INfluenza VaccInation To mitigate typE 1 Diabetes (INVITED): a study protocol for a randomised, double-blind, placebo-controlled clinical trial in children and adolescents with recent-onset type 1 diabetes.

INTRODUCTION: Children and adolescents with recent-onset type 1 diabetes (T1D) commonly maintain a certain level of insulin production during the remission phase, which can last months to years. Preserving ß-cell function can reduce T1D complications and improve glycaemic control. Influenza vaccination has pleiotropic effects and administration of the vaccine during the early phases of T1D may offer ß-cell protection. This study aims to assess the effect of influenza vaccination on preserving ß-cell function in children and adolescents with recent-onset T1D. METHODS AND ANALYSIS: The INfluenza VaccInation To mitigate typE 1 Diabetes trial is a randomised, double-blind, placebo-controlled, multicentre trial in paediatric patients with recent-onset T1D aged 7-17 years. 100 participants will be randomised in a 1:1 ratio to receive either a standard inactivated quadrivalent influenza vaccine or a placebo within 14 days of diagnosis. The primary outcome is a difference in mean change (from baseline to 12 months) in C-peptide level between groups during a 2-hour mixed-meal tolerance test. Secondary outcomes include mean change (from baseline to 6 months) in C-peptide levels, haemoglobin A1c, ambulatory glucose profiles and insulin requirements. Exploratory outcomes are diabetes-related autoantibodies, inflammatory markers and serum haemagglutinin inhibition antibody titres against the influenza viruses. The current treatment for T1D is largely symptomatic, relying on insulin administration. There is a pressing need for novel pharmacological approaches aimed at modulating the immune system to preserve residual ß-cell function. Existing immunotherapies are cost-prohibitive and associated with multiple side effects, whereas influenza vaccination is inexpensive and generally well tolerated. A positive outcome of this study holds potential for immediate implementation into standard care for children and adolescents with recent-onset T1D and may guide future research on immune modulation in T1D. ETHICS AND DISSEMINATION: Ethical approval was obtained from Danish Health Authorities prior to participant enrollment. The trial results will be submitted to a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT05585983 and EudraCT Number 2022-500906-17-01.

Comparison of the influenza vaccination coverage among high-risk people between the online registration system and walk-in service system in Bangkok, Thailand.

Until recently, the Thai national program of seasonal influenza vaccination for high-risk people has been using a walk-in service system. However, in 2020, an online registration system was introduced in Bangkok to improve vaccine coverage. This study aimed to compare the coverage of influenza vaccination between the walk-in service and online registration systems. The study participants included 374,710 Thai individuals who obtained an influenza vaccination from the national program in the Bangkok health region in 2018 (n = 162,214) and in 2020 (n = 212,496). The registration systems that were examined were the walk-in service system in 2018 and the online registration system in 2020. The characteristics of vaccine recipients and the vaccine coverage in each risk group and health facility level were compared between the two systems. Coverage comparison in Bangkok between the years 2018 and 2020 showed an increase in coverage, particularly among individuals who had an influenza vaccination at health facilities of the primary level and in the elderly and obesity groups. The coverage among children was lowest among all high-risk groups. To improve coverage in Thailand, the online registration system should be introduced in all regions. Additionally, information about influenza vaccination for children should be disseminated to parents using handbooks or by word-of-mouth from healthcare workers.

Inter- and intra-individual differences regarding SARS-CoV-2 and influenza vaccination in pediatric kidney transplant recipients: An observational study.

