenza virus infection by host noncoding RNAs. Influenza viral non-coding RNAs are briefly discussed. Increased understanding of the molecular regulation of influenza viral replication will be beneficial in identifying potential therapeutic targets against the influenza virus.

The evolution and future of influenza pandemic preparedness

The influenza virus is a global threat to human health causing unpredictable yet recurring pandemics, the last four emerging over the course of a hundred years. As our knowledge of influenza virus evolution, distribution, and transmission has increased, paths to pandemic preparedness have become apparent. In the 1950s, the World Health Organization (WHO) established a global influenza surveillance network that is now composed of institutions in 122 member states. This and other surveillance networks monitor circulating influenza strains in humans and animal reservoirs and are primed to detect influenza strains with pandemic potential. Both the United States Centers for Disease Control and Prevention and the WHO have also developed pandemic risk assessment tools that evaluate specific aspects of emerging influenza strains to develop a systematic process of determining research and funding priorities according to the risk of emergence and potential impact. Here, we review the history of influenza pandemic preparedness and the current state of preparedness, and we propose additional measures for improvement. We also comment on the intersection between the influenza pandemic preparedness network and the current SARS-CoV-2 crisis. We must continually evaluate and revise our risk assessment and pandemic preparedness plans and incorporate new information gathered from research and global crises.

Prevalence of human respiratory syncytial virus, parainfluenza and adenoviruses in East Africa Community partner states of Kenya, Tanzania, and Uganda: A systematic review and meta-analysis (2007-2020)

Background

Viruses are responsible for a large proportion of acute respiratory tract infections (ARTIs). Human influenza, parainfluenza, respiratory-syncytial-virus, and adenoviruses are among the leading cause of ARTIs. Epidemiological evidence of those respiratory viruses is limited in the East Africa Community (EAC) region. This review sought to identify the prevalence of respiratory syncytial virus, parainfluenza, and adenoviruses among cases of ARTI in the EAC from 2007 to 2020.

Methods

A literature search was conducted in Medline, Global Index Medicus, and the grey literature from public health institutions and programs in the EAC. Two independent reviewers performed data extraction. We used a random effects model to pool the prevalence estimate across studies. We assessed heterogeneity with the I² statistic, and Cochran’s Q test, and further we did subgroup analysis. This review was registered with PROSPERO under registration number CRD42018110186.

Results

A total of 12 studies met the eligibility criteria for the studies documented from 2007 to 2020. The overall pooled prevalence of adenoviruses was 13% (95% confidence interval [CI]: 6–21, N = 28829), respiratory syncytial virus 11% (95% CI: 7–15, N = 22627), and parainfluenza was 9% (95% CI: 7–11, N = 28363). Pooled prevalence of reported ARTIs, all ages, and locality varied in the included studies. Studies among participants with severe acute respiratory disease had a higher pooled prevalence of all the three viruses. Considerable heterogeneity was noted overall and in subgroup analysis.

Conclusion

Our findings indicate that human adenoviruses, respiratory syncytial virus and parainfluenza virus are prevalent in Kenya, Tanzania, and Uganda. These three respiratory viruses contribute substantially to ARTIs in the EAC, particularly among those with severe disease and those aged five and above.

Preventing the next pandemic: the power of a global viral surveillance network

Dennis Carroll and colleagues call for a global early warning system to detect viruses with pandemic potential

Very little influenza in the WHO European Region during the 2020/21 season, weeks 40 2020 to 8 2021

Between weeks 40 2020 and 8 2021, the World Health Organization European Region experienced a 99.8% reduction in sentinel influenza virus positive detections (33/25,606 tested; 0.1%) relative to an average of 14,966/39,407 (38.0%; p < 0.001) over the same time in the previous six seasons. COVID-19 pandemic public health and physical distancing measures may have extinguished the 2020/21 European seasonal influenza epidemic with just a few sporadic detections of all viral subtypes. This might possibly continue during the remainder of the influenza season.

