Influenza Research Articles

Implications of the apparent extinction of B/Yamagata-lineage human influenza viruses.

Implications of the apparent extinction of B/Yamagata-lineage human influenza viruses.

2018-2019 human seasonal H3N2 influenza A virus spillovers into swine with demonstrated virus transmission in pigs were not sustained in the pig population.

Human seasonal H3 clade 3C3a influenza A viruses (IAV) were detected four times in U.S. pigs from commercial swine farms in Michigan, Illinois, and Virginia in 2019. To evaluate the relative risk of this spillover to the pig population, whole genome sequencing and phylogenetic characterization were conducted, and the results revealed that all eight viral gene segments were closely related to 2018-2019 H3N2 human seasonal IAV. Next, a series of in vitro viral kinetics, receptor binding, and antigenic characterization studies were performed using a representative A/swine/Virginia/A02478738/2018(H3N2) (SW/VA/19) isolate. Viral replication kinetic studies of SW/VA/19 demonstrated less efficient replication curves than all 10 swine H3N2 viruses tested but higher than three human H3N2 strains. Serial passaging experiments of SW/VA/19 in swine cells did not increase virus replication, but changes at HA amino acid positions 9 and 159 occurred. In swine transmission studies, wild-type SW/VA/19 was shed in nasal secretions and transmitted to all indirect contact pigs, whereas the human seasonal strain A/Switzerland/9715293/2013(H3N2) from the same 3C3a clade failed to transmit. SW/VA/19 induced minimal macroscopic and microscopic lung lesions. Collectively, these findings demonstrate that these human seasonal H3N2 3C3a-like viruses did not require reassortment with endemic swine IAV gene segments for virus shedding and transmission in pigs. Limited detections in the U.S. pig population in the subsequent period of time suggest a yet-unknown restriction factor likely limiting the spread of these viruses in the U.S. pig population.IMPORTANCEInterspecies human-to-swine IAV transmission occurs globally and contributes to increased IAV diversity in pig populations. We present data that a swine isolate from a 2018-2019 human-to-swine transmission event was shed for multiple days in challenged and contact pigs. By characterizing this introduction through bioinformatic, molecular, and animal experimental approaches, these findings better inform animal health practices and vaccine decision-making. Since wholly human seasonal H3N2 viruses in the United States were not previously identified as being transmissible in pigs (i.e., reverse zoonosis), these findings reveal that the interspecies barriers for transmission to pigs may not require significant changes to all human seasonal H3N2, although additional changes may be required for sustained transmission in swine populations.

Post-disappearance scenarios: policy implications following the potential disappearance of B/Yamagata lineage influenza viruses.

The COVID-19 pandemic and related preventive measures reduced influenza virus circulation, notably causing the disappearance of the B/Yamagata lineage of influenza viruses. In this Perspective, we discuss the implications that this development may have for global influenza epidemiology, and the adjustments that may need to be implemented concerning surveillance strategies and practices, laboratory safety protocols, and influenza vaccine formulations. The disappearance of the B/Yamagata lineage might indeed alter the dynamics of the influenza disease burden (although in a way that is difficult to predict at the moment), and associated diagnostic practices, and may also necessitate updated biosafety levels and revised influenza surveillance strategies. Furthermore, the World Health Organization (WHO) recommended in September 2023 the exclusion of B/Yamagata antigens from future vaccines, with a shift towards trivalent vaccines or modified quadrivalent vaccines; this new scenario underscores the importance of robust global respiratory virus surveillance, effective communication with healthcare professionals and the population to maintain trust in vaccines, and a collaborative approach among health policymakers and vaccine manufacturers to navigate this epidemiological change.

Obesity uncovers presence of inflammatory lung macrophage subsets with adipose tissue transcriptomic signature in influenza virus infection.

