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PubMedDate not supplied

[Treatment of tuberculosis in 100 children. A 5-year follow-up].

This paper presents the results of a five year follow-up study of a cohort of children under fifteen years of age with tuberculosis. One group received standard treatment, and the other group received short course treatment. In the standard group there were four treatment failures, while in the other group, all the subjects had an excellent evolution and there were no failures. There was not a statistically significant difference regarding treatment failures, it is recommended, however, to carry out similar studies with greater sample sizes in order to determine the benefits of the short course treatment.

Adolescent↗

PubMed1997

Derivation and validation of a pulmonary tuberculosis prediction model.

OBJECTIVE: To describe the derivation and validation of a pulmonary tuberculosis (TB) prediction model that would enable early discontinuation of unnecessary respiratory isolation. DESIGN: Patients placed in isolation for suspected pulmonary TB were studied retrospectively (derivation cohort) and prospectively (validation cohort). Independent predictors of pulmonary TB in the derivation cohort (January 1992-March 1994) were identified by retrospective analysis. Predictors in the model were assigned weights on the basis of the results of the multivariate analysis in order to quantitate the risk of TB in an individual patient. The prospective validation consisted of application of the model to patients placed in isolation during the period April 1994 to June 1995. The predictability of the model in the derivation and validation cohorts was evaluated using receiver operating characteristics (ROC), curve analysis, and calculation of the area under the ROC curve (AUC). SETTING: A university-affiliated, urban, public hospital with a large population of prison inmates and patients with human immunodeficiency virus infection. INTERVENTIONS: Prospective application of the prediction model to patients placed in isolation during the validation period. RESULTS: Four factors were found to be independent predictors of pulmonary TB among 296 isolation episodes in the derivation cohort; positive acid-fast sputum smear (odds ratio [OR], 5.8; 95% confidence interval [CI95], 3.0-11.0; weight = 3 points), localized chest radiograph findings (OR, 2.5; CI95, 1.3-4.9; weight = 2 points), residence in a correctional facility (OR, 2.3; CI95, 1.2-4.4; weight = 2 points), and history of weight loss (OR, 1.8; CI95, 1.0-3.2; weight = 1 points). Infection control practitioners applied the model prospectively to 220 isolation episodes. The mean (+/-SE) AUCs of the ROC curve for the derivation and validation cohorts were not significantly different (.86 +/- .04 vs .86 +/- .07; P = .90). There was a significant decline in the mean duration of isolation from the onset of an automatic TB isolation policy in August 1992 to the end of the study (P = .045 by analysis of variance). CONCLUSIONS: A pulmonary TB prediction model was derived and validated prospectively in a hospital with a moderately high prevalence of TB. The model quantitated the risk of TB in an individual patient and aided infection control practitioners and primary-care physicians in their decisions to discontinue isolation during the validation period. Utilization of the model was responsible, in part, for a decrease in the mean duration of isolation during the study period. Although the model may not have general applicability due to the uniqueness of the patient population studied, this study illustrates how prediction models can be developed and used effectively to deal with a clinical problem.

Adult↗

PubMed2006

Tuberculin testing of kidney allograft recipients and donors before transplantation.

UNLABELLED: Immunocompromised patients such as those with chronic renal failure requiring hemodialysis (HD) are at increased risk of developing tuberculosis (TB). The gold standard screening tool used to detect tuberculosis is the tuberculin test, which owes its popularity to its ease of administration and high sensitivity. This study was done to identify the incidence of tuberculin test positivity among dialysis patients before transplantation and also in volunteer living kidney donors. PATIENTS AND METHODS: This cross-sectional, comparative study was done on 308 kidney allograft recipient candidates, 80 potential living unrelated and related donors within a few months before transplantation, and 855 control cases before employment. Patients were tuberculin-tested using the Mantoux technique. The PPD (purified protein derivative)-positive dialysis patients were compared with PPD-negative subjects, regarding age, gender, dialysis duration, cause of chronic renal failure, and nutritional state as well as PPD test results in potential donors. Patients were divided into <10 mm versus > or =10 mm induration. Statistical analysis was performed using SPSS 11.0. RESULTS: The mean age of the donors was 26.6 +/- 4.6 years with a male:female ratio of 87.5%:12.5%. The tuberculin test was positive in 11.25% of cases, all of whom were males with with induration >10 mm. There was no significant difference regarding the PPD results and age. The mean age of recipients was 40.1 +/- 14.7 years with a male/female ratio of 1.3:1. The tuberculin test was positive in 33.6% of recipient candidates. Mean duration on dialysis was 2.5 +/- 1.2 years. No significant correlation existed regarding the dialysis duration, cause of renal failure, c-reactive protein, erythrocyte sedimentation rate, and response to tuberculin test. There was a direct relationship between age and PPD test results (Pearson correlation +192). CONCLUSION: Our results showed that more dialysis patients were PPD positive compared with donors.