In kidney transplant recipients (KTRs), viral infection can lead to antibody and/or T-cell mediated rejection, resulting in kidney transplant dysfunction. Therefore, it is critical to prevent infections. However, KTRs exhibit suboptimal responses to SARS-CoV-2 and/or influenza vaccines, partly due to immunosuppressant therapy. Inter- and intra-individual differences in the biological responses to vaccines may also affect patients' antibody production ability. This study included KTRs who received an messenger RNA SARS-CoV-2 vaccine (3 doses), and an inactivated quadrivalent influenza vaccine (1 or 2 doses). We measured the patients' total antibody titers against SARS-CoV-2 spike antigen, and hemagglutination inhibition (HI) titers against influenza A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Five patients were eligible for this study. Of these 5 KTRs, two produced anti-SARS-CoV-2 spike antibody titers to a seroprotective level, and also produced HI titers against A/H1N1 to a seroprotective level. Another 2 KTRs did not produce seroprotective anti-SARS-CoV-2 antibody titers, but produced seroprotective HI titers against A/H1N1. The remaining KTR produced a seroprotective anti-SARS-CoV-2 antibody titer, but did not produce a seroprotective HI titer against A/H1N1. The 2 KTRs who did not produce seroprotective anti-SARS-CoV-2 antibody titers following vaccination, later developed COVID-19, and this infection increased their titers over the seroprotective level. This study demonstrated that inter- and intra-individual differences in biological responses to vaccines should be considered in pediatric KTRs, in addition to immunosuppressant effects. Personalized regimens, such as augmented or booster doses of vaccines, could potentially improve the vaccination efficacy against SARS-CoV-2 and influenza.

Characteristics and factors of repeated influenza vaccination among elderly individuals in Shanghai, China from 2020 to 2022.

Elderly individuals face a high risk of hospitalization and death related to influenza, thus prioritizing them for influenza vaccination. Due to variations in the influenza virus and waning protective antibodies, annual influenza vaccination is recommended. However, research on repeated influenza vaccination among elderly individuals in China is limited. From 2020 to 2022, the average influenza vaccination coverage among registered elderly individuals in Shanghai was 4.1%, showing a declining trend over time. In 2020, the rate of repeated influenza vaccination among elderly individuals was 28.35%, which rose to almost two-thirds both in 2021 and 2022. No increased risk of adverse events following immunization was observed after repeated influenza vaccination during this period. Our study also found that elderly individuals with Shanghai household registration, managed by community clinics, and older age tended to receive more doses of repeated influenza vaccination throughout the period from 2020 to 2022. Increasing influenza vaccine coverage among elderly individuals in Shanghai is both urgent and challenging. Health authorities should intensify educational and promotional campaigns to encourage uptake of annual repeated influenza vaccination among elderly individuals.

Association Between Influenza Vaccination and SARS-CoV-2 Infection.

BACKGROUND: Recent data in nonpregnant individuals suggest a protective effect of influenza vaccination against SARS-CoV-2 infection and its severity. OBJECTIVES: Our primary objective was to evaluate whether influenza vaccination was associated with COVID-19 severity and pregnancy and neonatal outcomes among those infected with SARS-CoV-2. The secondary objective was to examine the association between influenza vaccination and SARS-CoV-2 infection. STUDY DESIGN: Secondary analysis of a multicenter retrospective cohort of pregnant people who tested positive for SARS-CoV-2 between March and August 2020, and a cohort of random deliveries during the same time period. The associations between 2019 influenza vaccination and the primary outcome of moderate-to-critical COVID-19 as well as maternal and perinatal outcomes were examined among all people who tested positive for SARS-CoV-2 between March and August 2020. The association between 2019 influenza vaccination and having a positive SARS-CoV-2 test was examined among a cohort of individuals who delivered on randomly selected dates between March and August 2020. Univariable and multivariable analyses were performed. RESULTS: Of 2325 people who tested positive for SARS-CoV-2, 1068 (45.9%) were vaccinated against influenza in 2019. Those who received the influenza vaccine were older, leaner, more likely to have private insurance, and identify as White or Hispanic. They were less likely to smoke tobacco and identify as Black. Overall, 419 (18.0%) had moderate, 193 (8.3%) severe, and 52 (2.2%) critical COVID-19. There was no association between influenza vaccination and moderate-to-critical COVID-19 (29.2% vs. 28.0%, adjusted OR 1.10, 95% CI 0.90-1.34) or adverse maternal and perinatal outcomes among those who tested positive. Of 8152 people who delivered in 2020, 4658 (57.1%) received the influenza vaccine. Prior vaccination was not associated with a difference in the odds of SARS-CoV-2 infection (3.8% vs. 4.2%, adjusted OR 0.94, 95% CI 0.74-1.19). CONCLUSION: Prior influenza vaccination was not associated with decreased severity of COVID-19 or lower odds of SARS-CoV-2 infection in pregnancy.

