Neonatal BCG protection against tuberculosis lasts for 20 years in Brazil.

Bacille Calmette-Guérin (BCG) efficacy against pulmonary disease is highly variable; until very recently there was no evidence of protection after 10 years. In the control arm of a trial of efficacy of revaccination of schoolchildren in Brazil we found substantial protection (39%; 95%CI 9-58) of neonatal BCG against all forms of tuberculosis (TB) 15-20 years after vaccination, much longer than previously believed. This confirms recent findings from an earlier trial, and must be considered in the design of trials of new TB vaccines and in policy decisions based on assumed lack of neonatal BCG protection with time.

Diarrhoea and garbage disposal in Salvador, Brazil.

The association of infantile diarrhoea with the presence of garbage in the environment was investigated in Canabrava, a peripheral neighbourhood of Salvador, northeast of Brazil. A cross-sectional study was conducted with all the 184 children aged less than two years residing in Canabrava, which is located close to the city garbage dump. Variables selected for study included the method used for the disposal of excrement, type of floor, mother's education, unemployment of the head of the family, regularity of the water supply, presence of toilet, storage of garbage inside the house, age, gender, duration of breastfeeding, and the number of people per room. The estimated prevalence of diarrhoea was 21.2%. Exposure to garbage in the environment was found to be the most important factor associated with diarrhoea (adjusted odds ratio [AOR] = 3.98, 95% CI 1.56-10.13). Other important variables were the mother's education (AOR = 2.79, 95% CI 1.09-7.13), maternal breastfeeding (AOR = 2.30, 95% CI 1.05-5.04), and unemployment of the head of the family (AOR = 2.09, 95% CI 0.93-4.69). These findings indicate the necessity of adopting solutions in the public domain and of intersectorial policies for the reduction of diarrhoea.

Risk of fatal adverse events associated with 17DD yellow fever vaccine.

Yellow fever (YF), an acute infectious disease, is endemic in the north and central-west of Brazil. This disease can be prevented by the use of a vaccine. In Brazil, four fatal adverse events have been associated with the YF vaccine used in the country (17DD vaccine). We briefly describe the last two fatalities, and estimate the risk of 17DD-associated fatal adverse events under different epidemiological scenarios. Controversies regarding the appropriate denominator that enters the estimation of risk serve as a motivation for each proposed scenario. The statistical procedures used show optimum behaviour when assessing the risk of rare events. Risk estimates vary from 0.043 (95 % CI 0.017-0.110) to 2.131 (95 % CI 0.109-12.071) fatalities per million doses administered. The robust estimates of the risk of fatal adverse events we present constitute an important element in future risk-benefit analysis and point to the need for good quality vaccine coverage and adverse-events surveillance data to assess the risk of vaccination. Although vaccination of YF endemic regions is necessary to maintain low disease prevalence, preventive administration of YF vaccine to the entire population should be cautiously analysed.

Lower prevalence of reported asthma in adolescents with symptoms of rhinitis that received neonatal BCG.

BACKGROUND: BCG is a vaccine used against tuberculosis and leprosy and is an immunostimulant that primes T(H)1 lymphocytes to produce cytokines that antagonize atopy both in animal models and in man. Considering that atopy is the main risk factor for asthma, one can hypothesize that vaccination inducing T(H)1 responses, such as BCG, can be protective against asthma. OBJECTIVE: To estimate the association between neonatal BCG vaccination and prevalence of asthma among adolescents. STUDY DESIGN: Cross-sectional study with schoolchildren aged 12-16 years. The presence of a scar compatible with BCG was used as a surrogate of neonatal vaccination. A self administered structured questionnaire was prepared based on that used by the International Study of Asthma and Allergies in Childhood. The prevalence of asthma was categorized according to the report of lifetime wheeze, lifetime asthma, lifetime asthma among those referring allergy and among those referring allergy and sneezing. RESULTS: Neonatal BCG vaccination was not associated with the overall prevalence of reported wheezing or asthma. However, in the subgroup reporting current allergy and sneezing, neonatal BCG was associated with a 37% reduction of prevalence of lifetime asthma. CONCLUSIONS: In the population we surveyed, neonatal BCG scar was associated with a reduction in the risk of asthma only in individuals with a past history suggestive of allergic rhinitis.

