Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-17 (of 17 Records) |
Query Trace: Tun Y[original query] |
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Changes in trachoma indicators in Kiribati with two rounds of azithromycin mass drug administration, measured in serial population-based surveys
Goodhew EB , Taoaba R , Harding-Esch EM , Gwyn SE , Bakhtiari A , Butcher R , Cama A , Guagliardo SAJ , Jimenez C , Mpyet CD , Tun K , Wickens K , Solomon AW , Martin DL , Tekeraoi R . PLoS Negl Trop Dis 2023 17 (7) e0011441 Baseline mapping in the two major population centers of Kiribati showed that trachoma was a public health problem in need of programmatic interventions. After conducting two annual rounds of antibiotic mass drug administration (MDA), Kiribati undertook trachoma impact surveys in 2019, using standardized two-stage cluster surveys in the evaluation units of Kiritimati Island and Tarawa. In Kiritimati, 516 households were visited and in Tarawa, 772 households were visited. Nearly all households had a drinking water source and access to an improved latrine. The prevalence of trachomatous trichiasis remained above the elimination threshold (0.2% in ≥15-year-olds) and was virtually unchanged from baseline. The prevalence of trachomatous inflammation-follicular (TF) in 1-9-year-olds decreased by approximately 40% from baseline in both evaluation units but remained above the 5% TF prevalence threshold for stopping MDA. TF prevalence at impact survey was 11.5% in Kiritimati and 17.9% in Tarawa. Infection prevalence in 1-9-year-olds by PCR was 0.96% in Kiritimati and 3.3% in Tarawa. Using a multiplex bead assay to measure antibodies to the C. trachomatis antigen Pgp3, seroprevalence in 1-9-year-olds was 30.2% in Kiritimati and 31.4% in Tarawa. The seroconversion rate, in seroconversion events/100 children/year, was 9.0 in Kiritimati and 9.2 in Tarawa. Seroprevalence and seroconversion rates were both assessed by four different assays, with strong agreement between tests. These results show that, despite decreases in indicators associated with infection at impact survey, trachoma remains a public health problem in Kiribati, and provide additional information about changes in serological indicators after MDA. |
Development of a Bead-Based Multiplex Assay for Use in Multianalyte Screening and Surveillance of HIV, Viral Hepatitis, Syphilis, and Herpes.
Yufenyuy EL , Vedapuri S , Zheng A , Cooley G , Danavall D , Mayur S , Kodani M , Chen C , Tun Y , Fakile YF , Martin D , Kamili S , Karem K , Parekh BS . J Clin Microbiol 2022 60 (5) e0234821 Diagnostic assays that can simultaneously determine the presence of infection with multiple pathogens are key for diagnosis and surveillance. Current multiplex diagnostic assays are complex and often have limited availability. We developed a simple, multianalyte, pathogen detection assay for screening and serosurveillance using the Luminex Magpix platform that is high throughput and can be helpful in monitoring multiple diseases. The Luminex bead-based 10-plex immunoassay for the detection of HIV-1, HIV-2, Treponema pallidum, hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus 1 (HSV-1), and HSV-2 infections was accomplished by coupling beads with specific antigens to detect IgG antibodies in plasma or serum samples. Each coupled antigen was systematically optimized, and the performance was evaluated using a panel of well-characterized specimens (n=417) that contained antibodies to HIV-1, HIV-2, T. pallidum, HBV, HCV, HSV-1, and HSV-2. The multiplex assay had a sensitivity of 92.2% (95% Clopper-Pearson confidence interval [CI], 90.2 to 94.0%) and a specificity of 98.1% (95% CI, 97.6 to 98.7%). The sensitivities and specificities for disease-specific biomarker detection ranged from 68.7 to 100% and 95.6 to 100%, respectively. The results showed that the 10-plex immunoassay had an overall agreement of 96.7% (95% CI, 96.7 to 97.3%) with reference tests and a corresponding kappa value of 0.91 (95% CI, 0.90 to 0.93). Kappa values for the individual pathogens ranged from 0.69 to 1.00. The assay is robust and allows the simultaneous detection of antibodies to multiple antigens using a small sample volume in a high-throughput format. This assay has the potential to simplify disease surveillance by providing an alternative to expensive and highly specialized individual tests. |
Expected Rates of Select Adverse Events following Immunization for COVID-19 Vaccine Safety Monitoring.
