Vaccine coverage and effectiveness against laboratory-confirmed symptomatic and severe Covid-19 in indigenous people in Brazil: a cohort study.

BACKGROUND: Indigenous people have historically suffered devastating impacts from epidemics and continue to have lower access to healthcare and be especially vulnerable to respiratory infections. We estimated the coverage and effectiveness of Covid-19 vaccines against laboratory-confirmed Covid-19 cases among indigenous people in Brazil. METHODS: We linked nationwide Covid-19 vaccination data with flu-like surveillance records and studied a cohort of vaccinated indigenous people aged ≥ 5 years between 18th January 2021 and 1st March 2022. We considered individuals unexposed from the date they received the first dose of vaccine until the 13th day of vaccination, partially vaccinated from the 14th day after the first dose until the 13th day after receiving the second dose, and fully vaccinated onwards. We estimated the Covid-19 vaccination coverage and used Poisson regression to calculate the relative risks (RR) and vaccine effectiveness (VE) of CoronaVac, ChAdOx1, and BNT162b2 against Covid-19 laboratory-confirmed cases incidence, mortality, hospitalisation, and hospital-progression to Intensive Care Unit (ICU) or death. VE was estimated as (1-RR)*100, comparing unexposed to partially or fully vaccinated. RESULTS: By 1st March 2022, 48.7% (35.0-62.3) of eligible indigenous people vs. 74.8% (57.9-91.8) overall Brazilians had been fully vaccinated for Covid-19. Among fully vaccinated indigenous people, we found a lower risk of symptomatic cases (RR: 0.47, 95%CI: 0.40-0.56) and mortality (RR: 0.47, 95%CI: 0.14-1.56) after the 14th day of the second dose. VE for the three Covid-19 vaccines combined was 53% (95%CI:44-60%) for symptomatic cases, 53% (95%CI:-56-86%) for mortality and 41% (95%CI:-35-75%) for hospitalisation. In our sample, we found that vaccination did not reduce Covid-19 related hospitalisation. However, among hospitalised patients, we found a lower risk of progression to ICU (RR: 0.14, 95%CI: 0.02-0.81; VE: 87%, 95%CI:27-98%) and Covid-19 death (RR: 0.04, 95%CI:0.01-0.10; VE: 96%, 95%CI: 90-99%) after the 14th day of the second dose. CONCLUSIONS: Lower coverage but similar Covid-19 VE among indigenous people than overall Brazilians suggest the need to expand access, timely vaccination, and urgently offer booster doses to achieve a great level of protection among this group.

Socioeconomic determinants of excess weight and obesity among Indigenous women: findings from the First National Survey of Indigenous People's Health and Nutrition in Brazil.

OBJECTIVE: This article assesses the nutritional status of Indigenous women from 14 to 49 years of age in Brazil. DESIGN: Sample size was calculated for each region considering a prevalence of 50 % for all disease outcomes, a relative error of 5 % and a CI of 95 %. In the initial data analysis, the prevalence of excess weight and obesity was calculated according to independent variables. Multivariate multilevel hierarchical analyses were conducted based on a theoretical model of two ranked blocks. SETTING: The 2010 Indigenous population in Brazil was 896 000, with approximately 300 Indigenous ethnic groups, making Brazil one of the most ethnically diverse countries in the Americas and the world. PARTICIPANTS: Of the total target sample of 6722 women evaluated by the National Survey, thirty did not participate, 939 were not eligible for analyses due to pregnancy or unknown pregnancy status, and thirty-nine were excluded due to missing anthropometric data. RESULTS: The evaluation of nutritional status was completed for 5714 non-pregnant women (99·3 % of eligible participants for this outcome). High prevalence rates were encountered for both excess weight (46·2 %) and obesity (15·8 %) among the sampled women. In the multivariate analyses, higher socioeconomic indicators, market-integrated living conditions and less reliance on local food production, as well as increased age and parity were associated with excess weight and obesity. CONCLUSION: Results point to distinct patterns of associations between socioeconomic indicators and the occurrence of excess weight and obesity among Indigenous women, which have potentially significant implications from a public policy perspective for Indigenous peoples in Brazil.

