SARS-CoV-2 antibody prevalence in Brazil: results from two successive nationwide serological household surveys

BACKGROUND

Population-based data on COVID-19 are essential for guiding policies. There are few such studies, particularly from low or middle-income countries. Brazil is currently a hotspot for COVID-19 globally. We aimed to investigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody prevalence by city and according to sex, age, ethnicity group, and socioeconomic status, and compare seroprevalence estimates with official statistics on deaths and cases.

METHODS

In this repeated cross-sectional study, we did two seroprevalence surveys in 133 sentinel cities in all Brazilian states. We randomly selected households and randomly selected one individual from all household members. We excluded children younger than 1 year. Presence of antibodies against SARS-CoV-2 was assessed using a lateral flow point-of-care test, the WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech, Guangzhou, China), using two drops of blood from finger prick samples. This lateral-flow assay detects IgG and IgM isotypes that are specific to the SARS-CoV-2 receptor binding domain of the spike protein. Participants also answered short questionnaires on sociodemographic information (sex, age, education, ethnicity, household size, and household assets) and compliance with physical distancing measures.

FINDINGS

We included 25 025 participants in the first survey (May 14-21) and 31 165 in the second (June 4-7). For the 83 (62%) cities with sample sizes of more than 200 participants in both surveys, the pooled seroprevalence increased from 1·9% (95% CI 1·7-2·1) to 3·1% (2·8-3·4). City-level prevalence ranged from 0% to 25·4% in both surveys. 11 (69%) of 16 cities with prevalence above 2·0% in the first survey were located in a stretch along a 2000 km of the Amazon river in the northern region. In the second survey, we found 34 cities with prevalence above 2·0%, which included the same 11 Amazon cities plus 14 from the northeast region, where prevalence was increasing rapidly. Prevalence levels were lower in the south and centre-west, and intermediate in the southeast, where the highest level was found in Rio de Janeiro (7·5% [4·2-12·2]). In the second survey, prevalence was similar in men and women, but an increased prevalence was observed in participants aged 20-59 years and those living in crowded conditions (4·4% [3·5-5·6] for those living with households with six or more people). Prevalence among Indigenous people was 6·4% (4·1-9·4) compared with 1·4% (1·2-1·7) among White people. Prevalence in the poorest socioeconomic quintile was 3·7% (3·2-4·3) compared with 1·7% (1·4-2·2) in the wealthiest quintile.

INTERPRETATION

Antibody prevalence was highly heterogeneous by country region, with rapid initial escalation in Brazil's north and northeast. Prevalence is strongly associated with Indigenous ancestry and low socioeconomic status. These population subgroups are unlikely to be protected if the policy response to the pandemic by the national government continues to downplay scientific evidence.

FUNDING

Brazilian Ministry of Health, Instituto Serrapilheira, Brazilian Collective Health Association, and the JBS Fazer o Bem Faz Bem.

Maternal knowledge on infant feeding in São Luís, Maranhão, Brazil

Abtract Objectives: to describe the knowledge of infant feeding on breastfeeding and the introduction of complementary feeding among mothers of children under one-year-old in São Luís, MA. Methods: a cross-sectional descriptive study using a single questionnaire, standardized by trained interviewers, who visited all the residents in 20 communities chosen by convenience. This questionnaire searched for socioeconomic, demographic information, care received during pregnancy, and the knowledge about infant feeding. The analysis was performed through the creation of knowledge scores, frequency listing, central tendency and dispersion measurements. Results: among the 709 interviewees, 53.5% presented satisfactory knowledge. The score on the percentage mean of knowledge on infant feeding was 66.7%. The specific score on the introduction of complementary feeding was 60.7% and breastfeeding was71.4%. The benefits of breastfeeding for the babies were better known than the advantages it confers on mothers. The worst result was related to porridge preparation,(13.5%). Conclusion: the proportion of mothers who did not know about the basic teachings of infant feeding is high. This can lead to reduce exclusive breastfeeding time, increase rates of improper introduction of food and drink, and in favor early weaning.

