Annual Influenza Vaccination Research Articles

Influenza and COVID-19 Vaccination Coverage Among Health Care Personnel - National Healthcare Safety Network, United States, 2023-24 Respiratory Virus Season.

The Advisory Committee on Immunization Practices (ACIP) recommends that health care personnel receive an annual influenza vaccine. In September 2023, ACIP recommended that everyone aged ≥6 months receive a 2023-2024 COVID-19 vaccine. Health care facilities, including acute care hospitals and nursing homes, report vaccination of health care personnel against influenza and COVID-19 to CDC's National Healthcare Safety Network (NHSN). During October 2023-March 2024, NHSN defined up-to-date COVID-19 vaccination as receipt of a 2023-2024 COVID-19 vaccine. This analysis describes influenza and 2023-2024 COVID-19 vaccination coverage among health care personnel working in acute care hospitals and nursing homes during the 2023-24 respiratory virus season (October 1, 2023-March 31, 2024). Influenza vaccination coverage was 80.7% among health care personnel at acute care hospitals and 45.4% among health care personnel at nursing homes. Coverage of 2023-2024 COVID-19 vaccination was 15.3% among health care personnel at acute care hospitals and 10.5% among health care personnel at nursing homes. Respiratory viral diseases including influenza and COVID-19 pose risks to health care personnel in U.S. health care settings, and vaccination of health care personnel is an effective strategy for maintaining a healthy workforce and improving health care system resiliency.

Electronic nudges to increase influenza vaccination in patients with chronic kidney disease: a prespecified analysis of NUDGE-FLU-CHRONIC

Abstract Background Annual influenza vaccination is recommended for individuals with chronic kidney disease (CKD); however, guideline adherence is suboptimal potentially related to lack of awareness of vaccine availability and effectiveness. Purpose This prespecified analysis of the NUDGE-FLU-CHRONIC trial investigated the effectiveness of digital behavioral nudges on influenza vaccine uptake based on the presence or absence of CKD. Methods NUDGE-FLU-CHRONIC was a randomized, nationwide trial, conducted during the 2023/2024 influenza season including younger and middle-aged (18-64 years) Danish citizens with chronic illnesses (making them eligible for the free Danish vaccine program). Participants were randomized in a ratio of 2.45:1:1:1:1:1:1 to receive either usual care (no letter) or one of six different letter-based nudges, delivered via the governmental electronic letter system on September 26, 2023. Baseline and outcome data were obtained with the Danish nationwide registers. Primary endpoint was receipt of an influenza vaccine no later than January 1, 2024. Results A total of 299,881 individuals were randomized in NUDGE-FLU-CHRONIC trial, among them, 15,208 (5.1%) had a history of CKD. Participants with CKD had a median age was 53.1 years (IQR, 42.2-59.6) and 46.0% were female. During follow-up, 43.7% of participants with CKD were vaccinated compared with 35.8% of participants without CKD (p<0.001). Any letter was highly effective in increasing influenza vaccination in the overall population but was slightly less effective in those with a history of CKD (p for interaction = 0.005). In participants with CKD, any letter increased vaccination by 25% versus no letter (46.3% vs. 37.1%; difference, 9.3 percentage points; 99.29%CI, 6.9-11.6; RR, 1.25; 99.29%CI, 1.18-1.33). In participants without CKD, any letter increased vaccination by 43% (39.2% vs. 27.4%; difference, 11.8 percentage points; 99.29%CI, 11.3-12.3; RR, 1.43; 99.29%CI, 1.41-1.45). Similar patterns were observed when assessing each intervention letter individually (Figure 1). Effectiveness of any letter vs. usual care was consistent across CKD subgroups, except for concomitant diabetes vs no diabetes (Figure 2). There was no observed effect modification by CKD duration (p for interaction = 0.78) or by estimated glomerular filtration rate (p for interaction = 0.78) modelled continuously for any letter vs. usual care. Conclusion In this prespecified analysis from the nationwide NUDGE-FLU-CHRONIC trial, only approximately 1 in 3 younger and middle-aged adults with CKD received influenza vaccination. Digital nudge letters emphasizing the importance of annual influenza vaccination significantly boosted rates of vaccination across a broad range of individuals with CKD.Figure 1Figure 2

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.

Knowledge, Attitudes, and Practices towards Influenza Vaccine among Guangzhou Residents: A Cross-Sectional Study.

