18 results on '"Tobias JL"'
Search Results
2. Nonparametric estimation in economics: Bayesian and frequentist approaches
- Author
-
Chan, JCC, Henderson, DJ, Parmeter, CF, and Tobias, JL
- Subjects
Statistics::Machine Learning ,Statistics::Theory ,Statistics::Methodology - Abstract
© 2017 Wiley Periodicals, Inc. We review Bayesian and classical approaches to nonparametric density and regression estimation and illustrate how these techniques can be used in economic applications. On the Bayesian side, density estimation is illustrated via finite Gaussian mixtures and a Dirichlet Process Mixture Model, while nonparametric regression is handled using priors that impose smoothness. From the frequentist perspective, kernel-based nonparametric regression techniques are presented for both density and regression problems. Both approaches are illustrated using a wage dataset from the Current Population Survey. WIREs Comput Stat 2017, 9:e1406. doi: 10.1002/wics.1406. For further resources related to this article, please visit the WIREs website.
- Published
- 2017
3. Priors and Posterior Computation in Linear Endogenous Variable Models with Imperfect Instruments
- Author
-
Chan, JCC and Tobias, JL
- Subjects
Econometrics - Abstract
© 2014 John Wiley & Sons, Ltd. In this paper we, like several studies in the recent literature, employ a Bayesian approach to estimation and inference in models with endogeneity concerns by imposing weaker prior assumptions than complete excludability. When allowing for instrument imperfection of this type, the model is only partially identified, and as a consequence standard estimates obtained from the Gibbs simulations can be unacceptably imprecise. We thus describe a substantially improved 'semi-analytic' method for calculating parameter marginal posteriors of interest that only require use of the well-mixing simulations associated with the identifiable model parameters and the form of the conditional prior. Our methods are also applied in an illustrative application involving the impact of body mass index on earnings.
- Published
- 2015
4. COVID-19 Vaccination Site Accessibility, United States, December 11, 2020-March 29, 2022.
- Author
-
Yee R, Carranza D, Kim C, Trinidad JP, Tobias JL, Bhatkoti R, and Kuwabara S
- Subjects
- Humans, United States epidemiology, Rural Population, Walking, Urban Population, COVID-19 prevention & control, COVID-19 epidemiology, COVID-19 Vaccines administration & dosage, SARS-CoV-2 immunology, Health Services Accessibility statistics & numerical data, Vaccination statistics & numerical data
- Abstract
During December 11, 2020-March 29, 2022, the US government delivered ≈700 million doses of COVID-19 vaccine to vaccination sites, resulting in vaccination of ≈75% of US adults during that period. We evaluated accessibility of vaccination sites. Sites were accessible by walking within 15 minutes by 46.6% of persons, 30 minutes by 74.8%, 45 minutes by 82.8%, and 60 minutes by 86.7%. When limited to populations in counties with high social vulnerability, accessibility by walking was 55.3%, 81.1%, 86.7%, and 89.4%, respectively. By driving, lowest accessibility was 96.5% at 15 minutes. For urban/rural categories, the 15-minute walking accessibility between noncore and large central metropolitan areas ranged from 27.2% to 65.1%; driving accessibility was 79.9% to 99.5%. By 30 minutes driving accessibility for all urban/rural categories was >95.9%. Walking time variations across jurisdictions and between urban/rural areas indicate that potential gains could have been made by improving walkability or making transportation more readily available.
- Published
- 2024
- Full Text
- View/download PDF
5. Reaching Youth Through Faith Leaders: Evaluation of the Faith Matters! Initiative.
- Author
-
Kanagasabai U, Aholou T, Chevalier MS, Tobias JL, Okuku J, Shiraishi RW, Sheneberger R, Pande YC, Chifuwe C, Mamane LE, Njika G, Obongo C, and Thorsen VC
- Subjects
- Humans, Adolescent, Health Promotion, Surveys and Questionnaires, Zambia, HIV Infections prevention & control, Acquired Immunodeficiency Syndrome
- Abstract
Faith leaders can be uniquely positioned to guide and support young people on health issues, particularly HIV/AIDS and sexual violence. Faith Matters!, a 2-day training workshop for faith leaders, was delivered in September 2021 in Zambia. Sixty-six faith leaders completed a questionnaire at baseline, 64 at posttraining, and 59 at 3-month follow-up. Participants' knowledge, beliefs, and comfort communicating about HIV/AIDS and sexual violence were assessed. More faith leaders accurately identified common places where sexual violence occurs at the 3-month point compared to baseline: at church (2 vs. 22, p = .000), the fields (16 vs. 29, p = .004), parties (22 vs. 36, p = .001), and clubs (24 vs. 35, p = .034). More faith leaders stated that they engaged in conversations that supported people living with HIV (48 at baseline vs. 53, p = .049 at 3-month follow-up). These findings can inform future HIV/AIDS initiatives focusing on increasing the capacity among communities of faith.
