1,091 research outputs found

    Childhood tuberculosis infection and disease: A spatial and temporal transmission analysis in a South African township

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    Background. Tuberculosis (TB) remains a leading cause of mortality and morbidity in South Africa. While adult TB results from both recent and past infection, childhood TB results from recent infection and reflects ongoing transmission despite current TB control strategies.Setting. A South African community with high rates of TB and HIV disease.Outcomes. A Geographic Information System was used to spatially and temporally define the relationships between TB exposure, infection and disease in childre

    Heterologous vaccination of BNT162b2 in Ad26. COV2.S-vaccinated healthcare workers elicits long-term humoral immune response

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    Background. To date, there are no immunological data for the SARS-CoV-2 heterologous vaccination schedule in the South African (SA) population.Objectives. To assess and compare the immunogenicity and reactogenicity of the Jansen Ad26.COV2.S vaccine with the Pfizer/BioNTech- BNT162b2 booster following prime Ad26.COV2.S in 65 SA healthcare workers.Methods. In a prospective, quantitative, cross-sectional trial on individuals >18 years of age vaccinated with a single Ad26.COV2.S dose or single Ad26.COV2.S and a BNT162b2 single-dose/both doses booster, participants filled in a questionnaire on their demographics, type of vaccination, breakthrough infection/s (BTI/s), vaccine reactogenicity, prior SARS-CoV-2 infection and dates of vaccination. Qualitative analysis for presence/absence of anti-S (spike) immunoglobulin G (IgG) was performed using the Euroimmun anti-IgG enzyme-linked immunoassay kit, and anti-S IgG titres were quantitatively assessed using the Abbott IgG Quant II kit.Results. Between 28 October 2021 and 30 November 2021, 65 individuals were enrolled and assigned as either prime Ad26.COV2.S (n=18) or Ad26.COV2.S with a BNT162b2 supplement (n=47) at Charlotte Maxeke Johannesburg Academic Hospital, SA (mean age 45 years (95% confidence interval (CI) 29.5 - 58), 42 women (64.6%) and 23 men (35.4%)). The median IgG titre for the primed Ad26.COV2.S group was 4 272.55 (95% CI 68.40 - 10 351.40) and that for the BNT162b2 supplement group was 7 360.80 (95% CI 4 207.40 - 15 372.60). In the univariate model, the BNT162b2 supplement group showed a significant 1.99 times higher antibody titre factor (95% CI 0.045 - 5.553; p<0.005) than the Ad26.COV2.S group. In both univariate and multivariate models, age, time since prime vaccination, BTI and prior infection failed to show any statistically significant association (p>0.05) with antibody titres in both groups. However, sex (–55.381 (95% CI –76.984 - –13.498; p=0.018) in a multivariate model was found to have a statistically significant association with anti-S IgG titres observed in both groups. Participants who received their first dose of BNT162b2 9 - 10 months after their prime Ad26.COV2.S (n=44) had a higher degree of antibody response than those who received it earlier. Reactogenicity was observed to be manageable, with mild/moderate adverse effects in the study population.Conclusion. A BNT162b2 supplement given in single or two doses as booster in individuals primed with Ad26.COV2.S induced immunological response, with acceptable and manageable reactogenicity. This study provides novel evidence of the highest degree of antibody response in individuals who received a BNT162b2 first dose 9 - 10 months after prime Ad26.COV2.S, implying that a longer time gap between the two vaccines stimulates higher antibody response than a shorter gap, and that this antibody response can persist for as long as 6 months after the last BNT162b2 dose

    First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei

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    A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure

    Measuring environmental health status in Oukasie, 1987

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    This article reports on some aspects of the physical environment and on envirorvnental health services at Oukasie. The data were collected over a weekend in August 1987 by an interview and by direct inspection of the environment using a standard schedule. We had a 100% response rate on the interviews. There was a mean of 2,2 ± 1,6 persons per room in the households, with brick houses being less crowded than non-brick houses. Private yards were generally kept very clean. Bucket latrines were unhygienic and used by an average of 4 families. No latrine was built to accepted standards. Garbage collection and emptying of the bucket latrines by the municipality seemed to be unsatisfactory. Our overall impression was that where responsibility for maintenance of hygiene is either undefined, such as the collection chambers of bucket latrines, or a responsibility of the public authorities, such as garbage collection and water drainage, there is an unsatisfactory state of hygiene. Where maintenance of cleanlness is clearly a private responsibility, such as the maintenance of the cleanliness of private yards, the general status of hygiene is good

    Isotopic evidence for dominant secondary production of HONO in near-ground wildfire plumes

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    Nitrous acid (HONO) is an important precursor to hydroxyl radical (OH) that determines atmospheric oxidative capacity and thus impacts climate and air quality. Wildfire is not only a major direct source of HONO, it also results in highly polluted conditions that favor the heterogeneous formation of HONO from nitrogen oxides (NOx= NO + NO2) and nitrate on both ground and particle surfaces. However, these processes remain poorly constrained. To quantitatively constrain the HONO budget under various fire and/or smoke conditions, we combine a unique dataset of field concentrations and isotopic ratios (15N / 14N and 18O / 16O) of NOx and HONO with an isotopic box model. Here we report the first isotopic evidence of secondary HONO production in near-ground wildfire plumes (over a sample integration time of hours) and the subsequent quantification of the relative importance of each pathway to total HONO production. Most importantly, our results reveal that nitrate photolysis plays a minor role (\u3c5 %) in HONO formation in daytime aged smoke, while NO2-to-HONO heterogeneous conversion contributes 85 %–95 % to total HONO production, followed by OH + NO (5 %–15 %). At nighttime, heterogeneous reduction of NO2 catalyzed by redox active species (e.g., iron oxide and/or quinone) is essential (≥ 75 %) for HONO production in addition to surface NO2 hydrolysis. Additionally, the 18O / 16O of HONO is used for the first time to constrain the NO-to-NO2 oxidation branching ratio between ozone and peroxy radicals. Our approach provides a new and critical way to mechanistically constrain atmospheric chemistry and/or air quality models on a diurnal timescale

