Seasonal Influenza Research Articles

Impact of perceived neighborhood social cohesion on vaccination intentions in the post-pandemic era

ObjectiveTo examine the relationship between perceived neighborhood social cohesion (NSC) and intentions to obtain seasonal influenza and COVID-19 vaccines among US adults post COVID-19 pandemic. MethodsWe conducted a cross-sectional, nationally representative survey of US residents (N = 2189) in May 2023 on their perceived NSC, COVID-19 and seasonal influenza vaccination intentions, healthcare access, perceived risk of COVID-19 or flu infection, loneliness, and trust in doctors. We used bivariate probit regressions to examine joint associations between perceived NSC and intentions to receive influenza and COVID-19 vaccines, controlling for several participant characteristics (e.g., race). Results2164 respondents provided consent to study questions. Trust-related NSC (trust in neighbors) was positively associated with intentions to become vaccinated against both influenza and COVID-19 viruses. Higher relational NSC (perception of a close-knit neighborhood) was positively associated while higher value-based NSC (perception that neighbors share the same values) was negatively associated with intentions to become vaccinated against COVID-19. Healthcare access, perceived risk of infection (COVID-19 or flu), and trust in doctors were positively associated with intentions to become vaccinated against both viruses. ConclusionsIn a post-pandemic era, higher trust-related and relational, perceived NSC (vaccine-dependent), greater access to healthcare, higher perceived risk of infection, and greater trust in doctors were related to higher influenza and COVID-19 vaccination intentions, while higher value-based NSC was related to lower COVID-19 vaccination intentions among US adults. Thus, specific aspects of NSC, healthcare access barriers, misinformation on infection risk, and medical mistrust may influence an individual's willingness and ultimate decision to become vaccinated.

Electronic Nudges and Influenza Vaccination Among Patients With a History of Myocardial Infarction: Insights From 3 Nationwide Randomized Clinical Trials.

Influenza vaccination in patients with acute myocardial infarction (AMI) reduces major adverse cardiac events and is strongly recommended in clinical practice guidelines. Effective strategies to improve vaccination are needed in these high-risk patients. To evaluate whether electronically delivered behavioral nudges improve influenza vaccine uptake in patients with AMI across 3 nationwide implementation randomized clinical trials (RCTs). Nationwide Utilization of Danish Government Electronic Letter System for Increasing Influenza Vaccine Uptake (NUDGE-FLU), Nationwide Utilization of Danish Government Electronic Letter System for Confirming the Effectiveness of Behavioral Nudges in Increasing Influenza Vaccine Uptake Among Older Adults (NUDGE-FLU-2), and Nationwide Utilization of Danish Government Electronic Letter System for Increasing Influenza Vaccine Uptake Among Adults With Chronic Disease (NUDGE-FLU-CHRONIC) were RCTs conducted during the 2022 to 2023 and 2023 to 2024 influenza seasons in Denmark. Participants were randomized to either usual care or various behaviorally informed, electronically delivered, letter-based nudges. In a prespecified participant-level pooled meta-analysis, interaction of AMI status on the effects of letter-based nudges vs usual care was examined. Pooled treatment effects were estimated using binomial regression models with identity link, adjustment for trial, and 2-way clustered SEs at the household and participant levels. Effect modification by recency of AMI as a continuous variable was assessed using restricted cubic spline modeling in NUDGE-FLU-CHRONIC. Behaviorally informed, electronically delivered, letter-based nudges or usual care. The primary end point was influenza vaccination receipt. Of 2 146 124 individual randomizations (mean [SD] age, 71.1 [11.6] years; 1 114 725 female [51.9%]) across all 3 trials, 59 458 (2.8%) had a history of AMI. Improvement in vaccine uptake was similar in patients with vs without a history of AMI who received any nudge letter compared with usual care (+1.81 vs +1.32 percentage points; P for interaction by AMI status = .09). A letter highlighting the cardiovascular benefits of vaccination (ie, cardiovascular-gain frame) resulted in larger improvements in vaccine uptake among patients with (vs without) a history of AMI (+3.91 vs +2.03 percentage points; P for interaction by AMI status = .002). Among patients with AMI, the benefits of the cardiovascular-gain frame letter were more pronounced in those not vaccinated in the prior season (+13.7 vs +1.48 percentage points; P for interaction <.001). Among younger participants with chronic disease, the cardiovascular-gain frame letter was particularly effective in patients with more recent AMI (P for interaction by continuous recency of AMI <.001). Across 3 nationwide RCTs of Danish citizens, messaging emphasizing the cardiovascular benefits of vaccination improved influenza vaccination uptake, with greater benefits observed in patients with a history of AMI. This low-cost, scalable implementation strategy should be considered to encourage influenza vaccination in high-risk patients. ClinicalTrials.gov Identifiers: NCT05542004, NCT06030726, NCT06030739.