Filling two needs with one deed: a combinatory mucosal vaccine against influenza A virus and respiratory syncytial virus.

Influenza A Virus (IAV) and Respiratory Syncytial Virus (RSV) are both responsible for millions of severe respiratory tract infections every year worldwide. Effective vaccines able to prevent transmission and severe disease, are important measures to reduce the burden for the global health system. Despite the strong systemic immune responses induced upon current parental immunizations, this vaccination strategy fails to promote a robust mucosal immune response. Here, we investigated the immunogenicity and efficacy of a mucosal adenoviral vector vaccine to tackle both pathogens simultaneously at their entry site. For this purpose, BALB/c mice were immunized intranasally with adenoviral vectors (Ad) encoding the influenza-derived proteins, hemagglutinin (HA) and nucleoprotein (NP), in combination with an Ad encoding for the RSV fusion (F) protein. The mucosal combinatory vaccine induced neutralizing antibodies as well as local IgA responses against both viruses. Moreover, the vaccine elicited pulmonary CD8+ and CD4+ tissue resident memory T cells (TRM) against the immunodominant epitopes of RSV-F and IAV-NP. Furthermore, the addition of Ad-TGFß or Ad-CCL17 as mucosal adjuvant enhanced the formation of functional CD8+ TRM responses against the conserved IAV-NP. Consequently, the combinatory vaccine not only provided protection against subsequent infections with RSV, but also against heterosubtypic challenges with pH1N1 or H3N2 strains. In conclusion, we present here a potent combinatory vaccine for mucosal applications, which provides protection against two of the most relevant respiratory viruses.

Self-Assembling Nanoparticle Hemagglutinin Influenza Vaccines Induce High Antibody Response.

As a highly pathogenic avian virus, H5 influenza poses a serious threat to livestock, the poultry industry, and public health security. Hemagglutinin (HA) is both the dominant epitope and the main target of influenza-neutralizing antibodies. Here, we designed a nanoparticle hemagglutinin influenza vaccine to improve the immunogenicity of the influenza vaccine. In this study, HA5 subtype influenza virus was used as the candidate antigen and was combined with the artificially designed double-branch scaffold protein I53_dn5 A and B. A structurally correct and bioactive trimer HA5-I53_dn5B/Y98F was obtained through secretion and purification using an insect baculovirus expression system; I53_dn5A was obtained by purification using a prokaryotic expression system. HA5-I53_dn5B/Y98F and I53_dn5A self-assembled into spherical nanoparticles (HA5-I53_dn5) in vitro with a diameter of about 45 nm. Immunization and serum test results showed that both HA5-I53_dn5B/Y98F and HA5-I53_dn5 could induce HA5-specific antibodies; however, the immunogenicity of HA5-I53_dn5 was better than that of HA5-I53_dn5B/Y98F. Groups treated with HA5-I53_dn5B and HA5-I53_dn5 nanoparticles produced IgG antibody titers that were not statistically different from those of the nanoparticle-containing adjuvant group. This production of trimerized HA5-I53_dn5B and HA5-I53_dn5 nanoparticles using baculovirus expression provides a reference for the development of novel, safe, and efficient influenza vaccines.

A synthetic TLR4 agonist significantly increases humoral immune responses and the protective ability of an MDCK-cell-derived inactivated H7N9 vaccine in mice.

Antigenically divergent H7N9 viruses pose a potential threat to public health, with the poor immunogenicity of candidate H7N9 vaccines demonstrated in clinical trials underscoring the urgent need for more-effective H7N9 vaccines. In the present study, mice were immunized with various doses of a suspended-MDCK-cell-derived inactivated H7N9 vaccine, which was based on a low-pathogenic H7N9 virus, to assess cross-reactive immunity and cross-protection against antigenically divergent H7N9 viruses. We found that the CRX-527 adjuvant, a synthetic TLR4 agonist, significantly enhanced the humoral immune responses of the suspended-MDCK-cell-derived H7N9 vaccine, with significant antigen-sparing and immune-enhancing effects, including robust virus-specific IgG, hemagglutination-inhibiting (HI), neuraminidase-inhibiting (NI), and virus-neutralizing (VN) antibody responses, which are crucial for protection against influenza virus infection. Moreover, the CRX-527-adjuvanted H7N9 vaccine also elicited cross-protective immunity and cross-protection against a highly pathogenic H7N9 virus with a single vaccination. Notably, NI and VN antibodies might play an important role in cross-protection against lethal influenza virus infections. This study showed that a synthetic TLR4 agonist adjuvant has a potent immunopotentiating effect, which might be considered worth further development as a means of increasing vaccine effectiveness.