Maternal Knowledge and Unsafe Baby Sleep Position: A Cross-Sectional Survey in Southern Brazil

Objective to evaluate women's knowledge about the best baby sleeping position and to identify factors associated with a greater probability of putting infants to sleep in an unsafe position, in Rio Grande, Southern Brazil. Method This is a cross-sectional population-based study that included all women who bore children in 2013 in this municipality. A single, standardized questionnaire was given within 48 h after delivery in the only two local maternity hospitals. The outcome was that women reported the lateral and the ventral decubitus as the best sleeping positions for babies. A Chi square test was used for proportions and Poisson regression was used with robust variance adjustment in the multivariate analysis. The prevalence ratio was the measure of effect used. Results We included 2624 women in this study. Of these, 82.1% (95% CI 80.6-83.6) stated that the baby should sleep in the lateral or ventral decubitus positions. 76.4% reported having acquired this knowledge from their mothers and 34.7% were willing to adopt the correct (supine) sleeping position for their child if recommended by doctors. The adjusted analysis showed that the lower the schooling of the mothers and the greater the number of people per bedroom and number of children, the greater the probability of women choosing an unsafe baby sleeping position. Conclusions for Practice This study showed that the percentage of women who are unaware of the correct baby sleeping position is very high, that doctors should be convinced to recommend the supine baby sleeping position, and that campaigns on this subject should also include grandparents as a priority intervention group.

Iniquidade na assistência à gestação e ao parto em município do semiárido brasileiro

OBJETIVOS: avaliar a iniquidade na assistência à gestação e ao parto para menores de cinco anos residentes no município de Caracol, Piauí, Brasil. MÉTODOS: usando delineamento transversal, amostragem sistemática e aplicação de questionário domiciliar foram coletadas informações sobre características demográficas de mães e crianças, assistência à gestação e ao parto e nível socioeconômico. Por meio da técnica de componentes principais, criou-se um escore em tercis. As associações deste escore com as variáveis relativas à assistência à gestação e ao parto foram avaliadas pelos testes qui-quadrado e Kruskal- Wallis. RESULTADOS: todas as 405 crianças incluídas no estudo eram provenientes de famílias com renda inferior a um salário mínimo mensal; 65% residiam em área rural. Mães pertencentes ao maior tercil socioeconômico realizaram um maior número de consultas de pré-natal; realizaram maior número de exames de urina, hemograma, citopatológico de colo uterino e ultrassonografia, tiveram o parto realizado por médico e foram mais frequentemente submetidas à cesariana. CONCLUSÕES: mesmo entre os mais pobres, há enormes iniquidades em saúde. Combater os determinantes desta pobreza com programas sociais mais agressivos é imperativo, assim como priorizar o atendimento aos mais pobres dentre os pobres.

Maternal knowledge on child survival in the poorest areas of North and Northeast Brazil: o caso de áreas pobres nas regiões Norte e Nordeste do Brasil

This study aimed to evaluate knowledge on child survival among mothers of children under five years of age living in nine municipalities in North and Northeast Brazil. A standardized questionnaire was used for home interviews of mothers visited by volunteers from the Pastorate of the Child and mothers not visited by the program (control areas). The association between independent variables and the outcome (visited versus not visited by the Pastorate of the Child) was evaluated using the chi-square test. Among the 752 mothers studied, 386 were visited by Pastorate of the Child volunteers and 366 were not visited. Mothers visited by the Pastorate of the Child, although poorer, showed better knowledge on monitoring child growth and identifying child development difficulties as compared to mothers from the control areas. Despite the better performance of mothers visited by the Pastorate of the Child volunteers, maternal knowledge on child survival in both groups was less than desirable. This hinders the identification of more serious cases, delays seeking medical care, and reduces the impact on child morbidity and mortality.