Microfluidic qPCR for detection of 21 common respiratory viruses in children with influenza-like illness.

Multiple respiratory viruses lead to high morbidity and mortality, yet global surveillance platforms focus primarily on seasonal influenza viruses. The COVID-19 pandemic and new RSV vaccines highlight the importance of a broader approach. Upper respiratory tract swabs from children aged 24-59months presenting with influenza-like illness in The Gambia were collected during follow-up of a live-attenuated influenza vaccine randomised controlled trial in 2017-18. A microfluidic quantitative polymerase chain reaction (qPCR) assay was established and used to detect 21 respiratory viruses. 76.6% of samples had one or more viruses detected (n = 121/158). The viruses detected most frequently were rhinovirus (n = 37/158, 23.4%) and adenovirus (n = 34/158, 21.5%), followed by parainfluenza virus 3, influenza B and human metapneumovirus B. A third of positive samples had multiple viruses detected (two n = 31/121, 25.6%; three n = 9/121, 7.4%). Our data demonstrates how microfluidic qPCR is a useful tool for high-throughput, comprehensive detection of multiple respiratory viruses in surveillance platforms. Rapidly changing epidemiology exemplifies the need for new, broader approaches to virus surveillance in low-resource settings to respond to future epidemics and to guide the need for and use of new prevention and therapeutic measures.

Underutilization of Influenza Antiviral Treatment Among Children and Adolescents at Higher Risk for Influenza-Associated Complications - United States, 2023-2024.

Annually, tens of thousands of U.S. children and adolescents are hospitalized with seasonal influenza virus infection. Both influenza vaccination and early initiation of antiviral treatment can reduce complications of influenza. Using data from two U.S. influenza surveillance networks for children and adolescents aged <18 years with medically attended, laboratory-confirmed influenza for whom antiviral treatment is recommended, the percentage who received treatment was calculated. Trends in antiviral treatment of children and adolescents hospitalized with influenza from the 2017-18 to the 2023-2024 influenza seasons were also examined. Since 2017-18, when 70%-86% of hospitalized children and adolescents with influenza received antiviral treatment, the proportion receiving treatment notably declined. Among children and adolescents with influenza during the 2023-24 season, 52%-59% of those hospitalized received antiviral treatment. During the 2023-24 season, 31% of those at higher risk for influenza complications seen in the outpatient setting in one network were prescribed antiviral treatment. These findings demonstrate that influenza antiviral treatment is underutilized among children and adolescents who could benefit from treatment. All hospitalized children and adolescents, and those at higher risk for influenza complications in the outpatient setting, should receive antiviral treatment as soon as possible for suspected or confirmed influenza.

Using a computational cognitive model to simulate the effects of personal and social network experiences on seasonal influenza vaccination decisions

IntroductionSeasonal influenza poses significant societal costs, including illness, mortality, and reduced work productivity. Vaccination remains the most effective strategy for preventing the disease, yet vaccination rates in the United States fall below 50% for adults. Understanding the factors influencing vaccination decisions is crucial for designing interventions to improve uptake. This study investigates how personal experiences and the experiences of social contacts affect individual decisions to get vaccinated against influenza.MethodsA multi-year longitudinal survey study was conducted to examine the impact of personal and social network experiences on vaccination decisions. Participants' vaccination behaviors and experiences with influenza were tracked over time. To model these influences, we developed a memory-based vaccination decision model using the Adaptive Control of Thought – Rational (ACT-R) integrated cognitive architecture, which incorporates cognitive processes associated with memory and decision-making.ResultsThe survey results demonstrated that both personal experiences with influenza and the experiences of close social contacts significantly influenced vaccination decisions. The memory-based model, built within the ACT-R framework, effectively captured these effects, providing a computational representation of how personal and social factors contribute to vaccination behaviors.DiscussionThe findings suggest that personal and social experiences play a critical role in shaping vaccination decisions, which can inform the development of targeted interventions to increase vaccination uptake. By incorporating cognitive processes into the model, we identified potential strategies to enhance vaccine promotion efforts, such as recalling past experiences with illness to motivate individuals to get vaccinated.