- Published
- 2023
- Full Text
- View/download PDF
6. Use of High-Resolution Geospatial and Genomic Data to Characterize Recent Tuberculosis Transmission, Botswana.
- Author
-
Baker CR, Barilar I, de Araujo LS, Rimoin AW, Parker DM, Boyd R, Tobias JL, Moonan PK, Click ES, Finlay A, Oeltmann JE, Minin VN, Modongo C, Zetola NM, Niemann S, and Shin SS
- Subjects
- Humans, Botswana epidemiology, Genotype, Genomics, Tuberculosis microbiology, Mycobacterium tuberculosis genetics
- Abstract
Combining genomic and geospatial data can be useful for understanding Mycobacterium tuberculosis transmission in high-burden tuberculosis (TB) settings. We performed whole-genome sequencing on M. tuberculosis DNA extracted from sputum cultures from a population-based TB study conducted in Gaborone, Botswana, during 2012-2016. We determined spatial distribution of cases on the basis of shared genotypes among isolates. We considered clusters of isolates with ≤5 single-nucleotide polymorphisms identified by whole-genome sequencing to indicate recent transmission and clusters of ≥10 persons to be outbreaks. We obtained both molecular and geospatial data for 946/1,449 (65%) participants with culture-confirmed TB; 62 persons belonged to 5 outbreaks of 10-19 persons each. We detected geospatial clustering in just 2 of those 5 outbreaks, suggesting heterogeneous spatial patterns. Our findings indicate that targeted interventions applied in smaller geographic areas of high-burden TB identified using integrated genomic and geospatial data might help interrupt TB transmission during outbreaks.
- Published
- 2023
- Full Text
- View/download PDF
7. Retaining Patients with Drug-Resistant Tuberculosis on Treatment During the COVID-19 Pandemic - Dharavi, Mumbai, India, 2020-2022.
- Author
-
Gomare MD, Bhide S, Deshmukh R, Kaipilyawar S, Puri V, Moonan PK, Khetade DK, Nyendak M, Yeldandi V, Smith JP, Tobias JL, Date A, Joshi R, Kumar R, and Ho CS
- Subjects
- Humans, Pandemics, India epidemiology, Antitubercular Agents therapeutic use, COVID-19 epidemiology, Tuberculosis, Multidrug-Resistant drug therapy, Tuberculosis, Multidrug-Resistant epidemiology, Tuberculosis drug therapy, Tuberculosis epidemiology
- Abstract
Mumbai, India's second largest city, has one of the highest prevalences of drug-resistant tuberculosis* (DRTB) in the world. Treatment for DRTB takes longer and is more complicated than treatment for drug-susceptible tuberculosis (TB). Approximately 300 persons receive a new DRTB diagnosis each year in Mumbai's Dharavi slum
† ; historically, fewer than one half of these patients complete DRTB treatment. As nationwide restrictions to mitigate the COVID-19 pandemic were implemented, a program to facilitate uninterrupted DRTB care for patients receiving treatment was also implemented. A comprehensive tool and risk assessment provided support to DRTB patients and linked those who relocated outside of Dharavi during the pandemic to DRTB care at their destination. During May 2020-September 2022, a total of 973 persons received DRTB treatment in Dharavi, including 255 (26%) who relocated during treatment. Overall, 25 (3%) DRTB patients were lost to follow-up, a rate substantially lower than the rate before the pandemic (18%). Proactive planning and implementation of simple tools retained patients on treatment during periods of travel restrictions and relocations, improving programmatic outcomes. This approach might aid public health programs serving migrant populations or patients receiving treatment for DRTB during public health emergencies., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.- Published
