Influenza Vaccination In Older Adults Research Articles

Safety and Immunogenicity of Respiratory Syncytial Virus Prefusion F Protein Vaccine when Co-administered with Adjuvanted Seasonal Quadrivalent Influenza Vaccine in Older Adults: A Phase 3 Randomized Trial.

We evaluated co-administration of adjuvanted seasonal quadrivalent influenza vaccine (FLU-aQIV) and respiratory syncytial virus (RSV) prefusion F protein-based vaccine (RSVPreF3 OA) in ≥65-year-olds. This phase 3, open-label trial randomized ≥65-year-olds to receive FLU-aQIV and RSVPreF3 OA concomitantly (Co-Ad) or sequentially, 1 month apart (Control). Primary objectives were to demonstrate the non-inferiority of FLU-aQIV and RSVPreF3 OA co-administration versus sequential administration in terms of hemagglutination inhibition (HI) titers for each FLU-aQIV strain and RSV-A and RSV-B neutralization titers, 1 month post-vaccination. Reactogenicity and safety were also assessed. Overall, 1045 participants were vaccinated (Co-Ad: 523; Control: 522). Non-inferiority of FLU-aQIV and RSVPreF3 OA co-administration versus sequential administration was demonstrated in terms of HI titers for the A/Victoria(H1N1), B/Victoria, and B/Yamagata influenza strains and RSV-A neutralization titers (upper limits [ULs] of 95% confidence intervals [CIs] for adjusted geometric mean titer [GMT] ratios [Control/Co-Ad] ≤1.50) but not for A/Darwin(H3N2) HI titers (95% CI UL = 1.53). The immune response to A/Darwin(H3N2) was further assessed post-hoc using a microneutralization assay; the post-vaccination adjusted GMT ratio (Control/Co-Ad) was 1.23 (95% CI: 1.06-1.42, ie, UL ≤1.50), suggesting an adequate immune response to A/Darwin(H3N2) following co-administration. RSV-B neutralization titers were comparable between groups (95% CI UL for adjusted GMT ratio ≤1.50). Solicited adverse events were mostly mild or moderate and transient; unsolicited and serious adverse event rates were balanced between groups. Adjuvanted FLU-aQIV and RSVPreF3 OA had acceptable reactogenicity/safety profiles when co-administered in ≥65-year-olds, without clinically relevant interference with the immune responses to either vaccine. NCT05568797.

Stroke After Influenza Vaccines in Older Adults in the US, 2016 to 2019.

This case series investigates whether an increase in stroke risk occurred after influenza vaccination among fee-for-service Medicare beneficiaries during the influenza seasons from 2016 to 2019.

Cost-effectiveness of the adjuvanted quadrivalent influenza vaccine for older adults in South Korea

ABSTRACT South Korea’s National Immunization Program administers the quadrivalent influenza vaccine (QIV) to manage seasonal influenza, with a particular focus on the elderly. After reviewing the safety and immune response triggered by the adjuvanted QIV (aQIV) in individuals aged 65 and older, the Ministry of Food and Drug Safety in Korea approved its use. However, the extensive impact of aQIV on public health is yet to be fully understood. This study assessed the cost-effectiveness of replacing QIV with aQIV in South Korean adults aged 65 years and older. A dynamic transmission model, calibrated with national influenza data, was applied to compare the influence of aQIV and QIV on older adults and the broader population throughout a single influenza season. This study considered both the direct and indirect effects of vaccination on the elderly. We derived the incremental cost-effectiveness ratios (ICERs) from quality-adjusted life-years (QALYs) and costs incurred, validated through a probabilistic sensitivity analysis with 5,000 simulations. Findings suggest that transitioning to aQIV from QIV in the elderly would be cost-effective, particularly if aQIV’s efficacy reaches or exceeds 56.1%. With an ICER of $29,267/QALY, considerably lower than the $34,998/QALY willingness-to-pay threshold, aQIV presents as a cost-effective option. Thus, implementing aQIV with at least 56.1% efficacy is beneficial from both financial and public health perspectives in mitigating seasonal influenza in South Korea.