Anemia among indigenous women in Brazil: findings from the First National Survey of Indigenous People's Health and Nutrition.

BACKGROUND: Anemia is recognized as a major public health problem that disproportionately affects vulnerable populations. Indigenous women of reproductive age in Brazil are thought to be at high risk, but lack of nationwide data limits knowledge about the burden of disease and its main determinants. This study aimed to assess the prevalence of anemia and associated factors in this population using data from The First National Survey of Indigenous People's Health and Nutrition in Brazil. METHODS: Data were collected from Indigenous women between 15 and 49 years old based on a nationwide sample of villages. The outcomes of interest were hemoglobin levels (g/dL) and anemia (< 12 g/dL for nonpregnant and < 11 g/dL for pregnant women). Multilevel models were used to explore associations with contextual (village) and individual (household/woman) level variables. RESULTS: Based on data for 6692 Indigenous women, the nationwide mean hemoglobin level was 12.39 g/dL (95% CI: 12.29-12.50). Anemia prevalence was high (33.0%; 95% CI: 30.40-35.61%) and showed pronounced regional disparities. No village-level characteristics were associated with anemia or hemoglobin levels in the multilevel model. Even after controlling for upper level variables, socioeconomic status, parity, body mass index, and having been treated for malaria were associated with anemia and hemoglobin levels. CONCLUSION: The prevalence of anemia in Brazilian Indigenous women was 12% greater than the national estimates for women of reproductive age. Anemia prevalence and mean hemoglobin levels among Indigenous women appear to be partly explained by some previously recognized risk factors, such as socioeconomic status, body mass index, and malaria; however, part of the variability in these outcomes remains unexplained. Knowledge of health status and its potential determinants is essential to guide public policies aimed at controlling anemia burden in Indigenous communities.

Diarrhea and health inequity among Indigenous children in Brazil: results from the First National Survey of Indigenous People's Health and Nutrition.

BACKGROUND: Globally, diarrhea is the second leading cause of death among children under five. In Brazil, mortality due to diarrhea underwent a significant reduction in recent decades principally due to expansion of the primary healthcare network, use of oral rehydration therapy, reduced child undernutrition, and improved access to safe drinking water. The First National Survey of Indigenous People's Health and Nutrition in Brazil, conducted in 2008-2009, was the first survey based on a nationwide representative sample to study the prevalence of diarrhea and associated factors among Indigenous children in the country. METHODS: The survey assessed the health and nutritional status of Indigenous children < 5 years of age based on a representative sample of major Brazilian geopolitical regions. A stratified probabilistic sampling was carried out for Indigenous villages. Within villages, children < 5 years of age in sampled households were included in the study. Interviews were based on a seven day recall period. Prevalence rates of acute diarrhea were calculated for independent variables and hierarchical multivariable analyses were conducted to assess associations. RESULTS: Information on diarrhea was obtained for 5,828 children (95.1% of the total sample). The overall prevalence of diarrhea was 23.5%. Regional differences were observed, with the highest rate being in the North (38.1%). Higher risk of diarrhea was observed among younger children and those who had less maternal schooling, lower household socioeconomic status, undernutrition (weight-for-age deficit), presence of another child with diarrhea in the household, and occurrence of upper respiratory infection. CONCLUSIONS: According to results of the First National Survey of Indigenous People's Health and Nutrition, almost a quarter of Indigenous children throughout the country had diarrhea during the previous week. This prevalence is substantially higher than that documented in 2006 for Brazilian children < 5 years generally (9.4%). Due to its exceedingly multicausal nature, the set of associated variables that remained associated with child diarrhea in the final multivariable model provide an excellent reflection of the diverse social and health inequities faced by Indigenous peoples in contemporary Brazil.