Adult↗

PubMed1996

Epidemiological studies in Japan.

The present article provides an overview of epidemiological studies in Japan. The origin of modern epidemiology of Japan can be traced back into the late 19th century. Baron K. Takaki at that time made brilliant epidemiological studies on beriberi and was thus able to eradicate the disease long before vitamin B1 deficiency was identified as the cause of the disease. Epidemiological studies really began to flourish in Japan after the end of World War II. Since the most of infectious diseases have been controlled, epidemiological studies on cancer, heart disease, stroke, and other chronic diseases have become the main target of investigations. It may be cautioned that, among infectious diseases, tuberculosis is still a serious health problem today and HIV infection has become a threatening health issue although the number of AIDS patients reported was still about 1,000 for the whole country in 1995. In contrast to other industrialized countries, heart disease is far less common in Japan, probably reflecting still not-too-rich diet among Japanese. There are a number of unique or unusual epidemiological studies in Japan, including a long-term surveillance of those who were exposed to A-bomb irradiation in 1945. Readers are encouraged to refer to detailed description of each, specific topic presented in this volume. Essential vital statistics are also presented as background information of epidemiological studies in Japan.

Beriberi↗

PubMed1998

Measurement and determinants of tuberculosis outcome in Karonga District, Malawi.

Evaluation of disease outcome is central to the assessment of tuberculosis (TB) control programmes. In the study reported in this article we examined the factors influencing the measurement of outcome, survival rates during and after treatment, smear conversion rates, and relapse rates for patients diagnosed with TB in a rural area of Malawi between 1986 and mid-1994. Patients with less certain diagnoses of TB were more likely to die than those with confirmed TB, both among those who were seropositive and those who were seronegative to human immunodeficiency virus (HIV). The mortality rate among smear-positive patients with a separate culture-positive specimen was half that of patients with no such diagnostic confirmation. Patients not registered by the Ministry of Health had much higher mortality and default rates than did registered patients. Among smear-positive patients, HIV serostatus was the most important influence on mortality both during and after treatment (crude hazard ratios (95% confidence intervals) = 5.6 (3.0-10) and 7.7 (3.4-17), resp.), but HIV serostatus did not influence smear conversion rates. The initial degree of smear positivity influenced smear conversion rates, but not mortality rates. No significant predictors of relapse were identified. Unless considerable care is taken to include all TB patients, and to exclude nontuberculous patients, recorded TB outcome statistics are difficult to interpret and may be misleading. In populations with high rates of HIV infection, TB target cure rates of 85% are unrealistic. When new interventions are assessed it cannot be assumed that factors which influence the smear conversion rate will also influence the mortality rate.

Adult↗

PubMedDate not supplied

Bronchial artery embolization for hemoptysis due to benign diseases: immediate and long-term results.

PURPOSE: To clarify the immediate effect and long-term results of bronchial artery embolization (BAE) for hemoptysis due to benign diseases and the factors influencing the outcomes. METHODS: One hundred and one patients (aged 34-89 years) received bronchial artery embolization with polyvinyl alcohol particles and gelatin sponge for massive or continuing moderate hemoptysis caused by benign pulmonary diseases and resistant to medical treatment. RESULTS: After BAE, bleeding stopped in 94 patients (94%). The immediate effect was unfavorable in cases where feeder vessels were overlooked or the embolization of the intercostal arteries was insufficient. Long-term cumulative hemoptysis nonrecurrence rates after the initial embolization were 77.7% for 1 year and 62.5% for 5 years. In bronchitis (n = 9) and active tuberculosis (n = 4) groups, an excellent (100%) 5-year cumulative nonrecurrence rate was obtained. The rate was lower in groups with pneumonia/abscess/pyothorax (n = 8) or with pulmonary aspergillosis (n = 9) (53.3%, 1-year cumulative nonrecurrence). There were higher incidences of early recurrence among patients with massive hemorrhage or more marked vascularity and systemic artery-pulmonary artery shunt in angiography: however, these trends were not statistically significant CONCLUSIONS: BAE can yield long-term benefit in patients with hemoptysis due to benign diseases. Technical problems in the procedure had an impact on the short-term effect. The degree of hemorrhage or the severity of angiographical findings were not significant factors affecting the outcome. The most significant factor affecting long-term results was whether the inflammation caused by the underlying disease was medically well controlled.

