Sensitivity and specificity of the BCG scar reading

OBJECTIVE: To validate the BCG scar as a marker of BCG vaccination status. METHODS: A cross-sectional survey was carried out among 53,348 schoolchildren aged 6-14 years who underwent BCG scar examination as part of a large BCG vaccine trial taking place in the city of Manaus, Brazil. Results of BCG scar reading were compared with information on vaccine status of their vaccination cards or provided by parents or guardians. Double-reading was performed in a sub-sample. Data analysis was conducted using Stata 7 and Kappa coefficient. RESULTS: Of 52,348 schoolchildren studied, vaccine status information from parents/guardian letters was available for 29,254 and from vaccination cards for 4,947. There was found a high agreement between the double-readings of the scars (Kappa=0.81). When the agreement between letter and card information was the gold standard, the sensitivity of BCG scar readings was 96.6% (95%CI 96.0-97.1) and the specificity was 71.1% (95%CI 55.7-83.7). The sensitivity was 96.1%, 97.3% and 95.3% for children vaccinated up to one month of age, four months and one year, respectively. CONCLUSIONS: Sensitivity and specificity did not show an association with the child's age at the scar reading. BCG scar was a good marker of BCG vaccination status regardless of age - from the first years of life up to 14 years old.     

Relationship between bacille Calmette-Guérin vaccination, Mantoux test positivity, and geohelminth infection

To investigate the potential protective effects of Bacille Calmette-Guerin (BCG) vaccination scar and sensitization to tuberculin against geohelminth infections, we conducted a cross-sectional study among school age children in rural communities in Pichincha Province in Ecuador where BCG vaccination is routinely given at birth. A total of 944 children aged 8-14 years were evaluated for the presence of BCG scars and sensitization to tuberculin, and underwent faecal examination for geohelminth parasites. BCG scars were present in 88.2% of children and positive Mantoux tests were observed in 19.1% of children. Geohelminth prevalence was high with 70.3% infected with any parasite, 52.1% with Ascaris lumbricoides, 52.3% with Trichuris trichiura, 7.6% with Ancylostoma duodenale, and 3.0% with Strongyloides stercoralis. In multivariate analyses, the presence of BCG vaccine scars was not significantly associated with infections with any geohelminth parasite (adjusted odds ratio [AOR] = 0.74, 95% CI 0.43-1.28, P = 0.28), but an inverse association was observed for infections with S. stercoralis that was of borderline statistical significance (AOR = 0.38, 95% CI 0.15-1.00, P = 0.05). There were no associations between sensitization to tuberculin and infection with geohelminth parasites. The data provide little support for an important protective role of neonatal BCG vaccination or current mycobacterial sensitization against geohelminth infections.     

Relationship between Bacille Calmette-Guérin vaccination, Mantoux test positivity, and geohelminth infection

To investigate the potential protective effects of Bacille Calmette-Guérin (BCG) vaccination scar and sensitization to tuberculin against geohelminth infections, we conducted a cross-sectional study among school age children in rural communities in Pichincha Province in Ecuador where BCG vaccination is routinely given at birth. A total of 944 children aged 8-14 years were evaluated for the presence of BCG scars and sensitization to tuberculin, and underwent faecal examination for geohelminth parasites. BCG scars were present in 88.2% of children and positive Mantoux tests were observed in 19.1% of children. Geohelminth prevalence was high with 70.3% infected with any parasite, 52.1 % with Ascaris lumbricoides, 52.3% with Trichuris trichiura, 7.6% with Ancylostoma duodenale, and 3.0% with Strongyloides stercoralis. In multivariate analyses, the presence of BCG vaccine scars was not significantly associated with infections with any geohelminth parasite (adjusted odds ratio [AOR] = 0.74, 95% CI 0.43-1.28, P = 0.28), but an inverse association was observed for infections with S. stercoralis that was of borderline statistical significance (AOR = 0.38, 95% CI 0.15-1.00, P = 0.05). There were no associations between sensitization to tuberculin and infection with geohelminth parasites. The data provide little support for an important protective role of neonatal BCG vaccination or current mycobacterial sensitization against geohelminth infections.     

Tuberculin reactivity in a population of schoolchildren with high BCG vaccination coverage.