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.

Optimizing influenza vaccine allocation: A predictive analytics approach for informed public health planning.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Excessive purchasing of influenza vaccine can lead to costly overages and waste of resources. Insufficient quantities, however, can jeopardize population health. Our project aimed to use predictive analytics to determine the influenza vaccine quantities that would be needed for the next influenza season while minimizing vaccine waste and meeting patient care demands. Several data sources were evaluated to develop a predictive analytics model to better estimate future influenza vaccine orders during upcoming influenza seasons. A retrospective analysis of influenza vaccine administrations over the last 4 influenza seasons allowed the team to develop an algorithm to predict influenza vaccine needs. Two regions within Mayo Clinic were selected to determine the validity of our ordering process. These 2 regions, identified as regions 3 and 5, ordered influenza vaccines based on the algorithm, while the other 3 regions acted as control groups, ordering though traditional methods based on purchasing data. Predictive analysis for the 2 intervention regions resulted in a savings of over $1 million when compared to traditional ordering methods. The model predicted that the quantity of vaccine ordered should be 17,574.16 and 9,164.29 quadrivalent influenza vaccines for regions 3 and 5, respectively. On the basis of actual administration data, 15,902 vaccines for region 3 and 9,016 vaccines for region 5 will be administered by the end of the season, both of which are less than the predicted amount needed, demonstrating the accuracy of the analytics. Compared to the traditional ordering method, ordering using predictive analytics allowed the team to more accurately determine future order volumes and spend, yielding significant cost savings.

Observational Study on the Clinical Reality of Community-Acquired Respiratory Virus Infections in Adults and Older Individuals

The impact of common respiratory virus infections on adults and older individuals in the community is unclear, excluding seasonal influenza viruses. We examined FilmArray® tests performed on 1828 children aged &lt;10 years and 10,803 adults, including cases with few respiratory symptoms, between January 2021 and June 2024. Approximately 80% of the children tested positive for ≥1 viruses, while 9.5% of the adults tested positive mostly for severe acute respiratory syndrome corona virus-2 (SARS-CoV-2). Besides SARS-CoV-2 infection, 66 out of 97 patients (68.0%) aged &gt;60 years with rhinovirus/enterovirus (RV/EV), respiratory syncytial virus (RSV), parainfluenza virus-3 (PIV-3), or human metapneumovirus (hMPV) infection required hospitalization, of whom seven died; 26 out of 160 patients (16.3%) aged &lt;60 years required hospitalization mostly because of deterioration of bronchial asthma, with no reported deaths. In older patients with RV/EV infection, three with few respiratory symptoms died due to worsened heart failure. Although the frequency of common respiratory virus infections in older adults is low, it may be overlooked because of subclinical respiratory symptoms, and its clinical significance in worsening comorbidities in older adults should not be underestimated.

COVID-19 pandemic interventions reshaped the global dispersal of seasonal influenza viruses.

The global dynamics of seasonal influenza viruses inform the design of surveillance, intervention, and vaccination strategies. The COVID-19 pandemic provided a singular opportunity to evaluate how influenza circulation worldwide was perturbed by human behavioral changes. We combine molecular, epidemiological, and international travel data and find that the pandemic's onset led to a shift in the intensity and structure of international influenza lineage movement. During the pandemic, South Asia played an important role as a phylogenetic trunk location of influenza A viruses, whereas West Asia maintained the circulation of influenza B/Victoria. We explore drivers of influenza lineage dynamics across the pandemic period and reasons for the possible extinction of the B/Yamagata lineage. After a period of 3 years, the intensity of among-region influenza lineage movements returned to pre-pandemic levels, with the exception of B/Yamagata, after the recovery of global air traffic, highlighting the robustness of global lineage dispersal patterns to substantial perturbation.