Adult↗

PubMed1997

Strategies to increase adherence with tuberculosis test reading in a high-risk population.

OBJECTIVE: To determine the most effective strategy to encourage adherence with tuberculosis test reading in a high-risk population. Design. Prospective randomized controlled trial. SETTING/PARTICIPANTS: Consecutive sample of 627 children ages 1 to 12 years due for a tuberculosis (TB) test in an urban children's hospital outpatient department. One child per family was enrolled. INTERVENTION: All families received education regarding the importance of skin testing for TB and the need for follow-up, and written and verbal instructions regarding test reading. Families were randomly assigned to one of five strategies for follow-up TB test reading at 48 to 72 hours: 1) routine verbal and written instructions, 2) reminder phone call, 3) transportation tokens and toy on return, 4) withholding of school forms until time of reading and need to repeat TB test if not timely read, 5) parents taught to read induration with nurse home visit. Those who did not have tests read at 48 to 72 hours by a trained professional were phoned 1 week later. RESULTS: The five groups did not differ with regard to TB risk factor score, maternal education, transportation source, or perceived importance of TB testing. Before the study the follow-up rate of TB test reading by a trained professional was 45%. Reading rates in this study were 58%, 70%, 67%, 70%, and 72% for groups 1 to 5, respectively. In group 4, only 39% had school forms to be completed and their adherence rate was 84% (53/63). Compared to group 1, the only statistically significant improvement was in group 4, especially for those who needed school forms completed, and in group 5. Those not adhering in groups 1 to 4 did not differ from returnees with regard to TB risk factors, maternal education, transportation, or perceived importance of testing. The most common reasons for failing to return included forgetfulness, transportation, and time constraints. Group 5 was stopped early because of difficulty with nurse visits (N = 98). When told of the nurse visit, 9% (9/98) families could not find a time for the visit. Seventeen percent (17/98) were visited but the child was not home, and 7% (7/98) were not visited because of a nurse scheduling problem. CONCLUSIONS: In a high-risk population, adherence with TB test reading is poor. However, education and return of school forms at reading time can significantly improve adherence. Although requiring larger investment in resources, visiting nurses may also aid in test reading.

Child↗

PubMed2004

UV-induced inactivation rates for airborne Mycobacterium bovis BCG.

Engineering ultraviolet irradiation systems as a control against infectious airborne diseases requires a knowledge of intrinsic ultraviolet (UV) inactivation rates of airborne bacteria. Ultraviolet inactivation rates for airborne Mycobacterium bovis bacillus Calmette-Guérin (BCG) were determined at 50% and 95% relative humidity (RH) in a 0.8 m3 bioaerosol reactor. Ultraviolet inactivation response of waterborne M. bovis BCG pure cultures was also determined. At 50% RH the airborne UV inactivation rates observed were two times greater than those observed in saturated air (RH = 95%), and rates at 95% RH were similar to those observed in otherwise identical cultures suspended in water. Intrinsic UV inactivation rates for M. bovis BCG were statistically similar to rates observed for Mycobacterium parafortuitum at 50% and 95% RH, indicating that M. parafortuitum is a valid surrogate for studying airborne UV responses of M. bovis BCG and Mycobacterium tuberculosis. Results also confirm that UV inactivation responses for bacteria suspended in water cannot be used to estimate UV dose response in unsaturated air.

Air Microbiology↗

PubMed1995

Molecular epidemiology of tuberculosis in Denmark in 1992.