Influenza vaccination is an important prevention strategy for flu illness. However, the vaccination rate is still low in Guangzhou, China. This study aimed to understand the status of knowledge, the attitude towards the vaccines' reliability and safety, and other aspects associated with the willingness and practice of influenza vaccines in the pediatric and adult populations of Guangzhou city. This study was performed in eleven districts in Guangzhou between November 2020 and December 2020, including the Yuexiu, Liwan, Haizhu, Tianhe, Baiyun, Panyu, Huadu, Nansha, Huangpu, Zengcheng, and Conghua districts. The parents of children and teenagers under the age of eighteen in Guangzhou were surveyed using self-administered questionnaires in four domains: demographic information, the knowledge status and perception of influenza vaccination, the willingness and attitude towards influenza vaccination, and previous vaccine uptake. A multivariable logistic regression was employed to assess the possible determinants of willingness and practice to receive influenza vaccination, calculating the odds ratios (ORs) and 95% confidence interval (CI). A two-sided p-value < 0.05 was deemed statistically significant. A total of 13,213 valid questionnaires were collected (validity rate 98.8%). Out of these participants, 42.62% (5631 participants) expressed a willingness to receive the influenza vaccine, while 55.40% (7320 participants) reported that their children and teenagers had been vaccinated against the flu. Furthermore, 40.44% of the respondents (5343 participants) or other family members had received the influenza vaccine. Logistic regression indicated that factors such as being female (OR = 1.395, 95% CI: 1.278-1.522), being involved in the work of COVID-19 prevention and control (1.551, 1.396-1.724), affirming the preventive effects of vaccination (2.474, 2.106-2.906), knowing about annual influenza vaccination (2.756, 2.540-2.992), and understanding prioritized influenza vaccination populations (1.464, 1.343-1.596) were all positively associated with vaccination willingness. Conversely, middle-aged persons (aged 40-49 years old) (0.726, 0.617-0.853), higher educational levels (undergraduate versus middle school) (0.858, 0.768-0.959), heightened concerns about vaccine safety (considering side effects are obvious versus considering it is safe and basically no side effects) (0.284, 0.188-0.429) and lower knowledge scores (0.813, 0.701-0.942) were adversely linked with vaccination willingness. These findings provide essential insights for altering the perception of influence and influenza vaccination, as well as enhancing health communication strategies to improve influenza vaccine uptake among Guangzhou residents.

Influenza in travelers from Germany returning from abroad: a retrospective case–control study

BackgroundInfluenza is the most common vaccine-preventable infection among travelers, affecting approximately one percent of those travelling to subtropical and tropical destinations.MethodsWe analysed demographic, travel-related and clinical information from travelers diagnosed with influenza at our travel clinic between January 2015 and March 2020 and influenza-negative controls.ResultsWe included 68 travelers diagnosed with influenza and 207 controls. In total, 22.1% of influenza patients (n = 15) were older than 60 years and/or had comorbidities for which annual influenza vaccination is recommended, but only one had received an influenza vaccine. Patients with respiratory and musculoskeletal symptoms who presented during the German influenza season had the highest risk proportion of positive tests (54%, n = 25/46). Overall, three (4.4%) influenza patients were hospitalised, two (2.9%) received antiviral treatment, and eight (11.8%) received antibiotic therapy.ConclusionsInfluenza occurs throughout the year in international travelers and can cause significant morbidity. Travelers with febrile illness should be tested for influenza, especially if they have respiratory or musculoskeletal symptoms, present during the local influenza season, or have travelled to South-East Asia. Influenza vaccination coverage among international travelers needs to be improved among high-risk individuals.

Interim Effectiveness Estimates of 2024 Southern Hemisphere Influenza Vaccines in Preventing Influenza-Associated Hospitalization - REVELAC-i Network, Five South American Countries, March-July 2024.