Obesity is a risk factor for increased lung damage and disease severity during influenza virus infection. White adipose tissue (WAT) inflammation is a key driver of disease pathogenesis in obesity. Whether and how obesity modifies lung and WAT immune cell character and function in obesity to amplify influenza disease severity remains unknown. We show that obesity establishes a proinflammatory transcriptome in lung immune cells that is further augmented upon influenza virus infection. Unexpectedly, we also show that influenza virus infection induces expression of inflammatory genes in visceral WAT and modifies WAT immune cell milieu in obesity. Notably, a decrease in WAT macrophage (ATM) populations inversely correlates to increase in infiltrating lung macrophage numbers in obese influenza virus-infected mice. Comparison of both lung and WAT immune cell transcriptional landscapes uncovers a presence of a macrophage subset in the lungs whose transcriptomic signatures matched those of an inflammatory ATM subset preferentially found in obese mice. Adoptive transfer of ATMs from obese mice into lean influenza-virus infected mice promotes host immune cell infiltration to the lungs. Together, our novel findings provide evidence of immune cell transcriptome and character changes in the lungs and WAT of influenza virus infected obese, but not lean, mice and suggest that visceral ATMs may contribute to the overall inflammatory milieu in this setting.

Scoping the barriers to influenza and pneumococcal vaccinations from the perspectives of patients with cancer: is there a role for the pharmacist?

AbstractBackgroundRoutine immunisation for influenza and pneumococcal disease has the potential to reduce morbidity and mortality in patients with cancer.AimThis scoping review aims to determine barriers to influenza and pneumococcal vaccinations from the perspective of patients with cancer and to discuss the potential role of the pharmacist in impacting these barriers.DesignA systematic search of seven databases, including MEDLINE (Ovid), Cochrane Library, Informit (health), PubMed, and CINAHL (complete), from database inception to 6 June 2023 was conducted. Search terms included: 'cancer', 'vaccination', 'influenza', 'pneumococcal', and 'barrier'. Articles published in English that describe barriers to receiving vaccinations from the perspectives of patients with cancers were included. Barriers were thematically analysed.ResultsTwenty‐five articles met the inclusion criteria. Barriers identified in the literature were analysed into three key themes: healthcare professionals, patients, and healthcare system barriers. A key healthcare professional barrier was lack of recommendations from the treating oncologist or haematologist. Patient barriers included lack of information about the indication for vaccination as part of patients' cancer treatment and fear of side effects. Access to vaccination services was reported as a healthcare system barrier.ConclusionThis scoping review highlights the significant barriers to influenza and pneumococcal vaccination according to patients with cancer. Healthcare professionals, patients, and health systems were identified as key barriers. Enablers to improve vaccination rates include patient education, increased healthcare professional vaccine recommendations, and improved access. Although pharmacists have a potential role to play in addressing these barriers, the feasibility and impact of their involvement requires further research.

Systematic Review on Influenza Burden in Emerging Markets in 2018–2023—An Evidence Update to Guide Influenza Vaccination Recommendations

Background: Influenza is a contagious respiratory illness responsible for seasonal epidemics and with potential to cause pandemics. The decline in influenza-related studies published since 2018 resulted in data gaps, particularly in emerging markets. Methods: This systematic review searched for studies in six databases and gray literature sources to define the clinical burden of influenza and influenza-like illness (ILIs) and their associated sequelae among humans across emerging markets. Eligible studies were published in English, Spanish, or Chinese between January 2018 and September 2023 and conducted in Asia, the Middle East, Africa, and Latin America. Results: In total, 256 articles were included, mostly on lab-confirmed influenza infections (n = 218). Incidences of lab-confirmed influenza cases in Asia (range 540–1279 cases/100,000 persons) and Sub-Saharan Africa (range 34,100–47,800 cases/100,000 persons) were higher compared to Latin America (range 0.7–112 cases/100,000 persons) and the Middle East and North Africa (range 0.1–10 cases/100,000 persons). Proportions of lab-confirmed influenza cases and influenza-associated outcomes (i.e., hospitalization, ICU admission and death) varied widely across regions. Temporal variation in influenza trend was observed before and during the COVID-19 pandemic. Conclusions: In conclusion, influenza causes significant disease burden in emerging markets. Robust large real-world studies using a similar methodology are needed to have more accurate estimates and compare studies within age groups and regions. Continuous monitoring of influenza epidemiology is important to inform vaccine programs in emerging markets with heavy influenza disease burden.