The incidence of tuberculosis (TB) is increasing all over the world, including in countries with a high standard of living and good social security. Denmark represents such a region. Furthermore, it is a small country (5 million inhabitants) with a long tradition in TB control, including a centralization of the bacteriological diagnostic facility. The present study was intended to analyze the transmission of Mycobacterium tuberculosis in a country in which TB has low endemicity by a combination of conventional epidemiological approaches and DNA fingerprinting techniques, whereby individual bacterial strains can be traced. M. tuberculosis isolates from 92% of all new cases of bacteriologically verified TB in Denmark during 1992 were subjected to IS6110 DNA fingerprinting to visualize the DNA restriction fragment length polymorphism (RFLP) patterns of the isolated strains. The data obtained from the RFLP analyses were interpreted by using demographic data, such as age, sex, ethnicity, and residence, for the patients. The risk factors among the patients for being part of an active chain of transmission, as opposed to demonstrating reactivation of a previously acquired latent infection, were estimated by statistical analyses. The magnitude of TB transmission in 1992 in Denmark was determined, and transmitted infections were shown to comprise at least one quarter of the total number of cases. Almost half of the TB cases involved patients of foreign origin. However, most of these isolates showed unique DNA fingerprint patterns and were rarely part of an active chain of transmission. The major chains of recent transmission were localized to distinct geographical regions in the country. TB is frequent among immigrants, especially from Asia and Africa, but it is apparently readily suspected, diagnosed, and treated by the health care system. Danish patients with pulmonary symptoms are not primarily suspected to have TB and, therefore, play an important role in recent TB transmission in Denmark.

Adolescent↗

PubMed2001

Screening of TB contacts by tuberculin skin tests in a low-incidence community by BCG vaccination.

A 36-year-old man, an unemployed waiter, a regular patron of two bars living in a Czech city suffered for about a year from disorders caused probably by tuberculosis (TB). When hospitalised, diabetes mellitus and extensive lung TB were diagnosed. TB was found also at the post mortem examination when the patient died one week later. Screening of his contacts by tuberculin skin tests (2TU RT23 W. Tw.80) provided data for analyzing the usefulness of tuberculin tests for monitoring of propagation of TB infection among BCG vaccinated population with high TB prevalence in the A statistically significant difference was found in tuberculin reactivity between 543 contacts and 232 individuals who had not reported contact with, the patient. A skin reaction of 12 mm and more was found in 55.6% contacts while only in 2.6% of those included in the second group. The high tuberculin reactivity was proved in the individuals exposed to massive TB infection. Neither BCG vaccination, nor possible previous contact with TB in the past seemed to influence the actual tuberculin reactivity in the group of non-contacts. Furthermore, it is indicative of the fact that unknown TB sources are rare among the Czech population. The high tuberculin reactivity is suggestive of a fresh infection and justifies the tuberculin testing and the application of chemoprophylaxis.

Adult↗

PubMedDate not supplied

The infectivity of sarcoid clinical material and its bacterial content inoculated in CBA mice.

BACKGROUND: Sarcoidosis is a multisystemic disorder that is currently viewed as the consequence of chronic immunological response associating genetic susceptibility and specific environmental or transmissible agents. Relevant evidence, although conflicting, justifies a concern about the involvement of specific pathogens to disease causation. In this study we assessed the infectivity of sarcoid clinical material, and of the pathogens found in it, to normal CBA mice used as a model of an immuno-competent host. MATERIALS AND METHODS: One hundred and eleven mice were inoculated into their footpads with fresh, filtered, and autoclaved, sputum and bronchoalveolar lavage homogenates, collected from patients with sarcoidosis, and with the mycobacterial and propionibacterial pathogens isolated from this material. RESULTS: The total number of positive reactors of the animals that received raw clinical material and the pathogens it contained was statistically significant compared to those of the control groups. However, the number of affected mice per group was in most cases less than 50% and inflammation was almost always mild and local. CONCLUSION: Based on the evidence provided by inoculation of normal CBA mice, some of the material under study, although of mild potency, can be infectious to an immuno-competent host.

Animals↗

PubMed1996

[Incidence, risk factors relating to bacillary tuberculosis and secondary infections from registered patients in Hunai-Gun, Kyoto Prefecture].