Impact of influenza vaccination history in the clinical course of older adults hospitalized with COVID-19

Background and purposeSome studies have shown that influenza vaccination is associated with a lower risk of SARS-CoV-2 infection; in patients with COVID-19 infection, admission to intensive care is reduced, with less need for mechanical ventilation, shorter hospital stays, and reduced mortality. This study aimed to determine if a history of annual influenza vaccination impacts the clinical course of SARS-CoV-2 infection during hospitalization. MethodsThis was an observational, prospective, cohort study of patients older than 65 admitted to the COVID-19 unit from January to June 2021. The history of influenza vaccination over the last 5 years was assessed in each patient during hospitalization. We measured the length of hospital stay, the need for admission to the intensive care unit (ICU), the patient's oxygen requirements, complications during hospitalization, and outcome (medical discharge or death). Patients with a history of vaccination against SARS-CoV-2 were not included. ResultsWe analyzed 125 patients, 50.4% (n=63) with history of influenza vaccination and 49.6% (n=62) without a history of influenza vaccination. In-hospital mortality was 44.8%, higher in the unvaccinated (54.8%) population (p=0.008). ICU admission was 27% higher in vaccinated (35%) patients (p=0.05). Patients without a history of influenza vaccination had a higher prevalence of cardiac (8% vs. 5%, p=0.04) and renal complications (29% vs. 13%, p=0.02). Patients with a history of vaccination had a greater need for invasive mechanical ventilation (25.4%, p=0.02). ConclusionIn this study, a history of influenza vaccination in older adults with SARS-CoV-2 infection was related to lower in-hospital mortality.

Immunogenicity of Enhanced Influenza Vaccines Against Mismatched Influenza Strains in Older Adults: A Review of Randomized Controlled Trials.

Antigenic drift is a major driver of viral evolution and a primary reason why influenza vaccines must be reformulated annually. Mismatch between vaccine and circulating viral strains negatively affects vaccine effectiveness and often contributes to higher rates of influenza-related hospitalizations and deaths, particularly in years dominated by A(H3N2). Several countries recommend enhanced influenza vaccines for older adults, who are at the highest risk of severe influenza complications and mortality. The immunogenicity of enhanced vaccines against heterologous A(H3N2) strains has been examined in nine studies to date. In six studies, an enhanced, licensed MF59-adjuvanted trivalent inactivated influenza vaccine (aIIV3) consistently increased heterologous antibody titers relative to standard influenza vaccine, with evidence of a broad heterologous immune response across multiple genetic clades. In one study, licensed high-dose trivalent inactivated influenza vaccine (HD-IIV3) also induced higher heterologous antibody titers than standard influenza vaccine. In a study comparing a higher dose licensed quadrivalent recombinant influenza vaccine (RIV4) with HD-IIV3 and aIIV3, no significant differences in antibody titers against a heterologous strain were observed, although seroconversion rates were higher with RIV4 versus comparators. With the unmet medical need for improved influenza vaccines, the paucity of studies especially with enhanced vaccines covering mismatched strains highlights a need for further investigation of cross-protection in older adults.

Podcast: Need for Quality Evidence for Decision-Making on Seasonal Influenza Vaccines.

Seasonal influenza is usually considered an acute respiratory infection with a full recovery within a week. In addition to the traditional outcomes, there is now evidence of indirect effects in terms of neurological and functional complications. Major organ systems can be affected, underlining the need for preventative measures against infection. The aim of this podcast, featuring Dr. Ann Falsey, Dr. Stefania Maggi, and Dr. Tor Biering-Sørensen, is to outline influenza complications beyond acute respiratory disease, as well as discussing the need for quality of evidence when evaluating influenza vaccines. Assessing the benefits of vaccination can be challenging. To ensure a high quality of evidence, the innovative randomization of patients within the study design to avoid bias and the assessment of additional outcomes beyond immunogenicity as well as the inclusion of a broad population-including frail or vulnerable individuals-are essential. Studies leveraging nationwide registries such as the DANFLU-2 trial in Denmark highlight the advantages of a digitalized healthcare system for conducting large-scale randomized trials. Furthermore, large-scale trials such as the Gravenstein study have supplied a sizable body of evidence supporting the use of high-dose influenza vaccine in older adults. In conclusion, achieving a high quality of evidence is key for decision-making on seasonal influenza vaccines.

Immunogenicity, Reactogenicity, and Safety of AS01E-adjuvanted RSV Prefusion F Protein-based Candidate Vaccine (RSVPreF3 OA) When Co-administered With a Seasonal Quadrivalent Influenza Vaccine in Older Adults: Results of a Phase 3, Open-Label, Randomized Controlled Trial.

