Seasonal Influenza Research Articles

Immune Response Against Influenza in a Cohort of Repeatedly Vaccinated Adults During the 2017/2018 and 2018/2019 Seasons

Background/Objectives: The influenza vaccination of healthcare workers (HCWs) is recommended each autumn and winter season by the relevant authorities in EU/EEA countries. The objective of this study was to evaluate the impact of repeated trivalent influenza vaccine (TIV) uptake during the 2017/2018 and 2018/2019 seasons on vaccine-derived immunity against influenza. Methods: A cohort study of HCWs vaccinated with an annual TIV was conducted from October 2017 to June 2019. The protective antibodies against the influenza vaccine strains were assessed at three time points: prior to vaccination and at one and six months following vaccination for each season. Sera were tested by hemagglutination inhibition assay. Participants were grouped according to their history of TIV vaccination over four seasons (since 2015/16), with the groups designated as “frequently vaccinated” (≥3 vaccines) and “occasionally vaccinated” (≤2 vaccines). Seroprevalence, geometric mean titer (GMT) and seroconversion rate were compared between the frequently and occasionally vaccinated groups. Results: A total of 97 healthcare workers (HCWs) were enrolled in the study; 49 HCWs participated in both seasons. Thirty-two (43.2%) and forty-three (59.7%) individuals had ≥3 vaccines since 2015/2016, at recruitment and during the 2017/2018 and 2018/2019 influenza seasons, respectively. One month following vaccination, HCWs who had received occasional vaccinations demonstrated a higher prevalence of protective antibodies and a greater GMT for both influenza A(H1N1)pdm09 and A(H3N2) viruses. For influenza B Victoria, the frequently vaccinated HCWs demonstrated a higher seroprevalence rate, seroconversion, and GMT. Conclusions: Previous vaccination can influence the immune response, although without substantially compromising the immunogenicity of annual influenza vaccination. HCW annual influenza vaccination is required to re-establish and maintain the antibody titers against influenza.

A Clinical and Economic Comparison of Cell-Based Versus Recombinant Influenza Vaccines in Adults 18–64 Years in the United States

Background: This analysis compares the cost-effectiveness of a cell-based influenza vaccine to a recombinant influenza vaccine, and each to no vaccination. The analysis is based on United States (US) commercial and societal perspectives. Methods: A Susceptible–Exposed–Infectious–Recovered (SEIR) transmission model of the total US population followed with a cost-effectiveness model for 18–64-year-olds was used to estimate the clinical and economic impact of vaccination over one influenza season (2018–2019). Deterministic and probabilistic sensitivity analyses were conducted. Results: Both enhanced vaccines prevented a substantial number of influenza cases and influenza-related deaths compared to no vaccination. The cell-based vaccine was associated with higher quality-adjusted life years (QALYs) gained compared to the recombinant vaccine or no vaccination. The cell-based vaccine had a 36% lower vaccination cost, amounting to $2.8 billion in cost savings, compared to the recombinant vaccine. The incremental cost-effectiveness ratios (ICERs) for the cell-based vaccine, compared to the recombinant vaccine or no vaccination, were dominant from all payer perspectives, regardless of risk groups. Conclusions: Overall, the cell-based vaccine was cost-saving compared to the recombinant vaccine for subjects aged 18–64 years in the US, achieving comparable health outcomes with a significant reduction in associated costs.

Fight the Flu: Protect Yourself and Others

As flu season approaches, it's crucial to take steps to protect yourself and those around you. The flu, a contagious respiratory illness caused by the influenza virus, can lead to severe complications, especially in young children, the elderly, and those with weakened immune systems. The best defense against the flu is vaccination. Flu vaccines are updated yearly to match circulating strains, reducing your chances of getting sick. Even if you catch the flu, the vaccine can lessen the severity of symptoms and prevent hospitalization. Different types of vaccines, such as standard-dose, high-dose, and adjuvanted vaccines, are tailored for various age groups, including children, adults, and seniors. In addition to vaccination, practicing good hygiene, like frequent handwashing, covering coughs, and staying home if sick, plays a crucial role in flu prevention. Together, these strategies form a strong defense against the flu, safeguarding communities during flu season.