Global production capacity of seasonal and pandemic influenza vaccines in 2019

Vaccines will be an important element in mitigating the impact of an influenza pandemic. While research towards developing universal influenza vaccines is ongoing, the current strategy for vaccine supply in a pandemic relies on seasonal influenza vaccine production to be switched over to pandemic vaccines. Understanding how much vaccine could be produced, in which regions of the world and in what timeframe is critical to informing influenza pandemic preparedness. Through the Global Action Plan for Influenza Vaccines, 2006-2016, WHO promoted an increase in vaccine production capacity and monitors the landscape through periodically surveying influenza vaccine manufacturers. This study compares global capacity for production of influenza vaccines in 2019 with estimates from previous surveys; provides an overview of countries with established production facilities; presents vaccine production by type and manufacturing process; and discusses limitations to these estimates. Results of the current survey show that estimated annual seasonal influenza vaccine production capacity changed little since 2015 increasing from 1.47 billion to 1.48 billion doses with potential maximum annual influenza pandemic vaccine production capacity increasing from 6.37 billion to 8.31 billion doses. However, this figure should be interpreted with caution as it presents a best-case scenario with several assumptions which may impact supply. Further, pandemic vaccines would not be immediately available and could take four to six months for first supplies with several more months needed to reach maximum capacity. A moderate-case scenario is also presented of 4.15 billion doses of pandemic vaccine in 12 months. It is important to note that two doses of pandemic vaccine are likely to be required to elicit an adequate immune response. Continued efforts are needed to ensure the sustainability of this production and to conduct research for vaccines that are faster to produce and more broadly protective taking into account lessons learned from COVID-19 vaccine development.

Exploring the impacts of COVID-19 related social distancing on loneliness, psychological needs and symptomatology

Loneliness may be a consequence of social distancing, a measure imposed by several governments to try to reduce the contagion of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). Despite being necessary, this measure may have thus caused a rise in mental health issues, leading to higher psychological distress and symptomatology. Thus, it is also important to explore how loneliness relates to the regulation of psychological needs. This study aims to explore the relationships between loneliness, symptomatology, and the regulation of psychological needs. 142 individuals (M age=32.7, SD=10.9), answered self-report questionnaires in a cross-sectional design. Results show that loneliness is positively correlated with symptomatology and difficulties in the regulation of psychological needs, with these relationships being mediated by psychological distress and psychological well-being. We discuss our results with a focus on loneliness and related psychopathological symptomatology, as they seem to be core factors in the regulation of psychological needs.

Influenza Myocarditis: A Literature Review

Viral myocarditis is not uncommon but the role of the influenza virus in causing myocarditis is less studied. It is difficult to diagnose influenza myocarditis. Due to bacterial and viral co-infection during influenza outbreaks, it becomes more difficult to distinguish influenza myocarditis from other causes. Our article provides current information on influenza myocarditis. We did a literature search using appropriate terms and reviewed articles published by November 2020. Our study highlights the incidence of influenza myocarditis and the need to become aware of this condition, especially during epidemics and pandemics. Our study highlights that although influenza myocarditis is a rare condition, it can be fatal. There should be increased awareness about the condition. By the early diagnosis and treatment of influenza myocarditis, we can prevent fatal complications.

What makes people intend to take protective measures against influenza? Perceived risk, efficacy, or trust in authorities

BACKGROUND

Influenza outbreaks occur annually across the world, causing a global health challenge. This study aims to explore the association between risk perception (perceived severity and perceived probability), perceived efficacy (individual's efficacy and government's efficacy), trust in authorities, and intention to implement influenza protective behaviors.

METHODS

The data (N = 1,372) used in this paper comes from the 2013 Taiwan Social Change Survey dataset. Six intentions of protective behaviors (getting vaccinated, wearing a mask, washing hands, avoiding going to public settings, sanitizing home, and eating nutritional supplements) were investigated. Tobit and ordered logistic regressions were used to conduct data analysis.

RESULTS

Respondents were most inclined to washing hands, followed by wearing a mask, avoiding going to public settings, getting vaccine, sanitizing their homes, and eating nutritional supplements. Perceived severity and individual's efficacy were positively correlated with all 6 behavioral intentions. Trust in authorities has positive effect on all the protective behaviors except sanitizing home. Moreover, perceived probability has positive relationships with overall intention, intention to wear mask, and intention to wash hands. Government's efficacy was only positively correlated with eating nutritional supplements.

CONCLUSIONS

Perceived severity and perceived response efficacy towards flu, as well as trust in authorities were relatively important factors in motivating people's intention to adopt influenza protective behaviors.

Influenza Vaccines toward Universality through Nanoplatforms and Given by Microneedle Patches

Influenza is one of the top threats to public health. The best strategy to prevent influenza is vaccination. Because of the antigenic changes in the major surface antigens of influenza viruses, current seasonal influenza vaccines need to be updated every year to match the circulating strains and are suboptimal for protection. Furthermore, seasonal vaccines do not protect against potential influenza pandemics. A universal influenza vaccine will eliminate the threat of both influenza epidemics and pandemics. Due to the massive challenge in realizing influenza vaccine universality, a single vaccine strategy cannot meet the need. A comprehensive approach that integrates advances in immunogen designs, vaccine and adjuvant nanoplatforms, and vaccine delivery and controlled release has the potential to achieve an effective universal influenza vaccine. This review will summarize the advances in the research and development of an affordable universal influenza vaccine.