OBJECTIVE: To investigate the influence of BCG vaccination or revaccination on tuberculin skin test reactivity, in order to guide the correct interpretation of this test in a setting of high neonatal BCG vaccination coverage and an increasing BCG revaccination coverage at school age. METHODS: We conducted tuberculin skin testing and BCG scar reading in 1 148 children aged 7-14 years old in the city of Salvador, Bahia, Brazil. We measured the positive effect of the presence of one or two BCG scars on the proportion of tuberculin skin test results above different cut-off levels (induration sizes of > or = 5 mm, > or = 10 mm, and > or = 15 mm) and also using several ranges of induration size (0, 1-4, 5-9, 10-14, and > or = 15 mm). We also measured the effects that age, gender, and the school where the child was enrolled had on these proportions. RESULTS: The proportion of tuberculin results > or = 10 mm was 14.2% (95% confidence interval (CI) = 8.0%-20.3%) for children with no BCG scar, 21.3% (95% CI = 18.5%-24.1%) for children with one BCG scar, and 45.0% (95% CI = 32.0%-58.0%) for children with two BCG scars. There was evidence for an increasing positive effect of the presence of one and two BCG scars on the proportion of results > or = 5 mm and > or = 10 mm. Similarly, there was evidence for an increasing positive effect of the presence of one and two scars on the proportion of tuberculin skin test results in the ranges of 5-9 mm and of 10-14 mm. The BCG scar effect on the proportion of results > or = 5 mm and > or = 10 mm did not vary with age. There was no evidence for BCG effect on the results > or = 15 mm. CONCLUSIONS: In Brazilian schoolchildren, BCG-induced tuberculin reactivity is indistinguishable, for results under 15 mm, from reactivity induced by Mycobacterium tuberculosis infection. BCG revaccination at school age increases the degree of BCG-induced tuberculin reactivity found among schoolchildren. This information should be taken into account in tuberculin skin test surveys intended to estimate M. tuberculosis prevalence or to assess transmission patterns as well as in tuberculin skin testing of individuals used as an auxiliary tool in diagnosing tuberculosis. Taking this information into consideration is especially important when there is increasing BCG revaccination coverage.     

The relationship between nutritional and sociodemographic factors and the likelihood of children in the Dominican Republic having a BCG scar.

OBJECTIVES: To critically assess the prevalence among schoolchildren 6 to 9 years of age throughout the Dominican Republic of a bacille Calmette-Guérin (BCG) vaccination scar, and to examine the relationship between nutritional and sociodemographic factors and the likelihood of having a BCG scar. METHODS: This correlational study used the database of the Second National Census on Height and Weight of Elementary School First Grade Students, which was conducted in the Dominican Republic August 2001-May 2002, to provide a critical assessment of BCG coverage nationwide. The Census information for the children included the presence of BCG scar, their nutritional status, and basic demographic data. We developed a new sociodemographic indicator, the "Rosa Index," to examine the potential influence of poverty and other environmental characteristics on scar presence. We used logistic regression models to predict the presence of a BCG scar. RESULTS: An overall BCG scar prevalence of 55.3% (85,644/154,887) was found. Malnourished children were less likely to have a BCG scar than were children with adequate nutritional status (odds ratio = 0.91; 95% confidence interval: 0.87, 0.95, P < 0.05). Children who were 7-9 years old were less likely to have a BCG scar than were children 6 years old. Children in the areas of the country more than two hours' driving distance from the capital city of Santo Domingo more often exhibited lower BCG scar prevalence levels than did children in Santo Domingo. A higher Rosa Index (better level of socioeconomic characteristics) was correlated with higher BCG scar prevalence values (r = 0.54, P < 0.05). CONCLUSIONS: Our study findings indicate that BCG coverage appears to be inadequate for schoolchildren in the Dominican Republic. Nevertheless, the presence of a scar in a higher proportion of younger children suggests that coverage has improved in recent years. More programmatic and economic emphasis needs to be placed on extending early BCG vaccination coverage to the areas of the country where vaccination coverage is lower, and on examining the potential role that poverty may have on vaccination effectiveness.     