Immunogenicity and Efficacy of Combined mRNA Vaccine Against Influenza and SARS-CoV-2 in Mice Animal Models

Background. The combined or multivalent vaccines are actively used in pediatric practice and offer a series of advantages, including a reduced number of injections and visits to the doctor, simplicity of the vaccination schedule and minimization of side effects, easier vaccine monitoring and storage, and lower vaccination costs. The practice of widespread use of the combined vaccines has shown the potential to increase vaccination coverage against single infections. The mRNA platform has been shown to be effective against the COVID-19 pandemic and enables the development of combined vaccines. There are currently no mRNA-based combined vaccines approved for use in humans. Some studies have shown that different mRNA components in a vaccine can interact to increase or decrease the immunogenicity and efficacy of the combined vaccine. Objectives. In the present study, we investigated the possibility of combining the mRNA vaccines, encoding seasonal influenza and SARS-CoV-2 antigens. In our previous works, both vaccine candidates have shown excellent immunogenicity and efficacy profiles in mice. Methods. The mRNA-LNPs were prepared by microfluidic mixing, immunogenicity in mice was assessed by hemagglutination inhibition assay, enzyme-linked immunoassay and virus neutralization assay. Immunological efficacy was assessed in a mouse viral challenge model. Results. In this work, we demonstrated that the individual mRNA components of the combined vaccine did not affect the immunogenicity level of each other. The combined vaccine demonstrated excellent protective efficacy, providing a 100% survival rate when mice were infected with the H1N1 influenza virus and reducing the viral load in the lungs. Four days after the challenge with SARS-CoV-2 EG.5.1.1., no viable virus and low levels of detectable viral RNA were observed in the lungs of vaccinated mice. Conclusions. The combination does not lead to mutual interference between the individual vaccines. We believe that such a combined mRNA-based vaccine could be a good alternative to separated human vaccinations for the prevention of COVID-19 and influenza.

Evaluating a WeChat-Based Intervention to Enhance Influenza Vaccination Knowledge, Attitude, and Behavior Among Chinese University Students Residing in the United Kingdom: Controlled, Quasi-Experimental, Mixed Methods Study.

University students, who often live in close quarters and engage in frequent social interaction, face a heightened risk of influenza morbidity. Still, vaccination rates among this group, particularly Chinese students, remain consistently low due to limited awareness and insufficient access to vaccinations. This study examines the effectiveness of a cocreated WeChat-based intervention that targets mainland Chinese university students in the United Kingdom, aiming to improve their knowledge, attitude, and behavior (KAB) toward seasonal influenza vaccination. A quasi-experimental mixed methods design was used, incorporating an intervention and comparison group, with baseline and follow-up self-reported surveys. The study was conducted from December 19, 2022, to January 16, 2023. The primary outcome is the KAB score, which was measured before and after the intervention phases. System-recorded data and user feedback were included in the analysis as secondary outcomes. A series of hypothesis testing methods were applied to test the primary outcomes, and path analysis was used to explore the relationships. Our study included 596 students, of which 303 (50.8%) were in the intervention group and 293 (49.2%) were in the control group. The intervention group showed significant improvements in knowledge, attitude, and intended behavior scores over time, whereas the control group had only a slight increase in intended behavior scores. When comparing changes between the 2 groups, the intervention group displayed significant differences in knowledge and attitude scores compared to the control group, while intended behavior scores did not significantly differ. After the intervention, the actual vaccination rate was slightly higher in the intervention group (63/303, 20.8%) compared to the control group (54/293, 18.4%). Path analysis found that the intervention had a significant direct impact on knowledge but not on attitudes; knowledge strongly influenced attitudes, and both knowledge and attitudes significantly influenced intended behavior; and there was a strong correlation between intended and actual behavior. In the intervention group, participants expressed a high level of satisfaction and positive review of the content and its use. This study demonstrates how a WeChat intervention effectively improves KAB related to seasonal influenza vaccination among Chinese students, highlighting the potential of social media interventions to drive vaccination behavior change. It contributes to the broader research on digital health intervention effectiveness and lays the groundwork for tailoring similar interventions to different health contexts and populations.

Influenza Vaccine Effectiveness Against Illness and Asymptomatic Infection in 2022-2023: A Prospective Cohort Study.