Synergistic effects of Lianhuaqingwen in combination with Oseltamivir and Baloxavir against seasonal influenza virus: in vitro and in vivo assessment

Ethnopharmacological relevanceLianhuaqingwen (LH), a traditional Chinese medicine, presents a broad-spectrum antiviral effect and has been widely used to treat influenza. Given the potential rise of drug-resistant influenza viruses, it is necessary to develop new antiviral drugs and explore combination therapies involving LH in tandem with existing antivirals such as Oseltamivir acid (Osel) or Baloxavir (Bal). These multidrug combinations could help effectively control the seasonal influenza epidemics and reduce the disease burden. Aim of the studyThis study aimed to evaluate the antiviral effects of LH, alone and in combination with Osel or Bal, against human seasonal influenza viruses in vitro and in vivo models. Materials and methodsThe antiviral efficacy of LH alone and LH in combination with Osel/Bal against seasonal influenza A viruses (IAVs) (H1N1 and H3N2 subtypes) and influenza B viruses (IBVs) (BV- and BY-lineages) was assessed in vitro using MDCK cells. The median effective concentration (EC50) was determined, and the drug synergies were analyzed. Additionally, the antiviral activity of LH monotherapy and LH + Osel/Bal combination therapy were evaluated in vivo using an H1N1-infected BABL/c mouse model by monitoring changes in body weight, survival rate, lung viral titer, pathological damage, and inflammatory reaction. ResultsIn vitro, LH alone and in combination with Osel/Bal exhibited antiviral activity against both IAVs and IBVs. The addition of LH to Osel/Bal improved the therapeutic efficacy compared to Osel/Bal alone. In vivo, LH monotherapy reduced body weight loss and increased the survival rates of H1N1-infected mice. LH in combination with Osel/Bal resulted in lower virus titers, more effective relief of pathological damage, and comparable low expression of inflammatory factors in the lungs of H1N1-infected mice compared to the use of Osel/Bal alone. Transcriptomic analysis of the lungs revealed that LH+Osel/Bal significantly increased the expression of genes associated with antiviral and anti-inflammatory effects. ConclusionsThis study evaluated the antiviral effects of LH monotherapy and combination therapy with Osel/Bal against human seasonal influenza viruses in vitro and in vivo models. The results suggest that combining LH with Osel or Bal could enhance the antiviral efficiency for influenza viruses compared to the monotherapy using any of these three drugs.

Selective and complementary antimicrobial and antiviral activity of silver, copper, and selenium nanoparticle suspensions in deep eutectic solvent

Metallic and nonmetallic nanoparticles are bioactive compounds that exhibit broad resistance to bacteria, fungi, and even viruses. In this paper, a deep eutectic solvent (DES) based on betaine, glucose, and ethylene glycol was used to obtain suspensions of silver, copper, and selenium nanoparticles. Depending on the nanoparticle precursor used, Ag, Cu, and Se nanoparticles (NPs) with an average particle size of 50−100 nm were prepared, and the properties of the products were confirmed by the STEM, XPS, DLS, and UV-VIS methods. The use of a DES, without the need for additional reactants, allowed the production of stable nanoparticles with increased bioactivity against microorganisms. The obtained systems showed high bioactivity against strains of S. aureus, E. coli, and C. albicans. Nanosuspensions, by generating reactive oxygen species (ROSs), caused enzyme inactivation and the inhibition of the metabolic processes of microorganisms. Particle-generated cell degradation processes were investigated through ROS generation assays, API assays, the determination of the MIC/MBC, and cell decomposition rate assays in the early logarithmic growth phase. Copper nanoparticles derived from copper(II) acetate were also highly active against the human influenza A/H1N1 viruses, human coronavirus (HCoV-OC43, Betacoronavirus 1), and vesicular stomatitis virus (VSV, Rhabdoviridae), showing a virus titer reduction of more than 93.7−99.96%.

Sialylated IgG induces the transcription factor REST in alveolar macrophages to protect against lung inflammation and severe influenza disease.