Abara WE , Gee J , Delorey M , Tun Y , Mu Y , Shay DK , Shimabukuro T . J Infect Dis 2021 225 (9) 1569-1574 Using meta-analytic methods, we calculated expected rates of 21 potential adverse events of special interest (AESI) that would occur following COVID-19 vaccination within 1-, 7-, and 42-day intervals without causal associations. Based on these expected rates, if 10,000,000 persons are vaccinated, 0.5, 3.7, and 22.5 Guillain-Barre syndrome cases; 0.3, 2.4, and 14.3 myopericarditis cases; and 236.5, 1655.5, and 9932.8 all-cause deaths would occur coincidentally within 1, 7, and 42 days post-vaccination, respectively. Expected rates of potential AESI can contextualize events associated temporally with immunization, aid in safety signal detection, guide COVID-19 vaccine health communications, and inform COVID-19 vaccine benefit-risk assessments. |
National and subnational size estimation of female sex workers in Ghana 2020: Comparing 3-source capture-recapture with other approaches
Guure C , Dery S , Afagbedzi S , Tun W , Weir SS , Quaye S , Ankomah A , Torpey K . PLoS One 2021 16 (9) e0256949 BACKGROUND: Key Population size estimation (PSE) is instrumental for HIV/STI preventive, treatment and care services planning, implementation and delivery. The objective was to estimate the overall population of female sex workers (FSW) in all the 16 regions of Ghana using different PSE methods. METHOD: Mapping of venues and complete enumeration of seaters was conducted at the formative stage prior to the bio-behavioral survey (BBS). Three PSE methods were used to derive the size estimates of FSW in the 16 regions. These include: Capture-recapture (CRC), service multiplier and three-source capture recapture (3SCRC) methods. The final choice of the estimation method used to estimate the roamer population was 3SCRC. This method was chosen because of its perfect record-linkage-hierarchic combination of three names that minimizes overmatching as well as the addition of an interaction term in the model which corrects for the dependencies in CRC. RESULTS: The total population size estimate of the female sex workers in the country obtained for roamers using capture re-capture was 41,746 (95% CI: 41,488-41,932). Using the service multiplier, the total population for both the roamers and seaters was 41,153 (95% CI: 37,242-45,984). The 3-source capture re-capture yielded 55,686 roamers FSW (95% CI: 47,686-63,686). The seater population was 4,363 FSW based on census/complete enumeration. The total population size estimate of FSW (seaters and roamers) in Ghana was 60,049 when 3SCRC and census were added. This represents about 0.76% of all estimated adult females aged 15-49yrs in Ghana. CONCLUSION: We report population size estimates (PSE) for FSW in Ghana. These estimates are the results of 3SCRC. These findings provide a valid and reliable source of information that should be referenced by government officials and policymakers to plan, implement and provide HIV/STI preventive, treatment, and care services for FSW in Ghana. |
Performance of a fully-automated system on a WHO malaria microscopy evaluation slide set.
Horning MP , Delahunt CB , Bachman CM , Luchavez J , Luna C , Hu L , Jaiswal MS , Thompson CM , Kulhare S , Janko S , Wilson BK , Ostbye T , Mehanian M , Gebrehiwot R , Yun G , Bell D , Proux S , Carter JY , Oyibo W , Gamboa D , Dhorda M , Vongpromek R , Chiodini PL , Ogutu B , Long EG , Tun K , Burkot TR , Lilley K , Mehanian C . Malar J 2021 20 (1) 110 BACKGROUND: Manual microscopy remains a widely-used tool for malaria diagnosis and clinical studies, but it has inconsistent quality in the field due to variability in training and field practices. Automated diagnostic systems based on machine learning hold promise to improve quality and reproducibility of field microscopy. The World Health Organization (WHO) has designed a 55-slide set (WHO 55) for their External Competence Assessment of Malaria Microscopists (ECAMM) programme, which can also serve as a valuable benchmark for automated systems. The performance of a fully-automated malaria diagnostic system, EasyScan GO, on a WHO 55 slide set was evaluated. METHODS: The WHO 55 slide set is designed to evaluate microscopist competence in three areas of malaria diagnosis using Giemsa-stained blood films, focused on crucial field needs: malaria parasite detection, malaria parasite species identification (ID), and malaria parasite quantitation. The EasyScan GO is a fully-automated system that combines scanning of Giemsa-stained blood films with assessment algorithms to deliver malaria diagnoses. This system was tested on a WHO 55 slide set. RESULTS: The EasyScan GO achieved 94.3 % detection accuracy, 82.9 % species ID accuracy, and 50 % quantitation accuracy, corresponding to WHO microscopy competence Levels 1, 2, and 1, respectively. This is, to our knowledge, the best performance of a fully-automated system on a WHO 55 set. CONCLUSIONS: EasyScan GO's expert ratings in detection and quantitation on the WHO 55 slide set point towards its potential value in drug efficacy use-cases, as well as in some case management situations with less stringent species ID needs. Improved runtime may enable use in general case management settings. |
Molecular strain typing of the yaws pathogen, Treponema pallidum subspecies pertenue.