Co-administration of vaccines against respiratory syncytial virus (RSV) and influenza can be considered given their overlapping seasonality, and may increase vaccine uptake and compliance. In this phase 3, open-label, randomized study, we evaluated the immunogenicity, reactogenicity, and safety of the AS01E-adjuvanted RSV prefusion F protein-based candidate vaccine (RSVPreF3 OA) when co-administered with a seasonal quadrivalent influenza vaccine (FLU-QIV) in older adults. Participants aged ≥60 years (randomized 1:1) received either RSVPreF3 OA and FLU-QIV simultaneously on day 1 (Co-Ad group) or FLU-QIV on day 1 followed by RSVPreF3 OA on day 31 (sequential administration [SA] group). The co-primary objectives were to demonstrate noninferiority of RSVPreF3 OA in terms of RSV-A neutralization geometric mean titer (GMT) ratio and FLU-QIV in terms of hemagglutination inhibition GMT ratio for each FLU-QIV strain, when co-administered versus when administered alone at 1-month post-vaccination. Noninferiority was demonstrated if the upper limit of the 95% confidence interview of the group GMT ratio (SA/Co-Ad) was ≤1.5. Secondary descriptive objectives comprised additional immunogenicity assessments, reactogenicity, and safety. Of the 885 participants who received one dose of the study vaccines, 837 were included in the per protocol set. Demographic and baseline characteristics were balanced between the groups. Both co-primary objectives were met for both vaccines. Reported adverse events in both groups were mild-to-moderate, with a low frequency of grade 3 events. Data from this study demonstrate that RSVPreF3 OA can be co-administered with FLU-QIV. Co-administration is well tolerated, with an acceptable safety profile. NCT04841577.

A clinical and economic assessment of adjuvanted trivalent versus standard egg-derived quadrivalent influenza vaccines among older adults in the United States during the 2018-19 and 2019-20 influenza seasons

ABSTRACT Background Clinical evidence supports use of enhanced influenza vaccines in older adults. Few economic outcome studies have compared adjuvanted trivalent inactivated (aIIV3) and standard egg-derived quadrivalent inactivated influenza vaccines (IIV4e). Research Design and Methods A retrospective cohort study was conducted leveraging deidentified US hospital data linked to claims data during the 2018–19 and 2019–20 influenza seasons. Relative vaccine effectiveness (rVE) was compared in adults aged ≥ 65 years receiving aIIV3 or IIV4e using inverse probability of treatment weighting (IPTW) and Poisson regression. An economic assessment quantified potential real-world cost savings. Results The study included 715,807 aIIV3 and 320,991 IIV4e recipients in the 2018–19 and 844,169 aIIV3 and 306,270 IIV4e recipients in the 2019–20 influenza seasons. aIIV3 was significantly more effective than IIV4e in preventing cardiorespiratory disease (2018–19 rVE = 6.2%; and 2019–20 rVE = 6.0%) and respiratory disease (2018–19 rVE = 8.9%; and 2019–20 rVE = 10.1%). During the 2018–19 influenza season cardiorespiratory hospitalization cost savings for the aIIV3 population were $392 M, and $221 M for the 2019–20 season. Respiratory hospitalization cost savings for the aIIV3 population were $145 M and $97 M, respectively. Conclusions Our findings suggest that aIIV3 provides clinical and economic advantages versus IIV4e in the elderly.

Excessive daytime sleepiness is associated with impaired antibody response to influenza vaccination in older male adults.