While most respiratory viral infections resolve with little harm to the host, severe symptoms arise when infection triggers an aberrant inflammatory response that damages lung tissue. Host regulators of virally induced lung inflammation have not been well defined. Here, we show that enrichment for sialylated, but not asialylated immunoglobulin G (IgG), predicted mild influenza disease in humans and was broadly protective against heterologous influenza viruses in a murine challenge model. Mechanistic studies show that sialylated IgG mediated this protection by inducing the transcription factor repressor element-1 silencing transcription factor (REST), which repressed nuclear factor κB (NF-κB)-driven responses, preventing severe lung inflammation and protecting lung function during influenza infection. Therapeutic administration of a recombinant, sialylated Fc molecule in clinical development similarly activated REST and protected against severe influenza disease, demonstrating that this pathway could be clinically harnessed. Overall, induction of REST through sialylated IgG signaling is a strategy to limit inflammatory disease sequelae in infections caused by antigenically distinct influenza strains.

SARS-CoV-2 Encephalitis versus Influenza Encephalitis: More Similarities than Differences.

From time to time, physicians face challenging diagnostic and therapeutic issues concerning the acute management of children with viral encephalitis. The aim of this article is to provide an updated narrative review on the similarities and differences between SARS-CoV-2 and influenza encephalitis. A PubMed search was performed with the function "Clinical Queries" using the key terms "SARS-CoV-2" OR "Influenza" AND "Encephalitis". The search strategy included metaanalyses, clinical trials, randomized controlled trials, reviews and observational studies. The search was restricted to the English literature and pediatric population. This article compares similarities and contrasts between SARS-CoV-2 and influenza-associated encephalitis. Encephalitis is an uncommon manifestation of both influenza and SARS-CoV-2. Both viruses are associated with fever and respiratory symptoms. However, SARS-CoV-2 patients may only have mild symptoms or be asymptomatic as silent carriers, rendering the disease spread difficult to control. Influenza patients usually have more severe symptomatology and are often bed bound for several days limiting its spread. Influenza is associated with seasonal and annual outbreaks, whereas SARS-CoV-2 has become endemic. Complications of encephalitis are rare in both viral infections but, when present, may carry serious morbidity and mortality. Many long-term sequelae of COVID- 19 infections (long COVID-19) have been described but not with influenza infections. Mortality associated with encephalitis appears higher with influenza than with SARS-CoV-2. Prophylaxis by immunization is available for both influenza and SARS-CoV-2. Specific efficacious antivirals are also available with oseltamivir for influenza and nirmatrelvir/ritonavir for SARS-CoV-2. Steroids are indicated with more severe SARS-CoV-2 but their role is not distinct in influenza disease. Encephalitis is a rare complication of influenza and SARS-CoV-2 infections. Both carry significant morbidity and mortality. Efficacious vaccines for prophylaxis and antivirals for treatment are available for both viruses.

Inno4Vac Workshop Report Part 1: Controlled Human Influenza Virus Infection Model (CHIVIM) Strain Selection and Immune Assays for CHIVIM Studies, November 2021, MHRA, UK.

Controlled human infection models (CHIMs) are a critical tool for the understanding of infectious disease progression, characterising immune responses to infection and rapid assessment of vaccines or drug treatments. There is increasing interest in using CHIMs for vaccine development and an obvious need for widely available and fit-for-purpose challenge agents. Inno4Vac is a large European consortium working towards accelerating and de-risking the development of new vaccines, including the development of CHIMs for influenza, respiratory syncytial virus and Clostridioides difficile. This report (in two parts) summarises a workshop held at the MHRA in 2021, focused on how to select CHIM candidate strains of influenza and respiratory syncytial virus (RSV) based on desirable virus characteristics and which immune assays would provide relevant information for assessing pre-existing and post-infection immune responses and defining correlates of protection. This manuscript (Part 1) summarises presentations and discussions centred around influenza CHIMs and immune assays (a second manuscript summarises RSV CHIM and immune assays: Inno4Vac workshop report Part 2: RSV CHIM strain selection and immune assays for RSV CHIM studies, November 2021, MHRA, UK).

