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Urban children are more likely to be vaccinated than rural children, but that advantage is not evenly distributed. Children living in poor urban areas face unique challenges, living far from health facilities and with lower-quality health services, which can impact their access to life-saving vaccines. Our goal was to compare the prevalence of zero-dose children in poor and non-poor urban and rural areas of low- and middle-income countries (LMICs). Zero-dose children were those who failed to receive any dose of a diphtheria-pertussis-tetanus (DPT) containing vaccine. We used data from nationally representative household surveys of 97 LMICs to investigate 201,283 children aged 12-23 months. The pooled prevalence of zero-dose children was 6.5% among the urban non-poor, 12.6% for the urban poor, and 14.7% for the rural areas. There were significant differences between these areas in 43 countries. In most of these countries, the non-poor urban children were at an advantage compared to the urban poor, who were still better off or similar to rural children. Our results emphasize the inequalities between urban and rural areas, but also within urban areas, highlighting the challenges faced by poor urban and rural children. Outreach programs and community interventions that can reach poor urban and rural communities-along with strengthening of current vaccination programs and services-are important steps to reduce inequalities and ensure that no child is left unvaccinated.
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Países em Desenvolvimento , Acessibilidade aos Serviços de Saúde , População Rural , População Urbana , Humanos , Lactente , População Rural/estatística & dados numéricos , População Urbana/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Feminino , Masculino , Vacina contra Difteria, Tétano e Coqueluche/administração & dosagem , Pobreza , Cobertura Vacinal/estatística & dados numéricos , Programas de Imunização/estatística & dados numéricos , PrevalênciaRESUMO
Background: Identification of unvaccinated children is important for preventing deaths due to infections. Number of siblings and birth order have been postulated as risk factors for zero-dose prevalence. Methods: We analysed nationally representative cross-sectional surveys from 85 low and middle-income countries (2010-2020) with information on immunisation status of children aged 12-35 months. Zero-dose prevalence was defined as the failure to receive any doses of DPT (diphtheria-pertussis-tetanus) vaccine. We examined associations with birth order and the number of siblings, adjusting for child's sex, maternal age and education, household wealth quintiles and place of residence. Poisson regression was used to calculate zero-dose prevalence ratios. Findings: We studied 375,548 children, of whom 13.7% (n = 51,450) were classified as zero-dose. Prevalence increased monotonically with birth order and with the number of siblings, with prevalence increasing from 11.0% for firstborn children to 17.1% for birth order 5 or higher, and from 10.5% for children with no siblings to 17.2% for those with four or more siblings. Adjustment for confounders attenuated but did not eliminate these associations. The number of siblings remained as a strong risk factor when adjusted for confounders and birth order, but the reverse was not observed. Among children with the same number of siblings, there was no clear pattern in zero-dose prevalence by birth order; for instance, among children with two siblings, the prevalence was 13.0%, 14.7%, and 13.3% for firstborn, second, and third-born, respectively. Similar results were observed for girls and boys. 9513 families had two children aged 12-35 months. When the younger sibling was unvaccinated, 61.9% of the older siblings were also unvaccinated. On the other hand, when the younger sibling was vaccinated, only 5.9% of the older siblings were unvaccinated. Interpretation: The number of siblings is a better predictor than birth order in identifying children to be targeted by immunization campaigns. Zero-dose children tend to be clustered within families. Funding: Gavi, the Vaccine Alliance.
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Background: The literature on the association between religion and immunization coverage is scant, mostly consisting of single-country studies. Analyses in low and middle-income countries (LMICs) to assess whether the proportions of zero-dose children vary according to religion remains necessary to better understand non-socioeconomic immunization barriers and to inform interventions that target zero-dose children. Methods: We included 66 LMICs with standardized national surveys carried out since 2010, with information on religion and vaccination. The proportion of children who failed to receive any doses of a diphtheria-pertussis-tetanus (DPT) containing vaccine - a proxy for no access to routine vaccination or "zero-dose" status - was the outcome. Differences among religious groups were assessed using a test for heterogeneity. Additional analyses were performed controlling for the fixed effect of country, household wealth, maternal education, and urban-rural residence to assess associations between religion and immunization. Findings: In 27 countries there was significant heterogeneity in no-DPT prevalence according to religion. Pooled analyses adjusted for wealth, maternal education, and area of residence showed that Muslim children had 76% higher no-DPT prevalence than Christian children. Children from the majority religion in each country tended to have lower no-DPT prevalence than the rest of the population except in Muslim-majority countries. Interpretation: Analyses of gaps in coverage according to religion are relevant to renewing efforts to reach groups that are being left behind, with an important role in the reduction of zero-dose children.