Katz SS , Chi KH , Nachamkin E , Danavall D , Taleo F , Kool JL , Addo KK , Ampofo W , Simpson SV , Ye T , Asiedu KB , Ballard RC , Chen CY , Pillay A . PLoS One 2018 13 (9) e0203632 Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue. The disease primarily affects children under 15 years of age living in low socioeconomic conditions in tropical areas. As a result of a renewed focus on the disease owing to a recent eradication effort initiated by the World Health Organization, we have evaluated a typing method, adapted from and based on the enhanced Centers for Disease Control and Prevention typing method for T. pallidum subsp. pallidum, for possible use in epidemiological studies. Thirty DNA samples from yaws cases in Vanuatu and Ghana, 11 DNA samples extracted from laboratory strains, and 3 published genomic sequences were fully typed by PCR/RFLP analysis of the tpr E, G, and J genes and by determining the number of 60-bp repeats within the arp gene. Subtyping was performed by sequencing a homonucleotide "G" tandem repeat immediately upstream of the rpsA gene and an 84-bp region of tp0548. A total of 22 complete strain types were identified; two strain types in clinical samples from Vanuatu (5q11/ak and 5q12/ak), nine strain types in clinical samples from Ghana (3q12/ah, 4r12/ah, 4q10/j, 4q11/ah, 4q12/ah, 4q12/v, 4q13/ah, 6q10/aj, and 9q10/ai), and twelve strain types in laboratory strains and published genomes (2q11/ae, 3r12/ad, 4q11/ad, 4q12/ad, 4q12/ag, 4q12/v, 5r12/ad, 6r12/x, 6q11/af, 10q9/r, 10q12/r, and 12r12/w). The tpr RFLP patterns and arp repeat sizes were subsequently verified by sequencing analysis of the respective PCR amplicons. This study demonstrates that the typing method for subsp. pallidum can be applied to subsp. pertenue strains and should prove useful for molecular epidemiological studies on yaws. |
Community-based mass treatment with azithromycin for the elimination of yaws in Ghana - Results of a pilot study
Abdulai AA , Agana-Nsiire P , Biney F , Kwakye-Maclean C , Kyei-Faried S , Amponsa-Achiano K , Simpson SV , Bonsu G , Ohene SA , Ampofo WK , Adu-Sarkodie Y , Addo KK , Chi KH , Danavall D , Chen CY , Pillay A , Sanz S , Tun Y , Mitja O , Asiedu KB , Ballard RC . PLoS Negl Trop Dis 2018 12 (3) e0006303 INTRODUCTION: The WHO yaws eradication strategy consists of one round of total community treatment (TCT) of single-dose azithromycin with coverage of > 90%.The efficacy of the strategy to reduce the levels on infection has been demonstrated previously in isolated island communities in the Pacific region. We aimed to determine the efficacy of a single round of TCT with azithromycin to achieve a decrease in yaws prevalence in communities that are endemic for yaws and surrounded by other yaws-endemic areas. METHODS: Surveys for yaws seroprevalence and prevalence of skin lesions were conducted among schoolchildren aged 5-15 years before and one year after the TCT intervention in the Abamkrom sub-district of Ghana. We used a cluster design with the schools as the primary sampling unit. Among 20 eligible primary schools in the sub district, 10 were assigned to the baseline survey and 10 to the post-TCT survey. The field teams conducted a physical examination for skin lesions and a dual point-of-care immunoassay for non-treponemal and treponemal antibodies of all children present at the time of the visit. We also undertook surveys with non-probabilistic sampling to collect lesion swabs for etiology and macrolide resistance assessment. RESULTS: At baseline 14,548 (89%) of 16,287 population in the sub-district received treatment during TCT. Following one round of TCT, the prevalence of dual seropositivity among all children decreased from 10.9% (103/943) pre-TCT to 2.2% (27/1211) post-TCT (OR 0.19; 95%CI 0.09-0.37). The prevalence of serologically confirmed skin lesions consistent with active yaws was reduced from 5.7% (54/943) pre-TCT to 0.6% (7/1211) post-TCT (OR 0.10; 95% CI 0.25-0.35). No evidence of resistance to macrolides against Treponema pallidum subsp. pertenue was seen. DISCUSSION: A single round of high coverage TCT with azithromycin in a yaws affected sub-district adjoining other endemic areas is effective in reducing the prevalence of seropositive children and the prevalence of early skin lesions consistent with yaws one year following the intervention. These results suggest that national yaws eradication programmes may plan the gradual expansion of mass treatment interventions without high short-term risk of reintroduction of infection from contiguous untreated endemic areas. |