Previous estimates of vaccine effectiveness (VE) against asymptomatic influenza virus infection based on seroconversion have varied widely and may be biased. We estimated 2022-2023 influenza VE against illness and asymptomatic infection in a prospective cohort. In the HEROES-RECOVER cohort, adults at increased occupational risk of influenza exposure across 7 US sites provided weekly symptom reports and nasal swabs for reverse transcription-polymerase chain reaction (RT-PCR) influenza testing. Laboratory-confirmed influenza virus infections were classified as symptomatic (≥1 symptom) or asymptomatic during the week of testing. Participants reported demographic information and vaccination through surveys; most sites verified vaccination through medical record and immunization registry review. Person-time was calculated as days from the site-specific influenza season start (September-October 2022) through date of infection, study withdrawal, or season end (May 2023). We compared influenza incidence among vaccinated versus unvaccinated participants overall, by symptom status, and by influenza A subtype, using Cox proportional hazards regression adjusted for site and occupation. We estimated VE as (1 - adjusted hazard ratio) × 100%. In total, 269 of 3785 (7.1%) participants had laboratory-confirmed influenza, including 263 (98%) influenza A virus infections and 201 (75%) symptomatic illnesses. Incidence of laboratory-confirmed influenza illness among vaccinated versus unvaccinated participants was 23.7 and 33.2 episodes per 100 000 person-days, respectively (VE: 38%; 95% CI: 15%-55%). Incidence of asymptomatic influenza virus infection was 8.0 versus 11.6 per 100 000 (VE: 13%; 95% CI: -47%, 49%). Vaccination reduced incidence of symptomatic but not asymptomatic influenza virus infection, suggesting that influenza vaccination attenuates progression from infection to illness.

Multiplexed Antibody Sequencing and Profiling of the Human Hemagglutinin-specific Memory B Cell Response following Influenza Vaccination.

Influenza virus is a highly contagious respiratory pathogen causing between 9.4 and 41 million infections per year in the United States in the last decade. Annual vaccination is recommended by the World Health Organization, with the goal to reduce influenza severity and transmission. Ag-specific single B cell sequencing methodologies have opened up new avenues into the dissection of the Ab response to influenza virus. The improvement of these methodologies is pivotal to reduce the associated costs and optimize the operational workflow and throughput, especially in the context of multiple samples. In this study, PBMCs and serum samples were collected longitudinally from eight influenza vaccinees either vaccinated yearly for four consecutive influenza seasons or once for one season. Following the serological and B cell profiling of their polyclonal Ab response to a panel of historical, recent, and next-generation influenza vaccine hemagglutinin (HA) and virus strains, a single multiplexed Ag-specific single B cell sequencing run allowed to capture HA-specific memory B cells that were analyzed for preferential Ig H chain/L chain pairing, isotype/subclass usage, and the presence of public BCR clonotypes across participants. Binding and functional profiles of representative private and public clonotypes confirmed their HA specificity, and their overall binding and functional activity were consistent with those observed at the polyclonal level. Collectively, this high-resolution and multiplexed Ab repertoire analysis demonstrated the validity of this optimized methodology in capturing Ag-specific BCR clonotypes, even in the context of a rare B cell population, such as in the case of the peripheral Ag-specific memory B cells.

Contribution of immunoglobulin products in influencing seasonal influenza infection and severity in antibody immune deficiency patients receiving immunoglobulin replacement therapy

Seasonal and pandemic influenza infection present a potential threat to patients with antibody deficiency. The acceptance and effect of the current recommendation for annual vaccination against influenza for patients with antibody deficiency is not well investigated and due to antigenic drift or shift the protective capacity of regular IgG replacement therapy (IgRT) is considered low. This narrative review considers the effect of influenza vaccination in immunodeficient patients and discusses available information on the effect of immunoglobulin products on seasonal influenza infectivity and severity in antibody deficiency patients receiving IgRT. The humoral immune response to seasonal influenza vaccination is reduced in patients with antibody immune deficiency. However, there is no evidence that the proportion of patients with primary antibody deficiency who develop influenza illness, and the severity of such illness, is increased when compared with the general population. The IgRT that patients receive has been shown to contain neutralizing antibodies as a consequence of past flu infections against both the hemagglutinin and neuraminidase surface proteins and other viral internal proteins of different influenza A virus strains. Studies have demonstrated not only significant levels of specific but also cross-reactive antibodies against seasonal influenza virus strains. Thus, despite the yearly changes in influenza viral antigenicity that occur, IgRT could potentially contribute to the protection of patients against seasonal influenza. Currently, only limited clinical data are available confirming a preventative effect of IgRT with respect to seasonal influenza infection. In conclusion, there is some evidence that IgRT could contribute to protection against seasonal influenza in patients with antibody-related immunodeficiency. However, additional clinical data are needed to confirm the extent and relevance of this protection and identify the main responsible virus targets of that protection.