Vaccination technique, PPD reaction and BCG scarring in a cohort of children born in Guinea-Bissau 2000-2002

The rates of positive tuberculin skin test (TST) reactions and BCG scarring after BCG vaccination vary between studies and populations. Tuberculin reactivity and BCG scarring may be related to better child survival in low-income countries. We therefore studied determinants for TST reaction and scarring in Guinea-Bissau. In a cohort of children born in suburban Bissau from March 2000 to July 2002, we assessed a Mantoux test with Purified protein derivative (PPD) (SSI, 2 T.U.) at 2 (2689 children), 6 (N=2148) and 12 months (N=1638) of age, and BCG scar was assessed at 2 (N=2698) and 6 months (N=2225) of age. In a subgroup of the children the vaccination technique was monitored by direct observation of post-vaccination wheal and route of administration. Three different types of BCG vaccine supplied by the local Extended Programme on Immunization were used. At 6 months of age the rate of PPD reactors (>1mm) after BCG vaccination was 25% and the rate of scarring was 89%. One BCG strain was associated with fewer PPD reactors (OR=0.54 (0.31-0.91)) and BCG scars (OR=0.13 (0.05-0.37)) and larger post-vaccination wheals produced more PPD reactions (OR 1.21 (95% CI 1.02-1.43)) and BCG scars (OR 1.66 (1.24-2.21)). In the multivariable analyses of BCG-vaccinated children assessed at 6 months of age, monitoring of vaccination technique and type of BCG vaccine were important. This was not changed by control for other determinants, including sex, season, vaccination place, birthplace, ethnic group, low birth weight, place of residence, education and civil status of mother. We reason that vaccination technique and BCG strain are important for PPD reaction and scarring in response to BCG vaccination. Considering that these responses are associated with better infant survival, the importance of monitoring vaccination technique and of different BCG strains should be evaluated with respect to infant mortality.     

Protective effect of Bacillus Calmette-Guerin (BCG) vaccination in children with extra-pulmonary tuberculosis, but not the pulmonary disease. A case-control study in Rosario, Argentina

A hospital-based case-control study was carried out at the Vilela Children's Hospital in Rosario, Argentina, to measure the protection conferred by BCG vaccination against tuberculosis (TB). The study included 148 newly diagnosed cases of TB (75 males and 73 females, mean age 3.34+/-2.97 years, S.D.), 134 of them with pulmonary TB and 14 cases with extra-pulmonary disease. Controls (425 males and 357 females, 3.39+/-2.98 years) were selected randomly among children who attended to the Hospital showing, neither respiratory diseases nor any other infectious illnesses. Information on BCG vaccination history was assessed from scars or immunisation records. All participants were negative to human immunodeficiency virus and belonged to the lower and upper-lower socioeconomic status, being similar in place of residence and ethnic characteristics. Rate of vaccinated children was 92.6% of cases and 94.5% of controls (3.4 and 3.9% of them without scars, respectively). Regarding the total cases, the protective association between BCG and TB was statistically insignificant, as was for the pulmonary form. Among cases with extra-pulmonary disease, vaccine effectiveness attained significance [79% (95% CI=26-94)], no matter their age, sex or nutritional status. BCG vaccination exerted a beneficial role in extra-pulmonary TB, even in children not seriously undernourished.     

BCG vaccination scar associated with better childhood survival in Guinea-Bissau

BACKGROUND: Recent studies have suggested that Bacille Calmette-Guerin (BCG) vaccination may have a non-specific beneficial effect on infant survival and that a BCG scar may be associated with lower child mortality. No study has previously examined the influence of BCG vaccination on cause of death. METHODS: Two cohorts (A and B) were used to describe the mortality pattern for children with and without BCG scar and to determine specific causes of death. In cohort A (n = 1813), BCG scar was assessed at 6 months of age and as previously described children with a BCG scar had lower mortality over the next 12 months than children with no BCG scar. In cohort B, 1617 children aged 3 months to 5 years of age had their BCG scar status assessed in a household-based survey and mortality was assessed during a 12-month period. Causes of death were determined by verbal autopsy (VA) and related to BCG scar status in a cause-specific hazard function. RESULTS: Controlling for background factors associated with mortality, there was lower mortality for children with a BCG scar than without in cohort B, the mortality ratio (MR) being 0.45 (95% CI 0.21-0.96). Exclusion of children exposed to TB did not have any impact on the result. In a combined analysis of cohorts A and B, the MR was 0.43 (95% CI 0.28-0.65) controlling for background factors. There were no large differences in distribution of the five major causes of death (malaria, pneumonia, acute diarrhoea, chronic diarrhoea, and meningitis/encephalitis) according to BCG scar status in the two cohorts. Having a BCG scar significantly reduced the risk of death from malaria [MR 0.32 (95% CI 0.13-0.76)]. CONCLUSIONS: A BCG scar is a marker of better survival among children in countries with high child mortality. BCG vaccination may affect the response to several major infections including malaria.     