Pivoting From Influenza to COVID-19 Vaccinations: How a Minnesota Vaccination Program Reduced Barriers for Refugee, Immigrant, and Migrant Communities Accessing Vaccines During the COVID-19 Pandemic.

The Minnesota Immunization Networking Initiative (MINI) led by Fairview Health Services has addressed barriers to accessing immunizations through partnerships with community organizations to provide free influenza vaccinations to historically underserved communities, especially refugee, immigrant, and migrant communities. Once the COVID-19 vaccine was available, MINI quickly pivoted operations to distribute the vaccine and provide technical assistance to community partners amidst rapidly evolving guidance. With infrastructure and a vaccination team in place, MINI responded to new and emerging needs, eg, implementing a more accessible and low-tech scheduling system, increasing staffing to meet growing needs, and expanding partnerships with community organizations and leaders. From February 2021 to September 2023, MINI organized 1120 community-based vaccine clinics and administered 43,123 COVID-19 vaccinations. Of those vaccine recipients, 88% identified as Black, Indigenous, and other people of color, and for preferred language, over half stated that they preferred a language other than English. These demographics are similar to those of the earlier influenza clinics, even as average annual clinics have tripled and average total vaccinations have quadrupled since the pivot to COVID-19 vaccination clinics. Some keys to success were: (1) consistent, bidirectional communication and shared decision-making with community partners; (2) prioritizing sustainable staffing models with the support of administrative leadership and resources; and (3) having a community-informed approach supported by the practice of hiring staff from communities served. Because of the effectiveness of this model, MINI is primed to respond to planned and unplanned emergent public health crises.

Antibody response to sequential vaccination with cell culture, recombinant, or egg-based influenza vaccines among U.S. adults.

The immune response to inactivated influenza vaccines (IIV) is influenced by multiple factors, including hemagglutinin content and egg-based manufacturing. Only two US-licensed vaccines are manufactured without egg passage: cell culture-based inactivated vaccine (ccIIV) and recombinant vaccine (RIV). We conducted a randomized open-label trial in central Wisconsin during the 2018-19 and 2019-20 seasons to compare immunogenicity of sequential vaccination. Participants 18-64 years old were randomized 1:1:1 to receive RIV, ccIIV or IIV in strata defined by number of influenza vaccine doses in the prior 3 years. They were revaccinated with the same product in year two. Paired serum samples were tested by hemagglutination inhibition against egg-adapted and cell-grown vaccine viruses. Serologic endpoints included geometric mean titer (GMT), mean fold rise, and percent seroconversion. There were 373 participants randomized and vaccinated in 2018-19; 332 were revaccinated in 2019-20. In 2018-19, RIV and ccIIV were not more immunogenic than IIV against A/H1N1. The post-vaccination GMT against the cell-grown 3C.2a A/H3N2 vaccine virus was higher for RIV vs IIV (p = .001) and RIV vs ccIIV (p = .001). The antibody response to influenza B viruses was similar across study arms. In 2019-20, GMT against the cell-grown 3C.3a A/H3N2 vaccine virus was higher for RIV vs IIV (p = .03) and for RIV vs ccIIV (p = .001). RIV revaccination generated significantly greater backboosting to the antigenically distinct 3C.2a A/H3N2 virus (2018-19 vaccine strain) compared to ccIIV or IIV. This study adds to the evidence that RIV elicits a superior immunologic response against A/H3N2 viruses compared to other licensed influenza vaccine products.

Enhancing cross-protection against influenza by heterologous sequential immunization with mRNA LNP and protein nanoparticle vaccines.