In Vitro Combinations of Baloxavir Acid and Other Inhibitors against Seasonal Influenza A Viruses

Two antiviral classes, the neuraminidase inhibitors (NAIs) and polymerase inhibitors (baloxavir marboxil and favipiravir) can be used to prevent and treat influenza infections during seasonal epidemics and pandemics. However, prolonged treatment may lead to the emergence of drug resistance. Therapeutic combinations constitute an alternative to prevent resistance and reduce antiviral doses. Therefore, we evaluated in vitro combinations of baloxavir acid (BXA) and other approved drugs against influenza A(H1N1)pdm09 and A(H3N2) subtypes. The determination of an effective concentration inhibiting virus cytopathic effects by 50% (EC50) for each drug and combination indexes (CIs) were based on cell viability. CompuSyn software was used to determine synergism, additivity or antagonism between drugs. Combinations of BXA and NAIs or favipiravir had synergistic effects on cell viability against the two influenza A subtypes. Those effects were confirmed using a physiological and predictive ex vivo reconstructed human airway epithelium model. On the other hand, the combination of BXA and ribavirin showed mixed results. Overall, BXA stands as a good candidate for combination with several existing drugs, notably oseltamivir and favipiravir, to improve in vitro antiviral activity. These results should be considered for further animal and clinical evaluations.

A chimeric influenza hemagglutinin delivered by parainfluenza virus 5 vector induces broadly protective immunity against genetically divergent influenza a H1 viruses in swine

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An HA-based vaccine candidate, created by DNA shuffling (HA-113), can be immunogenic when recombinant antigen is expressed by PIV5 (PIV5-113).

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Immunity induced by the PIV5-113 vaccine can protect mice against infection with 4 of 5 parental HAs used to create the vaccine.

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Immunity induced by PIV5-113 can protect pigs against infection with an influenza virus isolate that is known to be infectious in pigs.

Pigs are an important reservoir for human influenza viruses, and influenza causes significant economic loss to the swine industry. As demonstrated during the 2009 H1N1 pandemic, control of swine influenza virus infection is a critical step toward blocking emergence of human influenza virus. An effective vaccine that can induce broadly protective immunity against heterologous influenza virus strains is critically needed. In our previous studies [McCormick et al., 2015; PLoS One, 10(6):e0127649], we used molecular breeding (DNA shuffling) strategies to increase the breadth of the variable and conserved epitopes expressed within a single influenza A virus chimeric hemagglutinin (HA) protein. Chimeric HAs were constructed using parental HAs from the 2009 pandemic virus and swine influenza viruses that had a history of zoonotic transmission to humans. In the current study, we used parainfluenza virus 5 (PIV-5) as a vector to express one of these chimeric HA antigens, HA-113. Recombinant PIV-5 expressing HA-113 (PIV5-113) were rescued, and immunogenicity and protective efficacy were tested in both mouse and pig models. The results showed that PIV5-113 can protect mice and pigs against challenge with viruses expressing parental HAs. The protective immunity was extended against other genetically diversified influenza H1-expressing viruses. Our work demonstrates that PIV5-based influenza vaccines are efficacious as vaccines for pigs. The PIV5 vaccine vector and chimeric HA-113 antigen are discussed in the context of the development of universal influenza vaccines and the potential contribution of PIV5-113 as a candidate universal vaccine.

Prevalence and factors influencing the distribution of influenza viruses in Kenya: Seven-year hospital-based surveillance of influenza-like illness (2007-2013)

Background

Influenza viruses remain a global threat with the potential to trigger outbreaks and pandemics. Globally, seasonal influenza viruses’ mortality range from 291 243–645 832 annually, of which 17% occurs in Sub-Saharan Africa. We sought to estimate the overall prevalence of influenza infections in Kenya, identifying factors influencing the distribution of these infections, and describe trends in occurrence from 2007 to 2013.

Methods

Surveillance was conducted at eight district hospital sites countrywide. Participants who met the case definition for influenza-like illness were enrolled in the surveillance program. The nasopharyngeal specimens were collected from all participants. We tested all specimens for influenza viruses with quantitative reverse transcriptase real-time polymerase chain reaction (RT-qPCR) assay. Bivariate and multivariate log-binomial regression was performed with a statistically significant level of p<0.005. An administrative map of Kenya was used to locate the geographical distribution of surveillance sites in counties. We visualized the monthly trend of influenza viruses with a graph and chart using exponential smoothing at a damping factor of 0.5 over the study period (2007–2013).

