ObjectiveTo conduct a systematic review to estimate the prevalence of asymptomatic Zika virus infection in the general population and in specific population groups.MethodsWe searched PubMed®, Embase® and LILACS online databases from inception to 26 January 2018. We included observational epidemiological studies where laboratory testing was used to confirm positive exposure of participants to Zika virus and in which Zika virus symptom status was also recorded. We excluded studies in which having symptoms of Zika virus was a criterion for inclusion. The main outcome assessed was percentage of all Zika virus-positive participants who were asymptomatic. We used a quality-effects approach and the double arcsine transformation for the meta-analysis.FindingsWe assessed 753 studies for inclusion, of which 23 were included in the meta-analysis, totalling 11 305 Zika virus-positive participants. The high degree of heterogeneity in the studies (I2 = 99%) suggests that the pooled prevalence of asymptomatic Zika virus-positive participants was probably not a robust estimate. Analysis based on subgroups of the population (general population, returned travellers, blood donors, adults with Guillain–Barré syndrome, pregnant women and babies with microcephaly) was not able to explain the heterogeneity. Funnel and Doi plots showed major asymmetry, suggesting selection bias or true heterogeneity.ConclusionBetter-quality research is needed, using standardized methods, to determine the true prevalence of asymptomatic Zika virus and whether it varies between populations or over time.

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Background Progress towards universal health coverage requires health policies and systems that are informed by contextualised and actionable research. Many challenges impede the uptake of evidence to enhance health policy implementation and the coverage, quality, efficiency and equity of health systems. To address this need, we developed an innovative model of implementation research embedded in real-world policy and programme cycles and led directly by policy-makers and health systems decision-makers. The approach was tested in ten settings in Latin America and the Caribbean, supported under a common funding and capacity strengthening initiative. The present study aims to analyse ten embedded implementation research projects in order to identify barriers and facilitators to embedding research into policy and practice as well as to assess the programme, policy and systems improvements and the cross-cutting lessons in conducting research embedded in real-world policy and systems decision-making. Methods The multi-country analysis is based on the triangulation of data collected via three methods, namely (1) document review, (2) an electronic questionnaire and (3) in-depth interviews with decision-makers. Data from the document review was charted and narratively synthesised. Data from the questionnaire was used to assess three characteristics of the decision-maker’s participation in embedded research, namely (1) level of engagement in different stages of research; (2) extent to which their capacities to conduct and use research were developed; and (3) the level of confidence in undertaking implementation research activities. Interview data was analysed using a thematic approach. Results The main barriers to effective delivery or scale-up of health interventions identified in the research projects were inadequate financing, fragmentation of healthcare services and information systems, limited capacity of health system stakeholders, insufficient time, cultural factors, and a lack of information. Decision-makers’ experience in embedded research showed strong engagement in protocol development, moderate engagement in data collection and low engagement in data analysis. The in-depth interviews identified 17 facilitators and 8 barriers to embedding research into policy and systems. The principal facilitating factors were actionability of findings, relevance of research and engagement of decision-makers, whereas the main barriers were time and political processes. In Argentina, the research led to the development of new monitoring indicators to improve the implementation of the perinatal health policy, while in Chile, empirical findings supported the establishment of a training programme on reproductive rights, targeted to municipal health facilities. Conclusions This multi-country analysis contributes to the evidence base for the embedded research approach to support health policy and systems decisions-making. Embedding research into policy and practice stimulates the relevance and applicability of research, while promoting decision-makers’ engagement and likelihood to use research evidence in policy-making and health systems strengthening.

Objectives.To evaluate the potential associations between chronic kidney disease of uncertain or non-traditional etiology (CKDnT) and agrochemicals, heat stress, heavy metals, and other factors identified in the literature in any region of the world and at any time.Methods.This was a systematic review of the most frequent exposures suspected to be possible causes of CKDnT. A search was conducted of PubMed, LILACS, World Wide Science electronic databases, among other sources. Only medium- and high-quality studies were included. The synthesis of evidence included a narrative synthesis, meta-analysis, and meta-regression.Results.Four systematic reviews and 61 primary studies were included. Results of the meta-analysis suggest that exposure to agrochemicals and working in agriculture increase the risk of CKDnT, but this only reached significance for working in agriculture. When cross-sectional studies were excluded, agrochemical exposure became significant. However, there is substantial heterogeneity in the effect sizes.Conclusions.Based on the existing evidence and the precautionary principle, it is important to implement preventive measures to mitigate the damage caused by CKDnT to both agricultural workers and their communities (i.e., improvement of working conditions, cautious management of agrochemicals, etc.). More high-quality research is needed to measure impact and to build the evidence base.