The reduced effectiveness of standard-dose influenza vaccines in persons ≥65 years of age led to the preferential recommendation to use high-dose (HDFlu) or MF59-adjuvanted (MF59Flu) vaccines for this age group. Sleep is an important modulator of immune responses to vaccines and poor sleep health is common in older adults. However, potential effects of poor sleep health on immune responses to influenza vaccination in older adults remain largely unknown. We conducted a cohort study of 210 healthy participants age ≥65 years, who received either seasonal high-dose (HDFlu) or MF59-adjuvanted (MF59Flu) influenza vaccine. We assessed sleep characteristics in this cohort by standardized questionnaires and measured the antibody titer against influenza A/H3N2 virus in serum of study participants by hemagglutination inhibition assay on the day of immunization and 28 days thereafter. We then assessed the association between sleep characteristics and antibody titers. Our results demonstrated that male, but not female, study participants with excessive daytime sleepiness had an impaired influenza A/H3N2-specific antibody response at Day 28 post-vaccination. No other associations were found between antibody titer and other sleep characteristics, including sleep quality and obstructive sleep apnea. Our results provide an additional and easily measured variable explaining poor vaccine effectiveness in older adults. Our results support that gaining sufficient sleep is a simple non-vaccine interventional approach to improve influenza immune responses in older adults. Our findings extend the literature on the negative influence of excessive daytime sleepiness on immune responses to influenza vaccination in older male adults.

Ocular Adverse Events After Influenza Vaccination in Older Adults: Self-Controlled Case Series Using a Large Database in Japan

ABSTRACT Background To clarify the risk of adverse ocular events following influenza vaccination. Methods This self-controlled case series study used a claims database linked to vaccination records of a large city in Japan between April 2014 and September 2021. Individuals aged ≥ 65 years who developed adverse ocular events during the follow-up period were included. The exposure was influenza vaccination. The primary outcome was defined as the occurrence of at least one of the following five eye diseases: uveitis, scleritis, retinal vein occlusion, retinal artery occlusion, or optic neuritis. Conditional Poisson regression was used to estimate the within-subject incidence rate ratio of ocular adverse events during the risk period (0–56 days after vaccination) compared to the control period. Results A total of 4,527 cases were eligible for the study (median age, 74 years; male, 42%). The incidence rate ratio for the outcome during the risk period was 0.99 (95% confidence interval, 0.87 to 1.14). No increased risk was observed for individual components of the outcome either; the incidence rate ratio was 0.94 (0.78 to 1.13) for uveitis, 1.17 (0.86 to 1.59) for scleritis, 0.98 (0.76 to 1.27) for retinal vein occlusion, 0.89 (0.42 to 1.87) for retinal artery occlusion, and 0.87 (0.44 to 1.70) for optic neuritis. Conclusions This self-controlled case series showed no apparent increase in the risk of adverse ocular events after influenza vaccination among older adults. These results mitigate the concerns of older adults who may hesitate to receive influenza vaccination for fear of adverse ocular events. Abbreviation HR = hazard ratio; CI = confidence interval; RVO = retinal vein occlusion; SCCS = self-controlled case series

Supplemental Material for Optimizing Mood Prior to Influenza Vaccination in Older Adults: A Three-Arm Randomized Controlled Trial

Supplemental Material for Optimizing Mood Prior to Influenza Vaccination in Older Adults: A Three-Arm Randomized Controlled Trial

Influenza vaccination in older adults and patients with chronic disorders: A position paper from the Portuguese Society of Pulmonology, the Portuguese Society of Cardiology, the Portuguese Society of Diabetology, the Portuguese Society of Infectious Diseases and Clinical Microbiology, the Portuguese Society of Geriatrics and Gerontology, and the Study Group of Geriatrics of the Portuguese Society of Internal Medicine

Influenza affects millions of people worldwide each year and can lead to severe complications, hospitalizations, and even death, especially among vulnerable populations such as older adults and those with chronic medical conditions. Annual vaccination is considered the most effective measure for preventing influenza and its complications. Despite the widespread availability of influenza vaccines, however, vaccination coverage rates remain suboptimal in several countries. Based on the latest scientific evidence and expert opinions on influenza vaccination in older people and patients with chronic disease, the Portuguese Society of Pulmonology (SPP), the Portuguese Society of Diabetology (SPD), the Portuguese Society of Cardiology (SPC), the Portuguese Society of Geriatrics and Gerontology (SPGG), the Study Group of Geriatrics of the Portuguese Society of Internal Medicine (NEGERMI-SPMI), and the Portuguese Society of Infectious Diseases and Clinical Microbiology (SPDIMC) discussed best practices for promoting vaccination uptake and coverage and drew up several recommendations to mitigate the impact of influenza. These recommendations focus on the efficacy and safety of available vaccines; the impact of influenza vaccination on older adults; patients with chronic medical conditions, namely cardiac and respiratory conditions, diabetes, and immunosuppressive diseases; and health care professionals, optimal vaccination timing, and strategies to increase vaccination uptake and coverage. The resulting position paper highlights the critical role that vaccinations play in promoting public health, raising awareness, and encouraging more people to get vaccinated.