- 2023
- Full Text
- View/download PDF
8. Tuberculosis attributed to transmission within healthcare facilities, Botswana-The Kopanyo Study.
- Author
-
Smith JP, Modongo C, Moonan PK, Dima M, Matsiri O, Fane O, Click ES, Boyd R, Finlay A, Surie D, Tobias JL, Zetola NM, and Oeltmann JE
- Subjects
- Humans, Prospective Studies, Botswana epidemiology, Delivery of Health Care, Tuberculosis epidemiology, Mycobacterium tuberculosis genetics
- Abstract
Objective: Healthcare facilities are a well-known high-risk environment for transmission of M. tuberculosis , the etiologic agent of tuberculosis (TB) disease. However, the link between M. tuberculosis transmission in healthcare facilities and its role in the general TB epidemic is unknown. We estimated the proportion of overall TB transmission in the general population attributable to healthcare facilities., Methods: We combined data from a prospective, population-based molecular epidemiologic study with a universal electronic medical record (EMR) covering all healthcare facilities in Botswana to identify biologically plausible transmission events occurring at the healthcare facility. Patients with M. tuberculosis isolates of the same genotype visiting the same facility concurrently were considered an overlapping event. We then used TB diagnosis and treatment data to categorize overlapping events into biologically plausible definitions. We calculated the proportion of overall TB cases in the cohort that could be attributable to healthcare facilities., Results: In total, 1,881 participants had TB genotypic and EMR data suitable for analysis, resulting in 46,853 clinical encounters at 338 healthcare facilities. We identified 326 unique overlapping events involving 370 individual patients; 91 (5%) had biologic plausibility for transmission occurring at a healthcare facility. A sensitivity analysis estimated that 3%-8% of transmission may be attributable to healthcare facilities., Conclusions: Although effective interventions are critical in reducing individual risk for healthcare workers and patients at healthcare facilities, our findings suggest that development of targeted interventions aimed at community transmission may have a larger impact in reducing TB.
- Published
- 2022
- Full Text
- View/download PDF
9. Characterizing tuberculosis transmission dynamics in high-burden urban and rural settings.
- Author
-
Smith JP, Oeltmann JE, Hill AN, Tobias JL, Boyd R, Click ES, Finlay A, Mondongo C, Zetola NM, and Moonan PK
- Subjects
- Humans, Prospective Studies, Rural Population, Urban Population, Mycobacterium tuberculosis genetics, Tuberculosis epidemiology
- Abstract
Mycobacterium tuberculosis transmission dynamics in high-burden settings are poorly understood. Growing evidence suggests transmission may be characterized by extensive individual heterogeneity in secondary cases (i.e., superspreading), yet the degree and influence of such heterogeneity is largely unknown and unmeasured in high burden-settings. We conducted a prospective, population-based molecular epidemiology study of TB transmission in both an urban and rural setting of Botswana, one of the highest TB burden countries in the world. We used these empirical data to fit two mathematical models (urban and rural) that jointly quantified both the effective reproductive number, [Formula: see text], and the propensity for superspreading in each population. We found both urban and rural populations were characterized by a high degree of individual heterogeneity, however such heterogeneity disproportionately impacted the rural population: 99% of secondary transmission was attributed to only 19% of infectious cases in the rural population compared to 60% in the urban population and the median number of incident cases until the first outbreak of 30 cases was only 32 for the rural model compared to 791 in the urban model. These findings suggest individual heterogeneity plays a critical role shaping local TB epidemiology within subpopulations., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