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Cobertura Vacinal , Vacinas , Criança , Humanos , Países em Desenvolvimento , Prevalência , RendaRESUMO
The concept of multiple deprivation recognizes that the same individuals, households, and communities are often exposed to several forms of scarcity. We assessed whether lack of immunization is also associated with nutritional, environmental, and educational outcomes. We analyzed data from nationally representative surveys from 80 low- and middle-income countries with information on no-DPT (children aged 12-23 months without any doses of a diphtheria, pertussis and tetanus containing vaccine), stunting, wasting, maternal education and use of contraception, improved water and sanitation, and long-lasting insecticidal nets. Analyses of how these characteristics overlap were performed at individual and ecological levels. Principal component analyses (PCA) provided additional information on indicator clustering. In virtually all analyses, no-DPT children were significantly more likely to be exposed to the other markers for deprivation. The strongest, most consistent associations were found with maternal education, water, and sanitation, while the weakest associations were found for wasting and bed nets. No-DPT prevalence reached 46.1% in the most deprived quintile from first PCA component derived from deprivation indicators. All children were immunized in the two least deprived quintiles of the component. Our analyses provide strong support for the hypothesis that unimmunized children are also affected by other forms of deprivation.
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BACKGROUND: The Sustainable Development Goals (SDGs) recommend stratification of health indicators by ethnic group, yet there are few studies that have assessed if there are ethnic disparities in childhood immunisation in low-income and middle-income countries (LMICs). METHODS: We identified 64 LMICs with standardised national surveys carried out since 2010, which provided information on ethnicity or a proxy variable and on vaccine coverage; 339 ethnic groups were identified after excluding those with fewer than 50 children in the sample and countries with a single ethnic group. Lack of vaccination with diphtheria-pertussis-tetanus vaccine-a proxy for no access to routine vaccination or 'zero-dose' status-was the outcome of interest. Differences among ethnic groups were assessed using a χ2 test for heterogeneity. Additional analyses controlled for household wealth, maternal education and urban-rural residence. FINDINGS: The median gap between the highest and lowest zero-dose prevalence ethnic groups in all countries was equal to 10 percentage points (pp) (IQR 4-22), and the median ratio was 3.3 (IQR 1.8-6.7). In 35 of the 64 countries, there was significant heterogeneity in zero-dose prevalence among the ethnic groups. In most countries, adjustment for wealth, education and residence made little difference to the ethnic gaps, but in four countries (Angola, Benin, Nigeria and Philippines), the high-low ethnic gap decreased by over 15 pp after adjustment. Children belonging to a majority group had 29% lower prevalence of zero-dose compared with the rest of the sample. INTERPRETATION: Statistically significant ethnic disparities in child immunisation were present in over half of the countries studied. Such inequalities have been seldom described in the published literature. Regular analyses of ethnic disparities are essential for monitoring trends, targeting resources and assessing the impact of health interventions to ensure zero-dose children are not left behind in the SDG era.
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Países em Desenvolvimento , Etnicidade , Criança , Humanos , Imunização , Prevalência , VacinaçãoRESUMO
Despite advances in scaling up new vaccines in low- and middle-income countries, the global number of unvaccinated children has remained high over the past decade. We used 2000-2019 household survey data from 154 surveys representing 89 low- and middle-income countries to assess within-country, economic-related inequality in the prevalence of one-year-old children with zero doses of diphtheria-tetanus-pertussis (DTP) vaccine. Zero-dose DTP prevalence data were disaggregated by household wealth quintile. Difference, ratio, slope index of inequality, concentration index, and excess change measures were calculated to assess the latest situation and change over time, by country income grouping for 17 countries with high zero-dose DTP numbers and prevalence. Across 89 countries, the median prevalence of zero-dose DTP was 7.6%. Within-country inequalities mostly favored the richest quintile, with 19 of 89 countries reporting a rich-poor gap of ≥20.0 percentage points. Low-income countries had higher inequality than lower-middle-income countries and upper-middle-income countries (difference between the median prevalence in the poorest and richest quintiles: 14.4, 8.9, and 2.7 percentage points, respectively). Zero-dose DTP prevalence among the poorest households of low-income countries declined between 2000 and 2009 and between 2010 and 2019, yet economic-related inequality remained high in many countries. Widespread economic-related inequalities in zero-dose DTP prevalence are particularly pronounced in low-income countries and have remained high over the previous decade.
