Humoral immunity and safety of respiratory virus vaccines in systemic lupus erythematosus population: a meta-analysis based on twenty-five observational studies.

BACKGROUND: Systemic lupus erythematosus (SLE), an extensive autoimmune disorder, compromises viral resistance and alters immune responses post respiratory virus vaccines. This study aims to assess immune response levels and safety in SLE patients following respiratory virus vaccines. METHODS: Extensive searches, until 1 March 2024, were conducted using PubMed, EMBASE, and Cochrane Library. Outcomes, encompassing seroconversion rate (SCR), antibody and IgG titers, neutralizing antibodies, anti-spike antibodies, anti-receptor binding domain (RBD) IgG, and adverse events, were appraised. RESULTS: Sixteen articles, comprising 25 observational studies, were included. SLE patients exhibited lower SCR (OR = 0.42, 95%CI: 0.26 to 0.69), antibody titers (SMD=-2.84, 95%CI: -3.36 to -1.61), and neutralizing antibodies (OR = 0.27, 95%CI: 0.13 to 0.56) compared to the healthy population post respiratory virus vaccines. Notably, differences were statistically insignificant for anti-RBD IgG (OR = 1.75, 95%CI: 0.10 to 29.42), IgG titers (SMD=-2.54, 95%CI: -5.57 to -0.49), anti-spike antibodies (OR = 0.35, 95%CI: 0.08 to 1.53), injection site discomfort (OR = 1.03, 95%CI: 0.52 to 2.06), fatigue (OR = 1.23, 95%CI: 0.74 to 2.03), fever (OR = 1.02, 95%CI: 0.64 to 1.63), localized reactions (OR = 0.69, 95%CI: 0.37 to 1.30), systemic reactions (OR = 1.00, 95%CI: 0.59 to 1.69), allergic reactions (OR = 5.11, 95%CI: 0.24 to 107.10), self-reported vaccination-related adverse events (OR = 1.61, 95%CI: 0.56 to 4.63), and disease flares after vaccination (OR = 1.00, 95%CI: 0.14 to 7.28). CONCLUSION: Despite the reduced immune response and host protection in SLE patients post-Corona Virus Disease 2019 (COVID-19) and influenza vaccines compared to the healthy population, safety profiles are comparable. Therefore, it is recommended that SLE patients receive COVID-19 and influenza viral vaccines to fortify their resistance.

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

Introduction: 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. Methods: Questionnaires were self-administered or researcher-administered between October 2023 and February 2024 in an immunization center in the southern part of Italy. Results: 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. Conclusion: 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.

A broad-spectrum multiepitope vaccine against seasonal influenza A and B viruses in mice.

BACKGROUND: Influenza viruses pose a persistent threat to global public health, necessitating the development of innovative and broadly effective vaccines. METHODS: This study focuses on a multiepitope vaccine (MEV) designed to provide broad-spectrum protection against different influenza viruses. The MEV, containing 19 B-cell linear epitopes, 7 CD4+ T cells, and 11 CD8+ T cells epitopes identified through enzyme-linked immunospot assay (ELISPOT) in influenza viruses infected mice, was administered through a regimen of two doses of DNA vaccine followed by one dose of a protein vaccine in C57BL/6 female mice. FINDINGS: Upon lethal challenge with both seasonal circulating strains (H1N1, H3N2, BV, and BY) and historical strains (H1N1-PR8 and H3N2-X31), MEV demonstrated substantial protection against different influenza seasonal strains, with partial efficacy against historical strains. Notably, the increased germinal centre B cells and antibody-secreting cells, along with robust T cell immune responses, highlighted the comprehensive immune defence elicited by MEV. Elevated hemagglutinin inhibition antibody was also observed against seasonal circulating and historical strains. Additionally, mice vaccinated with MEV exhibited significantly lower counts of inflammatory cells in the lungs compared to negative control groups. INTERPRETATION: Our results demonstrated the efficacy of a broad-spectrum MEV against influenza viruses in mice. Conducting long-term studies to evaluate the durability of MEV-induced immune responses and explore its potential application in diverse populations will offer valuable insights for the continued advancement of this promising vaccine. FUNDING: Funding bodies are described in the Acknowledgments section.

Analysis of factors influencing influenza outbreaks in schools in Taicang City, China.