[Child health in poor areas: findings from a population-based study in Caracol, Piauí, and Garrafão do Norte, Pará, Brazil]

The aim of this study was to evaluate child health indicators in the municipalities (counties) of Caracol, Piauí State, and Garrafão do Norte, Pará State, Brazil. Through household visits using systematic sampling, previously trained interviewers applied a standard questionnaire to mothers of under-five children, investigating socioeconomic status, housing and environmental sanitation, demographic characteristics, disease patterns, and prenatal and childbirth care. The analysis used the t-test and chi-square test to compare indicators between the two municipalities. Of the 1,728 children studied, 60% were from families with incomes less than one monthly minimum wage (approximately U$200), 41% had no type of sewage treatment or disposal, 10% of mothers reported zero prenatal visits, 30% of the children were born in the same municipality, and 30% had been taken to a pediatric consultation in the previous 3 months; 20% had a height-for-age deficit > 2 standard deviations. All target indicators were deficient in both the municipalities (especially in Garrafão do Norte). Expanding health care supply and improving housing and sanitation conditions are priorities in both municipalities.

[Profile of the elderly population in two poor municipalities in North and Northeast Brazil: the results of a cross-sectional population-based survey]

This study aimed to determine the profile of the elderly population (>or= 60 years) in two poor municipalities in North and Northeast Brazil in 2005. Using a cross-sectional survey with a systematic sample, previously trained interviewers applied a standard household questionnaire on demographic characteristics, socioeconomic status, household conditions, physical activity, immunization status, health problems, and expenditures on medicines. Of the total sample (n = 1,013), 528 lived in Caracol, Piauí State, and 478 in Garrafão do Norte, Pará State. 56% were 60-69 years old, 10% lived alone, 69% were illiterate, 8% had a family income less than the minimum wage, 24% of the households had a flush toilet, 60% had a radio, television, and refrigerator, 88% reported at least one chronic disease, 47% had to purchase all their medicines out-of-pocket, 84% had received influenza vaccination, and 90% were able to perform normal activities of daily living. Elderly people included in this study showed poor household conditions, inadequate access to health care, and high levels of morbidity.

Diferentes estratégias de visita domiciliar e seus efeitos sobre a assistência pré-natal no extremo Sul do Brasil

Este estudo do tipo intervenção comunitária controlada unicega não randomizada teve por objetivo avaliar o impacto das visitas realizadas pelos agentes comunitários de saúde e líderes voluntários da Pastoral da Criança sobre o pré-natal de gestantes pobres em Rio Grande, Rio Grande do Sul, Brasil. Aplicaram-se questionários padronizados antes e depois do parto buscando conhecer suas características demográficas, reprodutivas, assistência recebida durante o pré-natal e nível sócio-econômico e condição de moradia. Estas gestantes foram divididas em três grupos, sendo dois grupos-intervenção e um controle. Dentre as 339 gestantes estudadas, 115 pertenciam ao grupo cuja intervenção foi realizada pelos agentes comunitários de saúde, 116 pelos líderes voluntários da pastoral e 108 pertenciam ao grupo controle. Gestantes visitadas pelos agentes comunitários iniciaram o pré-natal mais precocemente, realizaram maior número de consultas, exames clínicos e testes laboratoriais, foram mais comumente orientadas sobre amamentação e suplementadas com sulfato ferroso. A participação de familiares nas consultas de pré-natal foi maior entre gestantes visitadas pelos líderes voluntários. Visitas domiciliares podem melhorar a qualidade do pré-natal entre gestantes pobres e aumentar a participação de familiares, sobretudo do marido, na gestação.

