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T F Brewer

Publications and source records attributed to T F Brewer.

At least 19 recordsLinked to original sources
PubMed2001

Strategies to decrease tuberculosis in us homeless populations: a computer simulation model.

CONTEXT: The rate of tuberculosis (TB) among US homeless persons may be 20 times that of the general adult population. Studies suggest that the majority of urban homeless TB cases are attributable to ongoing transmission of TB. Optimal TB-control strategies in both chronically and transiently homeless populations are not known. OBJECTIVE: To examine the effects of TB-control strategies on projected TB cases and deaths in US homeless populations using a computer-based simulation model. DESIGN, SETTING, AND POPULATION: The US general population and a theoretical population of 2 million homeless individuals in 1995 were divided into 18 clinical states based on the risk for or presence of TB and human immunodeficiency virus (HIV) infection in a semi-Markov model. MAIN OUTCOME MEASURES: Prevalence of transiently and chronically homeless individuals with active TB and deaths from TB as a function of public health measures taken to control and eliminate TB, including improvement of treatment effectiveness, improvement in access to treatment, and vaccination with BCG. RESULTS: A 10% increase in access to treatment among homeless persons with active TB produced larger declines in predicted TB cases and deaths after 10 years (cases and deaths among chronically homeless persons decreased 12.5% and 19.8% and among transiently homeless persons dropped 35.9% and 32.4%, respectively) than improvements in the effectiveness of treatment programs (cases and deaths among chronically homeless persons declined 7.2% and 3.1% and among transiently homeless persons dropped 10.9% and 4.1%, respectively). A 10% increase in access to treatment among homeless persons with latent TB infection led to a 6.7% decline in TB among chronically homeless persons and a 5.7% decline among transiently homeless persons, while a 10% improvement in effectiveness of treatment for latent TB infection was associated with declines of 3.0% and 3.3%, respectively. When treatment for latent TB infection was modeled to be the same in vaccinated and nonvaccinated populations, BCG vaccination led to TB case declines of 15.4% and 21.5% in chronically and transiently homeless populations, respectively. CONCLUSIONS: Overcoming barriers faced by homeless individuals in accessing TB treatment programs will be crucial to reducing the burden of TB in this high-risk group. Increased treatment access, improvement in the effectiveness of treatment programs, and BCG vaccination of HIV-negative homeless individuals have the best chance to markedly decrease TB morbidity and mortality.

Antitubercular Agents↗
PubMed2000

Preventing tuberculosis with bacillus Calmette-Guérin vaccine: a meta-analysis of the literature.

This article reviews a previously published meta-analysis of 1264 titles or abstracts and 70 selected studies for evaluation of the efficacy of bacillus Calmette-Guérin (BCG) vaccine in preventing tuberculosis. Following review, data from 26 studies were included in the analysis. These 26 studies reveal that vaccination with BCG significantly reduces the risk of tuberculosis by an average of 50%. This level of protection persists across a number of subgroups defined by age at vaccination and study design. Vaccination with BCG was significantly associated with a reduction in the incidence of pulmonary tuberculosis and extrapulmonary disease. In general, the results of this meta-analysis lend weight and confidence to arguments favoring the use of BCG vaccine.

BCG Vaccine↗
PubMed2000

Pediatric tuberculosis: what needs to be done to decrease morbidity and mortality.