Risk factors for hospital admission due to acute lower respiratory tract infection in Guarani indigenous children in southern Brazil: a population-based case-control study.

OBJECTIVE: To assess risk factors associated with hospital admission due to acute lower respiratory tract infection (ALRTI) in indigenous Guarani children <5 years of age in southern Brazil. METHODS: Population-based matched case-control study from May 2007 to June 2008 in 81 Guarani villages. Cases were defined as hospital admissions due to confirmed ALRTI. Two controls free from acute respiratory infection, matched according to age, sex and place of residence, were selected for each case at the time of the case's hospitalisation. Both cases and controls were recruited by a surveillance routine established for the study. RESULTS: The analysis was performed on 120 cases and 201 controls. The risk factors that remained significantly associated with hospitalisation due to ALRTI in the hierarchical multivariate conditional logistic regression were: low stable monthly per capita household income (

Nutritional status of indigenous children: findings from the First National Survey of Indigenous People's Health and Nutrition in Brazil.

INTRODUCTION: The prevalence of undernutrition, which is closely associated with socioeconomic and sanitation conditions, is often higher among indigenous than non-indigenous children in many countries. In Brazil, in spite of overall reductions in the prevalence of undernutrition in recent decades, the nutritional situation of indigenous children remains worrying. The First National Survey of Indigenous People's Health and Nutrition in Brazil, conducted in 2008-2009, was the first study to evaluate a nationwide representative sample of indigenous peoples. This paper presents findings from this study on the nutritional status of indigenous children < 5 years of age in Brazil. METHODS: A multi-stage sampling was employed to obtain a representative sample of the indigenous population residing in villages in four Brazilian regions (North, Northeast, Central-West, and Southeast/South). Initially, a stratified probabilistic sampling was carried out for indigenous villages located in these regions. Households in sampled villages were selected by census or systematic sampling depending on the village population. The survey evaluated the health and nutritional status of children < 5 years, in addition to interviewing mothers or caretakers. RESULTS: Height and weight measurements were taken of 6,050 and 6,075 children, respectively. Prevalence rates of stunting, underweight, and wasting were 25.7%, 5.9%, and 1.3%, respectively. Even after controlling for confounding, the prevalence rates of underweight and stunting were higher among children in the North region, in low socioeconomic status households, in households with poorer sanitary conditions, with anemic mothers, with low birthweight, and who were hospitalized during the prior 6 months. A protective effect of breastfeeding for underweight was observed for children under 12 months. CONCLUSIONS: The elevated rate of stunting observed in indigenous children approximates that of non-indigenous Brazilians four decades ago, before major health reforms greatly reduced its occurrence nationwide. Prevalence rates of undernutrition were associated with socioeconomic variables including income, household goods, schooling, and access to sanitation services, among other variables. Providing important baseline data for future comparison, these findings further suggest the relevance of social, economic, and environmental factors at different scales (local, regional, and national) for the nutritional status of indigenous peoples.

Prevalence of anemia and associated factors among indigenous children in Brazil: results from the First National Survey of Indigenous People's Health and Nutrition.