Headless hemagglutinin-containing influenza viral particles direct immune responses toward more conserved epitopes.

Seasonal influenza vaccines provide mostly strain-specific protection due to the elicitation of antibody responses focused on evolutionarily plastic antigenic sites in the hemagglutinin head domain. To direct the humoral response toward more conserved epitopes, we generated an influenza virus particle where the full-length hemagglutinin protein was replaced with a membrane-anchored, "headless" variant while retaining the normal complement of other viral structural proteins such as the neuraminidase as well as viral RNAs. We found that a single administration of a headless virus particle-based vaccine elicited high titers of antibodies that recognized more conserved epitopes on the major viral glycoproteins. Furthermore, the vaccine could elicit these responses even in the presence of pre-existing, hemagglutinin (HA) head-focused influenza immunity. Importantly, these antibody responses mediated protective, but non-neutralizing functions such as neuraminidase inhibition and antibody-dependent cellular cytotoxicity. Additionally, we show the vaccine can provide protection from homologous and heterologous challenges in mouse models of severe influenza without any measurable HA head-directed antibody responses. Thus, headless hemagglutinin containing viral particles may represent a tool to drive the types of antibody responses predicted to increase influenza vaccine breadth and durability.IMPORTANCECurrent seasonal influenza vaccines provide incomplete protection from disease. This is partially the result of the antibody response being directed toward parts of the virus that are tolerant of mutations. Redirecting the immune response to more conserved regions of the virus has been a central strategy of next-generation vaccine designs and approaches. Here, we develop and test a vaccine based on a modified influenza virus particle that expresses a partially deleted hemagglutinin protein along with the other viral structural proteins. We demonstrate this vaccine elicits antibodies that recognize the more conserved viral epitopes of the hemagglutinin stalk and neuraminidase protein to facilitate protection against influenza viruses despite a lack of classical viral neutralization activity.

Revolutionizing Influenza Treatment: A Deep Dive into Targeted Drug Delivery Systems.

Influenza, a highly transmissible respiratory infection caused by influenza viruses A and B, poses a persistent threat to global public health due to its high mutation rate, ability to develop resistance to existing antiviral drugs, and capacity for rapid spread. Current treatment options, including four main classes of antiviral agents-adamantanes, neuraminidase inhibitors, RNA-dependent RNA polymerase inhibitors, and polymerase acidic endonuclease inhibitors- are limited by the emergence of drug-resistant viral strains, non-specific drug distribution, and adverse side effects. Moreover, the effectiveness of traditional vaccines is often compromised by antigenic drift and shift, necessitating the development of alternative therapeutic strategies. This review comprehensively explores the potential of novel targeted drug delivery systems to address these limitations and improve influenza management. Nanotechnology-based platforms, including lipid-based, polymer-based, inorganic, and hybrid nanoparticles, offer enhanced drug delivery through improved bioavailability, targeted action, and controlled release, thus minimizing systemic toxicity and optimizing therapeutic outcomes. Inhalation delivery systems such as dry powder inhalers (DPIs), nebulizers, and nanotechnology-based inhalation formulations provide direct delivery of antiviral agents to the respiratory tract, ensuring rapid onset of action with reduced systemic side effects. Transdermal delivery methods, including microneedle patches and hydrogel-based systems, offer non-invasive alternatives that enhance patient compliance and allow for sustained drug release. Furthermore, this review discusses recent innovations, such as responsive drug delivery systems and multifunctional nanoparticles capable of simultaneous delivery of multiple therapeutic agents, representing a significant advancement in the fight against influenza. These novel approaches promise improved targeting and efficacy and enable personalized treatment strategies, enhancing patient outcomes in both seasonal flu and pandemic scenarios. Integrating these advanced drug delivery systems into clinical practice could revolutionize the management of influenza, offering a promising pathway toward more effective and safer therapies.