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Background: To help provide a global understanding of the role of gender-related barriers to vaccination, we have used a broad measure of women's empowerment and explored its association with the prevalence of zero-dose children aged 12-23 months across many low- and middle-income countries, using data from standardized national household surveys. Methods: We used data from Demographic and Health Surveys (DHS) of 50 countries with information on both women's empowerment and child immunisation. Zero-dose was operationally defined as the proportion of children who failed to receive any doses of the diphtheria, pertussis, and tetanus containing vaccines (DPT). We measured women's empowerment using the SWPER Global, an individual-level indicator estimated for women aged 15-49 years who are married or in union and with three domains: social independence, decision-making and attitude towards violence. We estimated two summary measures of inequality, the slope index of inequality (SII) and the concentration index (CIX). Results were presented for individual and pooled countries. Results: In the country-level (ecological) analyses we found that the higher the proportion of women with high empowerment, the lower the zero-dose prevalence. In the individual level analyses, overall, children with highly-empowered mothers presented lower prevalence of zero-dose than those with less-empowered mothers. The social independence domain presented more consistent associations with zero-dose. In 42 countries, the lowest zero-dose prevalence was found in the high empowerment groups, with the slope index of inequality showing significant results in 28 countries. When we pooled all countries using a multilevel Poisson model, children from mothers in the low and medium levels of the social independence domain had respectively 3.3 (95% confidence interval (CI) = 2.3, 4.7) and 1.8 (95% CI = 1.5, 2.1) times higher prevalence of zero-dose compared to those in the high level. Conclusions: Our country-level and individual-level analyses support the importance of women's empowerment for child vaccination, especially in countries with weaker routine immunisation programs.
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Países em Desenvolvimento , Renda , Adolescente , Adulto , Criança , Pré-Escolar , Características da Família , Feminino , Humanos , Programas de Imunização , Lactente , Pessoa de Meia-Idade , Vacinação , Adulto JovemRESUMO
BACKGROUND: Unvaccinated children may live in households with limited access to other primary health care (PHC) services, and routine vaccination services may provide the opportunity to bring caregivers into contact with the health system. We aimed to investigate the overlap between not being vaccinated and failing to receive other PHC services in low- and middle-income countries (LMICs). METHODS: Using Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS) data between 2010-2019 from 92 LMICs, we analysed six vaccination indicators based on the bacille Calmette-Guérin (BCG), polio, diphtheria-pertussis-tetanus (DPT) and measles vaccines and their overlap with four other PHC indicators - at least four antenatal care (ANC) visits, institutional delivery, careseeking for common childhood illnesses or symptoms and place for handwashing in the home - in 211,141 children aged 12-23 months. Analyses were stratified according to wealth quintiles and World Bank income levels. FINDINGS: Unvaccinated children and their mothers were systematically less likely to receive the other PHC interventions. These associations were particularly marked for 4+ ANC visits and institutional delivery and modest for careseeking behaviour. Our stratified analyses confirm a systematic disadvantage of unvaccinated children and their families with respect to obtaining other health services in all levels of household wealth and country income. INTERPRETATION: We suggested that lack of vaccination goes hand in hand with missing out on other health interventions. This represents an opportunity for integrated delivery strategies that may more efficiently reduce inequalities in health service coverage. FUNDING: Bill & Melinda Gates Foundation, Gavi, the Vaccine Alliance, The Wellcome Trust, Associação Brasileira de Saúde Coletiva and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.
