OBJETIVO: Avaliar fatores de risco para hospitalização por doença respiratória aguda em crianças até um ano de idade. MÉTODOS: Estudo de casos e controles na cidade de Pelotas, RS. Os casos foram crianças de até um ano de idade, que se hospitalizaram por doença respiratória aguda, de agosto de 1997 a julho de 1998. Os controles foram crianças da comunidade, da mesma idade, sem hospitalização prévia por essa doença. Um questionário investigando exposição a fatores de risco foi aplicado às mães de casos e controles. Os dados foram submetidos à análise univariada, bivariada e multivariada por meio de regressão logística para avaliação dos fatores de risco sobre o desfecho de interesse. RESULTADOS: Foram analisadas 777 crianças, sendo 625 casos e 152 controles. Na análise bruta, os fatores de risco associados ao desfecho foram: sexo masculino, faixa etária menor de seis meses, aglomeração familiar, escolaridade materna, renda familiar, condições habitacionais inadequadas, desmame precoce, tabagismo materno, uso de bico, história de hospitalização e antecedentes de sintomas respiratórios. O trabalho materno foi fator de proteção para internação por doença respiratória aguda. Na análise multivariada, permaneceram associadas: ausência de ou baixa escolaridade materna (OR=12,5), história pregressa de sibilância (OR=7,7), desmame precoce (OR=2,3), uso de bico (OR=1,9), mãe fumante (OR=1,7), idade abaixo de seis meses (OR=1,7) e sexo masculino (OR=1,5). CONCLUSÕES: Os resultados mostraram a importância dos aspectos sociais e comportamentais da família, assim como morbidade respiratória anterior da criança como fatores de risco para hospitalização por doença respiratória aguda.

OBJECTIVE: To evaluate risk factors for acute respiratory disease hospitalizations in children under one year of age. METHODS: A case-control study was conducted in the city of Pelotas, Southern Brazil. Cases were children under one year of age who were hospitalized due to acute respiratory diseases from August 1997 to July 1998. Controls were same-age community children randomly selected without previous respiratory disease hospitalization. A questionnaire about risk factors exposure was applied to the mothers of cases and controls. Univariate, bivariate and multivariate analyses through logistic regression were carried out to evaluate risk factors for the outcome of interest. RESULTS: There were studied 777 children; 625 cases and 152 controls. In the crude analysis, the risk factors associated with the outcome were: being male, children under six months of age, household crowding, maternal education, family income, inadequate housing conditions, lack of breastfeeding, maternal smoking, use of pacifiers, and a previous history of hospitalization and respiratory symptoms. Maternal working was a protection factor associated with acute respiratory disease hospitalizations. In the multivariate analysis the following risk factors remained associated: maternal education (OR=12.5), previous history of wheezing (OR=7.7), lack of breastfeeding (OR=2.3), use of pacifiers (OR=1.9), maternal smoking (OR=1.7), children under six months of age (OR=1.7), and being male (OR=1.5). CONCLUSIONS: The study results show the importance of the family's social and behavioural aspects as well as previous respiratory disease as risk factors for acute respiratory disease hospitalizations in children under one year of age.

OBJETIVO: Avaliar fatores de risco para hospitalização por doença respiratória aguda em crianças até um ano de idade. MÉTODOS: Estudo de casos e controles na cidade de Pelotas, RS. Os casos foram crianças de até um ano de idade, que se hospitalizaram por doença respiratória aguda, de agosto de 1997 a julho de 1998. Os controles foram crianças da comunidade, da mesma idade, sem hospitalização prévia por essa doença. Um questionário investigando exposição a fatores de risco foi aplicado às mães de casos e controles. Os dados foram submetidos à análise univariada, bivariada e multivariada por meio de regressão logística para avaliação dos fatores de risco sobre o desfecho de interesse. RESULTADOS: Foram analisadas 777 crianças, sendo 625 casos e 152 controles. Na análise bruta, os fatores de risco associados ao desfecho foram: sexo masculino, faixa etária menor de seis meses, aglomeração familiar, escolaridade materna, renda familiar, condições habitacionais inadequadas, desmame precoce, tabagismo materno, uso de bico, história de hospitalização e antecedentes de sintomas respiratórios. O trabalho materno foi fator de proteção para internação por doença respiratória aguda. Na análise multivariada, permaneceram associadas: ausência de ou baixa escolaridade materna (OR=12,5), história pregressa de sibilância (OR=7,7), desmame precoce (OR=2,3), uso de bico (OR=1,9), mãe fumante (OR=1,7), idade abaixo de seis meses (OR=1,7) e sexo masculino (OR=1,5). CONCLUSÕES: Os resultados mostraram a importância dos aspectos sociais e comportamentais da família, assim como morbidade respiratória anterior da criança como fatores de risco para hospitalização por doença respiratória aguda.