BCG scar and positive tuberculin reaction associated with reduced child mortality in West Africa. A non-specific beneficial effect of BCG?

Previous studies have suggested that the bacille Calmette-Guérin (BCG) vaccine may have a non-specific beneficial effect on childhood survival in areas with high mortality. We examined whether BCG-vaccinated children with a BCG scar or a positive tuberculin reaction had better survival than children without such reactions. As part of an ongoing two-dose measles vaccine trial for which children were recruited at 6 months of age, we examined 1813 children for BCG scar at 6 months of age and 813 BCG-vaccinated children were skin-tested for delayed hypersensitivity to tuberculin, tetanus and diphtheria. We found that BCG-vaccinated children with a BCG scar had significantly lower mortality compared with BCG scar-negative children, the mortality ratio in the first 12 months of follow-up being 0.41 (0.25-0.67). BCG-vaccinated children with a positive tuberculin test had a mortality ratio of 0.45 (0.24-0.85) compared with tuberculin negative children. These results were unchanged by control for potential confounders or using different cut-off points for a tuberculin-positive response. Exclusion of dead children who had HIV antibodies did not modify the estimate (mortality rate (MR)=0.46 (0.23-0.94)). After censoring for tuberculosis (TB) exposure at home, the mortality ratios for having a scar and being tuberculin-positive were 0.46 (0.27-0.79) or 0.42 (0.21-0.84), respectively. Children positive to tetanus or diphtheria in the skin test had the same mortality as children not responding to these vaccine-related antigens. Thus, BCG scar and a positive tuberculin reaction were associated with better survival in early childhood in an area with high mortality. Since nothing similar was found for responders to diphtheria-tetanus-pertussis (DTP) vaccine, and the effect could not be explained by protection against tuberculosis, the effect of BCG vaccination could be due to non-specific immune-stimulation protecting against other infections.     

Tuberculin reaction, BCG scar, and lower female mortality

BACKGROUND: Recent studies have suggested that bacille Calmette-Guérin (BCG) immunization may have a nonspecific beneficial effect on infant survival and that the effect may be more pronounced among girls. In a prospective birth cohort, we examine whether a positive tuberculin skin test and BCG scar in response to BCG immunization were related to better overall survival in Guinea-Bissau and, if so, whether the effect was sex-specific. METHODS: Skin tests and BCG scarring were monitored at ages 2 months (n = 2332) and 6 months (n = 1817) in children born from March 2000 to July 2002. A tuberculosis (TB) surveillance system allowed us to exclude from the analysis children with likely TB exposure. The children were followed for survival until 18 months of age. RESULTS: Among children with a tuberculin skin test at 2 and 6 months of age, the mortality rate ratio for skin test reactors (>1 mm) versus nonreactors (0-1 mm) was 0.54 (95% confidence interval = 0.30-0.99). Comparing children with and without a BCG scar, the ratio was 0.55 (0.31-0.96). The effect of a skin test reaction or a BCG scar seemed stronger among girls; for those with positive reaction, the mortality ratio was 0.31 (0.11-0.88) among girls and 0.84 (0.39-1.82) among boys; and for BCG scar, the results were 0.41 (0.21-0.82) and 0.88 (0.34-2.30), respectively. CONCLUSIONS: A good response to BCG vaccination is related to lower child mortality. The effect seems most pronounced among girls. The findings may have implications for future vaccine trials and policy.     