Public health unit funding per capita and seasonal influenza vaccination among youth and adults in Ontario, Canada in 2013/2014 and 2018/2019

BackgroundInfluenza vaccines are crucial in reducing the risk of influenza symptoms. We aimed to: (1) estimate the association between public health unit (PHU) funding per capita and influenza vaccination among...

Factors Associated With Repeat Pediatric Influenza Vaccination Among Inconsistent Vaccinators.

Promoting consistent vaccination practices may help improve suboptimal influenza vaccination rates. This study evaluated the prevalence and correlates of repeat influenza (flu) vaccination among children who had previously received the vaccine inconsistently. An online survey study was conducted in 2022 among parents of commercially insured children ages 3 to 19 years who were previously inconsistently vaccinated. Of 317 respondents, 85% reported that their child received a flu vaccine in the 2021 to 2022 flu season. Among these parents, 61% reported concern that their child would get sick from flu as the most important reason for vaccinating. Repeat vaccination was less likely among parents who reported that school/daycare requirements were a reason for vaccinating in the prior season (odd ratio [OR] = 0.17, 95% confidence interval [CI] = 0.05-0.55). Our findings suggest that school policies may improve vaccination rates among inconsistent vaccinators.

Data note on the Avian Contact Study: a questionnaire resource for avian influenza public health planning

The Avian Contact Study is a cross-sectional questionnaire of poultry workers and other individuals who have contact with domestic and/or wild birds in the UK. The questionnaire was launched online in May 2024 and in-person responses were gathered at the British Pig and Poultry Fair in Birmingham on 15 and 16 May 2024. This Data Note documents questionnaire development, content and delivery methods. Data collected include information on demographics, seasonal influenza vaccination, avian influenza exposure, contact with birds and people, and awareness of avian influenza. This Data Note provides insights into the first data release collected up to 31 July 2024 for 225 respondents. Data have been released as a University of Bristol held dataset available upon request. The Avian Contact Study provides a pilot resource for research into avian influenza from a zoonotic perspective.

Attitudes and perceptions survey regarding tobacco smoking and risk of seasonal flu, SARS-COV-2 infection, and community-acquired pneumonia (CAP) among healthcare workers (HCWs)

Attitudes and perceptions survey regarding tobacco smoking and risk of seasonal flu, SARS-COV-2 infection, and community-acquired pneumonia (CAP) among healthcare workers (HCWs)

Factors associated with COVID-19 vaccination or intent to be vaccinated across three U.S. states

Objectives: Vaccine hesitancy represents an important challenge to the effective control of the COVID-19 pandemic. In prior research on seasonal influenza, childhood vaccination, and emergency vaccination programs, hesitancy has been associated with a wide range of demographic, psychological, and compliance factors.Methods: In January 2021, an online survey was distributed using the Qualtrics (Provo, UT) platform to a proportional quota sample of individuals in three states: Louisiana, New York, and Washington. Crude and adjusted risk differences and 95 % confidence intervals were calculated to describe the relationship between vaccination or intent to be vaccinated and demographic, psychological, compliance, and pandemic impact variables.Results: Of 812 respondents, 696 indicated their vaccination status or intent to be vaccinated. Sixty-six percent indicated they were vaccinated or intended to be when available (n = 457) and 34 % were not vaccinated and did not intend to be vaccinated (n = 239). In bivariate analysis, respondents who were older, male, married, white, and reported higher household incomes were more likely to be vaccinated or intend to be. Those who complied with mask wearing, social distancing, and avoided gatherings with people outside their household were also more likely to report vaccination or intention. In the multivariable model, backward elimination resulted in a model that retained sex, race, household income, and avoiding large gatherings.Conclusion: There are important demographic, behavioral, and other factors that influence vaccine acceptance. Identifying those factors is vital for targeted and effective messaging, education, and engagement to reach those most hesitant, increase vaccination coverage, and effectively address the COVID-19 pandemic.

Seasonal Influenza Vaccine Literacy and Hesitancy of Elderly Czechs: An Analysis Using the 5C Model of Psychological Antecedents.

