BACKGROUND: Contact tracing is used for multiple infectious diseases, most recently for COVID-19, but data regarding its effectiveness in disease control are scarce. To address this knowledge gap and inform public health decision making for COVID-19, we systematically reviewed the existing literature to determine the effectiveness of contact tracing in the control of communicable illness.
METHODS: We searched PubMed, Embase, and the Cochrane Library from database inception up to Nov 22, 2021, for published studies evaluating associations between provider-initiated contact tracing for transmissible infectious diseases and one of three outcomes of interest: case detection rates among contacts or at the community level, overall forward transmission, or overall disease incidence. Clinical trials and observational studies were eligible, with no language or date restrictions. Reference lists of reviews were searched for additional studies. We excluded studies without a control group, using only mathematical modelling, not reporting a primary outcome of interest, or solely examining patient-initiated contact tracing. One reviewer applied eligibility criteria to each screened abstract and full-text article, and two reviewers independently extracted summary effect estimates and additional data from eligible studies. Only data reported in published manuscripts or supplemental material was extracted. Risk of bias for each included study was assessed with the Cochrane Risk of Bias 2 tool (randomised studies) or the Newcastle-Ottawa Scale (non-randomised studies).
FINDINGS: We identified 9050 unique citations, of which 47 studies met the inclusion criteria: six were focused on COVID-19, 20 on tuberculosis, eight on HIV, 12 on curable sexually transmitted infections (STIs), and one on measles. More than 2 million index patients were included across a variety of settings (both urban and rural areas and low-resource and high-resource settings). Of the 47 studies, 29 (61·7%) used observational designs, including all studies on COVID-19, and 18 (38·3%) were randomised controlled trials. 40 studies compared provider-initiated contact tracing with other interventions or evaluated expansions of provider-initiated contact tracing, and seven compared programmatic adaptations within provider-initiated contact tracing. 29 (72·5%) of the 40 studies evaluating the effect of provider-initiated contact tracing, including four (66·7%) of six COVID-19 studies, found contact tracing interventions were associated with improvements in at least one outcome of interest. 23 (48·9%) studies had low risk of bias, 22 (46·8%) studies had some risk of bias, and two (4·3%) studies (both randomised controlled trials on curable STIs) had high risk of bias.
INTERPRETATION: Provider-initiated contact tracing can be an effective public health tool. However, the ability of authorities to make informed choices about its deployment might be limited by heterogenous approaches to contact tracing in studies, a scarcity of quantitative evidence on its effectiveness, and absence of specificity of tracing parameters most important for disease control.
FUNDING: The Sullivan Family Foundation, Massachusetts General Hospital Executive Committee on Research, and US National Institutes of Health.
BACKGROUND: Community-based active case-finding interventions might identify and treat more people with tuberculosis disease than standard case detection. We aimed to assess whether active case-finding interventions can affect tuberculosis epidemiology in the wider community.
METHODS: We did a systematic review by searching PubMed, Embase, Scopus, and Cochrane Library for studies that compared tuberculosis case notification rates, tuberculosis disease prevalence, or tuberculosis infection prevalence or incidence in children, between populations exposed and unexposed to active case-finding interventions. We included studies published in English between Jan 1, 1980, and April 13, 2020. Studies of active case-finding in the general population, in populations perceived to be at high risk for tuberculosis, and in closed settings were included, whereas studies of tuberculosis screening at health-care facilities, among household contacts, or among children only, and studies that screened fewer than 1000 people were excluded. To estimate effectiveness, we extracted or calculated case notification rates, prevalence of tuberculosis disease, and incidence or prevalence of tuberculosis infection in children, and compared ratios of these outcomes between groups that were exposed or not exposed to active case-finding interventions.