Vaccinia scars associated with better survival for adults. An observational study from Guinea-Bissau

BACKGROUND: Live vaccines including BCG and measles may have non-targeted beneficial effects on childhood survival in areas with high mortality. The authors therefore undertook a survey of vaccinia scars to evaluate subsequent mortality. SUBJECTS: Based on a population census, a cohort of 1893 adults in urban Guinea-Bissau was examined in 1998 and followed until 2002. MAIN OUTCOME MEASURE: All cause mortality, excluding accidents. RESULTS: The median age of vaccinia vaccinations had been 16-18 years. Adults with a vaccinia scar had a mortality ratio (MR) of 0.60 (0.41-0.87) compared to those without any scar. The effect was stronger for women. Mortality decreased with each additional vaccinia scar (MR=0.73 (0.56-0.95)). Among 502 individuals with information on HIV infection, the age-adjusted HIV-2 prevalence was 2.45 (1.06-5.65) for those with a vaccinia scar. Control for district, ethnic group, schooling, place of birth, quality of housing and HIV status had little effect on the estimate. Since vaccinia and BCG scars could have been confused, mortality for adults with vaccinia and/or BCG scar was compared to those without, the MR being 0.61 (0.41-0.89). CONCLUSION: Known cultural or socio-economic factors possibly associated with access to vaccination had no influence on the mortality ratio for having a vaccinia scar. Hence, vaccinia vaccination may have a prolonged beneficial effect on adult survival.     

Evidence of an effect of BCG revaccination on incidence of tuberculosis in school-aged children in Brazil: second report of the BCG-REVAC cluster-randomised trial

BCG revaccination is still used in some tuberculosis endemic countries. Until now, the little evidence available suggested that BCG revaccination confers very limited additional protection, although there was no information on whether protection depends on the setting and age of revaccination, or if protection increases with time since vaccination. Here we report on an extended follow up of the BCG-REVAC trial, a cluster randomised trial conducted in the Brazilian cities Salvador and Manaus including over 200,000 children aged 7-14 years aimed to evaluate the efficacy of BCG revaccination in children who had received neonatal BCG vaccination. With the extended follow-up (9 years) and the additional cases accrued we now have enough power to report vaccine efficacy separately for the two cities (with different distances from Equator and presumably different prevalence of non-tuberculosis mycobacteria), and by age at vaccination and clinical form. The overall vaccine efficacy was 12% (−2 to 24%) as compared to 9% (−16 to 29%) for the 5-year follow up. Vaccine efficacy was higher in Salvador (19%, 3 to 33%) than in Manaus (1%, −27 to 27%) with the highest vaccine efficacy in children from Salvador aged <11 years at revaccination (33%, 3 to 54%). The findings are in line with the hypothesis that BCG vaccination offers higher efficacy in low NTMb prevalence, and show that revaccination with BCG can offer weak protection in selected subgroups.     

2010年原平市流动儿童免疫规划疫苗接种率及其影响因素调查

[目的]了解原平市流动儿童免疫规划疫苗预防接种状况及其影响因素,为制定相应干预措施提供科学依据。[方法]2010年7月,在原平市抽取1～9岁本地儿童501名、流动儿童499名进行调查。[结果]调查流动儿童499名、本地儿童501名。接种证建证率、卡疤率,卡介苗、脊髓灰质炎减毒活疫苗、百白破混合制剂、麻疹减毒活疫苗的接种率,"四苗"全程接种率,乙肝疫苗首针及时接种率与全程接种率,流动儿童分别为90.78%、90.58%、90.58%、85.17%、85.57%、87.37%、80.76%、88.18%、79.56%,本地儿童分别为100.00%、98.00%、99.20%、99.60%、99.00%、99.80%、97.41%、99.60%、97.21%(P<0.01)。[结论]1～9岁流动儿童各种疫苗接种率均低于本地儿童。     

Effectiveness of Bacillus Calmette Guerin (BCG) vaccination in the prevention of leprosy: a population-based case-control study in Yavatmal District, India