OBJECTIVE: To evaluate risk factors for acute respiratory disease hospitalizations in children under one year of age. METHODS: A case-control study was conducted in the city of Pelotas, Southern Brazil. Cases were children under one year of age who were hospitalized due to acute respiratory diseases from August 1997 to July 1998. Controls were same-age community children randomly selected without previous respiratory disease hospitalization. A questionnaire about risk factors exposure was applied to the mothers of cases and controls. Univariate, bivariate and multivariate analyses through logistic regression were carried out to evaluate risk factors for the outcome of interest. RESULTS: There were studied 777 children; 625 cases and 152 controls. In the crude analysis, the risk factors associated with the outcome were: being male, children under six months of age, household crowding, maternal education, family income, inadequate housing conditions, lack of breastfeeding, maternal smoking, use of pacifiers, and a previous history of hospitalization and respiratory symptoms. Maternal working was a protection factor associated with acute respiratory disease hospitalizations. In the multivariate analysis the following risk factors remained associated: maternal education (OR=12.5), previous history of wheezing (OR=7.7), lack of breastfeeding (OR=2.3), use of pacifiers (OR=1.9), maternal smoking (OR=1.7), children under six months of age (OR=1.7), and being male (OR=1.5). CONCLUSIONS: The study results show the importance of the family's social and behavioural aspects as well as previous respiratory disease as risk factors for acute respiratory disease hospitalizations in children under one year of age.

INTRODUCTION: Acute respiratory diseases (ARDs) are a major cause of infant morbidity and mortality. OBJECTIVE: The present case-controlled study investigated the hospitalizations by ARDs in children under one year of age and the association with the respiratory syncytial virus (RSV) in za Pelotas, RS. METHODS: All children under one year of age hospitalized due to ARDs from August 1997 to July of 1998 were followed-up in the four hospitals of the city. A standardized questionnaire was applied to the children's mother regarding symptoms of the actual illness in addition to social and demographic variables, nutrition, and previous morbidity. The final diagnosis of ARDs was performed by an arbiter (a pediatrician) based on the hospital records of the children and the data on the questionnaire. Nasopharyngeal secretions were collected for RSV detection by direct immunofluorescence. RESULTS: The study included 650 children and the annual incidence rate of hospital admissions for ARDs was 13.9%. Admissions showed a seasonal pattern with most of the hospitalizations occurring from July to October. The main causes of admission were: pneumonia (43.7%), bronchiolitis (31.0%), asthma (20.3%), influenza (3.5%), otitis media (0.8%) and laryngitis (0.6%). The overall prevalence of RSV was 30.7%, with 40.2% in bronchiolitis, 28.6% in influenza, 27.4% in asthma, 26.3% in pneumonia, and 25% in otitis media. CONCLUSIONS: The results of the present study confirm the high morbidity of ARDs in childhood and the seasonal pattern of ARDs hospitalizations and their association with RSV infection.

The use of yellow fever (YF) virus 17D strain for vaccine production adapted in Brazil since its introduction in 1937 was reviewed. This was possible due to the availability of official records of vaccine production. The retrieved data highlight the simultaneous use of several serially passaged 17D substrain viruses for both inocula and vaccine preparation that allowed uninterrupted production. Substitution of these substrain viruses became possible with the experience gained during quality control and human vaccination. Post-vaccinal complications in humans and the failure of some viruses in quality control tests (neurovirulence for monkeys) indicated that variables needed to be reduced during vaccine production, leading to the development of the seed lot system. The 17DD substrain, still used today, was the most frequently used substrain and the most reliable in terms of safety and efficacy. For this reason, it is possible to derive an infectious cDNA clone of this substrain combined with production in cell culture that could be used to direct the expression of heterologous antigens and lead to the development of new live vaccines.