10. Zambia Assessment of Tuberculosis (TB) and HIV in the Mines (ZATHIM): implications for programs and policies.
- Author
-
Podewils LJ, Long EF, Fuller TJ, Mwakazanga D, Kapungu K, Tembo M, Mwanza S, Curran KG, Smith JP, Tobias JL, and Kasongo W
- Subjects
- Cough, HIV Infections diagnosis, Health Personnel psychology, Health Services Accessibility economics, Health Services Accessibility trends, Humans, Policy, Social Determinants of Health economics, Social Determinants of Health trends, Tuberculosis diagnosis, Tuberculosis prevention & control, Zambia epidemiology, HIV Infections epidemiology, Health Knowledge, Attitudes, Practice, Health Services Accessibility statistics & numerical data, Mining organization & administration, Tuberculosis epidemiology
- Abstract
Background: Mineworkers in Southern Africa have the highest rates of tuberculosis (TB) among working populations in the world (The World Bank, Benefits and costs associated with reducing tuberculosis among Southern Africa's mineworkers, 2014), making mineworkers a key population for TB program efforts. The current evaluation aimed to characterize mineworkers and former (ex-) mineworkers, and assess knowledge, attitudes and practices related to TB and HIV care among mineworkers and healthcare workers (HCWs) in Zambia., Methods: A mixed-methods evaluation of current and former (ex-) mineworkers and HCWs was conducted in the Copperbelt and North-Western provinces, Zambia. Knowledge, attitudes and practices (KAPs) related to TB care and policies were assessed using a structured survey. Focus Group Discussions (FGDs) were conducted with current and ex-mineworkers to understand perceptions, practices, and barriers related to accessing healthcare for TB., Results: Overall, 2,792 mineworkers and 94 HCWs completed the KAP survey, and 206 (171 current, 71 ex-) mineworkers participated in FGDs. Mineworkers and ex-mineworkers were knowledgeable about TB symptoms (cough; 94%), transmission (81.7%) and treatment (99.2%). Yet, barriers to seeking care were evident with 30% of mineworkers experiencing cough, and 19% reporting 2 or more TB symptoms at the time of the survey. The majority of mineworkers (70.9%) were aware of policies barring persons from working after a diagnosis of TB, and themes from FGDs and HCW comments (n = 32/62; 51.6%) recognized fear of job loss as a critical barrier to providing timely screening and appropriate care for TB among mineworkers. The majority (76.9%) of mineworkers indicated they would not disclose their TB status to their supervisor, but would be willing to share their diagnosis with their spouse (73.8%)., Conclusion: Fear of job loss, driven by governmental policy and mistrust in mining companies, is a major barrier to healthcare access for TB among mineworkers in Zambia. As a result of these findings, the government policy prohibiting persons from working in the mines following TB disease is being repealed. However, major reforms are urgently needed to mitigate TB among mineworkers, including ensuring the rights of mineworkers and their communities to healthy living and working environments, improved social responsibility of mining companies, and facilitating choice and access to affordable, timely, and high-quality healthcare services., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
11. Geospatial Transmission Hotspots of Recent HIV Infection - Malawi, October 2019-March 2020.
- Author
-
Telford CT, Tessema Z, Msukwa M, Arons MM, Theu J, Bangara FF, Ernst A, Welty S, O'Malley G, Dobbs T, Shanmugam V, Kabaghe A, Dale H, Wadonda-Kabondo N, Gugsa S, Kim A, Bello G, Eaton JW, Jahn A, Nyirenda R, Parekh BS, Shiraishi RW, Kim E, Tobias JL, Curran KG, Payne D, and Auld AF
- Subjects
- Adult, Female, Humans, Malawi epidemiology, Male, Public Health, Software, Young Adult, Disease Hotspot, HIV Infections diagnosis, HIV Infections epidemiology, HIV Infections transmission, HIV Testing methods, Sentinel Surveillance, Spatial Analysis
- Abstract
Persons infected with HIV are more likely to transmit the virus during the early stages (acute and recent) of infection, when viral load is elevated and opportunities to implement risk reduction are limited because persons are typically unaware of their status (1,2). Identifying recent HIV infections (acquired within the preceding 12 months)* is critical to understanding the factors and geographic areas associated with transmission to strengthen program intervention, including treatment and prevention (2). During June 2019, a novel recent infection surveillance initiative was integrated into routine HIV testing services in Malawi, a landlocked country in southeastern Africa with one of the world's highest prevalences of HIV infection.