OBJECTIVE: To estimate the effectiveness of Bacillus Calmette Guerin (BCG) vaccination in the prevention of leprosy. Study design. Population-based case-control study. METHODS: The study was carried out in Yavatmal District, Maharashtra, India. It included 364 cases of leprosy (diagnosed by the World Health Organization's criteria), born since 1962, that were detected during a leprosy survey conducted by the Government of Maharashtra in 2,175,514 people. Each case was pair-matched with one neighbourhood control for age, sex and socio-economic status. Exclusion criteria for controls included past or current history of tuberculosis or leprosy. BCG vaccination status was assessed by examination for the presence of a BCG scar, immunization records if available and information from subjects/parents of children. Subjects who were uncertain about BCG vaccination were not included. RESULTS: A significant protective association between BCG and leprosy was observed [odds ratio=0.46, 95% confidence intervals (CI) 0.34-0.61]. Overall vaccine effectiveness (VE) was 54% (95% CI 39-66). BCG effectiveness against multibacillary, paucibacillary and single skin lesion leprosy was 68% (95% CI 26-86), 57% (95% CI 29-74) and 48% (95% CI 22-65), respectively. Analysis of linear trend revealed a significant linear association between the protective effect of BCG and the type of leprosy. The BCG vaccine was more effective in those aged < or =20 years compared with those aged >20 years (VE 61%, 95% CI), among females compared with males (VE 60%, 95% CI), in lower socio-economic strata compared with upper and middle strata (VE 57%, 95% CI), and in subjects who had a BCG scar size < or =5 mm compared with those with a BCG scar size >5 mm (VE 61%, 95% CI). However, these differences were not statistically significant, as reflected by the overlapping 95% CIs. The overall prevented fraction was 35% (95% CI 22-46). CONCLUSION: The current study identified a beneficial role of BCG vaccination in the prevention of leprosy in the study population.     

Risk factors for positive tuberculin skin test in Guinea-Bissau

BACKGROUND: The tuberculin skin test is used for tracing of tuberculosis transmission and identifying individuals in need of prophylactic treatment. METHODS: Using a case-control study design, we recruited 220 smear-positive tuberculosis cases and 223 randomly selected healthy community controls in Bissau, Guinea-Bissau, during 1999-2000. Tuberculin skin tests were performed on family members of cases and controls (n = 1059 and n = 921, respectively). Induration of 10 mm or greater was considered positive. Risk factors were calculated for children (<15 years) and adults separately in multivariate logistic regression analysis. RESULTS: The prevalence of positive tuberculin skin test was 41% in case-contacts compared with 22% in control-contacts, resulting in a prevalence ratio of 1.48 (95% confidence interval = 1.37-1.60). Positive skin tests among case-contacts increased with age for children, as well as with proximity to a case during the night, for both children and adults. A Bacille Calmette Guerin scar increased the likelihood of having a positive tuberculin skin test for adults in case households, but not in other categories of contacts. Among control-contacts the prevalence of positive skin test was associated with older age in children, history of tuberculosis in the family, and a positive tuberculin skin test of the control person. CONCLUSIONS: Risk factors for a positive tuberculin skin test among case- and control-contacts are closely related to tuberculosis exposure. Having a BCG scar did not increase the risk of positive skin test in unexposed individuals. Tuberculin skin testing remains a useful tool for diagnosing tuberculosis infection.     

某部干部乙肝免疫无或低应答因素调查研究

目的探讨军人乙肝疫苗免疫效果,查找无或低应答原因。方法利用某部干部年度体检资料,调查2000--2007年间乙肝疫苗免疫后抗-HBs阳转率统计分析免疫应答的影响因素。结果调查3830名干部在8年间从年度抗-HBs阳转率9．30％逐步提高为59．5％（P〈0．01）。由基因重组（酵母）乙肝疫苗改用基因重组（CHO细胞）乙肝疫苗后,抗-HBs阳转率提高到72．96％,（P〈0．01）。大年龄组抗-HBs阳转率低于小年龄组,机关干部低于旅（团）干部,吸烟和饮酒者低于不吸烟和不饮酒者,经统计学检验,均P〈0．01。结论成人接种乙肝疫苗抗-HBs阳转率明显低于儿童,乙肝疫苗种类应首选基因重组（CHO细胞）疫苗。年龄及不良生活行为对抗一HBs阳转率有一定的影响。     

BCG vaccination scars: incidence and acceptance amongst British high-school children

Summary In order to determine the incidence and acceptance of BCG scars, 287 high-school children of different ethnic origins, in a London district, were examined for their BCG scars and interviewed for self-appraisal of their scars 6–30 months after vaccination. BCG scars developed in a high proportion of children (89·5%). There was a female predominance among the 10·5% of children who did not develop scars (girls 12·8%, boys 5·9%, P < 0·05). Hypertrophic scars (defined as the largest diameter of scar > 13·24 mm, [i.e. 2 SD above mean]) were found in 3·11% and hypopigmented scars in 67·8% of the children and both tended to occur amongst hyperpigmented races. A high proportion of children found the scars unacceptable (23·4%), mostly girls (girls 35%, boys 7·8%, P < 0·0·004) and they showed a preference for other sites including inner aspect of arm and buttock for vaccination.     