To reduce influenza-associated morbidity and mortality, countries in South America recommend annual influenza vaccination for persons at high risk for severe influenza illness, including young children, persons with preexisting health conditions, and older adults. Interim estimates of influenza vaccine effectiveness (VE) from Southern Hemisphere countries can provide early information about the protective effects of vaccination and help guide Northern Hemisphere countries in advance of their season. Using data from a multicountry network, investigators estimated interim VE against influenza-associated severe acute respiratory illness (SARI) hospitalization using a test-negative case-control design. During March 13-July 19, 2024, Argentina, Brazil, Chile, Paraguay, and Uruguay identified 11,751 influenza-associated SARI cases; on average, 21.3% of patients were vaccinated against influenza, and the adjusted VE against hospitalization was 34.5%. The adjusted VE against the predominating subtype A(H3N2) was 36.5% and against A(H1N1)pdm09 was 37.1%. These interim VE estimates suggest that although the proportion of hospitalized patients who were vaccinated was modest, vaccination with the Southern Hemisphere influenza vaccine significantly lowered the risk for hospitalization. Northern Hemisphere countries should, therefore, anticipate the need for robust influenza vaccination campaigns and early antiviral treatment to achieve optimal protection against influenza-associated complications.

Antibody responses against influenza A decline with successive years of annual influenza vaccination: results from an Australian Healthcare Worker cohort.

Influenza vaccine effectiveness and immunogenicity can be compromised with repeated vaccination. We assessed immunological markers in a cohort of healthcare workers (HCW) from six public hospitals around Australia during 2020-2021. Sera were collected pre-vaccination and ~ 14 and ~ 180 days post-vaccination and assessed in haemagglutination inhibition assay against egg-grown vaccine and equivalent cell-grown viruses. Responses to vaccination were compared by the number of prior vaccinations. Baseline sera were available for 595 HCW in 2020 and 1031 in 2021. 5% had not been vaccinated during five years prior to enrolment and 55% had been vaccinated every year. Post-vaccination titres for all vaccine antigens were lowest among HCW vaccinated in all 5-prior years and highest among HCW with 0 or 1 prior vaccinations, even after adjustment. This was observed for both influenza A subtypes and was dependent on pre-vaccination titre. Expanded cohorts are needed to better understand how this translates to vaccine effectiveness.

Enhancing COVID-19 Vaccination Awareness and Uptake in the Post-PHEIC Era: A Narrative Review of Physician-Level and System-Level Strategies.

Following the World Health Organization's declaration that the COVID-19 pandemic is no longer a public health emergency of international concern (PHEIC), COVID-19 remains an ongoing threat to human health and healthcare systems. Vaccination plays a crucial role in reducing the disease's incidence, mitigating its severity, and limiting transmission, contributing to long-term public health resilience. However, incomplete vaccination coverage and vaccine hesitancy exist. This narrative review investigates strategies at the system and physician levels aimed at sustaining awareness and uptake of COVID-19 vaccination in a post-PHEIC era. Through an examination of the existing literature, this review explores the effectiveness of diverse approaches utilized by healthcare systems and individual providers. These approaches address every component of the 5C model of vaccine hesitancy: confidence, complacency, constraints/convenience, calculation, and collective responsibility. Physician-level approaches include appropriate message framing, persuasive communication containing safety and personal/social benefit information, sharing of personal stories, creating a safe space for discussion, harnessing co-administration with annual influenza vaccines, and use of decision aids and visual messages. System-level approaches include messaging, mass media for health communication, on-site vaccine availability, pharmacist delivery, healthcare protocol integration, incentives, and chatbot use.

Differential effects of social versus monetary incentives on inhibitory control under acute inflammation

While the impact of chronic, low-grade inflammation on cognitive functioning is documented in the context of neurodegenerative disease, less is known about the association between acute increases in inflammation and cognitive functioning in daily life. This study investigated how changes in interleukin-6 (IL-6) levels were associated with performance on an inhibitory control task, the go/no-go task. We further examined whether the opportunity to earn different incentive types (social or monetary) and magnitudes (high or low) was associated with differential performance on the task, depending on IL-6 levels. Using a within-participant design, individuals completed an incentivized go/no-go task before and after receiving the annual influenza vaccine. Multilevel logistic regressions were performed on the trial-level data (Nobs = 30,528). For no-go trials, we did not find significant associations between IL and 6 reactivity between the sessions and changes in trial accuracy. For go trials, we found significant differences in the associations between IL and 6 reactivity and changes in accuracy from session 1 to session 2 as a function of the incentive condition. Notably, greater IL-6 reactivity was consistently associated with fewer omission errors (i.e., greater accuracy on go trials) on high-magnitude social incentives (i.e., viewing a picture of a close-other picture) when compared to both low-magnitude social and high-magnitude monetary incentives. Together, these results suggest that mild fluctuations in inflammation might alter the valuation of an incentive, and possibly a shift toward devoting greater attentional resources when a large social incentive is on the line. Overall, this study sheds light on how everyday, low-grade fluctuations in inflammation may influence cognitive abilities essential for daily life and effective inhibitory control.