Enteroviruses, Respiratory Syncytial Virus and Seasonal Coronaviruses in Influenza-like Illness Cases in Nepal

Acute respiratory infection is one of the leading causes of morbidity and mortality among children in low- and middle-income countries. Due to limited diagnostic capability, many respiratory pathogens causing influenza-like illness go undetected. This study aims to detect enterovirus, respiratory syncytial virus, seasonal coronavirus and respiratory pathogens other than influenza in patients with influenza-like illness. A total of 997 (54.3%) respiratory samples (collected in the years 2016–2018) were randomly selected from 1835 influenza-negative samples. The xTAG Respiratory Viral Panel (RVP) FAST v2 panel was used to detect respiratory pathogens including enterovirus/rhinovirus (EV/RV), respiratory syncytial virus (RSV) and seasonal coronavirus (HKU1, OC43, NL63 and 229E). A total of 78.7% (785/997) were positive for respiratory viruses. Of these viruses, EV/RV was detected in 36.3% (362/997), which is the highest number, followed by RSV in 13.7% (137/997). The seasonal coronaviruses HKU1 and OC43 (1.5%, 15/997), NL63 (1.2%, 12/997) and 229E (1%, 10/997) were also detected. The EV/RV-positive samples were sequenced, of which 16.7% (5/30) were confirmed as EVs and were identified as coxsackievirus (CV) types CVB5, CVB3, CV21 and CVB2. The findings of this study highlight the importance of strengthening influenza-like illness surveillance programs in the region by including other respiratory viruses in their scope besides seasonal human influenza viruses.

Are we prepared for the next pandemic: Monitor on increasing human and animal H5N1 avian influenza infection.

Are we prepared for the next pandemic: Monitor on increasing human and animal H5N1 avian influenza infection.

Backyard flock sampling and artificial intelligence: A dual strategy for early detection of Avian Influenza and Newcastle Disease

Avian Influenza (AI) and Newcastle Disease (ND) are significant avian diseases that pose substantial threats to the commercial poultry industry due to their high contagion rates and potential for severe outcomes. Recent shifts in the epidemiology and ecology of both viruses have led to devastating impacts on wild bird and poultry populations, as well as farms and communities worldwide. These challenges underscore the necessity for One Health approaches to pandemic prevention and preparedness, emphasizing the need for multisectoral collaboration among animal, environmental, and public health sectors. To mitigate future pandemic risks, it is essential to control the transmission of AI and ND viruses among domestic and wild animals as well as humans. This involves addressing the upstream drivers of outbreaks, ensuring rapid response mechanisms, and conducting thorough risk assessments for zoonotic diseases. Effective implementation and maintenance of prevention programs, surveillance, and outbreak responses require strong political commitment and sustainable funding. A robust combination of active and passive surveillance strategies should be applied to monitor and control them. In addition, the integration of modern technologies, such as artificial intelligence and big data analytics, can enhance both active and passive surveillance efforts by improving the accuracy and speed of data collection, analysis, and reporting. The use of backyard flocks as an early warning system for avian diseases represents a proactive approach to understanding and managing the risks associated with AI and ND through targeted surveillance and timely interventions. In response to these challenges, the EpirORNIS Project aimed to leverage these sentinel backyard flocks for early detection of AI and ND, thereby enhancing surveillance and control strategies.

Boosting influenza vaccination rates through policy gamification: the ‘Let’s Control Flu’ project

Abstract Background Influenza remains a public health challenge globally, leading to substantial morbidity and mortality, particularly among vulnerable groups. Despite the benefits of vaccination, achieving the desired vaccination coverage rates (VCR) proves challenging across Europe. The ‘Let’s Control Flu’ (LCF) tool emerges as a new contribution, merging gamification with epidemiological data and public health policies to help increase influenza VCR. Methods The LCF tool, developed from an extensive literature review and validated by a National Advisory Board, initially showcased its capabilities in Sweden. Offering an interactive simulation, it allows stakeholders to explore the outcomes of implementing 13 targeted public health policies (PHP) on influenza VCR and health outcomes such as infection rates, hospitalizations, and mortality. This approach simplifies epidemiological complexities, paving the way for informed decision-making. Results Following its success in Sweden, the LCF tool was extended to Germany and Czechia, underlining the value of gamified tools in public health decision-making. The application across these new countries not only resulted in paths to improve VCR but also provided insights into the tool’s scalability and adaptability different landscapes. Conclusions The LCF project underscores the efficacy of integrating gamification into health policy decision-making, offering a replicable model for enhancing influenza vaccination uptake across Europe. With the tool now successfully applied in multiple countries, its potential for broader European and global application is evident. This initiative aligns with WHO’s objectives, spotlighting gamification as a relevant component in improving vaccination strategies and readiness for influenza and other preventable diseases, thereby reinforcing the importance of innovative approaches in public health policy development. Key messages • The LCF tool integrates gamification with public health strategies to help effectively raise influenza vaccination coverage. • By merging gamification and epidemiological insights, the LCF tool also serves as a scalable model for Europe, supporting WHO’s goals to improve vaccine strategies and preparedness.