RESULTS: 27 883 abstracts were screened and 988 articles underwent full text review. 28 studies contributed data for analysis of tuberculosis case notifications, nine for prevalence of tuberculosis disease, and two for incidence or prevalence of tuberculosis infection in children. In one cluster-randomised trial in South Africa and Zambia, an active case-finding intervention based on community mobilisation and sputum drop-off did not affect tuberculosis prevalence, whereas, in a cluster-randomised trial in Vietnam, an active case-finding intervention based on sputum tuberculosis tests for everyone reduced tuberculosis prevalence in the community. We found inconsistent, low-quality evidence that active case-finding might increase the number of cases of tuberculosis notified in populations with structural risk factors for tuberculosis.
INTERPRETATION: Community-based active case-finding for tuberculosis might be effective in changing tuberculosis epidemiology and thereby improving population health if delivered with high coverage and intensity. If possible, active case-finding projects should incorporate a well designed, robust evaluation to contribute to the evidence base and help elucidate which delivery methods and diagnostic strategies are most effective.
FUNDING: WHO Global TB Programme.
BACKGROUND: Directly observed therapy (DOT), as recommended by the World Health Organization, is used in many countries to deliver tuberculosis (TB) treatment. The effectiveness of community-based (CB DOT) versus clinic DOT has not been adequately assessed to date. We compared TB treatment outcomes of CB DOT (delivered by community health workers or community volunteers), with those achieved through conventional clinic DOT.
METHODS: We performed a systematic review and meta-analysis of studies before 9 July 2014 comparing treatment outcomes of CB DOT and clinic DOT. The primary outcome was treatment success; the secondary outcome was loss to follow-up.
RESULTS: Eight studies were included comparing CB DOT to clinic DOT, one a randomised controlled trial. CB DOT outperformed clinic DOT treatment success (pooled odds ratio (OR) of 1.54, 95% confidence interval (CI) 1.01 - 2.36, p = 0.046, I(2) heterogeneity 84%). No statistically significant difference was found between the two DOT modalities for loss to follow-up (pooled OR 0.86, 95% CI 0.48 to 1.55, p = 0.62, I(2) 83%).
CONCLUSIONS: Based on this systematic review, CB DOT has a higher treatment success compared to clinic DOT. However, as only one study was a randomised controlled trial, the findings have to be interpreted with caution.
BACKGROUND: Tuberculosis (TB) requires at least six months of treatment. If treatment is incomplete, patients may not be cured and drug resistance may develop. Directly Observed Therapy (DOT) is a specific strategy, endorsed by the World Health Organization, to improve adherence by requiring health workers, community volunteers or family members to observe and record patients taking each dose.
OBJECTIVES: To evaluate DOT compared to self-administered therapy in people on treatment for active TB or on prophylaxis to prevent active disease. We also compared the effects of different forms of DOT.
SEARCH METHODS: We searched the following databases up to 13 January 2015: the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; EMBASE; LILACS and mRCT. We also checked article reference lists and contacted relevant researchers and organizations.
SELECTION CRITERIA: Randomized controlled trials (RCTs) and quasi-RCTs comparing DOT with routine self-administration of treatment or prophylaxis at home.
DATA COLLECTION AND ANALYSIS: Two review authors independently assessed risk of bias of each included trial and extracted data. We compared interventions using risk ratios (RR) with 95% confidence intervals (CI). We used a random-effects model if meta-analysis was appropriate but heterogeneity present (I(2) statistic > 50%). We assessed the quality of the evidence using the GRADE approach.