Awareness of the General population about Influenza Vaccine in Tabuk, Saudi Arabia

Objectives: Increasing national influenza vaccination rates continues to be a challenge for Saudi Arabia. Therefore, the purpose of this study was to explore the Saudi public perceptions toward seasonal influenza vaccination and their association with the rate of vaccination. Methods: This is a descriptive cross-sectional study. The study includes the general population in Tabuk, Northern Saudi Arabia. The study includes Saudi and none Saudi who speaks Arabic or English, from any age group (18-60 years), male or female, any level of education (from primary to university or more) and low, moderate or high socioeconomic level. Results: Regarding to gender, the study showed that the largest percentage of the study members are male with a percentage of (63.3 %), while there is a percentage of (36.6%) females. According to” Received influenza vaccine” there are (63.3%) of the respondents chose (Yes) and (36.6%) of the respondents chose (No). according to” Influenza vaccination is effective in preventing influenza infection” there are (53.3%) of the respondents chose (Yes), (26.66%) of the respondents chose (No) and (20%) chose (Don’t Know). Conclusion: The findings of this study suggest that the rate of seasonal influenza vaccination is moderate among the Saudi population, which necessitates the launching of public awareness campaigns about the importance of the seasonal influenza vaccine.

Multi-strain modeling of influenza vaccine effectiveness in older adults and its dependence on antigenic distance

Influenza vaccine effectiveness (VE) varies seasonally due to host, virus and vaccine characteristics. To investigate how antigenic matching and dosage impact VE, we developed a mechanistic knowledge-based mathematical model. Immunization with a split vaccine is modeled for exposure to A/H1N1 or A/H3N2 virus strains. The model accounts for cross-reactivity of immune cells elicited during previous immunizations with new antigens. We simulated vaccine effectiveness (sVE) of high dose (HD) versus standard dose (SD) vaccines in the older population, from 2011 to 2022. We find that sVE is highly dependent on antigenic matching and that higher dosage improves immunogenicity, activation and memory formation of immune cells. In alignment with clinical observations, the HD vaccine performs better than the SD vaccine in all simulations, supporting the use of the HD vaccine in the older population. This model could be adapted to predict the impact of alternative virus strain selection on clinical outcomes in future influenza seasons.

Occurrence, ecological, and health risk assessment of antibiotics in water from the Karst River during influenza season

Occurrence, ecological, and health risk assessment of antibiotics in water from the Karst River during influenza season

Advances in Discovery and Design of Anti-influenza Virus Peptides.

The influenza virus, a well-known pathogen that causes respiratory illness, remains an important global health threat because of the significant morbidity and mortality rates of people infected with the virus annually. The influenza virus undergoes frequent antigenic variation, and with the increasing frequency of resistant influenza strains against existing antiviral drugs, there is an urgent need for the development of new anti- influenza treatment strategies. Peptides have the potential to offer high potency, selectivity, and relatively low drug resistance. As such, the design and screening of novel anti- influenza virus peptides with high potency have become increasingly important in an effort to fight global influenza epidemics. Herein, we introduce three approaches to developing anti-influenza virus peptides: discovery from natural products, library construction for antiviral peptide screening, and rational design based on functional regions of influenza viral proteins. This review summarizes recent progress in the discovery and design of anti-influenza virus peptides over the past 20 years.

National Influenza Annual Report 2023-2024: A focus on influenza B and public health implications.

The 2023-2024 influenza epidemic saw the return of typical late-season influenza B circulation. The epidemic was declared in week 45 (week ending November 11, 2023) due to the predominant circulation of influenza A(H1N1) and peaked in week 52 (week ending December 30, 2023); however, as influenza A circulation decreased, influenza B detections and the percentage of tests positive increased, reaching its peak in week 14 (week ending April 6, 2024). Influenza B/Victoria dominated this wave of activity, contributing to the ongoing discussion about the apparent disappearance of influenza B/Yamagata. With the recommendation for the removal of influenza B/Yamagata lineages from the recommended seasonal influenza vaccine components, the influenza surveillance community is preparing for the possibility of a new seasonal pattern dominated by influenza B/Victoria circulation. This season, as a result of influenza B/Victoria's overwhelming predominance, younger age groups were primarily affected by the wave of influenza B activity. Over the course of the season, among all influenza B detections, 52% occurred in children aged 0-19 years. Among all influenza B-associated hospitalizations, 46.4% were in children aged 0-19 years, and the highest cumulative hospitalization rates for influenza B were among children younger than five years (n=37 per 100,000 population) and children between the ages of 5-19 years (n=15 per 100,000 population). Continued vigilance and surveillance around influenza B trends and epidemiology is required to contribute to effective epidemic preparedness.