Association of COVID-19 and influenza vaccinations and cardiovascular drugs with hospitalisation and mortality in COVID-19 and Long COVID: 2-year follow-up of 17 million individuals in England

Abstract Introduction For COVID-19 and Long COVID, determining the highest-risk subgroups, particularly in the context of compound pressures such as influenza and cardiovascular disease (CVD), may identify effective interventions to prevent adverse health outcomes, and inform public health and policy decisions. Methods Using national, linked electronic health records for England (NHS England Secure Data Environment: via CVD-COVID-UK/COVID-IMPACT Consortium), we studied individuals with COVID-19 and Long COVID from January 2020 to February 2023. We compared all-cause hospitalisation and mortality in unmatched and matched cohort analyses, by prior CVD, high CVD risk (by QRISK2), COVID-19 and influenza vaccination status, and prescription of CVD preventive therapies. We investigated potential impact of targeted vaccination and CVD prevention strategies on mortality and hospitalisations by calculating population preventable fractions. Results We identified 17,373,850 individuals with COVID-19 [54.4% female; mean age 38.8 years; COVID-19 vaccination ≥2 doses:50.0%, influenza vaccination (≥1 dose):27.8%; mean follow-up 1.28 years] and 301,115 with Long Covid [61.8% female; mean age 46.0 years; COVID-19 vaccination ≥2 doses:66.4%, influenza vaccination:33.1%; mean follow-up 1.1 years]. Hospitalisation and mortality rates were 15.3% and 2.0% in COVID-19 (Long COVID rate 1.3%) and 16.8% and 1.4% in Long COVID, respectively. Adjusted risk of mortality and hospitalisation were reduced with COVID-19 vaccination ≥2 doses (COVID-19:HR 0.36, 95% CI 0.34-0.38 and 0.69, 0.68-0.69; Long COVID:0.44, 0.42-0.47 and 0.90, 0.89-0.91). With influenza vaccination, mortality was reduced, but not hospitalisation (COVID-19: 0.86, 0.85-0.86 and HR 1.01, 1.01-1.01, and Long COVID: 0.72, 0.67-0.76, and 1.05, 1.03-1.07), with greatest effect in those with prior CVD and high CVD risk. Mortality and hospitalisation were also reduced by CVD prevention in those with CVD, e.g. anticoagulants- COVID-19: 0.69, 0.69-0.70 and 0.92, 0.91-0.93; Long Covid: 0.59, 0.54-0.64, and 0.88, 0.84-0.92. COVID-19 vaccination, influenza vaccination and CVD drugs (Anticoagulants) averted 101117 of 193598, 2138 of 4017 and 16573 of 36847 preventable deaths among individuals after COVID-19, and 875 of 1189, 65 of 127 and 507 of 1007 preventable deaths among those with Long COVID, particularly in people with CVD. Conclusions Prior CVD and high CVD risk are associated with increased hospitalisation and mortality risk in people with COVID-19 and Long COVID. Targeted improvement in COVID-19 vaccination and CVD prevention, especially in those with CVD are priority interventions in pandemics to avoid excess hospitalisation and mortality.Baseline Characteristics and OutcomesHospitalisation/mortality by COVID vaccn

Vaccine Quality Challenges in Secretly Traded H5 and H9 Avian Influenza Vaccines in Nigeria