Safety and Immunogenicity of Bivalent RSVpreF Vaccine Coadministered With Seasonal Inactivated Influenza Vaccine in Older Adults.

Respiratory syncytial virus (RSV) and influenza are both typically seasonal diseases, with winter peaks in temperate climates. Coadministration of an RSV vaccine and influenza vaccine could be a benefit, requiring 1 rather than 2 visits to a healthcare provider for individuals receiving both vaccines. The primary immunogenicity objective of this phase 3, 1:1 randomized, double-blind, placebo-controlled study in healthy adults aged ≥65 years in Australia was to demonstrate noninferiority of immune responses with coadministration of the stabilized RSV prefusion F protein-based vaccine (RSVpreF) and seasonal inactivated influenza vaccine (SIIV) versus SIIV or RSVpreF administered alone, using a 1.5-fold noninferiority margin (lower bound 95% confidence interval >.667). Safety and tolerability were evaluated by collecting reactogenicity and adverse event data. Of 1403 participants randomized, 1399 received vaccinations (median age, 70; range, 65‒91 years). Local reactions and systemic events were mostly mild or moderate when RSVpreF was coadministered with SIIV or administered alone. No vaccine-related serious adverse events were reported. Geometric mean ratios were 0.86 for RSV-A and 0.85 for RSV-B neutralizing titers at 1 month after RSVpreF administration and 0.77 to 0.90 for strain-specific hemagglutination inhibition assay titers at 1 month after SIIV. All comparisons achieved the prespecified 1.5-fold noninferiority margin. The primary study objectives were met, demonstrating noninferiority of RSVpreF and SIIV immune responses when RSVpreF was coadministered with SIIV and that RSVpreF had an acceptable safety and tolerability profile when coadministered with SIIV. The results of this study support coadministration of RSVpreF and SIIV in an older-adult population. https://clinicaltrials.gov/study/NCT05301322.

The intersection of biological sex and gender in adverse events following seasonal influenza vaccination in older adults

BackgroundWomen/females report more adverse events (AE) following immunization than men/males for many vaccines, including the influenza and COVID-19 vaccines. This discrepancy is often dismissed as a reporting bias, yet the relative contributions of biological sex and gender are poorly understood. We investigated the roles of sex and gender in the rate of AE following administration of the high-dose seasonal influenza vaccine to older adults (≥ 75 years) using an AE questionnaire administered 5–8 days post-vaccination. Participant sex (male or female) was determined by self-report and a gender score questionnaire was used to assign participants to one of four gender categories (feminine, masculine, androgynous, or undifferentiated). Sex steroid hormones and inflammatory cytokines were measured in plasma samples collected prior to vaccination to generate hypotheses as to the biological mechanism underpinning the AE reported.ResultsA total of 423 vaccines were administered to 173 participants over four influenza seasons (2019-22) and gender data were available for 339 of these vaccinations (2020-22). At least one AE was reported following 105 vaccinations (25%), by 23 males and 82 females. The majority of AE occurred at the site of injection, were mild, and transient. The odds of experiencing an AE were 3-fold greater in females than males and decreased with age to a greater extent in females than males. The effects of gender, however, were not statistically significant, supporting a central role of biological sex in the occurrence of AE. In males, estradiol was significantly associated with IL-6 and with the probability of experiencing an AE. Both associations were absent in females, suggesting a sex-specific effect of estradiol on the occurrence of AE that supports the finding of a biological sex difference.ConclusionsThese data support a larger role for biological sex than for gender in the occurrence of AE following influenza vaccination in older adults and provide an initial investigation of hormonal mechanisms that may mediate this sex difference. This study highlights the complexities of measuring gender and the importance of assessing AE separately for males and females to better understand how vaccination strategies can be tailored to different subsets of the population.