Enhancing influenza vaccine cross-protection is imperative to alleviate the significant public health burden of influenza. Heterologous sequential immunization may synergize diverse vaccine formulations and routes to improve vaccine potency and breadth. Here we investigate the effects of immunization strategies on the generation of cross-protective immune responses in female Balb/c mice, utilizing mRNA lipid nanoparticle (LNP) and protein-based PHC nanoparticle vaccines targeting influenza hemagglutinin. Our findings emphasize the crucial role of priming vaccination in shaping Th bias and immunodominance hierarchies. mRNA LNP prime favors Th1-leaning responses, while PHC prime elicits Th2-skewing responses. We demonstrate that cellular and mucosal immune responses are pivotal correlates of cross-protection against influenza. Notably, intranasal PHC immunization outperforms its intramuscular counterpart in inducing mucosal immunity and conferring cross-protection. Sequential mRNA LNP prime and intranasal PHC boost demonstrate optimal cross-protection against antigenically drifted and shifted influenza strains. Our study offers valuable insights into tailoring immunization strategies to optimize influenza vaccine effectiveness.

Increased adherence to influenza vaccination among Palermo family pediatricians: a study on safety and compliance of qLAIV vaccination.

BACKGROUND: Influenza represents a serious public health threat, especially for the management of severe cases and complications of the disease, requiring the implementation of control measures. We aimed to assess the acceptance and impact of qLAIV vaccination among a representative sample of family paediatricians (FPs) operating in Palermo Local Health Authority (LHA). To this end we evaluated vaccination coverage rates, comparing it with that observed in Sicilian context, while actively monitoring possible adverse reactions and their severity. METHODS: An observational descriptive non-controlled study was conducted in two phases, from September 2022 to June 2023. The first phase involved a formative and educational intervention with a pre-intervention questionnaire to assess the knowledge and attitudes of FPs on paediatric influenza vaccination. The second phase consisted of an active surveillance on qLAIV safety and acceptance among the paediatric population assisted by the participating FPs, from October 2022 to April 2023. Frequencies, chi-squared tests, and comparisons statistics were performed using Stata/MP 14.1. RESULTS: The overall coverage rate among the paediatric population involved in the intervention was 13.2%, with an I.M./qLAIV ratio of vaccine administered of 1/4.25. This coverage rate was significantly higher (p-value <0.001) when compared to the average values reported in the population under the Palermo Local Health Authority (LHA) (6.7%) and in the entire Sicily (5.9%). Adverse events in the qLAIV group were mild, with only 3.3% experiencing them, primarily presenting as a feverish rise (3.2%). No severe adverse reaction was reported. CONCLUSIONS: The educational intervention significantly raised paediatric influenza vaccination rates among the participating FPs, and in general improved influenza vaccination coverage rates in the Palermo's LHU. Minimal, non-serious adverse events underscored the vaccine's safety. Training sessions ensured paediatricians stayed informed, enabling them to provide comprehensive information to parents for secure and informed vaccination decisions in their practices.

Protection against the H1N1 influenza virus using self-assembled nanoparticles formed by lumazine synthase and bearing the M2e peptide.

There is an urgent need for influenza vaccines that offer broad cross-protection. The highly conserved ectodomain of the influenza matrix protein 2 (M2e) is a promising candidate; however, its low immunogenicity can be addressed. In this study, we developed influenza vaccines using the Lumazine synthase (LS) platform. The primary objective of this study was to determine the protective potential of M2e proteins expressed on Lumazine synthase (LS) nanoparticles. M2e-LS proteins, produced through the E. coli system, spontaneously assemble into nanoparticles. The study investigated the efficacy of the M2e-LS nanoparticle vaccine in mice. Mice immunized with M2e-LS nanoparticles exhibited significantly higher levels of intracellular cytokines than those receiving soluble M2e proteins. The M2e-LS protein exhibited robust immunogenicity and provided 100% protection against cross-clade influenza.

Innovations in cell culture-based influenza vaccine manufacturing - from static cultures to high cell density cultivations.