To review how to strengthen tuberculosis program in Hunai-Gun, Kyoto Prefecture, the recent trend of incidence of tuberculosis and 148 index cases with pulmonary tuberculosis newly registered from 1987 to 1992 were analyzed regarding the mode of detection, conditions when consulting medical facilities, risk factors, bacteriological findings, and secondary infections among contacts. 1. The high crude incidence of tuberculosis in Hunai-Gun is explained by the high proportion (19.3%) of the elderly population of 65 years old and over in Hunai-Gun compared with the average (12.6%) in the Prefecture and the high tuberculosis incidence among age group of 70 years old and over in Hunai-Gun compared with the prefectural average. However, the reason of higher incidence of tuberculosis among the elderly in the district was not clear. 2. The proportion of bacillary as well as culture positive cases were higher among patients who were diagnosed by consulting medical facilities than those detected by regular health check. The proportion of bacillary cases without risk factors for tuberculosis among patients who were diagnosed at medical facilities was the highest among those newly attending medical facilities due to complaints related to tuberculosis (group A), followed by those patients regularly attending medical facilities for other diseases but consulting because of additional complaints related to tuberculosis (group B), and lowest among patients regularly attending medical facilities but detected by chance while being examined for other diseases (group C). The severer the diseases stage, the higher the proportion of bacillary cases, however, there were no difference in the proportion of bacillary cases among the above three groups including those with risk factors. It is explained by the fact that the ratio of patients with risk factors was high in group C, which masked the higher proportion of bacillary cases among patients with risk factors. 3. As future activities of public health center on tuberculosis control, it is important to give health education to those with risk factors on the fact that the progression of the disease is faster among them in addition to the increased risk of the disease onset, and advise them to attend regular health check and visit medical facilities when they have any symptom related to tuberculosis. 4. Considering the fact that the risk of secondary infection to contacts is higher among smear positive patients than bacilli negative patients, it is needed to examine all contacts of sputum smear positive patients thoroughly. In addition, it is advisable to follow-up contacts of smear negative but culture positive patients with the similar intensity with those for smear positive patients because their risk of secondary infection to contacts was also higher than bacilli negative patients although it was not statistically significant.

Adolescent↗

PubMed1992

Six-months versus nine-months chemotherapy for tuberculosis of lymph nodes: preliminary results. British Thoracic Society Research Committee.

One-hundred and ninety-nine patients with peripheral lymph node tuberculosis were randomized to treatment with either E2H9R9, Z2H9R9 or Z2H6R6 regimens (E, ethambutol; H, isoniazid; R, rifampicin; Z, pyrazinamide; numbers denote duration of therapy in months). One-hundred and thirty-three patients were diagnosed by aspiration/biopsy leaving residual nodes, 44 were diagnosed after excision of the palpable nodes and 22 were diagnosed on clinical grounds supported by a strongly positive tuberculin test. Treatment was completed as planned by 157 patients. Eight patients required aspirations after commencing chemotherapy, seven on ethambutol and one on pyrazinamide (P = 0.005). There was no statistically significant difference between the regimens in speed of resolution of nodes, or in the percentage with residual nodes at the end of treatment, or in the numbers developing fluctuation or sinuses. Follow-up to 30 months from commencement of treatment continues in order to establish relapse rates for the regimens.

Adolescent↗

PubMed2004

Osmotically regulated asymmetric capsular systems for simultaneous sustained delivery of anti-tubercular drugs.

Sustained release asymmetric membrane capsular systems were developed for simultaneous oral delivery of rifampicin and isoniazid sodium in order to reduce the problems associated with the multi drug therapy of tuberculosis. Dense semipermeable membrane coating capsules were also prepared for the delivery of these drugs by adopting two different filling approaches. In vitro release studies were carried out for both types of systems and the results were compared. Asymmetric membrane capsules provided sustained release of rifampicin associated with initial burst release, where isoniazid release rates were comparatively high due to higher aqueous solubility. Dense semipermeable membrane systems provided controlled release of both drugs but were devoid of initial burst release of isoniazid. To overcome these drawbacks, a modified asymmetric system was developed by adding appropriate amount of hydrophilic polymer mixture with isoniazid. The system provided satisfactory sustained release of rifampicin and isoniazid with initial burst release may be sufficient to achieve minimum effective concentration in blood. In vitro dissolution kinetics of the systems followed first order kinetics and statistical analysis of release rate data proved that modified asymmetric system was better amongst the developed systems.

Antitubercular Agents↗

PubMedDate not supplied

Transforming growth factor-beta decreases survival of Mycobacterium bovis-activated T cells.