† The objectives of this initiative were to collect data on new HIV diagnoses, characterize the epidemic, and guide public health response (2). New HIV diagnoses were classified as recent infections based on a testing algorithm that included results from the rapid test for recent infection (RTRI)§ and HIV viral load testing (3,4). Among 9,168 persons aged ≥15 years with a new HIV diagnosis who received testing across 103 facilities during October 2019-March 2020, a total of 304 (3.3%) were classified as having a recent infection. Higher proportions of recent infections were detected among females, persons aged <30 years, and clients at maternal and child health and youth clinics. Using a software application that analyzes clustering in spatially referenced data, transmission hotspots were identified with rates of recent infection that were significantly higher than expected. These near real-time HIV surveillance data highlighted locations across Malawi, allowing HIV program stakeholders to assess program gaps and improve access to HIV testing, prevention, and treatment services. Hotspot investigation information could be used to tailor HIV testing, prevention, and treatment to ultimately interrupt transmission., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.- Published
- 2022
- Full Text
- View/download PDF
12. Where Are the Newly Diagnosed HIV Positives in Kenya? Time to Consider Geo-Spatially Guided Targeting at a Finer Scale to Reach the "First 90".
- Author
-
Waruru A, Wamicwe J, Mwangi J, Achia TNO, Zielinski-Gutierrez E, Ng'ang'a L, Miruka F, Yegon P, Kimanga D, Tobias JL, Young PW, De Cock KM, and Tylleskär T
- Subjects
- Cluster Analysis, Humans, Kenya epidemiology, Mass Screening, Epidemics, HIV Infections diagnosis
- Abstract
Background: The UNAIDS 90-90-90 Fast-Track targets provide a framework for assessing coverage of HIV testing services (HTS) and awareness of HIV status - the "first 90." In Kenya, the bulk of HIV testing targets are aligned to the five highest HIV-burden counties. However, we do not know if most of the new HIV diagnoses are in these five highest-burden counties or elsewhere. Methods: We analyzed facility-level HTS data in Kenya from 1 October 2015 to 30 September 2016 to assess the spatial distribution of newly diagnosed HIV-positives. We used the Moran's Index (Moran's I) to assess global and local spatial auto-correlation of newly diagnosed HIV-positive tests and Kulldorff spatial scan statistics to detect hotspots of newly diagnosed HIV-positive tests. For aggregated data, we used Kruskal-Wallis equality-of-populations non-parametric rank test to compare absolute numbers across classes. Results: Out of 4,021 HTS sites, 3,969 (98.7%) had geocodes available. Most facilities (3,034, 76.4%), were not spatially autocorrelated for the number of newly diagnosed HIV-positives. For the rest, clustering occurred as follows; 438 (11.0%) were HH, 66 (1.7%) HL, 275 (6.9%) LH, and 156 (3.9%) LL. Of the HH sites, 301 (68.7%) were in high HIV-burden counties. Over half of 123 clusters with a significantly high number of newly diagnosed HIV-infected persons, 73(59.3%) were not in the five highest HIV-burden counties. Clusters with a high number of newly diagnosed persons had twice the number of positives per 1,000,000 tests than clusters with lower numbers (29,856 vs. 14,172). Conclusions: Although high HIV-burden counties contain clusters of sites with a high number of newly diagnosed HIV-infected persons, we detected many such clusters in low-burden counties as well. To expand HTS where most needed and reach the "first 90" targets, geospatial analyses and mapping make it easier to identify and describe localized epidemic patterns in a spatially dispersed epidemic like Kenya's, and consequently, reorient and prioritize HTS strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Waruru, Wamicwe, Mwangi, Achia, Zielinski-Gutierrez, Ng'ang'a, Miruka, Yegon, Kimanga, Tobias, Young, De Cock and Tylleskär.)
- Published
- 2021
- Full Text
- View/download PDF
13. Population-Based Geospatial and Molecular Epidemiologic Study of Tuberculosis Transmission Dynamics, Botswana, 2012-2016.
- Author
-
Zetola NM, Moonan PK, Click E, Oeltmann JE, Basotli J, Wen XJ, Boyd R, Tobias JL, Finlay A, and Modongo C
- Subjects
- Adult, Botswana, Epidemiologic Studies, Genotype, Humans, Minisatellite Repeats, Molecular Epidemiology, Young Adult, Mycobacterium tuberculosis genetics, Tuberculosis
- Abstract
Tuberculosis (TB) elimination requires interrupting transmission of Mycobacterium tuberculosis. We used a multidisciplinary approach to describe TB transmission in 2 sociodemographically distinct districts in Botswana (Kopanyo Study). During August 2012-March 2016, all patients who had TB were enrolled, their sputum samples were cultured, and M. tuberculosis isolates were genotyped by using 24-locus mycobacterial interspersed repetitive units-variable number of tandem repeats. Of 5,515 TB patients, 4,331 (79%) were enrolled. Annualized TB incidence varied by geography (range 66-1,140 TB patients/100,000 persons). A total of 1,796 patient isolates had valid genotyping results and residential geocoordinates; 780 (41%) patients were involved in a localized TB transmission event. Residence in areas with a high burden of TB, age <24 years, being a current smoker, and unemployment were factors associated with localized transmission events. Patients with known HIV-positive status had lower odds of being involved in localized transmission.