Analysis of the incidence of influenza before and after the COVID-19 pandemic in South Korea.

Influenza outbreaks of varying size occur every year, but during the COVID-19 pandemic, many countries experienced influenza at lower levels. However, following the relaxation of COVID-19 prevention measures in 2022, the incidence of influenza began to increase gradually. Thus, this study compared the occurrence of influenza from week 36 of 2017, before the COVID-19 outbreak, until 2023. The analysis was conducted using influenza-like illness occurrence data available from the Korea Disease Control and Prevention Agency infectious disease website. Additionally, to examine the changes in COVID-19 and influenza occurrence during the pandemic, COVID-19 incidence data from 20 January 2020 to 31 August 2023 were obtained from the KDCA Coronavirus Disease 19 homepage. During the COVID-19 pandemic, which corresponds to the 2020/2021 and 2021/2022 influenza seasons, there was no seasonal influenza epidemic, and the incidence rates were below the usual outbreak levels. However, in the 2022/2023 season, when the spread of COVID-19 had eased, a seasonal pattern similar to that observed before the COVID-19 pandemic was noted. Furthermore, correlation analysis between the rates of influenza-like illness and COVID-19 incidence showed no significant correlation during the entire period. However, a significant correlation emerged in 2023 (r = 0.393, p <0.05). These results suggest that influenza was suppressed during the COVID-19 pandemic but returned to typical seasonal patterns after the COVID-19 prevention policies were eased. The positive correlation observed between the incidences of COVID-19 and influenza in 2023 indicates that COVID-19, no longer a novel pandemic-causing infectious disease, may have transitioned to an endemic pattern similar to seasonal influenza.

Hemagglutination-Inhibition Antibodies and Protection against Influenza Elicited by Inactivated and Live Attenuated Vaccines in Children.

Hemagglutinin (HA)-inhibiting antibodies contribute to the immune defense against influenza infection. However, there are insufficient data on the extent of correlation between vaccine-elicited HA antibodies and protection in children against different influenza strains, particularly when comparing live attenuated influenza vaccines (LAIV) versus inactivated influenza vaccines (IIV). We measured postvaccination hemagglutination-inhibition (HAI) titers in 3-15-year-old participants of a cluster-randomized controlled trial of trivalent LAIV(3) versus IIV(3) in Canadian Hutterite colonies. We assessed HAI titers as predictors of symptomatic, reverse transcription polymerase chain reaction (RT-PCR)-confirmed influenza over 3 influenza seasons using Cox proportional hazards regression models with vaccine type as a covariate. For each log2 unit increase in postvaccination HAI against A/H1N1 in 2013-2014, A/H3N2 2014-2015, and B/Yamagata in 2013-2014 (each the predominant circulating strain for the respective influenza season), the reduction in the risk of confirmed influenza was equal to 29.6% (95% confidence interval [CI], 17.1%-39.5%), 34.8% (95% CI, 17.2%-47.9%), and 31.8% (95% CI, 23.8%-38.5%), respectively. No reduction in the risk of influenza was observed with B/Yamagata-specific HAI titers in 2012-2013, which was dominated by a mixture of Yamagata and Victoria strains. Despite the overall lower HAI titers in the LAIV3 group, both H1N1 and H3N2 HAI titers were associated with protection against subtype matched influenza. Both LAIV3- and IIV3-elicited HA antibodies are associated with protection against influenza infection in seasons when the vaccine strains match the circulating influenza strain subtypes, supporting the use of HAI as a correlate of protection for both vaccine types in children.

Sequence and Phylogenetic Analysis of Influenza Virus (H1N1pdm2009) Circulating in Riyadh, Saudi Arabia

Influenza A virus (IAV) is the principal cause of seasonal flu and is often reported among pilgrims in Saudi Arabia (SA) due to their mass gatherings. The epidemiological, phylogenetic, and molecular details of A/H1N1pdm2009 in 200 clinical samples collected from hospitalized children in Riyadh during two epidemic seasons (2020/21 and 2021/22) are reported in this study. A total of 21 (10.50%) samples were positive for IAV, as determined using PCR. Fifteen isolates (71.42%) were identified as H1N1pdm2009: eight (53.33%) samples were from males, seven (46.67%) from females. The prevalence of H1N1pdm2009 isolates was significantly (p &lt; 0.05) higher among the age group 15-64 years than the other age groups. A comparison of hemagglutinin (HA) and neuraminidase (NA) amino acid sequences between SA H1N1pdm and certain vaccine strains revealed 19 mutations relative to reference strain A/California/07/2009. Among them, eight (0.47%) were in HA, and eight (0.56%) were in NA sequences that differed from vaccine strains. All isolates of the 2020–2022 seasons exhibited N- and O-glycosylation sites comparable to vaccine strains. Phylogenetically their HA and NA genes are divided into different clades. Most of the studied isolates (five) belonged to clade 5a.1 of HA. These data identify the genetic makeup of circulating influenza virus subtypes.

