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IntroductionQ fever, caused by the intracellular bacterium Coxiella burnetii, is considered an occupational and biodefense hazard and can result in debilitating long-term complications. While natural infection and vaccination induce humoral and cellular immune responses, the exact nature of cellular immune responses to C. burnetii is incompletely understood. The current study seeks to investigate more deeply the nature of long-term cellular recall responses in naturally exposed individuals by both cytokine release assessment and cytometry profiling.MethodsIndividuals exposed during the 2007-2010 Dutch Q fever outbreak were grouped in 2015, based on a C. burnetii-specific IFNγ release assay (IGRA), serological status, and self-reported clinical symptoms during initial infection, into asymptomatic IGRA-negative/seronegative controls, and three IGRA-positive groups (seronegative/asymptomatic; seropositive/asymptomatic and seropositive/symptomatic). Recall responses following in vitro re-stimulation with heat-inactivated C. burnetii in whole blood, were assessed in 2016/2017 by cytokine release assays (n=55) and flow cytometry (n=36), and in blood mononuclear cells by mass cytometry (n=36).ResultsCytokine release analysis showed significantly elevated IL-2 responses in all seropositive individuals and elevated IL-1β responses in those recovered from symptomatic infection. Comparative flow cytometry analysis revealed significantly increased IFNγ, TNFα and IL-2 recall responses by CD4 T cells and higher IL-6 production by monocytes from symptomatic, IGRA-positive/seropositive individuals compared to controls. Mass cytometry profiling and unsupervised clustering analysis confirmed recall responses in seropositive individuals by two activated CD4 T cell subsets, one characterized by a strong Th1 cytokine profile (IFNγ+IL-2+TNFα+), and identified C. burnetii-specific activation of CD8 T cells in all IGRA-positive groups. Remarkably, increased C. burnetii-specific responses in IGRA-positive individuals were also observed in three innate cell subpopulations: one characterized by an IFNγ+IL-2+TNFα+ Th1 cytokine profile and lack of canonical marker expression, and two IL-1β-, IL-6- and IL-8-producing CD14+ monocyte subsets that could be the drivers of elevated secretion of innate cytokines in pre-exposed individuals.DiscussionThese data highlight that there are long-term increased responses to C. burnetii in both adaptive and innate cellular compartments, the latter being indicative of trained immunity. These findings warrant future studies into the protective role of these innate responses and may inform future Q fever vaccine design.

BackgroundThe cumulative body of research on suicidality in later life describes its unique and complex features in older people when compared with that in other population groups. Yet significant gaps exist in how research informs the further development of suitable interventions. The perspectives of older people are also limited in research findings.AimsTherefore, this exploratory study aimed to (1) identify potential barriers and enablers in discussing suicidal thoughts and their expression in later life from the perspectives of lay older people and (2) explore where opportunities might occur in approach, place, relationships, and language with older people to discuss suicidal thoughts and their expression.MethodWe conducted in-depth qualitative individual interviews with 15 people aged 70–89 years. This method helped explore older peoples' own lay perspectives on suicidal thoughts in later life and how these are expressed, and their understanding of where and how people might seek support.ResultsA total of three themes were generated from the dataset: (1) intergenerational and socio-cultural differences in suicide expression, (2) the normalization of suicidal thoughts in later life, and (3) the importance and difficulties of everyday discussion and opportunities to express suicidal thoughts.ConclusionSuicidal thoughts and their expression appear commonly and are normalized in later life yet remain taboo and hidden. The participants revealed how such thoughts and behaviors are typically expressed through colloquial or “off-hand” remarks and comments and the importance of authentic listening. The findings highlight the importance of more informal discussions around these topics and how care professionals, practitioners, and providers might frame opportunities for dialogue with people who may want to access support. Further engagement with community-informed participatory research methods in which older people provide their own perspectives and experiences is important in addressing these gaps. There is a need for co-designing in developing screening, assessment, and signposting outside of clinical settings that can be used in everyday caring relationships with people in later life.