Recommendations for Prevention and Control of Influenza in Children, 2024-2025: Technical Report.

This technical report accompanies the recommendations of the American Academy of Pediatrics for the routine use of influenza vaccine and antiviral medications in the prevention and treatment of influenza in children during the 2024 to 2025 season. The rationale for the American Academy of Pediatrics recommendation for annual influenza vaccination of all children without medical contraindications starting at 6 months of age is provided. Influenza vaccination is an important strategy for protecting children and the broader community against influenza. This technical report summarizes recent influenza seasons, morbidity and mortality in children, vaccine effectiveness, and vaccination coverage and provides detailed guidance on vaccine storage, administration, and implementation. The report also provides a brief background on inactivated (nonlive) and live attenuated influenza vaccines, available vaccines for the 2024-2025 influenza season, vaccination during pregnancy and breastfeeding, diagnostic testing for influenza, and antiviral medications for treatment and chemoprophylaxis. Strategies to promote vaccine uptake are emphasized.

Recommendations for Prevention and Control of Influenza in Children, 2024-2025: Policy Statement.

This statement updates the recommendations of the American Academy of Pediatrics for the routine use of influenza vaccines and antiviral medications in the prevention and treatment of influenza in children during the 2024-2025 influenza season. A detailed review of the evidence supporting these recommendations is published in the accompanying technical report (www.pediatrics.org/cgi/doi/10.1542/peds.2024-068508). The American Academy of Pediatrics recommends annual influenza vaccination of all children without medical contraindications starting at 6 months of age. Children are at risk for hospitalization and death from influenza. Influenza vaccination is an important strategy for protecting children and the broader community as well as reducing the overall burden of respiratory illnesses when other viruses are cocirculating. Any licensed influenza vaccine appropriate for age and health status can be administered, ideally as soon as possible in the season, without preference for one product or formulation over another. All licensed influenza vaccines for use in the United States are trivalent for the 2024-2025 influenza season. Antiviral treatment of influenza is recommended for children with suspected (eg, influenza-like illness [fever with either cough or sore throat]) or confirmed influenza who are hospitalized or have severe or progressive disease or have underlying conditions that increase their risk of complications of influenza, regardless of duration of illness. Antiviral treatment should be initiated as soon as possible. Antiviral treatment may be considered in the outpatient setting for symptomatic children who are not at high risk for influenza complications with suspected or confirmed influenza disease, if treatment can be initiated within 48 hours of illness onset. Antiviral treatment may also be considered for children with suspected or confirmed influenza disease whose siblings or household contacts either are younger than 6 months or have a high-risk condition that predisposes them to complications of influenza. Antiviral chemoprophylaxis is recommended for the prevention of influenza virus infection as an adjunct to vaccination in certain individuals, especially exposed children who are asymptomatic and are at high risk for influenza complications but have not yet been immunized or those who are not expected to mount an effective immune response.

Patients with immune mediated inflammatory diseases are insufficiently protected against vaccine-preventable infections.

Patients with Immune Mediated Inflammatory Diseases (IMIDs) using immunosuppressive therapy are at increased risk of infections, including vaccine-preventable infections. In this study, we aimed to evaluate whether patients with IMIDs on systemic immunosuppressive therapy are vaccinated according to current guidelines. A survey was sent out, between August 2022 and March 2023, to all patients with IMIDs that visited the departments of dermatology, rheumatology and gastroenterology at an academic and regional hospital in Rotterdam, the Netherlands. Patient-reported vaccination status was compared to the Dutch guidelines on vaccinations in patients with chronic inflammatory diseases. A total of 1,905/5,987 patients responded to the survey (response rate 32%). After exclusion of patients without systemic immunosuppressive medication, the study population comprised 1,390 patients, median age 56 years (IQR 42-66) and 41% male. Most patients (92%) had been vaccinated according to the Dutch National Immunization Program. Before starting immunosuppressive therapy, 2% of the patients who were still considered at risk according to the Dutch guideline were vaccinated for measles, and 4% for diphtheria/tetanus/polio (DT-IPV). Additionally, 62% of patients received an annual influenza vaccine, 16% received a five-yearly pneumococcal vaccine, and 91% were fully vaccinated against COVID-19. Patients with IMIDs on immunosuppressive therapy are not vaccinated in accordance with the guidelines. Implementation strategies to improve the vaccination rates for patients with IMIDs should specifically focus on vaccinating against measles and diphtheria/tetanus/polio, and periodic vaccination against pneumococcal and influenza infections.