Avian Influenza Virus (AIV) especially the highly pathogenic subtype H5Nx causes Avian Influenza (AI) disease and it is a major threat to the poultry industry and public health worldwide. Vaccination is one of the control measures in many countries, though restricted in Nigeria. As such, some poultry farmers secretly employ imported H5 and H9 AI vaccines to vaccinate their chickens. This study investigated the antigenic quality of these imported vaccines. Four imported vaccine brands were tested using Hemagglutination (HA) test and Reverse Transcriptase Polymerase Chain Reaction (RTPCR). All four vaccine samples tested negative in the HA test, indicating a lack of detectable HA antigen titer. Similarly, RT-PCR failed to amplify the targeted region of the viral matrix gene in any of the vaccine samples against reference control. These negative results are of great concern and suggest that the imported H5 and H9 vaccines lack essential antigens that could stimulate antibodies. Thus, potentially rendering them ineffective against circulating AI subtypes. The failure in antigenic quality could be due to myriads of factors including improper storage, transport (often due to illegal import), or limitations in the original vaccine production process. Regardless of the specific cause, these findings highlight the potential risks associated with the use of unregulated vaccines. Poultry farmers who use these imported vaccines may be incurring unnecessary costs while receiving a false sense of security for their flocks. In conclusion, due to the apparent lack of efficacious antigens, we suggest a quality monitoring of imported H5 and H9 vaccines in Nigeria for compliance with local regulations on vaccine use, biosecurity measures and investigation into the root causes of the vaccine failure observed in this study.

Invasive Nontypeable Haemophilus influenzae Disease Outbreak at an Elementary School—Michigan, May 2023

Invasive Nontypeable Haemophilus influenzae Disease Outbreak at an Elementary School—Michigan, May 2023

Pre-existing H1N1 immunity reduces severe disease with bovine H5N1 influenza virus.

The emergence of highly pathogenic H5N1 avian influenza in dairy cattle herds across the United States has caused multiple mild human infections. There is an urgent need to understand the risk of spillover into humans. Here, we show that pre-existing immunity from the 2009 H1N1 pandemic influenza virus provided protection from mortality and severe clinical disease to ferrets intranasally infected with bovine H5N1. H1N1 immune ferrets exhibited a differential tissue tropism with little bovine H5N1 viral dissemination to organs outside the respiratory tract and significantly less H5N1 virus found in nasal secretions and the respiratory tract. Additionally, ferrets with H1N1 prior immunity produced antibodies that cross-reacted with H5N1 neuraminidase protein. Taken together, these results suggest that mild disease in humans may be linked to prior immunity to human seasonal influenza viruses.

Epidemiology and population-based incidence of influenza in two communities, Bandung district, West Java, Indonesia, 2008–2011

Influenza surveillance is important for monitoring influenza virus circulation and disease burden to inform influenza prevention and control measures. The aim of this study was to describe the epidemiology and to estimate the incidence of influenza in two communities in West Java, Indonesia, before and after the 2009 H1N1 pandemic. A population-based surveillance study in the community health care setting was conducted to estimate the annual incidence of influenza. A real-time reverse transcription polymerase chain reaction (RT-PCR) assay was used for influenza case ascertainment. A population census was implemented to calculate the population at risk and estimate community health care utilization rate. The mean annual incidence of influenza A and B, adjusted for healthcare utilization, was 1.6 (95%CI: 1.3–2.0) and 0.7 (95%CI: 0.5–1.0) per 1000 persons, respectively, with the most affected group being young and school-age children. The annual cumulative incidence of influenza A for children under five in 2009, 2010, and 2011 was 7.0 (95%CI: 4.4–11.2), 10.6 (95%CI: 7.3–15.4), and 6.3 (95%CI: 3.8–10.2). For influenza B was 4.3 (95%CI: 2.4–7.8), 2.0 (95%CI: 0.8–4.7), and 0.4 (95%CI: 0.1–2.8), respectively. This study highlights that the incidence of influenza among young and school-age children is consistently higher compared to adults and the elderly throughout these periods. These populations are potential targets for influenza vaccination in Indonesia.