MAIN RESULTS: Eleven trials including 5662 participants met the inclusion criteria. DOT was performed by a range of people (nurses, community health workers, family members or former TB patients) in a variety of settings (clinic, the patient's home or the home of a community volunteer). DOT versus self-administered Six trials from South Africa, Thailand, Taiwan, Pakistan and Australia compared DOT with self-administered therapy for treatment. Trials included DOT at home by family members, community health workers (who were usually supervised); DOT at home by health staff; and DOT at health facilities. TB cure was low with self-administration across all studies (range 41% to 67%), and direct observation did not substantially improve this (RR 1.08, 95% CI 0.91 to 1.27; five trials, 1645 participants, moderate quality evidence). In a subgroup analysis stratified by the frequency of contact between health services in the self-treatment arm, daily DOT may improve TB cure when compared to self-administered treatment where patients in the self-administered group only visited the clinic every month (RR 1.15, 95% CI 1.06 to 1.25; two trials, 900 participants); but with contact in the control becoming more frequent, this small effect was not apparent (every two weeks: RR 0.96, 95% CI 0.83 to 1.12; one trial, 497 participants; every week: RR 0.90, 95% CI 0.68 to 1.21; two trials, 248 participants).Treatment completion showed a similar pattern, ranging from 59% to 78% in the self-treatment groups, and direct observation did not improve this (RR 1.07, 95% CI 0.96 to 1.19; six trials, 1839 participants, moderate quality evidence). DOT at home versus DOT at health facility In four trials that compared DOT at home by family members, or community health workers, with DOT by health workers at a health facility there was little or no difference in cure or treatment completion (cure: RR 1.02, 95% CI 0.88 to 1.18, four trials, 1556 participants, moderate quality evidence; treatment completion: RR 1.04, 95% CI 0.91 to 1.17, three trials, 1029 participants, moderate quality evidence). DOT by family member versus DOT by community health workerTwo trials compared DOT at home by family members with DOT at home by community health workers. There was also little or no difference in cure or treatment completion (cure: RR 1.02, 95% CI 0.86 to 1.21; two trials, 1493 participants, moderate quality evidence; completion: RR 1.05, 95% CI 0.90 to 1.22; two trials, 1493 participants, low quality evidence). Specific patient categoriesA trial of 300 intravenous drug users in the USA evaluated direct observation with no observation in TB prophylaxis to prevent active disease and showed little difference in treatment completion (RR 1.00, 95% CI 0.88 to 1.13; one trial, 300 participants, low quality evidence).
AUTHORS' CONCLUSIONS: From the existing trials, DOT did not provide a solution to poor adherence in TB treatment. Given the large resource and cost implications of DOT, policy makers might want to reconsider strategies that depend on direct observation. Other options might take into account financial and logistical barriers to care; approaches that motivate patients and staff; and defaulter follow-up.
OBJECTIVE: To assess the design, delivery and outcomes of interventions to improve adherence to treatment for paediatric tuberculosis in low- and middle-income countries and develop a contextual framework for such interventions.
METHODS: We searched PubMed and Cochrane databases for reports published between 1 January 2003 and 1 December 2013 on interventions to improve adherence to treatment for tuberculosis that included patients younger than 20 years who lived in a low- or middle-income country. For potentially relevant articles that lacked paediatric outcomes, we contacted the authors of the studies. We assessed heterogeneity and risk of bias. To evaluate treatment success - i.e. the combination of treatment completion and cure - we performed random-effects meta-analysis. We identified areas of need for improved intervention practices.
FINDINGS: We included 15 studies in 11 countries for the qualitative analysis and of these studies, 11 qualified for the meta-analysis - representing 1279 children. Of the interventions described in the 15 studies, two focused on education, one on psychosocial support, seven on care delivery, four on health systems and one on financial provisions. The children in intervention arms had higher rates of treatment success, compared with those in control groups (odds ratio: 3.02; 95% confidence interval: 2.19-4.15). Using the results of our analyses, we developed a framework around factors that promoted or threatened treatment completion.
CONCLUSION: Various interventions to improve adherence to treatment for paediatric tuberculosis appear both feasible and effective in low- and middle-income countries.
OBJECTIVE: The objective of this study is to review and synthesise the best available research evidence that investigates the effectiveness of strategies to promote adherence to treatment by patients with newly diagnosed pulmonary tuberculosis (TB).