IntroductionZika virus (ZIKV) infection during pregnancy is a known cause of microcephaly and other congenital and developmental anomalies. In the absence of a ZIKV vaccine or prophylactics, principal investigators (PIs) and international leaders in ZIKV research have formed the ZIKV Individual Participant Data (IPD) Consortium to identify, collect and synthesise IPD from longitudinal studies of pregnant women that measure ZIKV infection during pregnancy and fetal, infant or child outcomes.Methods and analysisWe will identify eligible studies through the ZIKV IPD Consortium membership and a systematic review and invite study PIs to participate in the IPD meta-analysis (IPD-MA). We will use the combined dataset to estimate the relative and absolute risk of congenital Zika syndrome (CZS), including microcephaly and late symptomatic congenital infections; identify and explore sources of heterogeneity in those estimates and develop and validate a risk prediction model to identify the pregnancies at the highest risk of CZS or adverse developmental outcomes. The variable accuracy of diagnostic assays and differences in exposure and outcome definitions means that included studies will have a higher level of systematic variability, a component of measurement error, than an IPD-MA of studies of an established pathogen. We will use expert testimony, existing internal and external diagnostic accuracy validation studies and laboratory external quality assessments to inform the distribution of measurement error in our models. We will apply both Bayesian and frequentist methods to directly account for these and other sources of uncertainty.Ethics and disseminationThe IPD-MA was deemed exempt from ethical review. We will convene a group of patient advocates to evaluate the ethical implications and utility of the risk stratification tool. Findings from these analyses will be shared via national and international conferences and through publication in open access, peer-reviewed journals.Trial registration numberPROSPERO International prospective register of systematic reviews (CRD42017068915).

IntroductionGiven the severity and impact of the current Zika virus (ZIKV) outbreak in the Americas, numerous countries have rushed to develop research studies to assess ZIKV and its potential health consequences. In an effort to ensure that studies are comprehensive, both internally and externally valid, and with reliable results, the World Health Organization, the Pan American Health Organization, Institut Pasteur, the networks of Fiocruz, the Consortia for the Standardization of Influenza Seroepidemiology (CONSISE) and the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) have generated six standardized clinical and epidemiological research protocols and questionnaires to address key public health questions on ZIKV.MethodsWe conducted a systematic search of ongoing study protocols related to ZIKV research. We analyzed the content of protocols of 32 cohort studies and 13 case control studies for systematic bias that could produce erroneous results. Additionally we aimed to characterize the risks of bias and confounding in observational studies related to ZIKV and to propose ways to minimize them, including the use of six newly standardized research protocols.ResultsObservational studies of ZIKV face an array of challenges, including measurement of exposure and outcomes (microcephaly and Guillain-Barré Syndrome). Potential confounders need to be measured where known and controlled for in the analysis. Selection bias due to non-random selection is a significant issue, particularly in the case-control design, and losses to follow-up is equally important for the cohort design.ConclusionObservational research seeking to answer key questions on the ZIKV should consider these restrictions and take precautions to minimize bias in an effort to provide reliable and valid results. Utilization of the standardized research protocols developed by the WHO, PAHO, Institut Pasteur, and CONSISE will harmonize the key methodological aspects of each study design to minimize bias at different stages of the study. Biases need to be considered by researchers implementing the standardized protocols as well as by users of observational epidemiological studies of ZIKV.

We found that laparoscopy in women with acute lower abdominal pain, non-specific lower abdominal pain or suspected appendicitis led to a higher rate of specific diagnoses being made and a lower rate of removal of normal appendices compared with open appendicectomy only. Hospital stays were shorter. No evidence showed an increase in adverse events when any of these strategies were used.

1Este es un artículo de acceso abierto distribuido bajo los términos de la licencia Creative Commons Attribution-NonCommercial-NoDerivs 3.0 IGO, que permite su uso, distribución y reproducción en cualquier medio, siempre que el trabajo original se cite de la manera adecuada. No se permiten modificaciones a los artículos ni su uso comercial. Al reproducir un artículo no debe haber ningún indicio de que la OPS o el artículo avalan a una organización o un producto específico. El uso del logo de la OPS no está permitido. Esta leyenda debe conservarse, junto con la URL original del artículo. En las tres últimas décadas se ha notificado un creciente número de casos de personas que sufren un tipo específico de enfermedad renal crónica (ERC) y fallecen por esa causa en Centroamérica (1, 2). Aunque la mayoría de los países de Centroamérica no cuentan con sistemas de vigilancia que detecten la ERC, la tasa de mortalidad estandarizada por edad (codificada como CKD-N18) es notablemente mayor en hombres y mujeres en Nicaragua y El Salvador que en otros países de la Región de las Américas que RESUMEN Introducción. En 2013, los Estados Miembros de la OPS reconocieron la epidemia de enfermedad renal crónica de causas no tradicionales (ERCnT) como un grave problema de salud pública. Este artículo describe el establecimiento de prioridades de investigación para abordar de manera integral la ERCnT en Centroamérica. Métodos. Se estructuró una encuesta virtual utilizando la metodología Delphi mediante una búsqueda de estudios de investigación efectuados en Centroamérica y de agendas de inves Palabras claveInsuficiencia renal crónica; investigación; prioridades en salud; sistemas de salud; servicios de salud del trabajador.