Assistência à gestação e ao parto: resultados de dois estudos transversais em áreas pobres das regiões Norte e Nordeste do Brasil

Em 2002 e 2005 realizou-se inquérito transversal em áreas pobres das regiões Norte e Nordeste do Brasil visando avaliar a assistência à gestação e ao parto entre mães de menores de cinco anos. Foram estudadas 1.528 e 1.529 crianças em 2002 e 2005, respectivamente. Neste período, a escolaridade média das mães aumentou em 1,5 anos, a renda familiar em R$ 100,00 e o fornecimento de água tratada passou de 23% para 41%; a realização de seis ou mais consultas de pré-natal aumentou de 42% para 52% e a imunização contra tétano neonatal de 54% para 77%; a avaliação da altura uterina de 54% para 77% enquanto a realização de teste para HIV e sífilis duplicou, passando de cerca de 8% para aproximadamente 16% e de ultra-sonografia de 44% para 64%. No entanto, a realização de exames ginecológicos caiu de 41% para 31% e as orientações sobre amamentação de 66% para 55%. Apesar de melhorias expressivas na maioria dos indicadores estudados, verifica-se que ainda estão abaixo das regiões mais desenvolvidas do país. Esforços devem ser feitos visando reduzir estes diferenciais.

[Evaluation of knowledge on prenatal care and pregnancy risk among women living in a peripheral area of Rio Grande, Rio Grande do Sul State, Brazil]

The aim of this study was to assess knowledge on prenatal care and pregnancy risk among women in poor neighborhoods in the city of Rio Grande, Rio Grande do Sul State, Brazil. Data were collected using a cross-sectional design. A standard questionnaire was applied to all pregnant women from poor neighborhoods. Trained interviewers visited these women at home, covering demographic, socioeconomic, and reproductive data and knowledge concerning prenatal care and pregnancy risk factors. A total of 367 pregnant women were interviewed using non-random sampling. Except for urine tests and HIV testing, spontaneously reported as necessary, other procedures were reported by no more than 30% of the women. Digital vaginal examination, clinical breast examination, and Pap smear were reported by a maximum of 7% of the women. Only two-thirds felt that vaginal bleeding and abdominal pain were serious signs during gestation. Other signs and symptoms were reported by a maximum of one-third of the women. In conclusion, knowledge of prenatal tests and situations indicating serious risk fell far short of the desired levels. Improving this level of information in pregnant women could help reduce maternal and child morbidity and mortality.

[Self-reported vaginal discharge among pregnant women in an urban area in Southern Brazil: prevalence and associated factors]

The purpose of this study was to determine the prevalence and risk factors associated with self-reported vaginal discharge among pregnant women in the city of Rio Grande, South Brazil. Using a cross-sectional design, a standard interview was applied to pregnant women at home by previously trained interviewers, covering the following: demographic, reproductive, and socioeconomic data, household conditions, health care, and illnesses during pregnancy, including vaginal discharge. The chi-square test was used to compare proportions, and Poisson regression was used in the multivariate analysis. Among the 339 pregnant women interviewed, 52% reported vaginal discharge. The following variables were significantly associated with the outcome: age (prevalence rate, PR = 1.49), marital status (PR = 1.31), urinary tract infection (PR = 1.56), hyperglycemia (PR = 1.48), use of an intrauterine device (PR = 2.35), and history of preterm delivery (PR = 1.37), with oral contraception showing a protective effect (PR = 0.79). Prevalence of self-reported discharge was high among this group of pregnant women. Several risk factors were also identified for the disease under study. These findings can contribute to the implementation of preventive interventions.

Randomized clinical trial of the impact of a nutritional supplement "multimixture" on the nutritional status of children enrolled at preschools

OBJECTIVE

To evaluate the effect of adding a nutritional supplement "multimixture" to school meals on the nutritional status of children enrolled at municipal preschools.

METHODS

Longitudinal, controlled intervention study of 24 preschools which were compared before and after an intervention. The control and intervention groups were defined by drawing lots to choose schools that had previously been paired for nutritional status. The intervention consisted of the addition of 10 g of multimixture to the meals provided to children attending the 12 schools in the intervention group. Outcome measures include changes in z scores for the three nutritional indices and hemoglobin values over the 6-month period during which the supplement was added. A multilevel model was used for analyses.