Inexistem na literatura estudos sobre o possível papel das chupetas na transmissão da diarréia. Realizou-se um estudo transversal em 354 crianças menores de dois anos em duas vilas da periferia urbana de Pelotas, RS, Brasil, com precárias condições socioeconómicas. A maioria das crianças (79%) usava chupeta, 15% nunca as haviam utilizado e 6% já haviam abandonado o hábito. Dentre os usuários, 38% passavam a maior parte do tempo fazendo uso da chupeta (uso intenso). Foram realizadas culturas para coliformes fecais em 93% das chupetas em uso, indicando que 49% estavam contaminadas. Nas duas semanas anteriores à entrevista, 35% das crianças apresentaram diarréia - 40% entre as de uso intenso, 32% entre usuárias em tempo parcial e 37% entre não usuárias. Apesar da forte presença de coliformes fecais, parece não existir associação entre uso de chupeta e diarréia.

A cross-sectional study of 354 children under two years of age was carried out in two periurban slums, with poor sanitary and socioeconomic conditions, located in Pelotas, southern Brazil. Most (79%) of the children studied were current users of pacifiers, 15% had never used one and the remaining 6% were ex-users. Among current users, 38% sucked a pacifier most of the time ("constant users"). Of the pacifiers in constant use, 93% were cultured for evidence of fecal contamination. Fecal coliforms were present in 49% of these. Diarrhoea was reported in 35% of all the children in the two weeks preceding the survey. Among constant pacifiers users, 40% had had diarrhoea in the preceding fortnight; this proportion was 32% for occasional users and 37% for non-users. These diferences were not statistically significant.

Inexistem na literatura estudos sobre o possível papel das chupetas na transmissão da diarréia. Realizou-se um estudo transversal em 354 crianças menores de dois anos em duas vilas da periferia urbana de Pelotas, RS, Brasil, com precárias condições socioeconómicas. A maioria das crianças (79%) usava chupeta, 15% nunca as haviam utilizado e 6% já haviam abandonado o hábito. Dentre os usuários, 38% passavam a maior parte do tempo fazendo uso da chupeta (uso intenso). Foram realizadas culturas para coliformes fecais em 93% das chupetas em uso, indicando que 49% estavam contaminadas. Nas duas semanas anteriores à entrevista, 35% das crianças apresentaram diarréia - 40% entre as de uso intenso, 32% entre usuárias em tempo parcial e 37% entre não usuárias. Apesar da forte presença de coliformes fecais, parece não existir associação entre uso de chupeta e diarréia.

A cross-sectional study of 354 children under two years of age was carried out in two periurban slums, with poor sanitary and socioeconomic conditions, located in Pelotas, southern Brazil. Most (79%) of the children studied were current users of pacifiers, 15% had never used one and the remaining 6% were ex-users. Among current users, 38% sucked a pacifier most of the time ("constant users"). Of the pacifiers in constant use, 93% were cultured for evidence of fecal contamination. Fecal coliforms were present in 49% of these. Diarrhoea was reported in 35% of all the children in the two weeks preceding the survey. Among constant pacifiers users, 40% had had diarrhoea in the preceding fortnight; this proportion was 32% for occasional users and 37% for non-users. These diferences were not statistically significant.

Estudou-se a letalidade hospitalar devido à diarréia ou pneumonia em menores de um ano de idade na Região Metropolitana do Rio de Janeiro cujo óbito ocorreu entre abril/86 e maio/87. Foram investigados possíveis fatores prognósticos de letalidade hospitalar em relação a condições socioeconômicas, biológicas e amamentação aos 30 dias de vida. Foi utilizada metodologia de caso-controle, sendo casos as crianças internadas por diarréia ou por pneumonia que morreram, e controles aquelas que sobreviveram. Referências são feitas aos fenômenos de causalidade reversa e "overmatching" como possíveis viéses neste tipo de estudo. Razão de produtos cruzados (RPC) foi utilizada para estimar os riscos relativos, através de regressão logística não condicional. Os principais fatores prognósticos encontrados foram prematuridade, baixo peso ao nascer, mau estado geral e déficit peso/idade na hospitalização. Nas crianças com pneumonia a duração do aleitamento materno esteve associado com a letalidade (RPC=2,0). As condições biológicas evidenciaram-se como os principais fatores prognósticos de letalidade hospitalar por diarréia ou pneumonia.