Laboratory evaluation of the Chembio Dual Path Platform HIV-Syphilis Assay
Kalou MB , Castro A , Watson A , Jost H , Clay S , Tun Y , Chen C , Karem K , Nkengasong JN , Ballard R , Parekh B . Afr J Lab Med 2016 5 (1) 433 BACKGROUND: Use of rapid diagnostic tests for HIV and syphilis has increased remarkably in the last decade. As new rapid diagnostic tests become available, there is a continuous need to assess their performance and operational characteristics prior to use in clinical settings. OBJECTIVES: In this study, we evaluated the performance of the Chembio Dual Path Platform (DPP(®)) HIV-Syphilis Assay to accurately diagnose HIV, syphilis, and HIV/syphilis co-infection. METHOD: In 2013, 990 serum samples from the Georgia Public Health Laboratory in Atlanta, Georgia, United States were characterised for HIV and syphilis and used to evaluate the platform. HIV reference testing combined third-generation Enzyme Immunoassay and Western Blot, whereas reference testing for syphilis was conducted by the Treponema pallidum passive particle agglutination method and the TrepSure assay. We assessed the sensitivity and specificity of the DPP assay on this panel by comparing results with the HIV and syphilis reference testing algorithms. RESULTS: For HIV, sensitivity was 99.8% and specificity was 98.4%; for syphilis, sensitivity was 98.8% and specificity was 99.4%. Of the 348 co-infected sera, 344 (98.9%) were detected accurately by the DPP assay, but 11 specimens had false-positive results (9 HIV and 2 syphilis) due to weak reactivity. CONCLUSION: In this evaluation, the Chembio DPP HIV-Syphilis Assay had high sensitivity and specificity for detecting both HIV and treponemal antibodies. Our results indicate that this assay could have a significant impact on the simultaneous screening of HIV and syphilis using a single test device for high-risk populations or pregnant women needing timely care and treatment. |
Meta-analysis of the performance of a combined treponemal and non-treponemal rapid diagnostic test for syphilis and yaws
Marks M , Yin YP , Chen XS , Castro A , Causer L , Guy R , Wangnapi R , Mitja O , Aziz A , Castro R , da Luz Martins Pereira F , Taleo F , Guinard J , Belec L , Tun Y , Bottomley C , Ballard RC , Mabey DC . Clin Infect Dis 2016 63 (5) 627-633 BACKGROUND: The human treponematoses are important causes of disease. Mother-to-child transmission of syphilis remains a major cause of stillbirth and neonatal death. There are also almost 100,000 cases of endemic treponemal disease reported annually, predominantly yaws. Rapid diagnostic tests would improve access to screening for these diseases. Most RDTs cannot distinguish current and previous infection. The Dual Path Platform Syphilis Screen and Confirm test includes both a treponemal (T1) and non-treponemal (T2) component and may improve the accuracy of diagnosis. METHODS: We conducted a meta-analysis of published and unpublished evaluations of the DPP Rapid Diagnostic Test (RDT) for the diagnosis of syphilis and yaws. We calculated the sensitivity, specificity and overall agreement of the test compared to reference laboratory tests. RESULTS: Nine evaluations including a total of 7,267 tests were included. Sensitivity was higher in patients with higher titre RPR (≥1:16) for both the T1 (98.2% vs 90.1%, p<0.0001) and the T2 component (98.2% vs 80.6%, p<0.0001). Overall agreement between the DPP test and reference serology was 85.2% (84.4-86.1%). Agreement was highest for high titre active infection and lowest for past infection CONCLUSIONS: The RDT has good sensitivity and specificity of the treponemal and non-treponemal components both in cases of suspected syphilis and yaws, although the sensitivity is decreased at lower antibody titres. |
Lessons learned from respondent-driven sampling recruitment in Nairobi: experiences from the field