RESULTS

Mean z scores for weight for age at the end of follow-up were 0.40 (+/-1.34) and 0.31 (+/-1.32), for the intervention and control groups respectively. The multilevel analysis demonstrated non-significant differences in favor of the intervention in mean z scores for weight for age (beta 0.05; 95%CI -0.03 to 0.12) and height for age (beta 0.02; 95%CI -0.06 to 0.09). Mean change in hemoglobin was against the intervention, but this was also without significance (beta -0.01; 95%CI -0.36 to 0.34).

CONCLUSIONS

Supplementation with 10 g of multimixture did not have a significant effect on any of the nutritional indices or measurements of the municipal preschool pupils studied here.

[Child health in poor areas of North and Northeast Brazil: a comparison of areas covered by the Children's Mission and control areas]

Community surveys are essential to estimate health indicators, evaluate health programs, and define health interventions. In 2002, a cross-sectional survey of children under five was conducted in 18 areas of the poorest counties in North and Northeast Brazil. Nine areas were visited by volunteer community health workers (CHW) under the Children's Mission, and the others were not visited. Using a standard questionnaire, trained interviewers collected information at the household level for 1,528 children, 782 of whom were visited monthly by CHWs and 772 were not. All the children and their families were living below the poverty line; 40.0% of the parents were illiterate, per capita daily income was about US$0.30, and household conditions were substandard. However, most were living less than 1km from a public health service and almost all children who were referred to these services received medical care. Prenatal care was also poor in terms of number of medical visits and laboratory tests. Children visited by CHWs from the Children's Mission received better care in terms of growth monitoring, number of medical check-ups, and prenatal iron supplementation.

Qualidade e eqüidade da atenção ao pré-natal e ao parto em Criciúma, Santa Catarina, Sul do Brasil

Este estudo transversal de base populacional teve por objetivo avaliar a qualidade e a eqüidade da atenção ao pré-natal, ao parto e ao recém-nascido em uma amostra probabilística de 2180 crianças menores de três anos residentes na área urbana do município de Criciúma, SC. 96,6% das mães destas crianças realizaram pelo menos uma consulta de pré-natal; o parto hospitalar foi praticamente universal. As mães de menor renda iniciaram o pré-natal mais tarde e realizaram menos consultas. Gestantes com maior risco reprodutivo apresentaram menor percentagem de atendimento com qualidade adequada. Dos 13 procedimentos de pré-natal e parto pesquisados, o 1º e 4º quartil de renda familiar realizaram 8,6 e 9,4 procedimentos, respectivamente. Os exames ginecológico especular e de mamas foram os menos realizados (51% para ambos). As gestantes do 4º quartil de renda familiar total tiveram 1,5 e 1,9 vezes mais estes procedimentos em relação às do 1º quartil. Esforços devem ser feitos no sentido de captar precocemente as mães provenientes de famílias de menor poder aquisitivo e deve ser utilizado o enfoque de risco com discriminação positiva. Os médicos devem ser re-treinados quanto aos seus procedimentos tanto no pré-natal quanto na assistência ao parto.

Impacto da Pastoral da Criança sobre a nutrição de menores de cinco anos no Maranhão: uma análise multinível