Effectiveness of annual influenza campaigns and vaccination in reducing influenza burden in nursing homes of Canton Vaud in Switzerland

BackgroundInfluenza infections pose significant risks for nursing home (NH) residents. Our aim was to evaluate the impact of the cantonal influenza campaign, and influenza vaccination coverage of residents and healthcare workers (HCWs) on influenza burden in NHs in a context of enhanced infection prevention and control measures (IPC) during the SARS-CoV-2 pandemic.MethodsWe extracted data from epidemic reports provided by our unit to NHs over two consecutive winter seasons (2021-22 and 2022-23) and used linear regression to assess the impact of resident and HCW vaccination coverage, and participation in the campaign, on residents’ cumulative influenza incidence and mortality.ResultsThirty-six NHs reported 155 influenza cases and 21 deaths during the two winter seasons corresponding to 6.2% of infected residents and a case fatality ratio of 13.5%. Median vaccination coverage was 83% for residents, 25.8% for HCWs, while 87% of NHs participated in the campaign. Resident vaccination was significantly associated with a decrease in odds of death (odds ratio (OR) 0.96, 95% confidence interval (CI): 0.93–0.99). There was no significant effect of HCW vaccination coverage on resident infections and deaths. Campaign participation was associated with decreased odds of infection and death among residents (OR: 0.17, 95% CI: 0.06–0.47 and OR: 0.06, 95% CI: 0.02–0.17 respectively).ConclusionOur analysis suggests that in a context of reinforced IPC measures, influenza still represents a significant burden for NH residents. The most effective measures in decreasing resident influenza burden in NHs was participation in the cantonal influenza vaccination campaign and resident vaccination.

Simultaneous vaccination against seasonal influenza and COVID-19 among the target population in Italy.

Annual influenza and COVID-19 vaccinations are effective tools for reducing the disease burden. The goals of the present cross-sectional survey were to investigate attitudes and behaviors toward the simultaneous vaccination against seasonal influenza and COVID-19 and the factors associated. Questionnaires were self-administered or researcher-administered between October 2023 and February 2024 in an immunization center in the southern part of Italy. All 151 subjects eligible for influenza and COVID-19 vaccinations who attended the center agreed to participate. A total of 59.9% of respondents received concurrent seasonal influenza and COVID-19 vaccinations. Those who perceived that the simultaneous vaccination was safer and those who have been infected by SARS-CoV-2 fewer times were more likely to have simultaneously received both vaccinations. Regarding the reasons reported, half of the sample stated that the simultaneous vaccination was safe and that they were adequately informed. This was more likely indicated by the respondents who had received at least four doses of the COVID-19 vaccination. Among those who had not received the simultaneous vaccination, 70.7% and 29.3% had received only seasonal influenza and COVID-19. Educational health communication campaigns are necessary to improve compliance with simultaneous administration of seasonal influenza and COVID-19 vaccinations and to increase the unsatisfactory coverage.

Exploring Perceptions and Barriers: A Health Belief Model-Based Analysis of Seasonal Influenza Vaccination among High-Risk Healthcare Workers in China.

The annual seasonal influenza vaccination rate among high-risk healthcare workers (HCWs) has fallen below expectations, underscoring the importance of exploring the impact of perception on vaccination behavior. An online survey, grounded in the Health Belief Model (HBM), was administered to high-risk healthcare workers at West China Hospital. The data analysis encompassed descriptive statistics, logistic regression for univariate analysis, and path regression for multivariate analysis. A total of 1845 healthcare workers completed the survey, with an acceptance rate of 83.90% (95% CI, 82.20-85.60%). Path analysis revealed significant correlations between vaccination acceptance and perceived susceptibility (β = 0.142), perceived benefits (β = 0.129), perceived barriers (β = 0.075), exposure to vaccination advertisements (β = 0.115), and knowledge about seasonal influenza (β = 0.051). Vaccination education efforts should prioritize elucidating the risks associated with the disease and emphasizing the benefits of vaccination. Furthermore, leveraging advertising proves to be an effective strategy for promotion.