Objective: This study aims to analyze the awareness of influenza prevention and control and the behavioral attitudes toward the work among parents and staff in schools in Taicang City and the impact of the vaccination rate among students on influenza outbreaks in schools. The findings can provide references for the development of effective control strategies for the spread of influenza. Methods: An anonymous questionnaire survey was conducted on 10,962 students from 20 schools in Taicang City, with class as the unit of analysis. The survey investigated their awareness of influenza prevention and control, their attitudes, and the vaccination coverage. Results: From January to June 2023, a total of 388 influenza outbreaks were reported in schools in Taicang City, involving 77 schools. There were 3,475 confirmed cases, with an average infection rate of 18.53%. In schools where influenza outbreaks had occurred, the incidence rate of those who received influenza vaccine was significantly lower than those who did not, and the vaccine protection rate was 28.22%. The knowledge awareness rates of "the main transmission routes of influenza" and "influenza vaccination can prevent influenza" among parents of students were 95.49 and 93.16%, respectively. The differences between schools involved in the epidemic and non-epidemic were statistically significant (p < 0.05). The correct attitudes of parents toward "actively reporting relevant symptoms to teachers when their children show symptoms" and "avoiding classes with diseases when their children are suspected to be sick" are 98.80 and 96.26%, respectively. The differences between schools with and without epidemic are statistically significant (p < 0.05). The correct attitudes of the class teacher toward "correct management and control of students with flu like symptoms in the class" and "taking correct prevention and control measures in the event of a flu epidemic in the class" were 89.36 and 92.55%, respectively. The differences between epidemic related and non-epidemic related classes were statistically significant (p < 0.05). Conclusion: Enhance the knowledge level of influenza prevention and control among parents of students, Strengthening the training for class teachers in emergency response to infectious diseases and increasing vaccination coverage among students can effectively reduce the incidence of influenza and thereby the occurrence of cluster outbreaks in schools.

Impact of COVID-19 on vaccine confidence and uptake: A systematic literature review.

During the coronavirus disease 2019 (COVID-19) pandemic, scheduled vaccinations were postponed, mass vaccination programmes were suspended and opportunities for healthcare workers to administer vaccines ad hoc decreased. The aims of this systematic literature review were to determine the impact of the COVID-19 pandemic on vaccine confidence, intent and uptake in preexisting routine childhood or adult vaccination programmes, and to identify factors associated with changes in acceptance, intent and uptake of preexisting vaccines. Medline and Embase were searched for studies in Australia, Brazil, Canada, China, Japan, the USA, and European countries, published between 1 January 2021 and 4 August 2022. A complementary gray literature search was conducted between 11 and 13 October 2022, and supplemented with additional gray research in October 2023. In total, 54 citations were included in the review. Study design and geography were heterogeneous. The number of adults who received or intended to receive an influenza or pneumococcal vaccine was higher during the pandemic than in previous seasons (n = 28 studies). In addition, increased acceptance of adult vaccinations was observed during 2020-21 compared with 2019-20 (n = 12 studies). The rates of childhood vaccinations decreased during the COVID-19 pandemic across several countries (n = 11 studies). Factors associated with changes in intention to receive a vaccination, or uptake of influenza vaccine, included previous vaccination, older age, higher perceived risk of contracting COVID-19, anxiety regarding the pandemic and fear of contracting COVID-19. Acceptance and uptake of influenza and pneumococcal vaccines generally increased after onset of the COVID-19 pandemic.

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

BACKGROUND: Influenza 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. METHODS: We 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. RESULTS: Thirty-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). CONCLUSION: Our 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.

Engineered probiotic Escherichia coli elicits immediate and long-term protection against influenza A virus in mice.

Influenza virus infection remains a major global health problem and requires a universal vaccine with broad protection against different subtypes as well as a rapid-response vaccine to provide immediate protection in the event of an epidemic outbreak. Here, we show that intranasal administration of probiotic Escherichia coli Nissle 1917 activates innate immunity in the respiratory tract and provides immediate protection against influenza virus infection within 1 day. Based on this vehicle, a recombinant strain is engineered to express and secret five tandem repeats of the extracellular domain of matrix protein 2 from different influenza virus subtypes. Intranasal vaccination with this strain induces durable humoral and mucosal responses in the respiratory tract, and provides broad protection against the lethal challenge of divergent influenza viruses in female BALB/c mice. Our findings highlight a promising delivery platform for developing mucosal vaccines that provide immediate and sustained protection against respiratory pathogens.

Declining number of general practitioners can impair influenza vaccination uptake among Italian older adults: Results from a panel analysis.