Q fever is a zoonotic disease caused by the highly infectious Gram-negative coccobacillus, Coxiella burnetii (C. burnetii). The Q fever vaccine Q-VAX® is characterised by high reactogenicity, requiring individuals to be pre-screened for prior exposure before vaccination. To date it remains unclear whether vaccine side effects in pre-exposed individuals are associated with pre-existing adaptive immune responses to C. burnetii or are also a function of innate responses to Q-VAX®. In the current study, we measured innate and adaptive cytokine responses to C. burnetii and compared these among individuals with different pre-exposure status. Three groups were included: n=98 Dutch blood bank donors with unknown exposure status, n=95 Dutch village inhabitants with known natural exposure status to C. burnetii during the Dutch Q fever outbreak of 2007-2010, and n=96 Australian students receiving Q-VAX® vaccination in 2021. Whole blood cytokine responses following ex vivo stimulation with heat-killed C. burnetii were assessed for IFNγ, IL-2, IL-6, IL-10, TNFα, IL-1β, IP-10, MIP-1α and IL-8. Serological data were collected for all three cohorts, as well as data on skin test and self-reported vaccine side effects and clinical symptoms during past infection. IFNγ, IP-10 and IL-2 responses were strongly elevated in individuals with prior C. burnetii antigen exposure, whether through infection or vaccination, while IL-1β, IL-6 and TNFα responses were slightly increased in naturally exposed individuals only. High dimensional analysis of the cytokine data identified four clusters of individuals with distinct cytokine response signatures. The cluster with the highest levels of adaptive cytokines and antibodies comprised solely individuals with prior exposure to C. burnetii, while another cluster was characterized by high innate cytokine production and an absence of C. burnetii-induced IP-10 production paired with high baseline IP-10 levels. Prior exposure status was partially associated with these signatures, but could not be clearly assigned to a single cytokine response signature. Overall, Q-VAX® vaccination and natural C. burnetii infection were associated with comparable cytokine response signatures, largely driven by adaptive cytokine responses. Neither individual innate and adaptive cytokine responses nor response signatures were associated retrospectively with clinical symptoms during infection or prospectively with side effects post-vaccination.

T cell-mediated immunity plays a central role in the control and clearance of intracellular Coxiella burnetii infection, which can cause Q fever. Therefore, we aimed to develop a novel T cell-targeted vaccine that induces pathogen-specific cell-mediated immunity to protect against Q fever in humans while avoiding the reactogenicity of the current inactivated whole cell vaccine. Human HLA class II T cell epitopes from C. burnetii were previously identified and selected by immunoinformatic predictions of HLA binding, conservation in multiple C. burnetii isolates, and low potential for cross-reactivity with the human proteome or microbiome. Epitopes were selected for vaccine inclusion based on long-lived human T cell recall responses to corresponding peptides in individuals that had been naturally exposed to the bacterium during a 2007-2010 Q fever outbreak in the Netherlands. Multiple viral vector-based candidate vaccines were generated that express concatemers of selected epitope sequences arranged to minimize potential junctional neo-epitopes. The vaccine candidates caused no antigen-specific reactogenicity in a sensitized guinea pig model. A subset of the vaccine epitope peptides elicited antigenic recall responses in splenocytes from C57BL/6 mice previously infected with C. burnetii. However, immunogenicity of the vaccine candidates in C57BL/6 mice was dominated by a single epitope and this was insufficient to confer protection against an infection challenge, highlighting the limitations of assessing human-targeted vaccine candidates in murine models. The viral vector-based vaccine candidates induced antigen-specific T cell responses to a broader array of epitopes in cynomolgus macaques, establishing a foundation for future vaccine efficacy studies in this large animal model of C. burnetii infection.

Background: Defining the value of healthcare is an elusive target, and depends heavily on the decision context and stakeholders involved. Cost-utility analysis and the quality-adjusted life year (QALY) have become the method and value definition of choice for traditional value judgements in coverage and pricing decisions. Other criteria that may influence value are often not measured and therefore omitted from value assessments, or are only used to qualitatively contextualize assessments. The objective of this study was to engage two key stakeholders; patients and payers to elicit and rank the importance of additional value criteria, potentially assessed in Multiple Criteria Decision Analysis (MCDA).Methods: This study consisted of a focus group with cancer patients (n = 7), including follow-up questions through an electronic survey, and in-depth phone interviews with payers (n = 5).Results: For payers, value equated either with criteria that provided tangible benefits (from their perspective) such as new treatment options that respond to serious unmet need. For patients, population-level value equated to options that would potentially benefit them in the future and the value of hope. However, these criteria were seen by payers as difficult to measure and incorporate into objective decision making.Limitations: The findings from this study are primarily limited due to generalizability. Due to the small sample size, it was outside the scope of this study to calculate a weight for each criterion that could be used as part of a quantitative MCDA.Conclusion: MCDA, with particular attention to qualitative aspects, is an avenue to incorporate these additional criteria into value assessments, as well as provide an opportunity for reflecting the patient’s preferences in assessing the value of a treatment.