BACKGROUND: A comprehensive understanding of the immune response induced by Mycobacterium bovis Bacille Calmette-Guérin in activation of protective T cells against tuberculosis is important to develop effective therapies to combat this disease. In this study, our experiments were designed to determine effects of transforming growth factor (TGF)-beta on M. bovis-induced T-cell activation and survival. METHODS: Fluorescence-activated cell sorter (FACS) analysis was used for detection of apo-ptotic cells by three different methods: 1). scattered light change during early phase of apoptosis; 2). detection of hypodiploid DNA, or 3). terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) technique. Quantification of positively stained population was based on samples stained with isotype control antibodies analyzed on a FACScan. RESULTS: TGF-beta added at initiation of culture did not alter percentage of viable cells. By contrast, TGF-beta added 72 h post-activation decreased percentage of viable cells. This effect was statistically significant (p <0.05). Furthermore, addition of anti-TGF-beta MoAb together with TGF-beta abolished the ability of this cytokine to decrease survival in post-activated human T cells. Role of TGF-beta on post-activated human T cells was further confirmed by staining apoptotic nuclei with propidium iodide, which detects late events of apoptosis, and by DNA fragmentation determined using TUNEL assay. Interestingly, TGF-beta did not promote Fas-mediated killing. Finally, TGF-beta increased apoptosis of CD4(+) T cells after mycobacterial stimulation. CONCLUSIONS: This study indicated an important role for TGF-beta in suppression of protective immune response against M. bovis by promoting elimination of post-activated T cells. Furthermore, results showed that TGF-beta had no direct effect on M. bovis-induced up-regulation of Fas (CD95).

Animals↗

PubMed1982

A randomized, double-blind study of two combined and two progestogen-only oral contraceptives.

A randomized double-blind study of two combined oral contraceptives and two progestogen-only oral contraceptives was conducted using the same protocol at WHO Collaborating Centres for Clinical Research in Human Reproduction in Bombay and Ljubljana of the 518 women admitted to the trial, 123 received mestranol 50 micrograms + norethisterone 1mg (MES 50 + NET 1); 137 received ethinyl estradiol 30 micrograms + levonorgestrel 150 micrograms (EE 30 + LNG 150); 130 received norethisterone 350 micrograms/NET 350); and 128 received levonorgestrel 30 micrograms (LNG 30). At one year, between 52.6 and 61.0 percent of those recruited had discontinued oral contraceptive use for all reasons, and by two years, between 70.5 and 76.5 percent had discontinued the treatment. These rates did not differ between the four treatment groups. However, discontinuation rates for all medical reasons at one and two years, and at two years pregnancy rates and discontinuation rates for bleeding disturbances, were significantly lower in the EE/LNG preparation. The groups receiving the MES/NET, LNG and NET had similar pregnancy rates, discontinuation rates for all medical reasons and all bleeding disturbances. There were two ectopic pregnancies among the 22 pregnancies in the progestogen-only groups. Discontinuation because of headache, dizziness and other central nervous system symptoms were significantly more common in those receiving MES/NET compared to EE/LNG. In contrast, discontinuation for gastro-intestinal disturbances were significantly higher in the EE/LNG combined preparation. Bleeding disturbances in the first few cycles tended to be higher in NET than in the LNG group. The data suggest that greater consideration be given to the benefits and risks of including progestogen-only oral contraceptives in the family planning programmes of some countries.

Adolescent↗

PubMed2001

[Where do we stand with BCG vaccination programme in Japan?].