BACKGROUND: Seasonal influenza vaccination coverage in Italian older adults is insufficient and well below the minimum target of 75%. In Italy, most influenza vaccine doses are administered by general practitioners (GPs), whose number has been declining. In parallel, the number of patients per GP and GP workload increased dramatically, which theoretically may impair vaccination counselling. In this ecological study, we aimed to assess whether influenza vaccination coverage in older adults is associated with the density of GPs having high number of patients. METHODS: The study outcome was the influenza vaccination coverage rate in adults aged ≥ 65 years and registered in 20 Italian regions over the last 23 years. The independent variable of interest was the proportion of GPs with more than 1,500 adult patients, which is an imposed normative ceiling. This latter variable was considered as a proxy of GP overload. By adopting a panel regression approach, different specifications of fixed- and random-effects models were run to assess the association of interest, when adjusted for several social structural, economic and healthcare-related variables. RESULTS: Over the last two decades, most regions showed a negative association between influenza vaccination coverage rates and the density of GPs with a high number of patients. This latter negative association was confirmed (P < 0.05) in different panel model specifications. In particular, in the fully adjusted two-way fixed-effects model, each 10% increase in the number of GPs with more than 1,500 patients was associated with a 1.7% decrease in influenza vaccination coverage. However, this association was present only in region-years where at least 18% of GPs were deemed overloaded. CONCLUSIONS: In the upcoming years, the number of Italian GPs is projected to decline further. At the same time, the aging Italian population will determine an even greater workload for GPs. This study demonstrated that increased GP workload may partially explain the spatiotemporal variation in influenza vaccination uptake in the Italian elderly. With the imperative of increasing or at least maintaining influenza vaccination coverage rates, several short- and mid-term initiatives should be implemented in order to optimize GP workload during seasonal immunization campaigns.

Patient subtyping analysis of baseline multi-omic data reveals distinct pre-immune states associated with antibody response to seasonal influenza vaccination.

Understanding the molecular mechanisms underpinning diverse vaccination responses is critical for developing efficient vaccines. Molecular subtyping can offer insights into heterogeneous nature of responses and aid in vaccine design. We analyzed multi-omic data from 62 haemagglutinin seasonal influenza vaccine recipients (2019-2020), including transcriptomics, proteomics, glycomics, and metabolomics data collected pre-vaccination. We performed a subtyping analysis on the integrated data revealing five subtypes with distinct molecular signatures. These subtypes differed in the expression of pre-existing adaptive or innate immunity signatures, which were linked to significant variation in baseline immunoglobulin A (IgA) and hemagglutination inhibition (HAI) titer levels. It is worth noting that these differences persisted through day 28 post-vaccination, indicating the effect of initial immune state on vaccination response. These findings highlight the significance of interpersonal variation in baseline immune status as a crucial factor in determining the effectiveness of seasonal vaccines. Ultimately, incorporating molecular profiling could enable personalized vaccine optimization.

Evaluation of a novel intramuscular prime/intranasal boost vaccination strategy against influenza in the pig model.

Live-attenuated influenza vaccines (LAIV) offer advantages over the commonly used inactivated split influenza vaccines. However, finding the optimal balance between sufficient attenuation and immunogenicity has remained a challenge. We recently developed an alternative LAIV based on the 2009 pandemic H1N1 virus with a truncated NS1 protein and lacking PA-X protein expression (NS1(1-126)-ΔPAX). This virus showed a blunted replication and elicited a strong innate immune response. In the present study, we evaluated the efficacy of this vaccine candidate in the porcine animal model as a pertinent in vivo system. Immunization of pigs via the nasal route with the novel NS1(1-126)-ΔPAX LAIV did not cause disease and elicited a strong mucosal immune response that completely blocked replication of the homologous challenge virus in the respiratory tract. However, we observed prolonged shedding of our vaccine candidate from the upper respiratory tract. To improve LAIV safety, we developed a novel prime/boost vaccination strategy combining primary intramuscular immunization with a haemagglutinin-encoding propagation-defective vesicular stomatitis virus (VSV) replicon, followed by a secondary immunization with the NS1(1-126)-ΔPAX LAIV via the nasal route. This two-step immunization procedure significantly reduced LAIV shedding, increased the production of specific serum IgG, neutralizing antibodies, and Th1 memory cells, and resulted in sterilizing immunity against homologous virus challenge. In conclusion, our novel intramuscular prime/intranasal boost regimen interferes with virus shedding and transmission, a feature that will help combat influenza epidemics and pandemics.