Diarrhea and pneumonia are common diseases in children aged under one year, for which there are simple therapeutic measures. However, infant mortality due to these diseases is still very high, varying markedly according to socio-economic status. The characteristics of children who died (cases) and of those who were hospitalized with diarrhea or pneumonia, but survived (controls), were studied. The following groups of variables were studied: socio-economic, environmental and biological conditions, nutritional status and breast-feeding. Information on cases and controls was collected from hospital records and through home interviews. Important losses occurred in the latter: 40% of cases and 50% of controls were not interviewed. There were no significant differences between cases who were included and those who were not, in terms of age, sex or place of residence. To estimate relative risks of prognostic factors unconditional Logistic Regression was used to calculate the odds ratios and their 95% confidence intervals. Prematurity, low birth weight, weight/age deficit, presence of edema and poor general status at hospital admission were prognostic factors for hospital case-fatality. In relation to the anthropometric variables, it was not possible to conclude for certain whether the increased case-fatality was linearly or non-linearly (threshold) associated with nutritional deficit. The duration of breastfeeding was only associated with case-fatality for pneumonia. Socio-economic factors were not important for the prognosis of children admitted to hospital with diarrhea or pneumonia. Some of the expected risk factor associations were not detected, maybe due to the small sample size (resulting from the high losses) which was insufficient to show small differences. In this study the biological conditions of children with diarrhea or pneumonia appeared to be the important prognostic factors for hospital case-fatality.

Estudou-se a letalidade hospitalar devido à diarréia ou pneumonia em menores de um ano de idade na Região Metropolitana do Rio de Janeiro cujo óbito ocorreu entre abril/86 e maio/87. Foram investigados possíveis fatores prognósticos de letalidade hospitalar em relação a condições socioeconômicas, biológicas e amamentação aos 30 dias de vida. Foi utilizada metodologia de caso-controle, sendo casos as crianças internadas por diarréia ou por pneumonia que morreram, e controles aquelas que sobreviveram. Referências são feitas aos fenômenos de causalidade reversa e "overmatching" como possíveis viéses neste tipo de estudo. Razão de produtos cruzados (RPC) foi utilizada para estimar os riscos relativos, através de regressão logística não condicional. Os principais fatores prognósticos encontrados foram prematuridade, baixo peso ao nascer, mau estado geral e déficit peso/idade na hospitalização. Nas crianças com pneumonia a duração do aleitamento materno esteve associado com a letalidade (RPC=2,0). As condições biológicas evidenciaram-se como os principais fatores prognósticos de letalidade hospitalar por diarréia ou pneumonia.

Diarrhea and pneumonia are common diseases in children aged under one year, for which there are simple therapeutic measures. However, infant mortality due to these diseases is still very high, varying markedly according to socio-economic status. The characteristics of children who died (cases) and of those who were hospitalized with diarrhea or pneumonia, but survived (controls), were studied. The following groups of variables were studied: socio-economic, environmental and biological conditions, nutritional status and breast-feeding. Information on cases and controls was collected from hospital records and through home interviews. Important losses occurred in the latter: 40% of cases and 50% of controls were not interviewed. There were no significant differences between cases who were included and those who were not, in terms of age, sex or place of residence. To estimate relative risks of prognostic factors unconditional Logistic Regression was used to calculate the odds ratios and their 95% confidence intervals. Prematurity, low birth weight, weight/age deficit, presence of edema and poor general status at hospital admission were prognostic factors for hospital case-fatality. In relation to the anthropometric variables, it was not possible to conclude for certain whether the increased case-fatality was linearly or non-linearly (threshold) associated with nutritional deficit. The duration of breastfeeding was only associated with case-fatality for pneumonia. Socio-economic factors were not important for the prognosis of children admitted to hospital with diarrhea or pneumonia. Some of the expected risk factor associations were not detected, maybe due to the small sample size (resulting from the high losses) which was insufficient to show small differences. In this study the biological conditions of children with diarrhea or pneumonia appeared to be the important prognostic factors for hospital case-fatality.

The Oswaldo Cruz Foundation produces most of the yellow fever (YF) vaccine prepared world wide. As part of a broader approach to determine the genetic variability in YF l7D seeds and vaccines and its relevance to viral attenuation the 17DD virus was purifed directly from chick embryo homogenates which is the source of virus used for vaccination of millions of people in Brazil and other countries for half a century. Neutralization and hemagglutination tests showed that the purified virus is similar to the original stock. Furthermore, radioimmune precipitation of 35S-methionine-labeled viral proteins using mouse hyperimmune ascitic fluid revealed identical patterns for the purified 17DD virus and the YF l7D-204 strain except for the 17DD E protein which migrated slower on SDS-PAGE. This difference is likely to be due to N-linked glycosylation. Finally, comparison by northern blot nybridization of virion RNAs of purified 17DD with two other strains of YF virus only fenome-sized molecules for all three viruses. These observations suggest that vaccine phenotype is primarily associated with the accumulation of mutations.