Results

A total of 17446 participants enrolled in the program. The overall prevalence of influenza viruses was 19% (n = 3230), of which 76% (n = 2449) were type A, 21% (n = 669) type B and 3% (n = 112) A/ B coinfection. Of those with type A, 59% (n = 1451) were not subtyped. Seasonal influenza A/H3N2 was found in 48% (n = 475), influenza A/H1N1/pdm 2009 in 43% (n = 434), and seasonal influenza A/ H1N1 in 9% (n = 88) participants. Both genders were represented, whereas a large proportion of participants 55% were ≤1year age. Influenza prevalence was high, 2 times more in other age categories compared to ≤1year age. Category of occupation other than children and school attendees had a high prevalence of influenza virus (p< <0.001). The monthly trends of influenza viruses’ positivity showed no seasonal pattern. Influenza types A and B co-circulated throughout the annual calendar during seven years of the surveillance.

Conclusions

Influenza viruses circulate year-round and occur among children as well as the adult population in Kenya. Occupational and school-based settings showed a higher prevalence of influenza viruses. There were no regular seasonal patterns for influenza viruses.

CD137 costimulation enhances the antiviral activity of Vγ9Vδ2-T cells against influenza virus

Influenza epidemics and pandemics are constant threats to global public health. Although strategies including vaccines and antiviral drugs have achieved great advances in controlling influenza virus infection, the efficacy of these strategies is limited by the highly frequent mutations in the viral genome and the emergence of drug-resistant strains. Our previous study indicated that boosting the immunity of human Vγ9Vδ2-T cells with the phosphoantigen pamidronate could be a therapeutic strategy to treat seasonal and avian influenza virus infections. However, one notable drawback of γδ-T cell-based immunotherapy is the rapid exhaustion of proliferation and effector responses due to repeated treatments with phosphoantigens. Here, we found that the expression of CD137 was inducible in Vγ9Vδ2-T cells following antigenic stimulation. CD137⁺ Vγ9Vδ2-T cells displayed more potent antiviral activity against influenza virus than their CD137⁻ counterparts in vitro and in Rag2^-/- γc^-/- mice. We further demonstrated that CD137 costimulation was essential for Vγ9Vδ2-T cell activation, proliferation, survival and effector functions. In humanized mice reconstituted with human peripheral blood mononuclear cells, CD137 costimulation with a recombinant human CD137L protein boosted the therapeutic effects of pamidronate against influenza virus. Our study provides a novel strategy of targeting CD137 to improve the efficacy of Vγ9Vδ2-T cell-based immunotherapy.

Human Influenza Virus Hemagglutinins Contain Conserved Oligomannose N-Linked Glycans Allowing Potent Neutralization by Lectins

Hemagglutinins (HAs) from human influenza viruses adapt to bind α2-6-linked sialosides, overcoming a receptor-defined species barrier distinct from the α2-3 specificity of avian virus progenitors. Additionally, human-adapted HAs gain glycosylation sites over time, although their biological function is poorly defined. Using quantitative glycomic analysis, we show that HAs from human pandemic viruses exhibit significant proportions of high-mannose type N-linked glycans throughout the head domain. By contrast, poorly adapted avian-origin HAs contain predominately complex-type glycans, which have greater structural diversity. Although oligomannose levels vary, they are present in all tested recombinant HAs and whole viruses and can be specifically targeted for universal detection. The positions of high-mannose glycosites on the HA of human H1N1 and H3N2 strains are conserved. Additionally, high-mannose-binding lectins possess a broad capacity to neutralize and prevent infection with contemporary H3N2 strains. These findings reveal the biological significance of HA glycosylation and therapeutic potential of targeting these structures.

Challenges of Making Effective Influenza Vaccines

Seasonal influenza vaccines prevent influenza-related illnesses, hospitalizations, and deaths. However, these vaccines are not as effective as other viral vaccines, and there is clearly room for improvement. Here, we review the history of seasonal influenza vaccines, describe challenges associated with producing influenza vaccine antigens, and discuss the inherent difficulties of updating influenza vaccine strains each influenza season. We argue that seasonal influenza vaccines can be dramatically improved by modernizing antigen production processes and developing models that are better at predicting viral evolution. Resources should be specifically dedicated to improving seasonal influenza vaccines while developing entirely new vaccine platforms.