891 research outputs found

    Persistence of the immune response induced by BCG vaccination.

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    BACKGROUND: Although BCG vaccination is recommended in most countries of the world, little is known of the persistence of BCG-induced immune responses. As novel TB vaccines may be given to boost the immunity induced by neonatal BCG vaccination, evidence concerning the persistence of the BCG vaccine-induced response would help inform decisions about when such boosting would be most effective. METHODS: A randomised control study of UK adolescents was carried out to investigate persistence of BCG immune responses. Adolescents were tested for interferon-gamma (IFN-gamma) response to Mycobacterium tuberculosis purified protein derivative (M.tb PPD) in a whole blood assay before, 3 months, 12 months (n = 148) and 3 years (n = 19) after receiving teenage BCG vaccination or 14 years after receiving infant BCG vaccination (n = 16). RESULTS: A gradual reduction in magnitude of response was evident from 3 months to 1 year and from 1 year to 3 years following teenage vaccination, but responses 3 years after vaccination were still on average 6 times higher than before vaccination among vaccinees. Some individuals (11/86; 13%) failed to make a detectable antigen-specific response three months after vaccination, or lost the response after 1 (11/86; 13%) or 3 (3/19; 16%) years. IFN-gamma response to Ag85 was measured in a subgroup of adolescents and appeared to be better maintained with no decline from 3 to 12 months. A smaller group of adolescents were tested 14 years after receiving infant BCG vaccination and 13/16 (81%) made a detectable IFN-gamma response to M.tb PPD 14 years after infant vaccination as compared to 6/16 (38%) matched unvaccinated controls (p = 0.012); teenagers vaccinated in infancy were 19 times more likely to make an IFN-gamma response of > 500 pg/ml than unvaccinated teenagers. CONCLUSION: BCG vaccination in infancy and adolescence induces immunological memory to mycobacterial antigens that is still present and measurable for at least 14 years in the majority of vaccinees, although the magnitude of the peripheral blood response wanes from 3 months to 12 months and from 12 months to 3 years post vaccination. The data presented here suggest that because of such waning in the response there may be scope for boosting anti-tuberculous immunity in BCG vaccinated children anytime from 3 months post-vaccination. This supports the prime boost strategies being employed for some new TB vaccines currently under development

    Is 'Opt-Out HIV Testing' a real option among pregnant women in rural districts in Kenya?

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    PMTCT allows people living with HIV to actualize childbearing. However, it also complicates motherhood, as the medical consequences and public health implications of non-adherence to PMTCT service recommendations disrupt socio-cultural expectations of childbearing and parenthood. This thesis aimed to study childbearing and adherence to PMTCT interventions focusing on how women living with HIV realize motherhood in Kenya. We sought to answer how women on ART experience motherhood and how motherhood aggravate adherence to PMTCT services Methods: A quantitative cross sectional study (I) with a questionnaire survey conducted among pregnant women at their first visit to antenatal clinic to study consent to HIV testing and three qualitative studies analyzed with content analysis (II and IV) and narrative structuring (III) were included. Qualitative interviews were performed with women living with HIV who were pregnant, recently delivered and those actively planning a pregnancy to explore views and experiences when seeking a pregnancy (II), the reasoning and deciding about adherence to PMTCT (III) and how motherhood interferes with HIV treatment (IV). Results: ‘Striving for motherhood’ was the overriding theme describing the desire of women on ART to be parents while negotiating the challenges of living with HIV (IIV). Children improve women’s position in society and are a sign of a happy and fulfilled life (II-IV). Of 900 pregnant women surveyed at their first visit to antenatal care clinic, only 17% understood that HIV testing is optional (I). Making an informed decision to decline HIV testing was associated with knowing that testing was optional (OR=5.44, 95%CI 3.44-8.59), not having a stable relationship with the child’s father (OR=1.76, 95%CI 1.02-3.03), and not having discussed HIV testing with a partner before the ANC visit (OR=2.64 95%CI 1.79-3.86). Socio-economic affluence and residence influence behaviors such as no condom use, non-disclosure of HIV infection, use of traditional medicine simultaneously with ART, home delivery and stigma and discrimination from partners, family and community, all of which undermine adherence to PMTCT services (II-IV). Structural shortcomings in PMTCT result in the lack of antiretroviral HIV medicines, practice of mixed infant feeding and missed appointments (I, III, IV). Conclusion: Motherhood is achieved at the cost of striving to balance socio-cultural expectations of childbearing that also conceals their HIV infection at the cost of nonadherence to PMTCT recommendations. Being infected with HIV does not remove the desire of motherhood and related socio-cultural demands. It is important to acknowledge the significance childbearing among women infected with HIV to improve adherence. Women with chronic illness such as HIV-infection who are dependent on continuous medication and health check-ups struggle to balance the desire for children with the needs related to their illness and the expectations of being a ‘good mother’

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe
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