Risk of healthcare visits from influenza in subjects with diabetes and impacts of early vaccination.

INTRODUCTION: The objective of this study was to determine the burden of influenza disease in patients with or without diabetes in a population of American adults to understand the benefits of seasonal vaccination. RESEARCH DESIGN AND METHODS: We performed a retrospective cohort study using electronic medical records totaling 1,117,263 from two Louisiana healthcare providers spanning January 2012 through December 2017. Adults 18 years or older with two or more records within the study period were included. The primary outcome quantified was influenza-related diagnosis during inpatient (IP) or emergency room (ER) visits and risk reduction with the timing of immunization. RESULTS: Influenza-related IP or ER visits totaled 0.0122-0.0169 events per person within the 2013-2016 influenza seasons. Subjects with diabetes had a 5.6-fold more frequent influenza diagnosis for IP or ER visits than in subjects without diabetes or 3.7-fold more frequent when adjusted for demographics. Early immunization reduced the risk of influenza healthcare utilization by 66% for subjects with diabetes or 67% for subjects without diabetes when compared with later vaccination for the 2013-2016 influenza seasons. Older age and female sex were associated with a higher incidence of influenza, but not a significant change in risk reduction from vaccination. CONCLUSIONS: The risk for influenza-related healthcare utilization was 3.7-fold higher if patients had diabetes during 2013-2016 influenza seasons. Early immunization provides a significant benefit to adults irrespective of a diabetes diagnosis. All adults, but particularly patients with diabetes, should be encouraged to get the influenza vaccine at the start of the influenza season.

Influenza vaccination for heart failure patients: a cost-effectiveness analysis from the perspective of Chinese healthcare system.

Purpose: Influenza infection induces cardiovascular events in heart failure (HF) patients, with potential risk reduction through vaccination. This study aims to evaluate the cost-effectiveness of influenza vaccination for HF patients in China. Methods: We developed a Markov model with a 3-month cycle to simulate the cost-effectiveness of administering the influenza vaccine to patients with HF over a 3-year period. Patients in the model received either the influenza vaccine or a placebo, in addition to standard HF treatment. Cost data, sourced from the China Healthcare Statistic Yearbook and other public records, and effectiveness data from the IVVE (Influenza Vaccine to Prevent Adverse Vascular Events in HF) trial, were incorporated. Specifically, the cost of the influenza vaccine was 75 Chinese Yuan (CNY) (11 USD), the cost of hospitalization for heart failure (HHF) was 9,326 CNY (1,386 USD), and the cost of treatment for pneumonia was 5,984 CNY (889 USD). The study's primary outcome, the incremental cost-effectiveness ratio (ICER), quantifies the incremental cost (CNY and USD) per incremental quality-adjusted life year (QALY). Additional outcomes included total cost, total effectiveness, incremental cost, and incremental effectiveness. We conducted one-way and probabilistic sensitivity analyses (PSA) to assess certainty and uncertainty, respectively. Scenario analysis, considering various situations, was performed to evaluate the robustness of the results. Results: In the base case analysis, influenza vaccine, compared to placebo, among Chinese HF patients, resulted in a cost increase from 21,004 CNY (3,121 USD) to 21,062 CNY (3,130 USD) and in QALYs from 1.89 to 1.92 (2.55 life years vs. 2.57 life years) per patient. The resulting ICER was 2,331 CNY (346 USD) per QALY [2,080 CNY (309 USD) per life year], falling below the willingness-to-pay threshold based on per capita GDP. One-way sensitivity analysis revealed that disparities in HHF and cardiovascular death rates between groups had the most significant impact on the ICER, while the cost of vaccines had a marginal impact. PSA and scenario analysis collectively affirmed the robustness of our findings. Conclusion: This study suggests that adding the influenza vaccine to standard treatment regimens for Chinese patients with HF may represent a highly cost-effective option. Further real-world data studies are essential to validate these findings.

Lipid nanoparticle-encapsulated DNA vaccine confers protection against swine and human-origin H1N1 influenza viruses.