METHODS: The search sought to find published and unpublished studies. The search covered articles published from 1990 to 2010 in English and Thai. The database search included Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Cochrane Library, PubMed, Science Direct, Current Content Connect, Thai Nursing Research Database, Thai thesis database, Digital Library of Thailand Research Fund, Research of National Research Council of Thailand and Database of Office of Higher Education Commission. Studies were additionally identified from reference lists of all studies retrieved. Eligible studies were randomised controlled trials that explored different strategies to promote adherence to TB treatment of patients with newly diagnosed pulmonary TB and also included quasiexperimental studies. Two of the investigators independently assessed the studies and then extracted and summarised data from eligible studies. Extracted data were entered into Review Manager software and analysed.
RESULTS: A total of 7972 newly diagnosed pulmonary TB patients participated in 10 randomised controlled trials and eight quasiexperimental studies. The studies reported on the effectiveness of a number of specific interventions to improve adherence to TB treatment among newly diagnosed pulmonary TB patients. These interventions included directly observed treatment (DOT) coupled with alternative patient supervision options, case management with DOT, short-course directly observed treatment, the intensive triad-model programme and an intervention package aimed at improved counselling and communication, decentralisation of treatment, patient choice of a DOT supporter and reinforcement of supervision activities.
CONCLUSION: This review found evidence of beneficial effects from the DOT with regard to the medication adherence among TB patients in terms of cure rate and success rate. However, no beneficial effect was found from DOT intervention with increasing completion rate. In addition, the combined interventions to improve adherence to tuberculosis treatment included case management with directly observed treatment short-course program, the intensive triad-model programme and intervention package. These interventions should be implemented by healthcare providers and tailored to local contexts and circumstances, wherever appropriate.
Journal»The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease
BACKGROUND: Screening for tuberculosis (TB) disease aims to improve early TB case detection. The ultimate goal is to improve outcomes for people with TB and to reduce Mycobacterium tuberculosis transmission in the community through improved case detection, reduction in diagnostic delays and early treatment. Before screening programmes are recommended, evidence is needed of individual and/or community-level benefits.
METHODS: We conducted a systematic review of the literature to assess the evidence that screening for TB disease 1) initially increases the number of TB cases initiated on anti-tuberculosis treatment, 2) identifies cases earlier in the course of disease, 3) reduces mortality and morbidity, and 4) impacts on TB epidemiology.
RESULTS: A total of 28 798 publications were identified by the search strategy: 27 087 were excluded on initial screening and 1749 on full text review, leaving 62 publications that addressed at least one of the study questions. Screening increases the number of cases found in the short term. In many settings, more than half of the prevalent TB cases in the community remain undiagnosed. Screening tends to find cases earlier and with less severe disease, but this may be attributed to case-finding studies using more sensitive diagnostic methods than routine programmes. Treatment outcomes among people identified through screening are similar to outcomes among those identified through passive case finding. Current studies provide insufficient evidence to show that active screening for TB disease impacts on TB epidemiology.
CONCLUSION: Individual and community-level benefits from active screening for TB disease remain uncertain. So far, the benefits of earlier diagnosis on patient outcomes and transmission have not been established.
BACKGROUND: Preclinical studies and Monte Carlo simulations have suggested that there is a relatively limited role of adherence in acquired drug resistance (ADR) and that very high levels of nonadherence are needed for therapy failure. We evaluated the superiority of directly observed therapy (DOT) for tuberculosis patients vs self-administered therapy (SAT) in decreasing ADR, microbiologic failure, and relapse in meta-analyses.
METHODS: Prospective studies performed between 1965 and 2012 in which adult patients with microbiologically proven pulmonary Mycobacterium tuberculosis were separately assigned to either DOT or SAT as part of short-course chemotherapy were chosen. Endpoints were microbiologic failure, relapse, and ADR in patients on either DOT or SAT.