JUSTIFICATIVA: A Pastoral da Criança acompanha mais de 1,5 milhão de crianças mensalmente na promoção da saúde materno-infantil. Há necessidade de avaliações independentes para avaliar o seu impacto. OBJETIVO: Comparar indicadores de nutrição infantil em comunidades servidas pela Pastoral da Criança e em comunidades-controle através da análise tradicional e multinível. DELINEAMENTO: Estudo quase-experimental, comparando conglomerados de crianças acompanhadas por 60 líderes comunitárias da Pastoral e conglomerados-controle. LOCAL: Áreas urbanas e rurais (municípios São Luís e Timbiras) no Maranhão. PARTICIPANTES: 60 conglomerados em cada grupo (Pastoral e Controle) e média de 14 crianças por conglomerado, sendo efetivamente incluídas no estudo 1.629 crianças, das quais 820 eram acompanhadas pela Pastoral. RESULTADOS: A análise dos desfechos foi realizada através de métodos tradicionais, que ignoram a estrutura hierarquizada dos dados, e considerando as correlações intra-grupos através de análise multinível. Esta mostrou que a variabilidade do modelo de regressão estava distribuída em todos os 4 níveis estudados. Na análise tradicional do escore-Z de altura para idade, as crianças da Pastoral eram em média 0,184 escore-Z mais baixas do que as crianças controle (P=0,03). Após ajuste para o escore de fatores de confusão, esta diferença aumentou. No entanto, quando se ajustou para a idade das crianças o efeito diminuiu e deixou de ser significativo. A análise multinível não mostrou efeito significante da Pastoral em nenhum dos modelos de ajuste, ao contrário da análise tradicional. Tanto a análise tradicional quanto a multinível apresentaram resultados similares quanto ao desfecho de aleitamento materno exclusivo ou predominante no terceiro mês de vida, ambos evidenciando influência positiva da Pastoral da Criança, tanto na análise bruta quanto na análise ajustada (razões de odds de 4,37 e 4,63 respectivamente, ambas com p<0,001). CONCLUSÃO: A avaliação mostrou que a análise tradicional, ao ignorar as correlações intra-classes, pode apresentar resultados diversos da multinível. No presente estudo, a Pastoral da Criança esteve associada a melhoria do aleitamento materno exclusivo ou predominante, mas não em termos de altura/idade.

[The Children's Pastoral in Criciúma, Southern Brazil: coverage and socio-demographic characteristics of participating families]

This study describes the main social, economic, biological, and demographic characteristics of children and families who participate or have participated in the Children's Pastoral as compared to the overall urban population of Criciúma (Southern Brazil). A population-based cross-sectional study with a probabilistic sample of 2208 children under three years of age was conducted; 16.7% of the mothers confirmed having participated in the Pastoral at any given time, of whom 4.8% were currently participating, while the rest had dropped out. Black children and those over 12 months old or with two or more older siblings participated more frequently in the Pastoral. The main family factors associated with participation were mother's age (over 25), mother not working outside the home, low per capita income, low parental schooling, living in the neighborhood for more than 4 years, and death of sibling before age five. Reasons most often given by mothers for dropping out were migration, lack of time, and interruption of the Pastoral's activities in the neighborhood. The conclusion was that the Pastoral should prioritize the poorest of the poor and adopt measures to reduce drop-out rates.

[Assessment of the performance of Pastoral de Criança, a health support group, in promoting child survival and health education in Criciúma,a city in southern Brazil]

Thousands of children younger than 5 years of age still die all over the world as a result of preventable diseases. Community intervention measures emphasizing primary health and nutritional care have been identified as one of the solutions to this problem. This article describes a population-based cross-sectional study of the Pastoral da Criança, a Roman Catholic health support group in Brazil. The study assesses whether mothers and children assisted by the Pastoral present better health indicators and have a better knowledge of basic child survival actions than non-assisted mothers and children. The study was carried out in 1996 in an urban area of the municipality of Criciúma, in the state of Santa Catarina, in southern Brazil. The sample was composed of 2,208 children under 3 years of age. The adjusted analysis taking into consideration possible confounding factors showed that the presence of the Pastoral was significantly associated with maternal knowledge of appropriate feeding measures during diarrheal episodes, optimal duration of exclusive breast-feeding, implications of feeding powdered milk to infants, correct interpretation of the infant growth curve, and knowledge of the proper vaccination schedule for infants. Participation in the Pastoral was positively associated with longer total breast-feeding duration, later introduction of bottle-feeding, higher frequency of growth monitoring visits in the quarter before the study, and availability in the home of measuring spoons for oral rehydration. No significant association was found between participation in the Pastoral and duration of predominant or exclusive breast-feeding, or correct diarrhea management. The results showed Pastoral actions have a positive effect and also revealed areas in which greater investments are needed. It is recommended that the Pastoral, as well as other similar institutions, give priority to educating mothers on child care and to recruiting mothers early in pregnancy, when the impact of these actions is potentially greater.