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INTRODUCTION: Zero-dose prevalence refers to children who failed to receive any routine vaccination. Little is known about the "immunisation cascade" in low- and middle-income countries (LMICs), defined as how children move from zero dose to full immunisation. METHODS: Using data from national surveys carried out in 92 LMICs since 2010 and focusing on the four basic vaccines delivered in infancy (BCG, polio, DPT and MCV), we describe zero-dose prevalence and the immunisation cascade in children aged 12 to 23 months. We also describe the most frequent combinations of vaccines (or co-coverage) among children who are partially immunized. Analyses are stratified by country income groups, household wealth quintiles derived from asset indices, sex of the child and area of residence. Results were pooled across countries using child populations as weights. RESULTS: In the 92 countries, 7.7% were in the zero-dose group, and 3.3%, 3.4% and 14.6% received one, two or three vaccines, respectively; 70.9% received the four types and 59.9% of the total were fully immunised with all doses of the four vaccines. Three quarters (76.8%) of children who received the first vaccine received all four types. Among children with a single vaccine, polio was the most common in low- and lower-middle income countries, and BCG in upper-middle income countries. There were sharp inequalities according to household wealth, with zero-dose prevalence ranging from 12.5% in the poorest to 3.4% in the wealthiest quintile across all countries. The cascades were similar for boys and girls. In terms of dropout, 4% of children receiving BCG did not receive DPT1, 14% receiving DPT1 did not receive DPT3, and 9% receiving DPT3 did not progress to receive MCV. INTERPRETATION: Focusing on zero-dose children is particularly important because those who are reached with the first vaccine are highly likely to also receive remaining vaccines.
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Países em Desenvolvimento , Vacinas , Criança , Feminino , Humanos , Imunização , Programas de Imunização , Lactente , Masculino , VacinaçãoRESUMO
BACKGROUND: Achieving universal health coverage, including quality essential service coverage and financial protection for all, is target 3.8 of the Sustainable Development Goals (SDG). As a result, an index of essential health service coverage indicators was selected by the UN as SDG indicator 3.8.1. We have developed an index for measuring SDG 3.8.1, describe methods for compiling the index, and report baseline results for 2015. METHODS: 16 tracer indicators were selected for the index, which included four from within each of the categories of reproductive, maternal, newborn, and child health; infectious disease; non-communicable diseases; and service capacity and access. Indicator data for 183 countries were taken from UN agency estimates or databases, supplemented with submissions from national focal points during a WHO country consultation. The index was computed using geometric means, and a subset of tracer indicators were used to summarise inequalities. FINDINGS: On average, countries had primary data since 2010 for 72% of the final set of indicators. The median national value for the service coverage index was 65 out of 100 (range 22-86). The index was highly correlated with other summary measures of health, and after controlling for gross national income and mean years of adult education, was associated with 21 additional years of life expectancy over the observed range of country values. Across 52 countries with sufficient data, coverage was 1% to 66% lower among the poorest quintile as compared with the national population. Sensitivity analyses suggested ranks implied by the index are fairly stable across alternative calculation methods. INTERPRETATION: Service coverage within universal health coverage can be measured with an index of tracer indicators. Our universal health coverage service coverage index is simple to compute by use of available country data and can be refined to incorporate relevant indicators as they become available through SDG monitoring. FUNDING: Ministry of Health, Japan, and the Rockefeller Foundation.
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Objetivos , Cobertura Universal do Seguro de Saúde/estatística & dados numéricos , Bases de Dados Factuais , Saúde Global , Acessibilidade aos Serviços de Saúde , HumanosRESUMO
Measurements of health indicators are rarely available for every population and period of interest, and available data may not be comparable. The Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) define best reporting practices for studies that calculate health estimates for multiple populations (in time or space) using multiple information sources. Health estimates that fall within the scope of GATHER include all quantitative population-level estimates (including global, regional, national, or subnational estimates) of health indicators, including indicators of health status, incidence and prevalence of diseases, injuries, and disability and functioning; and indicators of health determinants, including health behaviours and health exposures. GATHER comprises a checklist of 18 items that are essential for best reporting practice. A more detailed explanation and elaboration document, describing the interpretation and rationale of each reporting item along with examples of good reporting, is available on the GATHER website (http://gather-statement.org).