Immunogenicity of adjuvanted versus high-dose inactivated influenza vaccines in older adults: a randomized clinical trial

BackgroundAdjuvanted inactivated influenza vaccine (aIIV) and high-dose inactivated influenza vaccine (HD-IIV) are U.S.-licensed for adults aged ≥ 65 years. This study compared serum hemagglutination inhibition (HAI) antibody titers for the A(H3N2) and A(H1N1)pdm09 and B strains after trivalent aIIV3 and trivalent HD-IIV3 in an older adult population.ResultsThe immunogenicity population included 342 participants who received aIIV3 and 338 participants who received HD-IIV3. The proportion of participants that seroconverted to A(H3N2) vaccine strains after allV3 (112 participants [32.8%]) was inferior to the proportion of participants that seroconverted after HD-IIV3 (130 participants [38.5%]) at day 29 after vaccination (difference, − 5.8%; 95%CI, − 12.9% to 1.4%). There were no significant differences between the vaccine groups in percent seroconversion to A(H1N1)pdm09 or B vaccine strains, in percent seropositivity for any of the strains, or in post-vaccination GMT for the A(H1N1)pdm09 strain. The GMTs for the post-vaccination A(H3N2) and B strains were higher after HD-IIV than after aIIV3.ConclusionsOverall immune responses were similar after aIIV3 and HD-IIV3. For the primary outcome, the aIIV3 seroconversion rate for H3N2 did not meet noninferiority criteria compared with HD-IIV3, but the HD-IIV3 seroconversion rate was not statistically superior to the aIIV3 seroconversion rate.Trial registrationClinicalTrials.gov Identifier: NCT03183908.

Real-World Evidence in Cost-Effectiveness Analysis of Enhanced Influenza Vaccines in Adults ≥ 65 Years of Age: Literature Review and Expert Opinion.

Influenza vaccination can benefit most populations, including adults ≥ 65 years of age, who are at greater risk of influenza-related complications. In many countries, enhanced vaccines, such as adjuvanted, high-dose, and recombinant trivalent/quadrivalent influenza vaccines (aTIV/aQIV, HD-TIV/HD-QIV, and QIVr, respectively), are recommended in older populations to provide higher immunogenicity and increased relative vaccine efficacy/effectiveness (rVE) than standard-dose vaccines. This review explores how efficacy and effectiveness data from randomized controlled trials and real-world evidence (RWE) are used in economic evaluations. Findings from published cost-effectiveness analyses (CEA) on enhanced influenza vaccines for older adults are summarized, and the assumptions and approaches used in these CEA are assessed alongside discussion of the importance of RWE in CEA. Results from many CEA showed that adjuvanted and high-dose enhanced vaccines were cost-effective compared with standard vaccines, and that differences in rVE estimates and acquisition price may drive differences in cost-effectiveness estimates between enhanced vaccines. Overall, RWE and CEA provide clinical and economic rationale for enhanced vaccine use in people ≥ 65 years of age, an at-risk population with substantial burden of disease. Countries that consider RWE when making vaccine recommendations have preferentially recommended aTIV/aQIV, as well as HD-TIV/HD-QIV and QIVr, to protect older individuals.

High-dose influenza vaccine in older adults by age and seasonal characteristics: Systematic review and meta-analysis update

This updated systematic review and meta-analysis of randomized and observational studies published up to April 2023 assessed the relative performance of high-dose inactivated influenza vaccine (HD-IIV) and standard-dose influenza vaccines (SD-IIV) against influenza-associated outcomes in older adults (≥65 years).The analysis included studies conducted over 12 influenza seasons (2009/2010 to 2019/2020, 2021/2022), including over 45 million individuals aged ≥ 65 years, and showed that HD-IIV provided significantly better protection than SD-IIV against influenza-like illness and influenza-related hospitalizations, as well as cardiovascular, cardiorespiratory, and all-cause hospitalizations. Subgroup analyses showed HD-IIV consistently provided better protection than SD-IIV against influenza outcomes across the age range (65+, 75+ 85+ years), and regardless of the predominantly circulating influenza strain and vaccine antigenic match/mismatch.Randomized studies continue to drive high-quality evidence on the effectiveness of high-dose inactivated influenza vaccine relative to SD-IIV against severe influenza outcomes in adults aged ≥ 65 years, supported by observational data.

Cost-Effectiveness of the Use of Adjuvanted Quadrivalent Seasonal Influenza Vaccine in Older Adults in Ireland.