Influenza remains a serious global health concern, causing significant morbidity and mortality each year. Vaccination is crucial to mitigate its impact, but requires rapid and efficient manufacturing strategies to handle timing and supply. Traditionally relying on egg-based production, the field has witnessed a paradigm shift toward cell culture-based methods offering enhanced flexibility, scalability, and process safety. This review provides a concise overview of available cell substrates and technological advancements. We summarize crucial steps toward process intensification - from roller bottle production to dynamic cultures on carriers and from suspension cultures in batch mode to high cell density perfusion using various cell retention devices. Moreover, we compare single-use and conventional systems and address challenges including defective interfering particles. Taken together, we describe the current state-of-the-art in cell culture-based influenza virus production to sustainably meet vaccine demands, guarantee a timely supply, and keep up with the challenges of seasonal epidemics and global pandemics.

Cytomegalovirus vaccine vector-induced effector memory CD4 + T cells protect cynomolgus macaques from lethal aerosolized heterologous avian influenza challenge.

An influenza vaccine approach that overcomes the problem of viral sequence diversity and provides long-lived heterosubtypic protection is urgently needed to protect against pandemic influenza viruses. Here, to determine if lung-resident effector memory T cells induced by cytomegalovirus (CMV)-vectored vaccines expressing conserved internal influenza antigens could protect against lethal influenza challenge, we immunize Mauritian cynomolgus macaques (MCM) with cynomolgus CMV (CyCMV) vaccines expressing H1N1 1918 influenza M1, NP, and PB1 antigens (CyCMV/Flu), and challenge with heterologous, aerosolized avian H5N1 influenza. All six unvaccinated MCM died by seven days post infection with acute respiratory distress, while 54.5% (6/11) CyCMV/Flu-vaccinated MCM survived. Survival correlates with the magnitude of lung-resident influenza-specific CD4 + T cells prior to challenge. These data demonstrate that CD4 + T cells targeting conserved internal influenza proteins can protect against highly pathogenic heterologous influenza challenge and support further exploration of effector memory T cell-based vaccines for universal influenza vaccine development.

Parent and family characteristics associated with reported pediatric influenza vaccination in a sample of Canadian digital vaccination platform users. An exploratory, cross-sectional study in the 2018-2019 influenza season.

Seasonal vaccination remains one of the best interventions to prevent morbidity and mortality from influenza in children. Understanding the characteristics of parents who vaccinate their children can inform communication strategies to encourage immunization. Using a cross-sectional study, we described parental characteristics of people who reported vaccinating their children against influenza during 2018/2019 in a cohort of Canadian digital immunization record users. Data was collected from a free, Pan-Canadian digital vaccination tool, CANImmunize. Eligible accounts contained at least one parental and one "child/dependent" record. Each parental characteristic (gender, age, family size, etc) was tested for association with pediatric influenza vaccination, and a multivariate logistic regression model was fit. A total of 6,801 CANImmunize accounts met inclusion criteria. After collapsing the dataset, the final sample contained 11,381 unique dyads. Influenza vaccination was reported for 32.3% of the children and 42.0% of the parents. In the multivariate logistic regression analysis, parents receiving the seasonal influenza vaccine were most strongly associated with reporting pediatric influenza vaccination (OR 17.05, 95% CI 15.08, 19.28). Having a larger family size and fewer transactions during the study period was associated with not reporting pediatric influenza vaccination. While there are several limitations to this large-scale study, these results can help inform future research in the area. Digital technologies may provide a unique and valuable source of vaccine coverage data and to explore associations between individual characteristics and immunization behavior. Policy makers considering digital messaging may want to tailor their efforts based on parental characteristics to further improve pediatric seasonal influenza vaccine uptake.

Surveillance of adverse events following immunisation in Australia annual report, 2021.