OBJECTIVE: Tuberculosis (TB) control programs have been less successful among children than among adults in the United States. Between 1992 and 1997, the rate of decline of TB cases among 0- to 14-year-old children was less than the rate of decline among any other age group of US-born persons. Because of the higher prevalence of active TB among adults and their higher infectivity, most programs for TB in the United States have targeted adults. The inherent assumption has been that by targeting adults, from whom children may become infected, TB morbidity and mortality among children also will be reduced effectively. METHODS: Using a semi-Markov model that divided the US population into age groups <15 years old and >/=15 years old and into 18 clinical states based on the risk for or presence of TB and human immunodeficiency virus infection, we developed a computer-based simulation model to examine the effect of a range of potential TB control strategies on projected TB cases and deaths in children. We compare the impact of interventions targeted at children with the impact of interventions targeted at adults on pediatric morbidity and mortality. RESULTS: After 10 years, a 5% increase in the number of adults with TB who enter treatment would only lead to a.05% decline in TB cases among children, compared with predicted cases without this intervention. Improving treatment efficacy among those adults who are already receiving treatment for their TB leads to a smaller decline in cases among children of only.003%. In contrast, a 5% increase in the number of children who enter treatment leads to a 25% decline, after 10 years, in the number of TB cases among children and a 16% decline in the number of TB deaths. In the presence of immigration of tuberculin-positive children, the benefit of targeting programs directly at children is magnified. CONCLUSIONS: Marginal changes in programs targeted directly at children are significantly more effective at further reducing pediatric TB morbidity and mortality than the same changes in programs targeted at adults with the indirect goal of reducing spread to children. Marginal increases in the number of children who enter treatment are far more effective at decreasing morbidity and mortality than equivalent marginal increases in treatment effectiveness. Unfortunately, declining insurance coverage and increasing restrictions on services to immigrants have made it harder for those who are at greatest risk of TB to get medical care. Marginal increases in preventive therapy rates substantially reduce future pediatric TB cases and deaths among children with TB infection and human immunodeficiency virus.

Adolescent↗
PubMed1998

An effectiveness and cost analysis of presumptive treatment for Mycobacterium tuberculosis.

BACKGROUND: Delay in treatment of tuberculosis has contributed to both the spread of tuberculosis and its case fatality rate. METHODS: Decision analysis was used to examine the effectiveness and cost of presumptive treatment in patients evaluated for tuberculosis. RESULTS: Over a range of assumptions, empiric antituberculous therapy for acid-fast bacillus smear-positive persons lowers mortality and cost per person evaluated when available rapid diagnostic laboratory methods for tuberculosis are used. In contrast, the average cost per life saved by giving presumptive treatment to all acid-fast bacillus smear- and HIV-negative patients exceeds. $1 million. Empiric treatment for HIV-infected patients with acid-fast bacillus-negative smears decreases average mortality by 2% at an additional cost of $8000 per life saved. When the prevalence of multiple-drug resistance exceeds 9.6%, presumptive drug-resistant therapy for acid-fast bacillus smear-positive patients, rather than the initial four-drug regimen recommended for much of the United States, minimizes both mortality and costs. CONCLUSIONS: Empiric antituberculous therapy often minimizes average mortality and cost for patients evaluated for tuberculosis when rapid diagnostic methods are used.

Antitubercular Agents↗
PubMed1998

The influence of program acceptability on the effectiveness of public health policy: a study of directly observed therapy for tuberculosis.

OBJECTIVES: This study examined how patient acceptability influences the effectiveness of directly observed therapy for tuberculosis. METHODS: Decision and sensitivity analyses were used in assessing influences. RESULTS: If mandatory directly observed therapy discourages 6% of initial tuberculosis patients (range: 4% to 10%) from seeking care, then such therapy will be less effective than self-administered therapy. Directly observed therapy is more effective than repeated self-administered therapy for patients failing to complete initial treatment unless 32% (range: 27% to 38%) of patients avoid seeking care. CONCLUSIONS: Patient acceptability must be taken into consideration before selecting public health strategies.

AIDS-Related Opportunistic Infections↗
PubMed1997

Tuberculosis control in Asia and the western Pacific: a role for computer modelling.