Enhanced vaccines (e.g., containing adjuvants) have shown increased immunogenicity and effectiveness in older adults, who often respond sub-optimally to conventional influenza vaccines. In this study, we evaluated the cost-effectiveness of an inactivated, seasonal, MF59-adjuvanted quadrivalent influenza vaccine (aQIV) for use in adults ≥ 65 years in Ireland. A published dynamic influenza model incorporating social contact, population immunity, and epidemiological data was used to assess the cost-effectiveness of aQIV in adults ≥ 65 years of age compared with a non-adjuvanted QIV. Sensitivity analysis was performed for influenza incidence, relative vaccine effectiveness, excess mortality, and the impact on bed occupancy from co-circulating influenza and COVID-19. The use of aQIV resulted in discounted incremental cost-effectiveness ratios (ICERs) of EUR 2420/quality-adjusted life years (QALYs) and EUR 12,970/QALY from societal and payer perspectives, respectively, both of which are below the cost-effectiveness threshold of EUR 45,000/QALY. Sensitivity analysis showed that aQIV was effective in most scenarios, except when relative vaccine effectiveness compared to QIV was below 3%, and resulted in a modest reduction in excess bed occupancy. The use of aQIV for adults ≥ 65 years old in Ireland was shown to be highly cost-effective from both payer and societal perspectives.

Association of Influenza Vaccination and Dementia Risk: A Meta-Analysis of Cohort Studies.

Dementia is a critical global public health problem. Previous cohort studies have found that influenza vaccination can decrease the risk of dementia. This meta-analysis aimed to systematically examine the relationship between influenza vaccination and dementia risk. We searched PubMed, Embase, Web of Science, ScienceDirect, medRxiv, and bioRxiv for studies investigating dementia risk based on influenza vaccination status, up to September 14, 2022. Relative risks (RRs) and 95% confidence intervals (95% CIs) were pooled in the meta-analysis. Subgroup analyses and sensitivity analyses were conducted as well. Of the 4,087 articles initially reviewed, 6 cohort studies were included in the final meta-analysis, and all eligible studies were at low risk of bias. There were 2,087,195 participants without dementia at baseline (mean age: 61.8-75.5 years, 57.05% males), and 149,804 (7.18%) cases of dementia occurred during 4.00-13.00 years of follow-up. Pooled analysis of adjusted RRs found that influenza vaccination could reduce dementia risk by 31% (RR = 0.69, 95% CI: 0.57-0.83). Subgroup analyses showed that in the study with a mean age of 75-80 years or 75%-100% males, the association was generally weakened compared with studies with a mean age of 60-75 years or 25%-50% males. The results were stable in the sensitivity analyses, and no publication bias was observed. Influenza vaccination in older adults was markedly associated with a decreased risk of dementia. More mechanistic studies and epidemiological studies are needed to clarify the association between influenza vaccination and decreased dementia risk.

Effect of a nationwide intervention of electronic letters with behavioural nudges on influenza vaccination in older adults in Denmark

Worldwide influenza epidemics result in an estimated 3–5 million cases of severe illness, and 290 000–650 000 respiratory deaths annually. 1 WHOInfluenza (seasonal). World Health Organization. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)Date accessed: February 19, 2023 Google Scholar Influenza also leads to high costs from direct medical expenses and lost productivity. 2 Putri W Muscatello DJ Stockwell MS Newall AT Economic burden of seasonal influenza in the United States. Vaccine. 2018; 36: 3960-3966 Crossref PubMed Scopus (212) Google Scholar Influenza vaccination is the single most important preventive measure against influenza, and as such is recommended worldwide. 1 WHOInfluenza (seasonal). World Health Organization. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)Date accessed: February 19, 2023 Google Scholar Adults aged 65 years or older are at particularly high risk for severe outcomes related to influenza. 1 WHOInfluenza (seasonal). World Health Organization. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)Date accessed: February 19, 2023 Google Scholar However, annual vaccination rates of older adults vary globally from less than 10% up to 80%. 3 Organisation for Economic Co-operation and DevelopmentInfluenza vaccination rates. https://data.oecd.org/healthcare/influenza-vaccination-rates.htmDate accessed: February 19, 2023 Google Scholar Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trialElectronically delivered letters highlighting potential cardiovascular benefits of influenza vaccination or sent again as a reminder significantly increased vaccination uptake across Denmark. Although the magnitude of effectiveness was modest, the low-touch, inexpensive, and highly scalable nature of these electronic letters might be informative for future public health campaigns. Full-Text PDF