Okal J , Raymond HF , Tun W , Musyoki H , Dadabhai S , Broz D , Nyamu J , Kuria D , Muraguri N , Geibel S . BMC Res Notes 2016 9 (1) 158 BACKGROUND: Respondent-driven sampling (RDS) is used in a variety of settings to study hard-to-reach populations at risk for HIV and sexually transmitted infections. However, practices leading to successful recruitment among diverse populations in low-resource settings are seldom reported. We implemented the first, integrated, bio-behavioural surveillance survey among men who have sex with men, female sex workers and people who injected drugs in Nairobi, Kenya. METHODS: The survey period was June 2010 to March 2011, with a target sample size of 600 participants per key populations. Formative research was initially conducted to assess feasibility of the survey. Weekly monitoring reports of respondent characteristics and recruitment chain graphs from NetDraw illustrated patterns and helped to fill recruitment gaps. RESULTS: RDS worked well with men who have sex with men and female sex workers with recruitment initiating at a desirable pace that was maintained throughout the survey. Networks of people who injected drugs were well-integrated, but recruitment was slower than the men who have sex with men and female sex workers surveys. CONCLUSION: By closely monitoring RDS implementation and conducting formative research, RDS studies can effectively develop and adapt strategies to improve recruitment and improve adherence to the underlying RDS theory and assumptions. |
Prevalence of HIV, sexually transmitted infections, and risk behaviours among female sex workers in Nairobi, Kenya: results of a respondent driven sampling study
Musyoki H , Kellogg TA , Geibel S , Muraguri N , Okal J , Tun W , Fisher Raymond H , Dadabhai S , Sheehy M , Kim AA . AIDS Behav 2015 19 Suppl 1 46-58 We conducted a respondent driven sampling survey to estimate HIV prevalence and risk behavior among female sex workers (FSWs) in Nairobi, Kenya. Women aged 18 years and older who reported selling sex to a man at least once in the past 3 months were eligible to participate. Consenting FSWs completed a behavioral questionnaire and were tested for HIV and sexually transmitted infections (STIs). Adjusted population-based prevalence and 95 % confidence intervals (CI) were estimated using RDS analysis tool. Factors significantly associated with HIV infection were assessed using log-binomial regression analysis. A total of 596 eligible participants were included in the analysis. Overall HIV prevalence was 29.5 % (95 % CI 24.7-34.9). Median age was 30 years (IQR 25-38 years); median duration of sex work was 12 years (IQR 8-17 years). The most frequent client-seeking venues were bars (76.6 %) and roadsides (29.3 %). The median number of clients per week was seven (IQR 4-18 clients). HIV testing was high with 86.6 % reported ever been tested for HIV and, of these, 63.1 % testing within the past 12 months. Of all women, 59.7 % perceived themselves at 'great risk' for HIV infection. Of HIV-positive women, 51.0 % were aware of their infection. In multivariable analysis, increasing age, inconsistent condom use with paying clients, and use of a male condom as a method of contraception were independently associated with unrecognized HIV infection. Prevalence among STIs was low, ranging from 0.9 % for syphilis, 1.1 % for gonorrhea, and 3.1 % for Chlamydia. The data suggest high prevalence of HIV among FSWs in Nairobi. Targeted and routine HIV and STI combination prevention strategies need to be scaled up or established to meet the needs of this population. |
HIV and STI prevalence and injection behaviors among people who inject drugs in Nairobi: results from a 2011 bio-behavioral study using respondent-driven sampling