Despite the availability of effective treatment, tuberculosis (TB) causes more deaths than any other infection. Most of the world's TB cases and deaths occur in Asia and the Western Pacific, and the growing prevalence of multiple drug-resistant TB and the spread of human immunodeficiency virus (HIV) present ever greater obstacles to effective TB control. The management of TB remains difficult, and epidemiologic studies to assess control programmes require significant time and expense and may not be generalizable to other regions. Computer models are powerful and relatively inexpensive tools for rapidly planning and evaluating TB control strategies. Models have demonstrated the value of targeted chemoprophylaxis strategies for the prevention of TB among HIV-infected individuals, and programmes to ensure that all HIV-infected individuals receive TB chemoprophylaxis should be considered in Asia and the Western Pacific. Though directly observed therapy (DOT) is effective when designed to be attractive to patients, modelling has shown that DOT, if poorly accepted by patients, may lead to fewer patients seeking care and thus to paradoxical rises in TB case rates. Models may be used to make accurate predictions of TB morbidity and programme costs using local epidemiologic and demographic inputs. The use of models in Asia and the Western Pacific offers a low-cost way to compare programmes, to improve the evaluation of programmes, to project future cases, and to examine programme needs while providing insights into TB control helpful to countries in and out of the region.

AIDS-Related Opportunistic Infections↗
PubMed1996

Evaluation of tuberculosis control policies using computer simulation.

OBJECTIVE: To develop more effective methods to assess tuberculosis (TB) control strategies so we can meet national goals for the elimination of TB in the United States. DESIGN: Using a semi-Markov model that divided the US population into 3 age groups and 18 clinical states based on disease status and risk for TB and human immunodeficiency virus (HIV) infection, we measured the effects of 5 changes in TB policy, introduced singly and in combination: (1) increased coverage and (2) improved efficacy of preventive therapy, (3) increased coverage and (4) improved efficacy of treatment, and (5) introduction of BCG vaccination. RESULTS: A BCG vaccination program that reached 10% of eligible children and 1% of eligible adults each year would produce a 17% reduction in cases and an 11% decline in deaths over 10 years. Preventive therapy programs among the general population would have little effect on the number of TB cases, but a program targeting HIV-infected patients would reduce HIV-associated TB cases and deaths 14% to 20%. A 10% improvement in the coverage and efficacy of both preventive therapy and treatment, coupled with the BCG vaccination program, would lead to a 47% decline in TB cases and a 50% decline in TB deaths relative to baseline over 10 years. CONCLUSIONS: Improvements in treatment coverage or effectiveness alone are unlikely to reach established national goals for the elimination of TB. These goals can be achieved through a combination of improvements in current programs with targeted preventive therapy and BCG vaccination programs.

Adolescent↗
PubMed1995

Relationship between bacille Calmette-Guérin (BCG) strains and the efficacy of BCG vaccine in the prevention of tuberculosis.

Bacille Calmette-Guérin (BCG) vaccination for the prevention of tuberculosis has been used in humans since 1921. Furthermore, for > 60 years it has been possible to separate BCG strains (defined here as a BCG vaccine maintained in a particular laboratory and used in a particular trial or set of trials) on the basis of in vitro and in vivo tests. Investigators have concluded that differences in the BCG strains used in efficacy trials on humans may be responsible for the wide range in levels of protection from tuberculosis reported in those trials. We review the development of the separate strains used in the trials included in a recent meta-analysis and examine data for and against the protective efficacy of different BCG strains. The difficulties in correlating results of in vitro and in vivo tests with protective efficacy in humans are discussed. The limited data available from human studies suggest that the BCG strain used for vaccination is not a significant determinant of the overall efficacy in the prevention of tuberculosis.

BCG Vaccine↗
PubMed1995

Bacille Calmette-Guérin vaccination for the prevention of tuberculosis in health care workers.

For 60 years vaccination with bacille Calmette-Guérin (BCG) has been used for the prevention of tuberculosis in health care workers. In 1988 the U.S. Advisory Committee on Immunization Practices removed the category of health care worker from the list of persons for whom vaccination with BCG should be considered. Nosocomial epidemics of tuberculosis, especially those caused by multidrug-resistant strains, have led to the reconsideration of vaccination with BCG for this population. We review the available studies of the efficacy of BCG vaccine in health care workers. Although the studies had too many methodological flaws to be combined in a quantitative meta-analysis, they suggest that vaccination with BCG is effective in reducing the incidence of tuberculosis among health care workers.