RESULTS: Ten studies, 5 randomized and 5 observational, met selection criteria: 8774 patients were allocated to DOT and 3708 were allocated to SAT. For DOT vs SAT, the pooled risk difference for microbiologic failure was .0 (95% confidence interval [CI], -.01 to .01), for relapse .01 (95% CI, -.03 to .06), and for ADR 0.0 (95% CI, -0.01 to 0.01). The incidence rates for DOT vs SAT were 1.5% (95% CI, 1.3%-1.8%) vs 1.7% (95% CI, 1.2%-2.2%) for microbiologic failure, 3.7% (95% CI, 0.7%-17.6%) vs 2.3% (95% CI, 0.7%-7.2%) for relapse, and 1.5% (95% CI, 0.2%-9.90%) vs 0.9% (95% CI, 0.4%-2.3%) for ADR, respectively. There was no evidence of publication bias.
CONCLUSIONS: DOT was not significantly better than SAT in preventing microbiologic failure, relapse, or ADR, in evidence-based medicine. Resources should be shifted to identify other causes of poor microbiologic outcomes.
Investigation of contacts of patients with tuberculosis (TB) is a priority for TB control in high-income countries, and is increasingly being considered in resource-limited settings. This review was commissioned for a World Health Organization Expert Panel to develop global contact investigation guidelines. We performed a systematic review and meta-analysis of all studies reporting the prevalence of TB and latent TB infection, and the annual incidence of TB among contacts of patients with TB. After screening 9,555 titles, we included 203 published studies. In 95 studies from low- and middle-income settings, the prevalence of active TB in all contacts was 3.1% (95% CI 2.2-4.4%, I(2)=99.4%), microbiologically proven TB was 1.2% (95% CI 0.9-1.8%, I(2)=95.9%), and latent TB infection was 51.5% (95% CI 47.1-55.8%, I(2)=98.9%). The prevalence of TB among household contacts was 3.1% (95% CI 2.1-4.5%, I(2)=98.8%) and among contacts of patients with multidrug-resistant or extensively drug-resistant TB was 3.4% (95% CI 0.8-12.6%, I(2)=95.7%). Incidence was greatest in the first year after exposure. In 108 studies from high-income settings, the prevalence of TB among contacts was 1.4% (95% CI 1.1-1.8%, I(2)=98.7%), and the prevalence of latent infection was 28.1% (95% CI 24.2-32.4%, I(2)=99.5%). There was substantial heterogeneity among published studies. Contacts of TB patients are a high-risk group for developing TB, particularly within the first year. Children <5 yrs of age and people living with HIV are particularly at risk. Policy recommendations must consider evidence of the cost-effectiveness of various contact tracing strategies, and also incorporate complementary strategies to enhance case finding.
BACKGROUND: Successful tuberculosis control depends upon effective treatment of patients which requires adherence throughout the full course of medical treatment. Poor adherence to treatment is a major obstacle in the global fight against tuberculosis. Therefore, interventions that promote adherence to the tuberculosis treatment regimen should be implemented. OBJECTIVE: To review and synthesise the best available research evidence that investigates the effectiveness of strategies to promote adherence to treatment by patients with pulmonary tuberculosis. INCLUSION CRITERIA: TYPES OF PARTICIPANTS: This review considered all studies that included adults aged ≥ 15 years diagnosed with smear positive and smear negative pulmonary tuberculosis (regardless of HIV infection) in community settings who had never received anti-tuberculosis drugs, or had taken them for less than one month. TYPES OF INTERVENTION: Intervention included strategies to promote adherence to tuberculosis treatment by patients with pulmonary tuberculosis. TYPES OF OUTCOME: Outcomes included measures for treatment completion rate, cure rate, and success rate. TYPES OF STUDIES: The review primarily considered any randomised controlled trials that explored different strategies to promote adherence to tuberculosis treatment of patients with pulmonary tuberculosis but also included quasi-experimental studies. SEARCH STRATEGY: The search sought to find published and unpublished studies. The time period of the search covered articles published from 1990 to 2010 in English and Thai language. The database searches included: CINAHL, EMBASE, Cochrane Library, PubMed, Science Direct, Current Content Connect, Thai Nursing Research Database, Thai thesis database, Digital Library of Thailand Research Fund, Research of National Research Council of Thailand, and Database of Office of Higher Education Commission. Studies were additionally identified from reference lists of all studies retrieved. METHODOLOGICAL QUALITY: Studies selected for retrieval were assessed by two independent reviewers for methodological quality using a standardised