Is tuberculin skin testing useful to diagnose latent tuberculosis in BCG-vaccinated children?

BACKGROUND: The tuberculin skin test (TST) is the most commonly used tool to detect infection with Mycobacterium tuberculosis. We sought to determine whether tuberculin skin testing is useful to detect latent infection by M. tuberculosis in a population that was vaccinated with the Bacille Calmette Guérin (BCG) vaccine. METHODS: We performed a cross-sectional study during October 2000-February 2001, enrolling first and sixth graders from a random, stratified sample of public elementary schools in Orizaba, Veracruz, Mexico. We assessed the relationship between sociodemographic and epidemiological information, BCG scars, and TST reactivity. RESULTS: There were 858 children enrolled in the study with a completed questionnaire and TST result. The prevalence of a positive TST result (> or =10 mm) was 12.4%. Controlling for BCG scar, age, and other characteristics, close contact with pulmonary tuberculosis patients (odds ratio 6.56, 95% confidence interval 2.05-21.07, P = 0.001) was independently associated with TST reactivity. CONCLUSIONS: TST results helped identify children in a BCG-vaccinated population who had recent exposure to persons with pulmonary tuberculosis, were probably infected with M. tuberculosis, and could benefit from treatment for their latent tuberculosis infection.     

Scar size and effectiveness of Bacillus Calmette Guerin (BCG) vaccination in the prevention of tuberculosis and leprosy: a case-control study

BACKGROUND: The study was undertaken to estimate the effectiveness of BCG vaccination in relation to scar size in the prevention of tuberculosis and leprosy. METHODS: The present study was designed as hospital-based pair-matched case-control study and was carried out at Government Medical College Hospital, Nagpur, Maharashtra, India. It included 877 cases of tuberculosis and 292 cases of leprosy (diagnosed by WHO criteria), born onwards 1962. Each case was pair-matched with one control for age, sex and socio-economic status. BCG vaccination status was assessed by examination for the presence of BCG scar, immunisation records if available and information from subjects/parents of children. Subjects uncertain about BCG vaccination were not included. The diameter of the BCG scar was measured both across and along the arm in millimeters using a plastic ruler. The average was then calculated. RESULTS: A significant protective association between BCG vaccination and tuberculosis (OR=0.38, 95% CI 0.31-0.47) and leprosy (OR = 0.38, 95% CI 0.26-0.55) was observed. The overall vaccine effectiveness (VE) was 62% (95% CI 53-69) against tuberculosis and 62% (95% CI 45- against leprosy. Vaccine effectiveness against tuberculosis and leprosy was non-significantly greater in the group who had BCG scar size < or =5 mm as compared to subjects who had BCG scar size > 5 mm. Thus there was no clear association between BCG scar size and its effectiveness. CONCLUSION: The current study did not identify any significant association between BCG scar size and its effectiveness against tuberculosis or leprosy.     

Jet gun or syringe? A trial of alternative methods of BCG vaccination

In a trial of alternative methods of BCG vaccination, 628 children were vaccinated by syringe and needle and 690 by needleless jet injector. The lesions produced by vaccination with the jet injector were significantly smaller than those resulting from intradermal injection by syringe and needle and only 31 (4%) of the lesions from the jet injector had failed to heal by 3 months, compared with 311 (50%) from the syringe and needle. All but one of the children vaccinated by jet injector developed scars of 4 mm or more in diameter but only one had a scar in excess of 10 mm, compared with 41 scars of this size among those vaccinated by syringe and needle. There was a significant difference in tuberculin conversion rates for the two vaccination methods in one of the districts possibly related to differing vaccine reconstitution techniques.The cost of vaccination per 1000 children by jet injector was less than 40% of the costfor syringe and needle, using a new disposable syringe and needle for each child.In terms of acceptability to the children, freedom from complications and lower cost vaccination the jet injector proved to be the better method.