BCG Vaccine↗
PubMed1995

The efficacy of bacillus Calmette-Guérin vaccination of newborns and infants in the prevention of tuberculosis: meta-analyses of the published literature.

OBJECTIVE: To quantify the efficacy of vaccination of infants with bacillus Calmette-Guérin (BCG) against tuberculosis. DATA SOURCES: MEDLINE with index terms BCG vaccine, tuberculosis, and human; lists of all known studies provided by experts at the Centers for Disease Control and Prevention, the World Health Organization, and other organizations. STUDY SELECTION: A total of 1264 articles and abstracts were reviewed for details on BCG vaccination, the availability of concurrent vaccinated and unvaccinated groups, and a tuberculosis outcome. Seventy articles were reviewed in depth for method of vaccine allocation used to create comparable groups, age at vaccination of study participants, comparability of surveillance and follow-up of recipient and concurrent control groups in trials, an appropriately defined control group in case-control studies, and outcome measures (tuberculosis cases and/or deaths). Five prospective trials and eleven case-control studies of vaccination during infancy were included in the present analyses. DATA EXTRACTION: We recorded study design, age range of study population, number of patients enrolled, efficacy of vaccine, location of the study, and a series of items to assess the potential for bias in study design, follow-up, and diagnosis. We extracted or computed vaccine efficacy by years since vaccination wherever possible. At least two readers independently extracted data and evaluated data validity. DATA SYNTHESIS: The relative risk (RR) or odds ratio (OR) for tuberculosis in vaccinated versus unvaccinated infants was the measure of vaccine efficacy analyzed. A random-effects method estimated a weighted average RR or OR from data extracted from the trials and case-control studies. The protective effect was then computed by 1-RR or 1-OR. Overall, the protective effect of vaccination against cases of tuberculosis was 0.74 (95% confidence interval [95% CI], 0.62 to 0.83) when estimated from four randomized controlled trials, and 0.52 (95% CI, 0.38 to 0.64) when estimated from nine case-control studies. Five trials reporting deaths from tuberculosis showed a BCG protective effect of 0.65 (95% CI, 0.12 to 0.86), five studies reporting on meningitis showed a protective effect of 0.64 (95% CI, 0.30 to 0.82), and three studies of disseminated tuberculosis showed a protective effect of 0.78 (95% CI, 0.58 to 0.88). Three case-control studies included separate results for laboratory-confirmed cases of tuberculosis. These studies documented a protective effect of 0.83 (95% CI, 0.58 to 0.93). In a random-effects regression model of the nine case-control studies, study validity score explained 15% of the heterogeneity among study-estimated protective effects, suggesting that better studies reported greater efficacy. Three trials and six case-control studies provided some age-specific information that allowed us to examine the duration of BCG efficacy. Most of this evidence suggested that BCG efficacy may persist through 10 years after infant vaccination. CONCLUSION: BCG vaccination of newborns and infants significantly reduces the risk of tuberculosis--by over 50%, on average. Protection has been observed across many populations, study designs, and forms of tuberculosis. Rates of protection against cases that are confirmed by laboratory tests, reflecting reduced error in disease classification and consequently more accurate estimates of BCG efficacy, are highest at 83%.

BCG Vaccine↗
PubMed1994

Efficacy of BCG vaccine in the prevention of tuberculosis. Meta-analysis of the published literature.