The current BCG vaccination program of Japan is critically discussed based on recent knowledge, especially with regard to its epidemiological aspects, in order to put the problem into perspective for Japan's future tuberculosis control program. 1. EFFICACY AND OVERALL EFFECTIVENESS: Various indicators of BCG efficacy have been proposed, and the meticulous analysis on the variability and the quality of these indicators seems to have formed a consensus on the efficacy, as seen in the recent meta-analysis studies. However, much has been left unanswered concerning the conditions under which the efficacy is guaranteed. The impact of the vaccination program on the population should also be considered in order to make decisions on the program. Comparing the age-specific tuberculosis notification rate between Japan and the USA, where there has been no BCG vaccination program, shows that the rate for 0 to 4 year olds is clearly lower in Japan than in the USA, while it is more than five times higher for all ages in Japan than in the USA. The statistics for Japanese children are superior to those of US children with respect to the speed of decline in notification rate as well. These observations support the overall effectiveness of BCG vaccination in Japan. 2. MECHANISMS OF BCG VACCINATION EFFICACY AND ITS DURATION: Two possible mechanisms of how BCG works to prevent tuberculosis were proposed. Epidemiological models based on each mechanism were subsequently tested by simulating 20 years' development of cases in the BCG vaccination trial by BMRC. In mechanism 1, the BCG-induced immunity is assumed to boost TB immunity in inhibiting the clinical breakdown of tuberculosis during the 10 to 15 years after the vaccination. In mechanism 2, the immunity makes the infection process abort (presumably, at 90%, during the seven years after infection, for example), leading to a smaller risk of future clinical development. So far, most epidemiological models implicitly assume mechanism 1 above. In animal experimental models, however, it has been difficult to simulate the mechanisms differentially, which has been one of the drawbacks to this argument. 3. EFFECTIVENESS OF REVACCINATION: Revaccination with BCG vaccine aims to restore or to endow immunological resistance through repeating vaccination to those who have partially or totally lost the immunity acquired from the primary vaccination. Although some animal experiments support the efficacy of revaccination with BCG, studies in humans have been rare and the results are variable. The observation of Polish infants and schoolchildren is suggestive of the efficacy, but it is not randomized and of questionable value. The recent study of Malawi is a randomized trial. It demonstrated that BCG revaccination protects against leprosy, but does not protect significantly against tuberculosis. It is possible, however, that it does protect against tuberculous lymphadenitis. The two above-mentioned possible mechanisms of BCG immunity were applied to a model analysis of BCG revaccination. It was known that revaccination effectiveness is very limited under any assumption, given the current Japanese epidemiological situation of tuberculosis, so that the demerits due to revaccination, such as strong local reactions, must not be neglected but should be carefully considered. At the same time, we should remember that this model analysis assumes that the primary vaccination is given to new borns with advanced and uniform techniques, which is not always true, and revaccination may supplement the technical failure of the primary vaccination. 4. DECIDING ON THE TOTAL DISCONTINUATION OF BCG VACCINATION PROGRAMME, JAPAN: The recommendations of WHO or IUATLD on the discontinuation of the BCG vaccination program are just conventional ones and the theoretical reasonings is difficult to accept. After all, the decision making should depend on the lay decision makers' subjective judgment balancing benefit and loss in terms of costs and health incurred by the policy, as shown by Waaler and Rouillon. The current Japanese BCG vaccination program is very expensive, but brings about some, though very small, benefit. This balance was compared with that of Sweden around 1975, when the program was discontinued. The comparison clearly showed that the cost-effectiveness of the program in Japan today in superior to that of Sweden in 1975.

BCG Vaccine↗

PubMed1998

[Clinical evaluation of a new non-radiometric automatic system for the rapid diagnosis of tuberculosis].

BACKGROUND: Tuberculosis (TB) is again a public health problem un many countries and is considered a re-emerging disease. The fastest possible diagnosis in our patients is essential for TB control programs. ESP is a non-radioactive, totally automated, continuously monitored system designed to detect mycobacteria. METHODS: Clinical evaluation of this new system for the rapid diagnosis of tuberculosis. During 1997 a total of 1,022 clinical sputum specimens were investigated. Specimens were processed in triplicate for ESP, BACTEC 460 TB and Löwenstein-Jensen systems. The validity, isolates of Mycobacterium tuberculosis and time required for detecting M. tuberculosis by the three systems were determined. RESULTS: The sensitivity, specificity, positive predictive and negative predictive values of the new systems were 98%, 99.8%, 98% and 99.8%, respectively. No significant differences were found between the recovery rates by the three systems. The mean time for detection was 10 days (range: 7-13 days) for specimens with positive bacilloscopy and 14 days (range: 10-28 days) for specimens with negative bacilloscopy. The difference was statistically significant between ESP and Löwenstein-Jensen, but not between ESP and BACTEC. CONCLUSIONS: The new system proved to have an excellent sensitivity and specificity, which along with its total automation renders it a system of great clinical interest for the rapid diagnosis of TB and an alternative method for radiometric systems.

Bacteriological Techniques↗