In 2009, a novel swine-origin H1N1 virus emerged, causing a pandemic. The virus, known as H1N1pdm09, quickly displaced the circulating H1 lineage and became the dominant seasonal influenza A virus subtype infecting humans. Human-to-swine spillovers of the H1N1pdm09 have occurred frequently, and each occurrence has led to sustained transmission of the human-origin H1N1pdm09 within swine populations. In the present study, we developed a lipid nanoparticle-based DNA vaccine (LNP-DNA) containing the hemagglutinin gene of a swine-origin H1N1pdm09. In pigs, this LNP-DNA vaccine induced a robust antibody response after a single intramuscular immunization and protected the pigs against challenge infection with the homologous swine-origin H1N1pdm09 virus. In a mouse model, the LNP-DNA vaccine induced antibody and T-cell responses and protected mice against lethal challenge with a mouse-adapted human-origin H1N1pdm09 virus. These findings demonstrate the potential of the LNP-DNA vaccine to protect against both swine- and human-origin H1N1pdm09 viruses. IMPORTANCE: Swine influenza A virus (IAV) is widespread and causes significant economic losses to the swine industry. Moreover, bidirectional transmission of IAV between swine and humans commonly occurs. Once introduced into the swine population, human-origin IAV often reassorts with endemic swine IAV, resulting in reassortant viruses. Thus, it is imperative to develop a vaccine that is not only effective against IAV strains endemic in swine but also capable of preventing the spillover of human-origin IAV. In this study, we developed a lipid nanoparticle-encapsulated DNA plasmid vaccine (LNP-DNA) that demonstrates efficacy against both swine- and human-origin H1N1 viruses. The LNP-DNA vaccines are non-infectious and non-viable, meeting the criteria to serve as a vaccine platform for rapidly updating vaccines. Collectively, this LNP-DNA vaccine approach holds great potential for alleviating the impact of IAV on the swine industry and preventing the emergence of reassortant IAV strains.

Influenza and COVID-19 Vaccination Rates Among Children Receiving Long-Term Ventilation.

This cohort study examines rates of vaccination for COVID-19 and for influenza among children receiving long-term home ventilation.

2024 Public Health Actions to Reduce the Burden of Asthma: Influenza and COVID-19 Vaccination Uptake Among People with Asthma.

This study sought to identify COVID-19 and influenza vaccination rates and barriers among people with asthma. The Asthma and Allergy Foundation of America (AAFA) conducted an online survey from April to May in 2022 among a convenience sample of 350 individuals with asthma. Most survey respondents reported that they had received an influenza vaccine for the 2021-2022 flu season (77%) and at least 1 dose of a COVID-19 vaccine (87%). Age, gender, race and ethnicity, and household income were significantly associated with influenza vaccination. Age and urban-rural classification were associated with COVID-19 vaccination. Access issues were not commonly reported as vaccination barriers, highlighting educational opportunities.

Biological, social, and healthcare factors for death due to influenza A(H1N1) during the 2009 epidemic in Brazil.

OBJECTIVE: To identify risk factors for death from influenza A(H1N1), including the effectiveness of the vaccine against influenza A(H1N1) concerning mortality. METHODS: A case-control of incident cases of influenza A(H1N1) reported in the epidemiological information systems of the states of São Paulo, Paraná, Pará, Amazonas, and Rio Grande do Sul was conducted. RESULTS: 305 participants were included, 70 of them cases and 235 controls, distributed as follows: Amazonas, 9 cases/10 controls; Pará, 22 cases/77 controls, São Paulo, 19 cases/49 controls; Paraná, 10 cases/54 controls; Rio Grande do Sul, 10 cases/45 controls. These participants had a mean age of 30 years, with 33 years among cases and 25 years among controls. There was a predominance of females both among the cases and controls. Biological (age), pre-existing diseases (congestive heart failure, respiratory disease, and diabetes mellitus), and care factors (ICU admission) associated with death from influenza A(H1N1) were identified. CONCLUSION: The risk factors identified in this investigation not only allowed subsidizing the elaboration of clinical conducts but also indicate important aspects for facing "new" influenza epidemics that are likely to occur in our country.

Incidence of laboratory-confirmed influenza and RSV and associated presenteeism and absenteeism among healthcare personnel, Israel, influenza seasons 2016 to 2019.