Abstract: Annual seasonal influenza epidemics cause substantial disease and economic burden worldwide. During the coronavirus disease 2019 (COVID-19) pandemic in 2020 and 2021, influenza activity significantly declined. However, influenza resurged in Australia following the relaxation of non-pharmaceutical interventions, with increased influenza virus circulation in early 2022 coinciding with the SARS-CoV-2 Omicron BA.2 variant wave. Together with other respiratory virus diseases, these disease impacts on the Australian population and healthcare system have re-emphasised the importance of influenza vaccination and control. We aim to provide an overview of the current seasonal influenza vaccination program in Australia and summarise evidence and considerations underpinning potential future immunisation strategies. Influenza causes disproportionately higher morbidity and mortality in young children and older adults. Other populations at elevated risk from influenza include Aboriginal and Torres Strait Islander peoples, pregnant women, and people with certain underlying medical conditions. All Australians aged ≥ 6 months are recommended to receive influenza vaccine every year. The National Immunisation Program (NIP) provides free vaccine for eligible at-risk populations. While approximately 70% of older adults had received influenza vaccine in 2022, coverage in other age groups remains suboptimal. There are several key unmet needs and challenges, but also potential strategies for enhancing the influenza vaccination program in Australia. Improved monitoring and evaluation, including the use of relevant linked datasets for such purposes, is imperative to better understand variations in coverage and vaccination impact in specific populations. Adoption of evidence-based strategies, such as culturally appropriate resources that consider the characteristics of diverse Australian populations, may also help to achieve higher vaccine coverage rates. Additionally, greater vaccine uptake across the population could be facilitated by expanding the NIP-eligible population where cost-effective, and adopting the use of more effective and different types of vaccines when available.

Single-cell analysis reveals lasting immunological consequences of influenza infection and respiratory immunization in the pig lung.

The pig is a natural host for influenza viruses and integrally involved in virus evolution through interspecies transmissions between humans and swine. Swine have many physiological, anatomical, and immunological similarities to humans, and are an excellent model for human influenza. Here, we employed single cell RNA-sequencing (scRNA-seq) and flow cytometry to characterize the major leukocyte subsets in bronchoalveolar lavage (BAL), twenty-one days after H1N1pdm09 infection or respiratory immunization with an adenoviral vector vaccine expressing hemagglutinin and nucleoprotein with or without IL-1ß. Mapping scRNA-seq clusters from BAL onto those previously described in peripheral blood facilitated annotation and highlighted differences between tissue resident and circulating immune cells. ScRNA-seq data and functional assays revealed lasting impacts of immune challenge on BAL populations. First, mucosal administration of IL-1ß reduced the number of functionally active Treg cells. Second, influenza infection upregulated IFI6 in BAL cells and decreased their susceptibility to virus replication in vitro. Our data provide a reference map of porcine BAL cells and reveal lasting immunological consequences of influenza infection and respiratory immunization in a highly relevant large animal model for respiratory virus infection.

Cost-effectiveness of seasonal influenza vaccination in WHO-defined high-risk populations in Bangladesh.

Background: Bangladesh carries a substantial health and economic burden of seasonal influenza, particularly among the World Health Organization (WHO)-defined high-risk populations. We implemented a modelling study to determine the cost-effectiveness of influenza vaccination in each of five high-risk groups (pregnant women, children under five years of age, adults with underlying health conditions, older adults (≥60 years), and healthcare personnel) to inform policy decisions on risk group prioritisation for influenza vaccination in Bangladesh. Methods: We implemented a Markov decision-analytic model to estimate the impact of influenza vaccination for each target risk group. We obtained model inputs from hospital-based influenza surveillance data, unpublished surveys, and published literature (preferentially from studies in Bangladesh, followed by regional and global ones). We used quality-adjusted life years (QALY) as the health outcome of interest. We also estimated incremental cost-effectiveness ratios (ICERs) for each risk group by comparing the costs and QALY of vaccinating compared to not vaccinating each group, where the ICER represents the additional cost needed to achieve one year of additional QALY from a given intervention. We considered a willingness-to-pay threshold (ICER) of less than one gross domestic product (GDP) per capita as highly cost-effective and of one to three times GDP per capita as cost-effective (per WHO standard). For Bangladesh, this threshold ranges between USD 2462 and USD 7386. Results: The estimated ICERs were USD -99, USD -87, USD -4, USD 792, and USD 229 per QALY gained for healthcare personnel, older adults (≥60), children aged less than five years, adults with comorbid conditions, and pregnant women, respectively. For all risk groups, ICERs were below the WHO willingness-to-pay threshold for Bangladesh. Vaccinating pregnant women and adults with comorbid conditions was highly cost-effective per additional life year gained, while vaccinating healthcare personnel, older adults (≥60), and children under five years were cost-saving per additional life year gained. Conclusions: Influenza vaccination to all target risk groups in Bangladesh would be either cost-saving or cost-effective, per WHO guidelines of GDP-based thresholds.