A comparison of dual skin test with mycobacterial antigens and tuberculin skin test alone in estimating prevalence of Mycobacterium tuberculosis infection from population surveys.

SETTING: City of Manaus, Amazonas, Brazil. OBJECTIVE: To compare estimates of Mycobacterium tuberculosis infection prevalence obtained using traditional tuberculin skin test (TST) criteria and dual skin test (DST) data. METHODS: A total of 1070 schoolchildren received DST with tuberculin and four environmental mycobacteria sensitins. Responses were classified as sensitin-dominant, tuberculin-dominant or non-dominant. Positive predictive values (PPV) were defined using 'narrow' and 'wide' standards based on DST responses. These predictive values were derived for each category of tuberculin indurations, and were used to calculate the prevalence estimates. RESULTS: Using DST data, the estimates of M. tuberculosis prevalence for scar-negative children were 7.4% (M. avium) and 7.8% (M. scrofulaceum) using the 'narrow' standard, and 16.9% (M. avium) and 15.2% (M. scrofulaceum) using the 'wide' standard. The percentage with TST > or =10 mm was 11.5%. Scar-positive children had higher estimates using both the 10 mm cut-off and DST data. CONCLUSION: In settings with a relatively low prevalence of M. tuberculosis infection and high cross-reactivity with environmental mycobacteria, DST can help to assess the validity of traditional thresholds for estimating the prevalence of M. tuberculosis infection. DST data with environmental antigens and tuberculin do not distinguish BCG-induced cross-reactivity.

Rates of adverse reactions to first and second doses of BCG vaccination: results of a large community trial in Brazilian schoolchildren.

OBJECTIVE: To evaluate the incidence of adverse reactions to first and second bacille Calmette-Guérin (BCG) vaccination in schoolchildren. SETTING AND DESIGN: Enhanced surveillance in a Brazilian trial. Suspected reactions were reported to a nurse who visited cases and completed a standard form. RESULTS: Among 71341 schoolchildren studied, 33 reactions were reported. Of these, 25 fulfilled the criteria, resulting in a rate of one per 2854 vaccinations, with no deaths or BCG-osis. Reactions to second doses were more common than to first BCG vaccinations, but this difference was not statistically significant. CONCLUSIONS: Adverse reactions to a second dose of BCG may be more frequent than reactions to a first dose, but they are still rare events.

Sensitivity and specificity of BCG scar reading in Brazil.

In a cross sectional survey within a community trial of BCG efficacy evaluation in Brazil, trained teams inspected children's upper arms and obtained information on BCG vaccination from guardian letters and vaccination cards. Nurses re-examined the sub-sample of children blindly. High agreement was found between the two scar readings (Kappa = 0.839). High sensitivity and low specificity was observed when guardian or card information was the gold standard. Sensitivity remained high when guardian and card information agreed. When disagreement occurred, sensitivity remained high and specificity was very low. BCG scar is a good indicator of BCG vaccination.

[Evaluation of a social and environmental indicator used in the identification of lymphatic filariasis transmission in urban centers]. / Avaliação de indicador sócio-ambiental utilizado no rastreamento de áreas de transmissão de filariose linfática em espaços urbanos.

The concept of a "socially organized space" supported by new analytical techniques and mapping of health events has guided innovative methodological developments in public health interventions. This study aimed to evaluate a social/environmental indicator constructed with a scoring methodology to stratify areas in the city of Olinda by different levels of risk for Bancroftian filariasis transmission. The study mapped areas and the location of sample households and identified all residents ages 5 to 65 years as part of the parasitological survey. Among the 3,232 individuals who had blood samples taken, 42 were microfilaremic (1.3% prevalence). Global statistical analysis of filarial case distribution has suggested spatial clustering. Some 85.7% of positive individuals resided in the two strata with the highest transmission risk. The high sensitivity of the proposed indicator for predicting the places where the vast majority of filariasis cases occurred justifies its use in planning and implementing interventions.

Human T-cell lymphotropic virus type 1 infection among pregnant women in northeastern Brazil.