Knowledge, attitudes, and practices associated with influenza vaccine uptake among healthcare personnel in Israel during three influenza seasons, 2016–2019

IntroductionDespite a longstanding Israel Ministry of Health recommendation that all healthcare personnel (HCP) receive a seasonal influenza vaccine, vaccine uptake among HCP remains below the country’s target of 60% coverage. To understand factors related to vaccine hesitancy, we used data from a prospective three-year (2016–2019) influenza vaccine effectiveness study among Israeli HCP to examine knowledge, attitudes, and practices (KAP) about influenza vaccination and their association with vaccine uptake. MethodsAt the start of each influenza season, all participating HCP completed a questionnaire that included questions about socio-demographic and occupational characteristics, health status, and KAP related to seasonal influenza vaccination. We extracted vaccination history from electronic medical records and employee vaccination registries. We used logistic regression models to identify demographic and occupational factors, and KAP about influenza vaccination, associated with receipt of vaccination. ResultA total of 2,126 HCP were enrolled and had available data on vaccination history. Their median age was 42 years [IQR 35–52], and 73 % self-identified as female. Influenza vaccine uptake in 2016, 2017 and 2018 was 46 %, 48 % and 47 %, respectively. Overall, 36 % of HCP had received an influenza vaccine in ≥ 4 of the eight years prior. HCP aged 35–49 years were less likely to receive influenza vaccine compared to HCP aged ≥ 50 years (OR: 0.81 [95 % CI: 0.67–0.98]). Nurses and allied personnel were less likely to receive influenza vaccine compared to physicians (OR: 0.63 [95 % CI: 0.50–0.78] and OR: 0.53 [95 % CI: 0.40–0.70], respectively). The emotional benefit of vaccination (e.g., anticipating regret if not vaccinated) and the perception of vaccine safety were factors associated with vaccine uptake (OR: 7.60 [95 % CI: 6.27–9.22] and OR: 3.43 [95 % CI:2.91–4.03], respectively). ConclusionAmong HCP at two hospitals in Israel, less than half received an annual influenza vaccine. Older HCP, physicians, and those who reported the emotional benefit of vaccination or agreed that influenza vaccines are safe were more likely to be vaccinated. Future influenza vaccination campaigns could focus on these demographic groups and tailor messages emphasizing the emotional benefits of vaccination and vaccine safety to increase seasonal influenza vaccine uptake among HCP in Israel.

Assessment of the herpes zoster risk among renal transplant recipients administered the influenza vaccine

BackgroundReactivation of the latent varicella-zoster virus can cause herpes zoster (HZ) infection, and renal transplant recipients undergoing immunosuppressive therapy are particularly susceptible to this condition. This study aims to evaluate the potential increase in HZ incidence following influenza vaccination among this specific patient population. MethodsThis study was a population-based, retrospective, self-controlled case series. Data were retrieved from Taiwan’s National Health Insurance Research Database spanning the years 2008 to 2017. Patients diagnosed with HZ within a 6-month period before and after receiving the influenza vaccine were eligible for inclusion. Two distinct time intervals were defined for analysis: the initial 15 days and 30 days following vaccination were categorized as risk intervals, while all other periods served as control intervals. Incidence rate ratios (IRRs) were computed to compare HZ incidence during the risk intervals with that during the control intervals. ResultsThis study encompassed a cohort of 4,222 renal transplant recipients who had received the influenza vaccine. Among this group, 67 recipients were subsequently diagnosed with HZ. The IRR during both the initial 15 days (IRR = 0.63; 95 % CI, 0.23–1.89) and the first 30 days (IRR = 1.50; 95 % CI, 0.71–3.16) following influenza vaccination did not demonstrate a statistically significant increase when compared to the post-exposure observation times. Comparable results were also observed when comparing these IRR values to the pre-exposure observation times. The subgroup analysis, stratified by age, sex, and underlying medical conditions (including cancer and autoimmune diseases), revealed that the IRRs did not exhibit statistically significant differences. ConclusionsNo significant association between the influenza vaccine and an elevated risk of HZ was detected. The administration of annual influenza vaccines appears to be a reasonable practice for renal transplant recipients.

Neutralizing antibody responses against contemporary and future influenza A(H3N2) viruses in paradoxical clades elicited by repeated and single vaccinations.