Seasonal influenza vaccination rates among the elderly in the Czech Republic are alarmingly low, making it one of the least vaccinated countries in Europe. This study explored the role of vaccine literacy and insurance coverage on vaccination status. An analytical cross-sectional study was conducted in Summer 2023 using a self-administered questionnaire covering vaccine literacy (functional, interactive, and critical skills), negative perceptions towards influenza vaccination, and the 5C model (confidence, complacency, constraints, calculation, and collective responsibility). Individuals aged 55 and older were included in the study. Mediation analyses assessed the indirect effects of insurance coverage on vaccination status. Significant differences were noted in vaccination rates based on insurance coverage, chronic diseases, regular medication use, and previous COVID-19 and pneumococcal vaccinations. Vaccine literacy, especially interactive and critical skills, was higher among vaccinated individuals. Confidence and collective responsibility were significant promoters, while complacency and constraints were barriers to vaccination. Mediation analyses indicated that negative perceptions, confidence, and collective responsibility significantly mediated the relationship between insurance coverage and vaccination status. Enhancing vaccine literacy and addressing psychological antecedents are crucial for improving influenza vaccination rates among the elderly. Policy measures should include improving vaccine literacy, building public confidence, and addressing negative perceptions.

MRNA-based influenza vaccine expands breadth of B cell response in humans.

Eliciting broad and durable antibody responses against rapidly evolving pathogens like influenza viruses remains a formidable challenge. The germinal center (GC) reaction enables the immune system to generate broad, high-affinity, and durable antibody responses to vaccination. mRNA-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines induce persistent GC B cell responses in humans. Whether an mRNA-based influenza vaccine could induce a superior GC response in humans compared to the conventional inactivated influenza virus vaccine remains unclear. We assessed B cell responses in peripheral blood and draining lymph nodes in cohorts receiving the inactivated or mRNA-based quadrivalent seasonal influenza vaccine. Participants receiving the mRNA-based vaccine produced more robust plasmablast responses and higher antibody titers to H1N1 and H3N2 influenza A viruses and comparable antibody titers against influenza B virus strains. Importantly, mRNA-based vaccination stimulated robust recall B cell responses characterized by sustained GC reactions that lasted at least 26 weeks post-vaccination in three of six participants analyzed. In addition to promoting the maturation of responding B cell clones, these sustained GC reactions resulted in enhanced engagement of low-frequency pre-existing memory B cells, expanding the landscape of vaccine-elicited B cell clones. This translated to expansion of the serological repertoire and increased breadth of serum antibody responses. These findings reveal an important role for the induction of persistent GC responses to influenza vaccination in humans to broaden the repertoire of vaccine-induced antibodies.

Comparison of Predictive Factors of Flu Vaccine Uptake Pre- and Post-COVID-19 Using the NIS-Teen Survey

Background: Seasonal influenza vaccination rates are very low among teenagers. Objectives: We used publicly available data from the NIS-Teen annual national immunization survey to explore factors that influence the likelihood of a teen receiving their seasonal flu shot. Methods: Traditional stepwise multivariable regression was used in tandem with machine learning to determine the predictive factors in teen vaccine uptake. Results and Conclusions: Age was the largest predictor, with older teens being much less likely to be vaccinated than younger teens (97.48% compared to 41.71%, p < 0.0001). Provider participation in government programs such as Vaccines for Children and the state vaccine registry positively impacts vaccine uptake (p < 0.0001). Identifying as non-Hispanic Black was a small, negative predictor of teen vaccine uptake (78.18% unvaccinated compared to 73.78% of White teens, p < 0.0001). The state quartile for COVID-19 vaccine uptake also strongly predicted flu vaccine uptake, with the upper quartile of state COVID-19 vaccine uptake being significantly more likely to also get vaccinated for influenza (76.96%, 74.94%, 74.55%, and 72.97%, p < 0.0001). Other significant factors are the number of providers, education of the mother, poverty status, and having a mixed provider facility type. Additionally, the multivariable regression analysis revealed little difference in the predictive factors of vaccine uptake between pre- and post-pandemic datasets.