Tun W , Sheehy M , Broz D , Okal J , Muraguri N , Raymond HF , Musyoki H , Kim AA , Muthui M , Geibel S . AIDS Behav 2015 19 Suppl 1 24-35 There is a dearth of evidence on injection drug use and associated HIV infections in Kenya. To generate population-based estimates of characteristics and HIV/STI prevalence among people who inject drugs (PWID) in Nairobi, a cross-sectional study was conducted with 269 PWID using respondent-driven sampling. PWID were predominantly male (92.5 %). An estimated 67.3 % engaged in at least one risky injection practice in a typical month. HIV prevalence was 18.7 % (95 % CI 12.3-26.7), while STI prevalence was lower [syphilis: 1.7 % (95 % CI 0.2-6.0); gonorrhea: 1.5 % (95 % CI 0.1-4.9); and Chlamydia: 4.2 % (95 % CI 1.2-7.8)]. HIV infection was associated with being female (aOR, 3.5; p = 0.048), having first injected drugs 5 or more years ago (aOR, 4.3; p = 0.002), and ever having practiced receptive syringe sharing (aOR, 6.2; p = 0.001). Comprehensive harm reduction programs tailored toward PWID and their sex partners must be fully implemented as part of Kenya's national HIV prevention strategy. |
HIV and STI prevalence and risk factors among male sex workers and other men who have sex with men in Nairobi, Kenya
Muraguri N , Tun W , Okal J , Broz D , Raymond HF , Kellogg T , Dadabhai S , Musyoki H , Sheehy M , Kuria D , Kaiser R , Geibel S . J Acquir Immune Defic Syndr 2015 68 (1) 91-6 Previous surveys of men who have sex with men (MSM) in Africa have not adequately profiled HIV status and risk factors by sex work status. MSM in Nairobi, Kenya, were recruited using respondent-driven sampling, completed a behavioral interview, and were tested for HIV and sexually transmitted infections. Overlapping recruitment among 273 male sex workers and 290 other MSM was common. Sex workers were more likely to report receptive anal sex with multiple partners (65.7% versus 18.0%, P < 0.001) and unprotected receptive anal intercourse (40.0% versus 22.8%, P = 0.005). Male sex workers were also more likely to be HIV infected (26.3% versus 12.2%, P = 0.007). |
Molecular differentiation of Treponema pallidum subspecies in skin ulceration clinically suspected as yaws in Vanuatu using real-time multiplex PCR and serological methods.
Chi KH , Danavall D , Taleo F , Pillay A , Ye T , Nachamkin E , Kool JL , Fegan D , Asiedu K , Vestergaard LS , Ballard RC , Chen CY . Am J Trop Med Hyg 2014 92 (1) 134-8 We developed a TaqMan-based real-time quadriplex polymerase chain reaction (PCR) to simultaneously detect Treponema pallidum subspecies pallidum, T. pallidum subsp. pertenue, and T. pallidum subsp. endemicum, the causative agents of venereal syphilis, yaws, and bejel, respectively. The PCR assay was applied to samples from skin ulcerations of clinically presumptive yaws cases among children on Tanna Island, Vanuatu. Another real-time triplex PCR was used to screen for the point mutations in the 23S rRNA genes that have previously been associated with azithromycin resistance in T. pallidum subsp. pallidum strains. Seropositivity by the classical syphilis serological tests was 35.5% among children with skin ulcerations clinically suspected with yaws, whereas the presence of T. pallidum subsp. pertenue DNA was only found in lesions from 15.5% of children. No evidence of T. pallidum subsp. pertenue infection, by either PCR or serology was found in approximately 59% of cases indicating alternative causes of yaws-like lesions in this endemic area. |
Factors associated with acceptability of HIV self-testing among health care workers in Kenya
Kalibala S , Tun W , Cherutich P , Nganga A , Oweya E , Oluoch P . AIDS Behav 2014 18 Suppl 4 405-14 Health care workers (HCWs) in sub-Saharan Africa are at a high risk of HIV infection from both sexual and occupational exposures. However, many do not seek HIV testing. This paper examines the acceptability of an unsupervised facility-based HIV self-testing (HIVST) intervention among HCWs and their partners and factors associated with uptake of HIVST among HCWs. HCWs in seven large Kenyan hospitals were invited to participate in pre-HIVST information sessions during which they were offered HIVST kits to take home for self-testing. A post-intervention survey was conducted among 765 HCWs. Forty-one percent attended the information session; of those, 89 % took the HIVST kits and of those, 85 % self-tested. Thirty-four percent of surveyed HCWs used the HIVST to test themselves. Of those who took the HIVST kit and had partners, 73 % gave the kit to their partner and 86 % of them indicated their partner self-tested. Factors positively associated with use of the HIVST on self were being female, being single, and being a HCW from Homa Bay Hospital (located in a high HIV prevalence area). HIVST is acceptable to HCWs and their partners. However, strategies are needed to increase HCWs attendance at pre-implementation information sessions. |