    Understanding treatment decisions from the perspective of people with relapsing remitting multiple Sclerosis: A critical interpretive synthesis

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    Background: Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system that mainly affects young adults. While there is no cure for MS, disease modifying treatments (DMTs) reduce the relapse rate and partial accrual of disability. More effective DMTs may have higher risks including life-threatening infections or secondary autoimmunity. The complexity and novelty of available treatments cause challenges for clinicians when prescribing treatments and for people with MS (PwMS) when deciding what trade-offs they are willing and ready to make. / Objective: To explore the experience of people with relapsing remitting MS (PwRRMS) and their perspectives in choosing treatments. / Methods: Critical interpretive synthesis was employed to review and synthesis the published literature. Eighty-three publications were selected in a multi-step systematic process. / Results: Findings are presented in four interrelated areas: the influence of the clinical evidence-base in decision making; the meaning of DMT efficacy for PwRRMS; the influence of models of decision-making and information acquisition practices in PwRRMS; and the importance of psychosocial dimensions in DMT decision making. Synthesis of the findings revealed that alongside medical and individual reasoning, contextual circumstances play an important role in making treatment decisions. / Conclusion: This review identifies and explains the importance of diverse contextual circumstances (clinical, social, psychological) that are important for PwRRMS when making treatment decisions. The findings demonstrate the importance of eliciting, understanding and addressing such contextual factors

    LIGHT AND ELECTRON MICROSCOPIC STUDY OF SURFACES OF TEST-SPECIMENS TESTED IN WEAR APPARATUSES

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    Objective: Symptoms of acute retroviral syndrome (ARS) may be used to identify patients with acute HIV-1 infection who seek care. ARS symptoms in African adults differ by region. We assessed whether reporting of ARS was associated with HIV-1 subtype in a multicentre African cohort study representing countries with predominant HIV-1 subtypes A, C, and D. Methods: ARS symptoms were assessed in adults enrolling within 6 weeks after the estimated date of infection in an acute and early HIV-1 infection cohort study. HIV-1 subtype was determined by POL genotyping. We used log-binomial regression to compare ARS symptom prevalence among those with subtype A vs. C or D, adjusting for sex, time since enrolment, and enrolment viral load. Results: Among 183 volunteers ascertained within 6 weeks after estimated date of infection, 77 (42.0%) had subtype A, 83 (45.4%) subtype C, and 23 (12.6%) subtype D infection. Individuals with subtype A were 1.40 (95% confidence interval: 1.17, 1.68) times as likely as individuals with subtypes C or D to report any ARS symptoms; each individual symptom other than rash was also more prevalent in subtype A than in subtype C or D, with prevalence ratios ranging from 1.94 (1.40, 2.70) for headache to 4.92 (2.24, 10.78) for lymphadenopathy. Conclusion: Individuals with subtype A were significantly more likely than individuals with subtypes C or D to report any ARS symptoms. HIV-1 subtypes may help explain differences in ARS that have been observed across regions in Africa, and may impact the yield of symptom-based screening strategies for acute HIV infection detection

    Men's preferences for prostate cancer screening: A discrete choice experiment

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    Background: Screening for prostate cancer (PC) may save lives, but overdiagnosis and overtreatment are serious drawbacks. We aimed to determine men's preferences for PC screening, and to elicit the trade-offs they make. Methods: A discrete choice experiment (DCE) was conducted among a population-based random sample of 1000 elderly men (55-75-years-old). Trade-offs were quantified with a panel latent class model between five PC screening aspects: risk reduction of PC-related death, screening interval, risk of unnecessary biopsies, risk of unnecessary treatments, and out-of-pocket costs. Results: The response rate was 46% (459/1000). Men were willing to trade-off 2.0% (CI: 1.6%-2.4%) or 1.8% (CI: 1.3%-2.3%) risk reduction of PC-related death to decrease their risk of unnecessary treatment or biopsy with 10%, respectively. They were willing to pay \[euro]188 per year (CI: \[euro]141-\[euro]258) to reduce their relative risk of PC-related death with 10%. Preference heterogeneity was substantial, with men with higher educational levels having a lower probability to opt for PC screening than men with lower educational levels. Conclusion: Men were willing to trade-off some risk reduction of PC-related death to be relieved of the burden of biopsies or unnecessary treatments. Increasing knowledge on overdiagnosis and overtreatment, especially for men with lower educational levels, is warranted to prevent unrealistic expectations from PC screening. © 2013 Cancer Research UK. All rights reserved

    A mixed-methods assessment of understanding (AoU) tool for AIDS vaccine trials in sub-Saharan Africa: results from a pilot study

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    Assessments of understanding (AoUs) in clinical trials are often composed of true/false multiple choice questions, however, these tools can be difficult for volunteers with limited education or without prior testing experience
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