OBJECTIVE: To quantify the efficacy of BCG vaccine against tuberculosis (TB). DATA SOURCES: MEDLINE with index terms BCG vaccine, tuberculosis, and human. Experts from the Centers for Disease Control and Prevention and the World Health Organization, among others, provided lists of all known studies. STUDY SELECTION: A total of 1264 articles or abstracts were reviewed for details on BCG vaccination, concurrent vaccinated and unvaccinated groups, and TB outcome; 70 articles were reviewed in depth for method of vaccine allocation used to create comparable groups, equal surveillance and follow-up for recipient and concurrent control groups, and outcome measures of TB cases and/or deaths. Fourteen prospective trials and 12 case-control studies were included in the analysis. DATA EXTRACTION: We recorded study design, age range of study population, number of patients enrolled, efficacy of vaccine, and items to assess the potential for bias in study design and diagnosis. At least two readers independently extracted data and evaluated validity. DATA SYNTHESIS: The relative risk (RR) or odds ratio (OR) of TB provided the measure of vaccine efficacy that we analyzed. The protective effect was then computed by 1-RR or 1-OR. A random-effects model estimated a weighted average RR or OR from those provided by the trials or case-control studies. In the trials, the RR of TB was 0.49 (95% confidence interval [CI], 0.34 to 0.70) for vaccine recipients compared with nonrecipients (protective effect of 51%). In the case-control studies, the OR for TB was 0.50 (95% CI, 0.39 to 0.64), or a 50% protective effect. Seven trials reporting tuberculous deaths showed a protective effect from BCG vaccine of 71% (RR, 0.29; 95% CI, 0.16 to 0.53), and five studies reporting on meningitis showed a protective effect from BCG vaccine of 64% (OR, 0.36; 95% CI, 0.18 to 0.70). Geographic latitude of the study site and study validity score explained 66% of the heterogeneity among trials in a random-effects regression model. CONCLUSION: On average, BCG vaccine significantly reduces the risk of TB by 50%. Protection is observed across many populations, study designs, and forms of TB. Age at vaccination did not enhance predictiveness of BCG efficacy. Protection against tuberculous death, meningitis, and disseminated disease is higher than for total TB cases, although this result may reflect reduced error in disease classification rather than greater BCG efficacy.

BCG Vaccine↗
PubMed1993

Bacon therapy and furuncular myiasis.

OBJECTIVE: To evaluate a simple, noninvasive method for removing fly larvae from patients with furuncular myiasis. DESIGN: Case series. SETTING: Ambulatory office of a tertiary care center. PATIENTS: Three patients who presented with Dermatobia hominis infestation. INTERVENTION: The patients with D hominis infestation were treated with the application of bacon fat over the larval apertures. MAIN OUTCOME MEASURE: Removal of intact larvae. RESULTS: Within 3 hours of the application of bacon, the larvae had migrated sufficiently far out of the skin to be removed with tweezers. Ten larvae were removed with this method. There were no treatment failures or complications. CONCLUSIONS: Furuncular myiasis will be seen more frequently in temperate areas as individuals travel to endemic areas. We describe the clinical characteristics of myiasis and a simple method of treatment that permits rapid diagnosis and cure.

Animals↗
PubMed1993

The infectious risks of transfusions in the United States: a decision-analytic approach.

INTRODUCTION: The development of AIDS as a result of HIV transmission and of cirrhosis as a result of chronic non-A, non-B hepatitis are the greatest infectious risks associated with transfusion in the United States. The goal of this study is to provide explicit quantitative guidelines to determine when the risk of death from all causes associated with transfusion exceeds the risk associated with anemia. METHODS: This study uses a decision-analytic model. RESULTS: On the basis of reported transfusion complication rates and an independent worst-case calculation of the risk of AIDS and non-A, non-B hepatitis, transfusion with red blood cells should be recommended as long as each unit received reduces the patient's risk of dying from anemia by at least 1/1100. DISCUSSION: Because of the relative safety of the blood supply as a result of universal screening and donor deferral, the overestimation in practice of fatal infectious complications, and the possible underestimation of the risk of anemia, undertransfusion has the potential to be as serious a problem in the United States as is overtransfusion. Although caution should be exercised not to undertransfuse when a patient has an appreciable risk of anemia-associated death, we must be wary not to overtransfuse for temporary relief of morbidity.

Acquired Immunodeficiency Syndrome↗