Analyzing Changes in Attitudes and Behaviors towards Seasonal Influenza Vaccination in Spain’s Adult Population over Three Seasons

Background/Objectives: The experience of the COVID-19 pandemic has turned the spotlight on the importance of public health measures and disease prevention. Despite this, the acceptance of influenza vaccination has remained low in most countries (and far from the 75% target set by the World Health Organization). The objective of this study has been to investigate how attitudes and behaviors regarding influenza vaccination in the Spanish adult population have changed over the last three years (from 2021 to 2024) in order to analyze trends in influenza vaccination. Methods: To this end, a cross-sectional study was conducted through 2206 telephone interviews, and the results were compared with those obtained in previous campaigns. Results: The findings indicate a significant decline in overall vaccination intent. Healthcare professionals remain the most influential factor in encouraging vaccination, yet there is a notable increase in the lack of vaccine recommendations, contributing to the decision not to vaccinate. This study also reveals low awareness of the influenza vaccine campaign, emphasizing the need for improved public health communication. Conclusions: To counteract these trends, this study recommends intensifying awareness campaigns, strengthening the role of healthcare providers in vaccine advocacy, and tailoring communication strategies. These efforts are crucial to enhancing vaccination coverage and protecting vulnerable populations against influenza.

Long-Term Trends in Antibiotic Use in a Low-Resource Medical Setting: Amman, Jordan (2010–2023)

Abstract Background Antimicrobial resistance (AMR) contributes to substantial morbidity and mortality. The misuse and overuse of antibiotics are major drivers of AMR. Lack of point-of-care testing to discern viral from bacterial infections complicates appropriate management in low-resource settings. This study examines antibiotic prescription practices in Amman, Jordan. Methods We conducted three prospective viral surveillance studies at the largest public hospital in Amman Jordan (2010–2013, 2020, and 2023). Our target population for this study was children <2 years old hospitalized with fever or respiratory symptoms. Through parental interviews and chart abstractions, we collected demographic and clinical data, including antibiotic use, as well as results of any blood, urine, and cerebrospinal fluid cultures performed at providers’ discretion. We classified antibiotics according to the 2023 World Health Organization AWaRe (Access, Watch, Reserve) antibiotic classification system, focusing on the utilization of Watch group antibiotics, which are recommended when first-line Access group antibiotics are ineffective or inappropriate. Research personnel also collected nasal or throat swabs from enrolled children, and these samples were tested in a research laboratory for common respiratory viruses using RT-PCR. Providers were unaware of viral testing results. We described categorical variables using absolute and relative frequencies and summarized continuous variables using the median and interquartile range (IQR). Results Of 4,950 children enrolled, we included 4,703. The median age was 3.5 months (IQR, 1.6–8.3), and 59.4% (n=2,793) were male. Most children were enrolled from the general ward (n=4,312 [91.9%]), with the remaining 380 (8.1%) being enrolled from the pediatric intensive care unit. Only 8 children (0.2%) among those eligible for seasonal influenza vaccination (n=1,624) had been vaccinated at presentation. The five most common admission diagnoses were bronchopneumonia (n=1,255 [26.7%]), rule-out sepsis (n=1,217 [25.9%]), bronchiolitis (n=866 [18.4%]), pneumonia (n=606 [12.9%]), and paroxysmal coughing or pertussis-like cough (n=273 [5.8%]). Blood, urine, or CSF samples were collected from 2,556 children (54.5%), 355 (13.9%) of whom tested positive for at least one bacterial species (Figure 1A). During hospitalization, 4,356 children (92.6%) received at least one antibiotic. Of those, 4,227 (97.0%) received at least one antibiotic from the Watch group (Figure 1B). The three most common Access group antibiotics prescribed were ampicillin (n=830 [17.7%]), gentamicin (n=96 [2.0%]), and amikacin (n=85 [1.8%]), whereas the three most common Watch group antibiotics prescribed were ceftriaxone (n=1,956 [41.7%]), cefuroxime (n=1,628 [34.7%]), and azithromycin (n=754 [16.1%]) Overall, 3,898 children (82.9%) were positive for at least one respiratory virus (Figure 1C). Providers ordered cultures most often for children 0–2 months old (n=1,575 [73.5%]) and those with an admission diagnosis of rule-out sepsis (n=1,161 [95.4%]). Despite seasonal variation, prescription and testing practices were consistent across study years. Conclusion Inappropriate antibiotic use remains a significant healthcare challenge in Jordan. Incorporating point-of-care viral testing for suspected respiratory infections and improving diagnostic testing for bacterial infections is crucial. Preventive strategies including influenza vaccination and the use of emerging therapies for RSV or other pathogens associated with high morbidity could indirectly limit inappropriate antibiotic use. Development of context-specific management guidelines and antimicrobial stewardship programs are urgently required to guide prescription practices.