As one of the most effective measures to prevent seasonal influenza viruses, annual influenza vaccination is globally recommended. Nevertheless, evidence regarding the impact of repeated vaccination to contemporary and future influenza has been inconclusive. A total of 100 subjects singly or repeatedly immunized with influenza vaccines including 3C.2a1 or 3C.3a1 A(H3N2) during 2018-2019 and 2019-2020 influenza season were recruited. We investigated neutralization antibody by microneutralization assay using four antigenically distinct A(H3N2) viruses circulating from 2018 to 2023, and tracked the dynamics of B cell receptor (BCR) repertoire for consecutive vaccinations. We found that vaccination elicited cross-reactive antibody responses against future emerging strains. Broader neutralizing antibodies to A(H3N2) viruses and more diverse BCR repertoires were observed in the repeated vaccination. Meanwhile, a higher frequency of BCR sequences shared among the repeated-vaccinated individuals with consistently boosting antibody response was found than those with a reduced antibody response. Our findings suggest that repeated seasonal vaccination could broaden the breadth of antibody responses, which may improve vaccine protection against future emerging viruses.

Resurgence of seasonal influenza driven by A/H3N2 and B/Victoria in succession during the 2023-2024 season in Beijing showing increased population susceptibility.

During the COVID-19 pandemic, non-pharmaceutical interventions were introduced to reduce exposure to respiratory viruses. However, these measures may have led to an "immunity debt" that could make the population more vulnerable. The goal of this study was to examine the transmission dynamics of seasonal influenza in the years 2023-2024. Respiratory samples from patients with influenza-like illness were collected and tested for influenza A and B viruses. The electronic medical records of index cases from October 2023 to March 2024 were analyzed to determine their clinical and epidemiological characteristics. A total of 48984 positive cases were detected, with a pooled prevalence of 46.9% (95%CI 46.3-47.5). This season saw bimodal peaks of influenza activity, with influenza A peaked in week 48, 2023, and influenza B peaked in week 1, 2024. The pooled positive rates were 28.6% (95%CI 55.4-59.6) and 18.3% (95%CI 18.0-18.7) for influenza A and B viruses, respectively. The median values of instantaneous reproduction number were 5.5 (IQR 3.0-6.7) and 4.6 (IQR 2.4-5.5), respectively. The hospitalization rate for influenza A virus (2.2%, 95%CI 2.0-2.5) was significantly higher than that of influenza B virus (1.1%, 95%CI 0.9-1.4). Among the 17 clinical symptoms studied, odds ratios of 15 symptoms were below 1 when comparing influenza A and B positive inpatients, with headache, weakness, and myalgia showing significant differences. This study provides an overview of influenza dynamics and clinical symptoms, highlighting the importance for individuals to receive an annual influenza vaccine.

Influenza Vaccination of Romanian Medical Students during COVID-19 Times: From Knowledge to Behavior.

In Romania, influenza vaccination uptake among healthcare workers decreased over time despite access to the vaccine being constantly improved. The aim of this paper is to provide a comparative analysis of the knowledge and attitudes of Dental Medicine and Medicine students towards recommended vaccinations for healthcare workers, focusing on influenza vaccination. A cross-sectional study was conducted during the entire 2021-2022 academic year. Data were collected using 2 electronic questionnaires which were applied to the students from the Faculty of Medicine (n = 883) and, respectively, the Faculty of Dental Medicine of the Carol Davila University of Medicine and Pharmacy, Bucharest, Romania. The questionnaires were offered to 1187 students and completed by 911 students (response rate = 77%). Out of these, 85% (n = 778) identified the influenza vaccine as recommended; 35% (n = 321) reported getting an annual influenza vaccination; and 37% (333) reported getting an influenza vaccination in the previous season. Overall, 45% (n = 222) of the respondents who completed the questionnaires from October 2021 to February 2022 reported that they intend to get vaccinated against influenza in the 2021-2022 season and approximately 8% (n = 39) reported that they had already been vaccinated. The multivariable analysis showed that the habit of getting annually vaccinated against influenza as well as the knowledge that influenza vaccine is recommended for all healthcare workers were associated with a higher probability of intending to get vaccinated. The current study emphasizes the need to raise awareness among medical students regarding influenza vaccination and to involve medical education institutions, public health authorities, and healthcare facilities in promoting this vaccination among students since the influenza vaccine uptake rate among medical students included in this study was suboptimal.