- Published
- 2021
- Full Text
- View/download PDF
14. A Neighbor-Based Approach to Identify Tuberculosis Exposure, the Kopanyo Study.
- Author
-
Moonan PK, Zetola NM, Tobias JL, Basotli J, Boyd R, Click ES, Dima M, Fane O, Finlay AM, Ogopotse M, Wen XJ, Modongo C, and Oeltmann JE
- Subjects
- Contact Tracing, Diagnostic Tests, Routine, Humans, Public Health, Mycobacterium tuberculosis, Tuberculosis diagnosis, Tuberculosis epidemiology
- Abstract
Contact investigation is one public health measure used to prevent tuberculosis by identifying and treating persons exposed to Mycobacterium tuberculosis. Contact investigations are a major tenet of global tuberculosis elimination efforts, but for many reasons remain ineffective. We describe a novel neighbor-based approach to reframe contact investigations.
- Published
- 2020
- Full Text
- View/download PDF
15. Possible Transmission Mechanisms of Mixed Mycobacterium tuberculosis Infection in High HIV Prevalence Country, Botswana.
- Author
-
Baik Y, Modongo C, Moonan PK, Click ES, Tobias JL, Boyd R, Finlay A, Oeltmann JE, Shin SS, and Zetola NM
- Subjects
- Bacterial Typing Techniques, Botswana epidemiology, DNA, Bacterial, Genotype, Humans, Minisatellite Repeats, Prevalence, HIV Infections complications, HIV Infections epidemiology, Mycobacterium tuberculosis genetics, Tuberculosis epidemiology
- Abstract
Tuberculosis caused by concurrent infection with multiple Mycobacterium tuberculosis strains (i.e., mixed infection) challenges clinical and epidemiologic paradigms. We explored possible transmission mechanisms of mixed infection in a population-based, molecular epidemiology study in Botswana during 2012-2016. We defined mixed infection as multiple repeats of alleles at >2 loci within a discrete mycobacterial interspersed repetitive unit-variable-number tandem-repeat (MIRU-VNTR) result. We compared mixed infection MIRU-VNTR results with all study MIRU-VNTR results by considering all permutations at each multiple allele locus; matched MIRU-VNTR results were considered evidence of recently acquired strains and nonmatched to any other results were considered evidence of remotely acquired strains. Among 2,051 patients, 34 (1.7%) had mixed infection, of which 23 (68%) had recently and remotely acquired strains. This finding might support the mixed infection mechanism of recent transmission and simultaneous remote reactivation. Further exploration is needed to determine proportions of transmission mechanisms in settings where mixed infections are prevalent.