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Coleta de Dados/normas , Saúde Global , Guias como Assunto , Indicadores Básicos de Saúde , Lista de Checagem , Comportamentos Relacionados com a Saúde , HumanosRESUMO
INTRODUCTION: HIV testing is the entry point for the elimination of mother-to-child transmission of HIV. Decreasing external funding for the HIV response in some low- and middle-income countries has triggered the question of whether a focused approach to HIV testing targeting pregnant women in high-burden areas should be considered. This study aimed at determining and comparing the cost-effectiveness of universal and focused HIV testing approaches for pregnant women across high to very low HIV prevalence settings. METHODS: We conducted a modelling analysis on health and cost outcomes of HIV testing for pregnant women using four country-based case scenarios (Namibia, Kenya, Haiti and Viet Nam) to illustrate high, intermediate, low and very low HIV prevalence settings. We used subnational prevalence data to divide each country into high-, medium- and low-burden areas, and modelled different antenatal and testing coverage in each. RESULTS: When HIV testing services were only focused in high-burden areas within a country, mother-to-child transmission rates remained high ranging from 18 to 23%, resulting in a 25 to 69% increase in new paediatric HIV infections and increased future treatment costs for children. Universal HIV testing was found to be dominant (i.e. more QALYs gained with less cost) compared to focused approaches in the Namibia, Kenya and Haiti scenarios. The universal approach was also very cost-effective compared to focused approaches, with $ 125 per quality-adjusted life years gained in the Viet Nam-based scenario of very low HIV prevalence. Sensitivity analysis further supported the findings. CONCLUSIONS: Universal approach to antenatal HIV testing achieves the best health outcomes and is cost-saving or cost-effective in the long term across the range of HIV prevalence settings. It is further a prerequisite for quality maternal and child healthcare and for the elimination of mother-to-child transmission of HIV.
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Infecções por HIV/diagnóstico , Complicações Infecciosas na Gravidez/diagnóstico , Diagnóstico Pré-Natal/economia , Sorodiagnóstico da AIDS , Adolescente , Adulto , Análise Custo-Benefício , Feminino , Infecções por HIV/economia , Infecções por HIV/epidemiologia , Haiti , Humanos , Transmissão Vertical de Doenças Infecciosas/economia , Quênia , Programas de Rastreamento/economia , Pessoa de Meia-Idade , Namíbia , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Prevalência , Anos de Vida Ajustados por Qualidade de Vida , Vietnã , Adulto JovemRESUMO
[This corrects the article DOI: 10.1371/journal.pmed.1002056.].
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Measurements of health indicators are rarely available for every population and period of interest, and available data may not be comparable. The Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) define best reporting practices for studies that calculate health estimates for multiple populations (in time or space) using multiple information sources. Health estimates that fall within the scope of GATHER include all quantitative population-level estimates (including global, regional, national, or subnational estimates) of health indicators, including indicators of health status, incidence and prevalence of diseases, injuries, and disability and functioning; and indicators of health determinants, including health behaviours and health exposures. GATHER comprises a checklist of 18 items that are essential for best reporting practice. A more detailed explanation and elaboration document, describing the interpretation and rationale of each reporting item along with examples of good reporting, is available on the GATHER website.
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Lista de Checagem , Saúde Global , Guias como Assunto/normas , Indicadores Básicos de Saúde , Coleta de Dados , Métodos Epidemiológicos , Pesquisa sobre Serviços de Saúde , HumanosRESUMO
Gretchen Stevens and colleagues present the GATHER statement, which seeks to promote good practice in the reporting of global health estimates.
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Coleta de Dados/normas , Métodos Epidemiológicos , Saúde Global , Indicadores Básicos de Saúde , Lista de Checagem , Pesquisa sobre Serviços de Saúde , HumanosRESUMO
Policy makers have paid considerable attention to the financial implications of insurance expansion under the Affordable Care Act (ACA), but there is little evidence of the law's potential health effects. To gain insight into these effects, we analyzed data for 1999-2012 from the National Health and Nutrition Examination Survey to evaluate relationships between health insurance and the diagnosis and management of diabetes, hypercholesterolemia, and hypertension. People with insurance had significantly higher probabilities of diagnosis than matched uninsured people, by 14 percentage points for diabetes and hypercholesterolemia and 9 percentage points for hypertension. Among those with existing diagnoses, insurance was associated with significantly lower hemoglobin A1c (-0.58 percent), total cholesterol (-8.0 mg/dL), and systolic blood pressure (-2.9 mmHg). If the number of nonelderly Americans without health insurance were reduced by half, we estimate that there would be 1.5 million more people with a diagnosis of one or more of these chronic conditions and 659,000 fewer people with uncontrolled cases. Our findings suggest that the ACA could have significant effects on chronic disease identification and management, but policy makers need to consider the possible implications of those effects for the demand for health care services and spending for chronic disease.