An evaluation of human T-cell lymphotropic virus type 1 (HTLV-1) infection among 6754 pregnant women in Salvador, Bahia, Brazil using enzyme-linked immunosorbent assay, Western blot analysis, and polymerase chain reaction assay found a rate of infection of 0.84% (57 of 6754 women). Epidemiologic and obstetric data on the HTLV-1-positive pregnant women were analyzed and compared with data on a control group of HTLV-1-negative pregnant women. The mean age of the HTLV-1-positive women was 26.2 years. All were seronegative for HIV and syphilis, and only 2 reported a past history of sexually transmitted infection and more than 10 sexual partners. Of the HTLV-1-positive women, 88.5% were breast-fed, 4% were bottle fed, and 7.5% did not know. Six women had received blood transfusions, and only 1 reported intravenous drug use. Fifty-two HTLV-1-positive women could be followed: 45 had full-term deliveries, 5 had premature deliveries, and 2 had abortions. Our results indicate that (1) the frequency of HTLV-1 infection among pregnant women is relatively high in Salvador, Bahia, Brazil; (2) maternal infection was probably acquired more frequently through breast-feeding, but the sexual route was certainly the second most important means of transmission; (3) HTLV-1-positive women had a history of eczema-like infections in childhood more frequently than the control group; (4) HTLV-1 infection did not interfere in the course of pregnancy; and (5) no associated congenital infections were observed in the HTLV-1-positive women.

Upward trend in the rate of detection of new cases of leprosy in the State of Bahia, Brazil.

BACKGROUND: The worldwide fall in the rate of detection of new cases of leprosy has been partly attributed to the introduction of multidrug therapy and other improvements in control programs. However, the rate of detection of new cases has not decreased in Brazil. METHODS: An analysis was made of the temporal distribution of 18,872 newly reported leprosy cases in Bahia, Brazil, from 1974 to 1997. Population denominators for the annual detection rate were obtained from population estimates based on the national census. Trends were presented by sex, date of birth, date of diagnosis, date of release, clinical form and by residence in areas which had notified cases in the 5 years prior to the rise in detection rate. RESULTS: There was a marked increase in the new case detection rate (NCDR) in the State of Bahia, from 0.19 to 1.43 cases per 10,000 inhabitants during the study period, an increment of nearly 7% to 8% per year. This increase was also observed in people aged 14 years and younger. During this period tuberculoid and indeterminate forms have become predominant among women and younger people. The average age of male cases has shifted toward younger ages. CONCLUSIONS: We interpret this pattern to mean that the increase in NCDR reflects a real increase in incidence of leprosy, whether or not accompanied by improved detection.

Outbreak of aseptic meningitis associated with mass vaccination with a urabe-containing measles-mumps-rubella vaccine: implications for immunization programs.

A mass immunization campaign with a Urabe-containing measles-mumps-rubella vaccine was carried out in 1997 in the city of Salvador, northeastern Brazil, with a target population of children aged 1-11 years. There was an outbreak of aseptic meningitis following the mass campaign. Cases of aseptic meningitis were ascertained through data collected from the records of children admitted to the local referral hospital for infectious diseases between March and October of 1997, using previously defined eligibility criteria. Vaccination histories were obtained through home visits or telephone calls. Eighty-seven cases fulfilled the study criteria. Of those, 58 cases were diagnosed after the vaccination campaign. An elevated risk of aseptic meningitis was observed 3 weeks after Brazil's national vaccination day compared with the risk in the prevaccination period (relative risk = 14.3; 95% confidence interval: 7.9, 25.7). This result was confirmed by a case series analysis (relative risk = 30.4; 95% confidence interval: 11.5, 80.8). The estimated risk of aseptic meningitis was 1 in 14,000 doses. This study confirms a link between measles-mumps-rubella vaccination and aseptic meningitis. The authors discuss the implications of this for the organization and planning of mass immunization campaigns.

Risk factors for human T cell lymphotropic virus type I among injecting drug users in northeast Brazil: possibly greater efficiency of male to female transmission.

