Evaluation of bias in HIV seroprevalence estimates from national household surveys

Submitted by Gilvan Almeida ([email protected]) on 2016-12-07T12:03:30Z No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) FieldEvaluation.pdf: 177639 bytes, checksum: 417e97b6da6816379d956c2c88c54fef (MD5)Rejected by Éder Freyre ([email protected]), reason: Refazer on 2017-02-14T16:35:23Z (GMT)Submitted by Gilvan Almeida ([email protected]) on 2019-02-06T16:28:18Z No. of bitstreams: 2 FieldEvaluation.pdf: 177639 bytes, checksum: 417e97b6da6816379d956c2c88c54fef (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Approved for entry into archive by Regiane Silva ([email protected]) on 2019-08-26T13:12:58Z (GMT) No. of bitstreams: 2 FieldEvaluation.pdf: 177639 bytes, checksum: 417e97b6da6816379d956c2c88c54fef (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Made available in DSpace on 2019-08-26T13:12:58Z (GMT). No. of bitstreams: 2 FieldEvaluation.pdf: 177639 bytes, checksum: 417e97b6da6816379d956c2c88c54fef (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008Fundação Alfredo da Matta. Manaus, AM, Brasil.London School of Hygiene & Tropical Medicine. London, UK.Fundação Alfredo da Matta. Manaus, AM, Brasil.Fundação Alfredo da Matta. Manaus, AM, Brasil.Fundação Alfredo da Matta. Manaus, AM, Brasil.Fundação Oswaldo Cruz. Escola Nacional de Saúde Pública Sergio Arouca. Rio de Janeiro, RJ, Brasil.World Health Organization. Geneva, Switzerland.OBJECTIVES: To assess the performance, usefulness and cost of a rapid treponemal antibody assay (VisiTect Syphilis) to detect syphilis in high risk populations. METHODS: People who attended STI clinics in Manaus, Brazil, were screened for syphilis using the fluorescent treponemal antibody absorption (FTA-Abs) test and a non-treponemal test (Venereal Diseases Research Laboratory (VDRL)), and for HIV. Finger prick blood samples were tested with VisiTect Syphilis. The rapid test was evaluated against the reference FTA-Abs and for its usefulness in detecting active syphilis (FTA-Abs and VDRL positive). Operational performance was assessed through providers' and patients' interviews. An economic evaluation was conducted from the provider's perspective. RESULTS: 510 patients (60% men) were enrolled, of whom 13 (2.5%) were HIV-1 seropositive. Syphilis prevalence (FTA-Abs) was 18% and active syphilis prevalence was 7.5%. 11% (57/506) of samples were positive by VisiTect. The sensitivity, specificity, positive and negative predictive values of VisiTect Syphilis were 57% (95% CI 45.8 to 66.7), 99% (95% CI 97.0 to 99.6), 91% (95% CI 80.0 to 96.7) and 91% (95% CI 88.0 to 93.5), respectively. VisiTect Syphilis identified 79% (30/38) of active syphilis cases. The cost per case of syphilis was $16.8 for VDRL,$33.2 for low cost and $56.3 for high cost VisiTect Syphilis; the cost per case of active syphilis was$21.3, $57.5 and$97.6, respectively. Patients identified finger prick pain and preference for venous blood collection as minor barriers to test use. CONCLUSION: VisiTect Syphilis had low sensitivity in field use and was less cost effective than conventional VDRL. However, rapid and correct identification of a high proportion of active syphilis cases combined with operational characteristics suggest a role in high risk populations

Regular Expression Subtyping for XML Query and Update Languages

XML database query languages such as XQuery employ regular expression types with structural subtyping. Subtyping systems typically have two presentations, which should be equivalent: a declarative version in which the subsumption rule may be used anywhere, and an algorithmic version in which the use of subsumption is limited in order to make typechecking syntax-directed and decidable. However, the XQuery standard type system circumvents this issue by using imprecise typing rules for iteration constructs and defining only algorithmic typechecking, and another extant proposal provides more precise types for iteration constructs but ignores subtyping. In this paper, we consider a core XQuery-like language with a subsumption rule and prove the completeness of algorithmic typechecking; this is straightforward for XQuery proper but requires some care in the presence of more precise iteration typing disciplines. We extend this result to an XML update language we have introduced in earlier work.Comment: ESOP 2008. Companion technical report with proof