BackgroundHealthcare personnel (HCP) are at high risk for respiratory infections through occupational exposure to respiratory viruses.AimWe used data from a prospective influenza vaccine effectiveness study in HCP to quantify the incidence of acute respiratory infections (ARI) and their associated presenteeism and absenteeism.MethodsAt the start and end of each season, HCP at two Israeli hospitals provided serum to screen for antibodies to influenza virus using the haemagglutination inhibition assay. During the season, active monitoring for the development of ARI symptoms was conducted twice a week by RT-PCR testing of nasal swabs for influenza and respiratory syncytial virus (RSV). Workplace presenteeism and absenteeism were documented. We calculated incidences of influenza- and RSV-associated ARI and applied sampling weights to make estimates representative of the source population.ResultsThe median age of 2,505 participating HCP was 41 years, and 70% were female. Incidence was 9.1 per 100 person-seasons (95% CI: 5.8-14.2) for RT-PCR-confirmed influenza and 2.5 per 100 person-seasons (95% CI: 0.9-7.1) for RSV illness. Each season, 18-23% of unvaccinated and influenza-negative HCP seroconverted. The incidence of seroconversion or RT-PCR-confirmed influenza was 27.5 per 100 person-seasons (95% CI: 17.8-42.5). Work during illness occurred in 92% (95% CI: 91-93) of ARI episodes, absence from work in 38% (95% CI: 36-40).ConclusionInfluenza virus and RSV infections and associated presenteeism and absenteeism were common among HCP. Improving vaccination uptake among HCP, infection control, and encouraging sick HCP to stay home are important strategies to reduce ARI incidence and decrease the risk of in-hospital transmission.

Lot-to-lot consistency, immunogenicity and safety of a quadrivalent split virion inactivated influenza vaccine in healthy population aged 9-59 years: A randomized, double-blind, controlled, phase IV clinical trial.

OBJECTIVES: This study was to assess the lot-to-lot consistency, immunogenicity and safety of three manufacturing lots of a quadrivalent inactivated influenza vaccine (IIV4). METHODS: A randomized, double-blind, phase IV clinical trial was conducted in healthy children, adolescents and adults aged 9-59 years in Guizhou Province, China. Eligible participants were enrolled and randomized into three groups in a ratio of 1:1:1 to receive a single dose of one of three manufacturing lots of IIV4. Serum samples were collected before and 28 days after vaccination for hemagglutination inhibition (HI) antibody testing. Safety data were collected for up to 28 days after vaccination. The primary objective was to evaluate the lot-to-lot consistency of immune response as assessed by the geometric mean titer (GMT) of HI antibody at 28 days after vaccination. RESULTS: Between November 27, 2022 and December 18, 2022, 1260 eligible participants were enrolled, with similar participant demographics among groups. Immune responses after vaccination were comparable across groups, with the 95% confidence intervals (CIs) of GMT ratios for all 4 strains falling into the equivalence criterion of (0.67, 1.5). The seroconversion rates (SCRs) and seroprotection rates (SPRs) met the US Center or Biologics Evaluation and Research (CBER) criteria for all strains for each lot (lower limit of 95% CI of SCR ≥ 40% and SPR ≥ 70%). The incidences of solicited and unsolicited adverse reactions were similar among three groups, most of which (91.9%) were mild or moderate in severity. A total of 11 serious adverse events were reported during the study, and all were considered unrelated to vaccination. CONCLUSION: The three manufacturing lots of IIV4 demonstrated consistent immunogenicity. IIV4 can elicit satisfactory immune responses for all four strains and no safety concerns were identified. CLINICAL TRIAL REGISTRATION: Identifier No. NCT05512494.

The response to influenza vaccination is associated with DNA methylation-driven regulation of T cell innate antiviral pathways.

BACKGROUND: The effect of vaccination on the epigenome remains poorly characterized. In previous research, we identified an association between seroprotection against influenza and DNA methylation at sites associated with the RIG-1 signaling pathway, which recognizes viral double-stranded RNA and leads to a type I interferon response. However, these studies did not fully account for confounding factors including age, gender, and BMI, along with changes in cell-type composition. RESULTS: Here, we studied the influenza vaccine response in a longitudinal cohort vaccinated over two consecutive years (2019-2020 and 2020-2021), using peripheral blood mononuclear cells and a targeted DNA methylation approach. To address the effects of multiple factors on the epigenome, we designed a multivariate multiple regression model that included seroprotection levels as quantified by the hemagglutination-inhibition (HAI) assay test. CONCLUSIONS: Our findings indicate that 179 methylation sites can be combined as potential signatures to predict seroprotection. These sites were not only enriched for genes involved in the regulation of the RIG-I signaling pathway, as found previously, but also enriched for other genes associated with innate immunity to viruses and the transcription factor binding sites of BRD4, which is known to impact T cell memory. We propose a model to suggest that the RIG-I pathway and BRD4 could potentially be modulated to improve immunization strategies.