It was observed in the city of Salvador, State of Bahia, the highest seroprevalence of human T cell lymphotropic virus type 1 (HTLV-I) infection in Brazil as demonstrated by national wide blood bank surveys. In this paper, we report results of an investigation of drug use and sexual behavior associated with HTLV-I infection among male and female injecting drug users (IDUs) in Salvador. A cross sectional study was conducted in the Historical District of Salvador from 1994-1996 (Projeto Brasil-Salvador) and 216 asymptomatic IDUs were selected using the snowball contact technique. Blood samples were collected for serological assays. Sera were screened for human immunodeficiency virus (HIV-1/2) and HTLV-I/II antibodies by ELISA and confirmed by Western blot. The overall prevalence of HTLV-I/II was 35.2% (76/216). The seroprevalence of HTLV-I, HTLV-II and HIV-I was for males 22%, 11.3% and 44.1% and for females 46.2%, 10.3% and 74.4% respectively. HTLV-I was identified in 72.4% of HTLV positive IDUs. Variables which were significantly associated with HTLV-I infection among males included needle sharing practices, duration of injecting drug use, HIV-I seropositivity and syphilis. Among women, duration of injecting drug use and syphilis were strongly associated with HTLV-I infection. Multivariate analysis did not change the direction of these associations. Sexual intercourse might play a more important role in HTLV-I infection among women than in men.

HTLV-I in Northeast Brazil: differences for male and female injecting drug users.

BACKGROUND: To investigate the seroprevalence of HTLV-I infection among male and female injecting drug users (IDUs). METHODS: A cross-sectional study conducted in Salvador, Brazil, from 1994 to 1996 (Projeto Brasil-Salvador). The study population of 216 asymptomatic IDUs was selected using snowball contact technique. Data on demographics, sexual behavior, and drug use practices were obtained and blood samples collected for serologic assays. Sera were screened for HIV-1/2 and HTLV-I and HTLV-II antibodies by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot. RESULTS: The overall prevalence of HTLV-I/II was 35.2% (76 of 216). The seroprevalence of HTLV-I, HTLV-II, and HIV-1 was for males 22.0%, 11.3%, and 44.1%, and for females 46.2%, 10.3%, and 74.4%, respectively. Specific seroprevalence of HTLV-I infection demonstrated linear trend with increasing age and increasing duration of drug use. Using univariate analysis, the variables that were significantly associated with HTLV-I infection among males included needle sharing practices, duration of IDU, HIV-1 seropositivity, and positive test result for syphilis. Among women, duration of injecting drug use and positive test result for syphilis were strongly associated with HTLV-I infection. CONCLUSIONS: Retrovirus infection is highly prevalent among IDUs in Salvador, Brazil and HTLV-I is more common that HTLV-II. Duration of drug use is an important correlate of HTLV-I infection.

Interleukin 6 and AIDS-associated Kaposi's sarcoma: a nested case control study within the Multicenter AIDS Cohort Study.

Since the beginning of the AIDS epidemic, there has been considerable research on the etiology of Kaposi's sarcoma (KS) among HIV-infected individuals. A number of studies have confirmed that HIV or HIV-encoded products can interact with human cells to induce the production of cytokines, including interleukin 6 (IL-6). In vitro observations have indicated that AIDS-KS cells can produce significant levels of IL-6 and also respond to this cytokine. Preliminary data suggested that IL-6 may be elevated among HIV-infected individuals that subsequently develop AIDS-KS. The objective of this study was to determine if elevated levels of IL-6 are associated with an increased incidence of AIDS-KS compared to other AIDS-defining illnesses such as opportunistic infections (OIs). Serum IL-6 levels were determined by ELISA in frozen sera collected from participants in the Multicenter AIDS Cohort Study (MACS) at 6 months prior to AIDS diagnosis, in 73 cases (AIDS-KS), and 152 controls (OI). Elevated IL-6 levels were more prevalent among men with AIDS-OI than those with AIDS-KS: crude odds ratio (OR), 0.4 (95% CI, 0.2-0.9). Models of multivariate logistic regression were used to study potential confounders. Sexual behavior variables did not seem to confound the association between IL-6 and AIDS-KS. The higher prevalence of IL-6 among controls could be explained by the association of higher levels of IL-6 with lower levels of CD4 T cell number. IL-6 may be a marker of severe immune dysfunction among HIV-infected individuals.