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Doença Crônica/economia , Cobertura do Seguro/estatística & dados numéricos , Seguro Saúde/estatística & dados numéricos , Pessoas sem Cobertura de Seguro de Saúde/estatística & dados numéricos , Patient Protection and Affordable Care Act/economia , Adulto , Doença Crônica/terapia , Bases de Dados Factuais , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/economia , Feminino , Custos de Cuidados de Saúde , Reforma dos Serviços de Saúde/economia , Humanos , Hipercolesterolemia/diagnóstico , Hipercolesterolemia/economia , Hipertensão/diagnóstico , Hipertensão/economia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Estados Unidos , Adulto JovemRESUMO
OBJECTIVE: To estimate cause-of-death distributions in the early (0-6 days of age) and late (7-27 days of age) neonatal periods, for 194 countries between 2000 and 2013. METHODS: For 65 countries with high-quality vital registration, we used each country's observed early and late neonatal proportional cause distributions. For the remaining 129 countries, we used multinomial logistic models to estimate these distributions. For countries with low child mortality we used vital registration data as inputs and for countries with high child mortality we used neonatal cause-of-death distribution data from studies in similar settings. We applied cause-specific proportions to neonatal death estimates from the United Nations Inter-agency Group for Child Mortality Estimation, by country and year, to estimate cause-specific risks and numbers of deaths. FINDINGS: Over time, neonatal deaths decreased for most causes. Of the 2.8 million neonatal deaths in 2013, 0.99 million deaths (uncertainty range: 0.70-1.31) were estimated to be caused by preterm birth complications, 0.64 million (uncertainty range: 0.46-0.84) by intrapartum complications and 0.43 million (uncertainty range: 0.22-0.66) by sepsis and other severe infections. Preterm birth (40.8%) and intrapartum complications (27.0%) accounted for most early neonatal deaths while infections caused nearly half of late neonatal deaths. Preterm birth complications were the leading cause of death in all regions of the world. CONCLUSION: The neonatal cause-of-death distribution differs between the early and late periods and varies with neonatal mortality rate level. To reduce neonatal deaths, effective interventions to address these causes must be incorporated into policy decisions.
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Causas de Morte , Saúde Global , Mortalidade Infantil , Doenças Transmissíveis/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Complicações na Gravidez/epidemiologia , Nascimento Prematuro/epidemiologiaRESUMO
OBJECTIVE: Describe modifications to the latest version of the Joint United Nations Programme on AIDS (UNAIDS) Estimation and Projection Package component of Spectrum (EPP 2013) to improve prevalence fitting and incidence trend estimation in national epidemics and global estimates of HIV burden. METHODS: Key changes made under the guidance of the UNAIDS Reference Group on Estimates, Modelling and Projections include: availability of a range of incidence calculation models and guidance for selecting a model; a shift to reporting the Bayesian median instead of the maximum likelihood estimate; procedures for comparison and validation against reported HIV and AIDS data; incorporation of national surveys as an integral part of the fitting and calibration procedure, allowing survey trends to inform the fit; improved antenatal clinic calibration procedures in countries without surveys; adjustment of national antiretroviral therapy reports used in the fitting to include only those aged 15-49 years; better estimates of mortality among people who inject drugs; and enhancements to speed fitting. RESULTS: The revised models in EPP 2013 allow closer fits to observed prevalence trend data and reflect improving understanding of HIV epidemics and associated data. CONCLUSION: Spectrum and EPP continue to adapt to make better use of the existing data sources, incorporate new sources of information in their fitting and validation procedures, and correct for quantifiable biases in inputs as they are identified and understood. These adaptations provide countries with better calibrated estimates of incidence and prevalence, which increase epidemic understanding and provide a solid base for program and policy planning.