Aortic Rupture in a Pediatric Patient With Influenza.

Influenza can lead to significant morbidity and mortality in children. Aortopathy tends to occur in adults during influenza season; however, aortic pathology in children with influenza is exceedingly rare. This report describes a child who experienced an aortic rupture during an influenza infection without evidence of secondary bacterial infection or connective tissue disorder.

Adapting COVID-19 research infrastructure to capture influenza and respiratory syncytial virus alongside SARS-CoV-2 in UK healthcare workers winter 2022/23 and beyond: protocol for a pragmatic sub-study

Introduction During the COVID-19 pandemic, extensive research was conducted on SARS-CoV-2; however, important questions about other respiratory pathogens remain unanswered. A severe influenza season in 2022–2023 with simultaneous circulation of SARS-CoV2 and respiratory syncytial virus is anticipated. This sub-study aims to determine the incidence and impact of these respiratory viruses on healthcare workers, the symptoms they experienced, the effectiveness of both COVID-19 and influenza vaccination and the burden of these infections on the National Health Service (NHS) workforce. Methods and analysis This is a longitudinal prospective cohort sub-study, utilising the population and infrastructure of the SARS-CoV-2 Immunity &amp; Reinfection Evaluation (SIREN) study, which focuses on hospital staff in the UK. Participants undergo fortnightly nucleic acid amplification testing on a multiplex assay including SARS-CoV-2, influenza A and B and RSV, regardless of symptoms. Questionnaires are completed every two weeks, capturing symptoms, sick days, exposures, and vaccination records. Serum samples are collected monthly or quarterly from participants associated with a SIREN site. This sub-study commenced on 28/11/22 to align with the predicted influenza season and participants’ influenza vaccine status. The SIREN Participant Involvement Panel shaped the aims and methods for the study, highlighting its acceptability. UK devolved administrations were supported to develop local protocols. Analysis plans include incidence of asymptomatic and symptomatic infection, comparisons of vaccination coverage, assessment of sick day burden, and effectiveness of seasonal influenza against infection and time off work. Data are also integrated into UKHSA nosocomial modelling. Ethics and dissemination The protocol was approved by the Berkshire Research Ethics Committee (IRAS ID 284460, REC Reference 20SC0230) on 14/11/2022. Participants were informed in advance. As the frequency and method of sampling remained the same, implied consent processes were approved by the committee. Participants returning to the study give informed consent. Regular reports to advisory groups and peer-reviewed publications are planned to disseminate findings and inform decision making. Clinical trial registration number: ISRCTN11041050; registration date: 12 January 2021. Sub study included in protocol version: v8.0, and amended in v9.0

Drug resistance and possible therapeutic options against influenza A virus infection over past years.

Influenza A virus infection, commonly known as the flu, has persisted in the community for centuries. Although we have yearly vaccinations to prevent seasonal flu, there remains a dire need for antiviral drugs to treat active infections. The constantly evolving genome of the influenza A virus limits the number of effective antiviral therapeutic options. Over time, antiviral drugs become inefficient due to the development of resistance, as seen with adamantanes, which are now largely ineffective against most circulating strains of the virus. Neuraminidase inhibitors have long been the drug of choice, but due to selection pressure, strains are becoming resistant to this class of drugs. Baloxavir marboxil, a drug with a novel mode of action, can be used against strains resistant to other classes of drugs but is still not available in many countries. Deep research into nanoparticles has shown they are effective as antiviral drugs, opening a new avenue of research to use them as antiviral agents with novel modes of action. As this deadly virus, which has killed millions of people in the past, continues to develop resistance, there is an urgent need for new therapeutic agents with novel modes of action to halt active infections in patients. This review article covers the available therapeutic antiviral drug options with different modes of action, their effectiveness, and resistance to various strains of influenza A virus.