Cost-effectiveness analysis of point-of-care rapid testing versus laboratory-based testing for antenatal screening of syphilis in Brazil

Objectives Severe consequences of mother-to-child transmission of syphilis and high increasing incidence of congenital syphilis remains an important public health problem in Brazil. Our objective was to assess the cost-effectiveness of a rapid point-of-care test (RT) and treatment of positive mothers immediately compared with a laboratory-based standard test (ST) with treatment at next follow-up visit. Methods A decision analytic model was developed to estimate the incremental cost-effectiveness ratio (ICER) between antenatal syphilis screening strategies. The model was built with lifetime horizon from Brazilian health system perspective using 3% and 5% discount rates. A hypothetical cohort of pregnant women at reproductive age were used in the model. Health outcomes: low birth weight, stillbirths, neonatal deaths and congenital syphilis were estimated in disability-adjusted life-years (DALYs) lost. Microcosting study and secondary data provided parameters of direct medical costs. Probabilistic sensitivity analysis was undertaken. Results For base case, the mean cost per pregnant woman screened was $2.63 (RT) and$2.48 (ST), respectively. Maternal syphilis was associated with a loss of 0.0043 DALYs (RT) and 0.0048 DALYs (ST) per mother screened. Expected value of incremental cost per DALY averted was $298.08. After 10 000 probabilistic sensitivity analysis model runs, incremental cost and health benefits were$0.15 (95% credible interval –1.56 to 1.92) and 0.00042 DALYs (95% credible interval –0.0036 to 0.0044), respectively, with a mean ICER of $357.44 per DALY. Screening with RT has a 58$3,200 per DALY. Conclusions In Brazil, antenatal screening with syphilis RT and immediate treatment is likely to be cost-effective compared with standard screening and must be prioritized in local settings

Factors associated with self-reported discrimination against men who have sex with men in Brazil

OBJECTIVE: To estimate self-reported discrimination due to sexual orientation among men who have sex with men (MSM) in Brazil and to analyze associated factors. METHODS: A cross-sectional study of 3,859 MSM recruited in 2008–2009 with respondent driven sampling. Data collection conducted in health centers in 10 Brazilian cities. A face-to-face questionnaire was used and rapid HIV and syphilis tests conducted. Aggregated data were weighted and adjusted odds ratio estimated to measure the association between selected factors and self-reported discrimination due to sexual orientation. RESULTS: The sample was predominantly young, eight plus years of schooling, pardo (brown), single, low-income, and identified themselves as gay or homosexual. The prevalence of self-reported discrimination due to sexual orientation was 27.7% (95%CI 26.2–29.1). Discrimination was independently associated with: age < 30 years, more years of schooling,community involvement and support, history of sexual and physical violence, suicidal thoughts, and unprotected receptive anal intercourse. CONCLUSIONS: The prevalence of self-reported discrimination among MSM in Brazil is high. These results challenge the assumptions that MSM-specific prevention and support programs are not required or that health professionals do not need special training to address MSM needs

A Counterexample Regarding Labelled Well-Quasi-Ordering

Korpelainen, Lozin, and Razgon conjectured that a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by only finitely many minimal forbidden induced subgraphs is labelled well-quasi-ordered, a notion stronger than that of n-well-quasi-order introduced by Pouzet in the 1970s. We present a counterexample to this conjecture. In fact, we exhibit a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by finitely many minimal forbidden induced subgraphs yet is not 2-well-quasi-ordered. This counterexample is based on the widdershins spiral, which has received some study in the area of permutation patterns

Point-of-Care Tests to Strengthen Health Systems and Save Newborn Lives: The Case of Syphilis

Rosanna Peeling and colleagues describe their experience of introducing point-of-care testing to screen for syphilis in pregnant women living in low- and middle-income countries