- Published
- 2020
- Full Text
- View/download PDF
16. Finding Hidden HIV Clusters to Support Geographic-Oriented HIV Interventions in Kenya.
- Author
-
Waruru A, Achia TNO, Tobias JL, Ngʼangʼa J, Mwangi M, Wamicwe J, Zielinski-Gutierrez E, Oluoch T, Muthama E, and Tylleskär T
- Subjects
- AIDS Serodiagnosis, Adolescent, Adult, Circumcision, Male, Cluster Analysis, Female, Geography, HIV Infections diagnosis, Humans, Kenya epidemiology, Male, Middle Aged, Prevalence, Risk Factors, Sexual Behavior, Young Adult, HIV Infections epidemiology
- Abstract
Background: In a spatially well known and dispersed HIV epidemic, identifying geographic clusters with significantly higher HIV prevalence is important for focusing interventions for people living with HIV (PLHIV)., Methods: We used Kulldorff spatial-scan Poisson model to identify clusters with high numbers of HIV-infected persons 15-64 years old. We classified PLHIV as belonging to either higher prevalence or lower prevalence (HP/LP) clusters, then assessed distributions of sociodemographic and biobehavioral HIV risk factors and associations with clustering., Results: About half of survey locations, 112/238 (47%) had high rates of HIV (HP clusters), with 1.1-4.6 times greater PLHIV adults observed than expected. Richer persons compared with respondents in lowest wealth index had higher odds of belonging to a HP cluster, adjusted odds ratio (aOR) 1.61 [95% confidence interval (CI): 1.13 to 2.3], aOR 1.66 (95% CI: 1.09 to 2.53), aOR 3.2 (95% CI: 1.82 to 5.65), and aOR 2.28 (95% CI: 1.09 to 4.78) in second, middle, fourth, and highest quintiles, respectively. Respondents who perceived themselves to have greater HIV risk or were already HIV-infected had higher odds of belonging to a HP cluster, aOR 1.96 (95% CI: 1.13 to 3.4) and aOR 5.51 (95% CI: 2.42 to 12.55), respectively; compared with perceived low risk. Men who had ever been clients of female sex worker had higher odds of belonging to a HP cluster than those who had never been, aOR 1.47 (95% CI: 1.04 to 2.08); and uncircumcised men vs circumcised, aOR 3.2 (95% CI: 1.74 to 5.8)., Conclusions: HIV infection in Kenya exhibits localized geographic clustering associated with sociodemographic and behavioral factors, suggesting disproportionate exposure to higher HIV risk. Identification of these clusters reveals the right places for targeting priority-tailored HIV interventions.
- Published
- 2018
- Full Text
- View/download PDF
17. Spatial-temporal trend for mother-to-child transmission of HIV up to infancy and during pre-Option B+ in western Kenya, 2007-13.
- Author
-
Waruru A, Achia TNO, Muttai H, Ng'ang'a L, Zielinski-Gutierrez E, Ochanda B, Katana A, Young PW, Tobias JL, Juma P, De Cock KM, and Tylleskär T
- Abstract
Introduction: Using spatial-temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (e-MTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial-temporal analysis of seven years of HIV early infant diagnosis (EID) data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use., Methods: We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran-Mantel-Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis (<8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine, and maternal antiretroviral therapy status. We examined these covariates and fitted spatial and spatial-temporal semiparametric Poisson regression models to explain HIV-infection rates using R-integrated nested Laplace approximation package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region., Results: Median age was two months, interquartile range 1.5-5.8 months. Unadjusted pooled positive rate was 11.8% in the seven-years period and declined from 19.7% in 2007 to 7.0% in 2013, p < 0.01. Uptake of testing ≤8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p < 0.01. By 2013, the overall standardized MTCT rate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial-temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT., Discussion: Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Cojoined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time., Conclusion: During this pre-Option B+ period, the prevention of mother to child transmission program in this region has not achieved e-MTCT target of ≤50 infections per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions., Competing Interests: The authors declare that they have no competing interests.
- Published
- 2018
- Full Text
- View/download PDF
18. Molecular, Spatial, and Field Epidemiology Suggesting TB Transmission in Community, Not Hospital, Gaborone, Botswana.
- Author
-
Surie D, Fane O, Finlay A, Ogopotse M, Tobias JL, Click ES, Modongo C, Zetola NM, Moonan PK, and Oeltmann JE
- Subjects
- Adolescent, Adult, Botswana epidemiology, Cluster Analysis, Community-Acquired Infections epidemiology, Disease Outbreaks, Female, Genotype, Humans, Male, Middle Aged, Molecular Epidemiology, Mycobacterium tuberculosis isolation & purification, Tuberculosis epidemiology, Young Adult, Community-Acquired Infections microbiology, Community-Acquired Infections transmission, Mycobacterium tuberculosis genetics, Tuberculosis microbiology, Tuberculosis transmission
- Abstract
During 2012-2015, 10 of 24 patients infected with matching genotypes of Mycobacterium tuberculosis received care at the same hospital in Gaborone, Botswana. Nosocomial transmission was initially suspected, but we discovered plausible sites of community transmission for 20 (95%) of 21 interviewed patients. Active case-finding at these sites could halt ongoing transmission.
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.