BACKGROUND: Anemia is the most prevalent nutritional deficiency globally, affecting about a quarter of the world population. In Brazil, about one-fifth of children under five years of age are anemic. Previous case studies indicate prevalence rates much higher among indigenous peoples in the country. The First National Survey of Indigenous People's Health and Nutrition in Brazil, conducted in 2008-2009, was the first survey based on a nationwide representative sample to study the prevalence of anemia and associated factors among indigenous children in Brazil. METHODS: The survey assessed the health and nutritional status of indigenous children < 5 years of age based on a representative sample of major Brazilian geopolitical regions. A stratified probabilistic sampling was carried out for indigenous villages. Within villages, children < 5 years of age in sampled households were included in the study. Prevalence rates of anemia were calculated for independent variables and hierarchical multivariate analysis were conducted to assess associations. RESULTS: Evaluation of hemoglobin levels was conducted for 5,397 children (88.1% of the total sample). The overall prevalence of anemia was 51.2%. Higher risk of presenting anemia was documented for boys, lower maternal schooling, lower household socioeconomic status, poorer sanitary conditions, presence of maternal anemia, and anthropometric deficits. Regional differences were observed, with the highest rate being observed in the North. CONCLUSIONS: The prevalence rates of anemia in indigenous children were approximately double than those reported for non-indigenous Brazilian children in the same age group. Similarly notable differences in the occurrence of anemia in indigenous and non-indigenous children have been reported for other countries. Deeper knowledge about the etiology of anemia in indigenous children in Brazil is essential to its proper treatment and prevention.

Prevalence of pneumonia and associated factors among indigenous children in Brazil: results from the First National Survey of Indigenous People's Health and Nutrition.

BACKGROUND: Based on data from a nationally representative sample of indigenous villages in Brazilian indigenous reserves, the study sought to estimate the prevalence of pneumonia and evaluate associated factors among indigenous children under 5 years of age. METHODS: Sociodemographic, clinical and reported data on child respiratory health from the First National Survey of Indigenous People's Health and Nutrition in Brazil were collected for 6128 children. Prevalence of pneumonia was calculated for independent variables and hierarchical multivariate analyses were performed to assess associations. RESULTS: The overall prevalence proportions of cough, nasal congestion, pneumonia, and pneumonia with fever were 44.4%, 31.0%, 2.63%, and 1.28%, respectively. In the multivariate model, pneumonia was more frequent among children living in the South/Southeast and North regions of Brazil. Children living in larger households or houses with wood or thatch roofing, as well those with low birthweight or stunting, presented higher risk of pneumonia. Pneumonia was less prevalent among children living in houses with wood flooring and those presenting low weight-for-age. CONCLUSIONS: The study results demonstrate that pneumonia is an important cause of illness among indigenous children throughout Brazil. The association between pneumonia and household characteristics suggests that indoor home environment is closely related to the respiratory health of indigenous children.

Prevalência de fatores de risco para doenças cardiovasculares na populaçäo Guaraní-Mbyá do Estado do Rio de Janeiro / Prevalence o risk factors for cardiovascular disease in the Guaraní-Mbyá population of the State of Rio de Janeiro

A distribuiçäo desigual das doenças crônico-degenerativas tem sido atribuída aos diferentes graus de transformaçäo social em diversas populaçöes. Estudos internacionais em populaçöes indígenas submetidas a mudanças em seus estilos de vida têm mostrado prevalências elevadas de hipertensäo arterial e de outros fatores de risco cardiovasculares. Foi feito um estudo de prevalência desses fatores de risco na populaçäo adulta das aldeias indígenas Sapukai, Paraty-Mirim e Araponga no Rio de Janeiro. Após recenseamento, a populaçäo teve os dados coletados através de entrevista e de avaliaçöes clínicas e bioquímicas. O universo estudado foi de 80 homens e 71 mulheres. As prevalências em toda a amostra foram respectivamente para: hipertensäo arterial (4,8 por cento, 2,6 por cento e 7,4 por cento); sobrepeso (26,7 por cento, 19,5 por cento e 34,8 por cento) e obesidade (4,8 por cento, 3,9 por cento e 5,8 por cento); alteraçöes lipídicas do colesterol total (2,8 por cento, 2,7 por cento e 2,9 por cento) e dos triglicerídios (12,6 por cento, 9,5 por cento e 15,9 por cento). Todas as prevalências foram superiores no sexo feminino e maiores nas idades mais avançadas. Os resultados sugerem que a populaçäo avaliada encontra-se sob o risco intermediário para as doenças crônicas, mostrando que devem ser empreendidos esforços para controlar os fatores de risco.