Cost-effectiveness of integrated routine offering of prenatal HIV and syphilis screening in China
Owusu-Edusei K Jr , Tao G , Gift TL , Wang A , Wang L , Tun Y , Wei X , Wang L , Fuller S , Kamb ML , Bulterys M . Sex Transm Dis 2014 41 (2) 103-10 BACKGROUND: In China, recent rises in syphilis and HIV cases have increased the focus on preventing mother-to-child transmission of these infections. We assess the health and economic outcomes of different strategies of prenatal HIV and syphilis screening from the local health department's perspective. METHODS: A Markov cohort decision analysis model was used to estimate the health and economic outcomes of pregnancy using disease prevalence and cost data from local sources and, if unavailable, from published literature. Adverse pregnancy outcomes included induced abortion, stillbirth, low birth weight, neonatal death, congenital syphilis in live-born infants, and perinatal HIV infection. We examined 4 screening strategies: no screening, screening for HIV only, for syphilis only, and for both HIV and syphilis. We estimated disability-adjusted life years (DALYs) for each health outcome using life expectancies and infections for mothers and newborns. RESULTS: For a simulated cohort of 10,000 pregnant women (0.07% prevalence for HIV and 0.25% for syphilis; 10% of HIV-positives were coinfected with syphilis), the estimated costs per DALY prevented were as follows: syphilis-only, $168; HIV-and-syphilis, $359; and HIV-only, $5636. The estimated incremental cost-effectiveness ratio if an existing HIV-only strategy added syphilis screening (i.e., move from the HIV-only strategy to the HIV-and-syphilis strategy) was $140 per additional DALY prevented. CONCLUSIONS: Given the increasing prevalence of syphilis and HIV among pregnant women in China, prenatal HIV screening programs that also include syphilis screening are likely to be substantially more cost-effective than HIV screening alone and prevent many more adverse pregnancy outcomes. |
A comparison of the analytical level of agreement of nine treponemal assays for syphilis and possible implications for screening algorithms
Castro A , Jost H , Cox D , Fakile Y , Kikkert S , Tun Y , Zaidi A , Park M . BMJ Open 2013 3 (9) e003347 OBJECTIVE: The serological diagnosis of syphilis requires the detection of two distinct antibodies, the non-treponemal and trepomenal. Center for Disease Control and Prevention (CDC) recommends screening first with a non-treponemal test such as (Rapid Plasma Reagin/Venereal Disease Research Laboratory), and then confirming those results with one of the several treponemal tests (Fluorescent Treponemal Antibody-Absorption (FTA-ABS), Enzyme Immunoassay, chemiluminescence, treponema pallidum particle agglutination (TP-PA) or Point of Care). Owing to the high volume of samples processed by some laboratories using automated systems, the screening with treponemal assays and confirming with non-treponemal tests is becoming the established norm. The purpose of this study was to evaluate eight treponemal assays using TP-PA as the predicate assay. METHODS: 290 stored serum samples were tested qualitatively according to the manufacturer's directions. RESULTS: Concordance with specimens tested as reactive or non-reactive using TP-PA was: FTA-ABS 94.5-100%, Trep-Sure 100-98.9%, BioELISA 100-98.9%, INNO-LIA 99.1-99.4%, BIOLINE 100-98.9%, CAPTIA IgG 100-97.2%, Trep-ID 100-100% and LIAISON 100-99.4%. In order to properly evaluate the performance of these assays, the analytical sensitivity was determined by endpoint titration of serial dilutions of the reactive serum samples in normal sera. The median endpoint titre varied from 1:4 for FTA-ABS to 1:512 for Trep-Sure. CONCLUSIONS: The performance of the treponemal serological assays was comparable while using medium and high-titre sera. However, the varying performance on specimen dilutions suggests that there may be differences in sensitivity with low-titre sera that are more prevalent in primary and late syphilis cases. |
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