BackgroundResearch has demonstrated that exposure to suicide can lead to increased vulnerability for self-harm or suicide. As a result, ideation-to-action models of suicide (e.g., the Integrated Motivational-Volitional Model of Suicide; IMV) recognise exposure as a significant risk factor which may be implicated in the translation of thoughts into actions. However, few studies have tested this theoretical link explicitly within an adolescent population, and examined how it compares to other types of bereavements.MethodsA 6-month prospective questionnaire study was conducted with 185 Scottish adolescents aged 11–17 (113 adolescents also completed the questionnaire at follow-up). The questionnaire included measures on experiences with bereavement and lifetime engagement in self-harm, as well as measures of defeat, entrapment, social support, coping, and other psychological variables.ResultsAt baseline, 12% of young people reported exposure to a suicide death, and 61% to a non-suicide death. In addition, 21% of pupils reported ever engaging in self-harm, while 23% had experienced self-harm ideation without engaging in it. Cross-sectional multivariate logistic regressions showed that family social support, glorifying/normalising beliefs about suicide, and family self-harm were significantly associated with self-harm group membership (control, ideation, or enactment groups). At follow-up, 10% of pupils reported exposure to a suicide death and 16% to a non-suicide death for the first time. A total of 26% of the sample reported self-harm at T2 (11% of participants for the first time), and 24% reported self-harm ideation without engaging in it. Multivariate analyses found that self-harm ideation and family self-harm at baseline were the only variables to predict self-harm group membership prospectively, in the expected directions. Bereavement experiences, whether by suicide or non-suicide, did not predict self-harm group status at baseline nor at follow-up.ConclusionsThis study provides support for the validity of a theoretical model of suicide, even though predictive ability over the 6-months period was limited. Although difficulties with recruitment may have limited the statistical power, this study provides insight into the prevalence and experiences of suicide bereavement among adolescents and the factors related to the onset and maintenance of self-harm.

Coxiella burnetii, the causative agent of Q fever, is a Gram-negative intracellular bacterium transmitted via aerosol. Regulatory approval of the Australian whole-cell vaccine Q-VAX® in the US and Europe is hindered by reactogenicity in previously exposed individuals. The aim of this study was to identify and rationally select C. burnetii epitopes for design of a safe, effective, and less reactogenic T-cell targeted human Q fever vaccine. Immunoinformatic methods were used to predict 65 HLA class I epitopes and 50 promiscuous HLA class II C. burnetii epitope clusters, which are conserved across strains of C. burnetii. HLA binding assays confirmed 89% of class I and 75% of class II predictions, and 11 HLA class II epitopes elicited IFNγ responses following heterologous DNA/DNA/peptide/peptide prime-boost immunizations of HLA-DR3 transgenic mice. Human immune responses to the predicted epitopes were characterized in individuals naturally exposed to C. burnetii during the 2007–2010 Dutch Q fever outbreak. Subjects were divided into three groups: controls with no immunological evidence of previous infection and individuals with responses to heat-killed C. burnetii in a whole blood IFNγ release assay (IGRA) who remained asymptomatic or who experienced clinical Q fever during the outbreak. Recall responses to C. burnetii epitopes were assessed by cultured IFNγ ELISpot. While HLA class I epitope responses were sparse in this cohort, we identified 21 HLA class II epitopes that recalled T-cell IFNγ responses in 10–28% of IGRA+ subjects. IGRA+ individuals with past asymptomatic and symptomatic C. burnetii infection showed a comparable response pattern and cumulative peptide response which correlated with IGRA responses. None of the peptides elicited reactogenicity in a C. burnetii exposure-primed guinea pig model. These data demonstrate that a substantial proportion of immunoinformatically identified HLA class II epitopes show long-lived immunoreactivity in naturally infected individuals, making them desirable candidates for a novel human multi-epitope Q fever vaccine.