critical appraisal tool from the Joanna Briggs Institute. DATA COLLECTION: Data extraction was performed using a standardised data extraction form from the Joanna Briggs Institute. DATA SYNTHESIS: The quantitative study results were pooled in statistical meta-analysis using the Review Manager software (RevMan 5.0) and summarised in narrative form where statistical pooling was not appropriate or possible. RESULTS: This systematic review included ten randomised controlled trials and eight quasi-experimental studies that report on the effectiveness of a number of specific interventions to improve adherence to tuberculosis treatment among newly diagnosed pulmonary tuberculosis patients. These interventions included Directly Observed Treatment coupled with alternative patient supervision options, case management with Directly Observed Treatment, Short-course, the intensive triad-model program, and an intervention package consisting of improving patients’ counselling and communication, decentralisation of treatment, patient choice of Directly Observed Treatment supporter, and reinforcement of supervision activities. CONCLUSION: The interventions that had the best outcomes for treatment adherence among newly diagnosed pulmonary tuberculosis patients were Directly Observed Treatment and Directly Observed Treatment, Short-course combined with case management, improving counselling and communication and decentralisation of treatment. These interventions should be implemented by health care providers and tailored to local contexts and circumstances, where appropriate.
Contact tracing is used for multiple infectious diseases, most recently for COVID-19, but data regarding its effectiveness in disease control are scarce. To address this knowledge gap and inform public health decision making for COVID-19, we systematically reviewed the existing literature to determine the effectiveness of contact tracing in the control of communicable illness.
METHODS:
We searched PubMed, Embase, and the Cochrane Library from database inception up to Nov 22, 2021, for published studies evaluating associations between provider-initiated contact tracing for transmissible infectious diseases and one of three outcomes of interest: case detection rates among contacts or at the community level, overall forward transmission, or overall disease incidence. Clinical trials and observational studies were eligible, with no language or date restrictions. Reference lists of reviews were searched for additional studies. We excluded studies without a control group, using only mathematical modelling, not reporting a primary outcome of interest, or solely examining patient-initiated contact tracing. One reviewer applied eligibility criteria to each screened abstract and full-text article, and two reviewers independently extracted summary effect estimates and additional data from eligible studies. Only data reported in published manuscripts or supplemental material was extracted. Risk of bias for each included study was assessed with the Cochrane Risk of Bias 2 tool (randomised studies) or the Newcastle-Ottawa Scale (non-randomised studies).
FINDINGS:
We identified 9050 unique citations, of which 47 studies met the inclusion criteria: six were focused on COVID-19, 20 on tuberculosis, eight on HIV, 12 on curable sexually transmitted infections (STIs), and one on measles. More than 2 million index patients were included across a variety of settings (both urban and rural areas and low-resource and high-resource settings). Of the 47 studies, 29 (61·7%) used observational designs, including all studies on COVID-19, and 18 (38·3%) were randomised controlled trials. 40 studies compared provider-initiated contact tracing with other interventions or evaluated expansions of provider-initiated contact tracing, and seven compared programmatic adaptations within provider-initiated contact tracing. 29 (72·5%) of the 40 studies evaluating the effect of provider-initiated contact tracing, including four (66·7%) of six COVID-19 studies, found contact tracing interventions were associated with improvements in at least one outcome of interest. 23 (48·9%) studies had low risk of bias, 22 (46·8%) studies had some risk of bias, and two (4·3%) studies (both randomised controlled trials on curable STIs) had high risk of bias.
INTERPRETATION:
Provider-initiated contact tracing can be an effective public health tool. However, the ability of authorities to make informed choices about its deployment might be limited by heterogenous approaches to contact tracing in studies, a scarcity of quantitative evidence on its effectiveness, and absence of specificity of tracing parameters most important for disease control.
FUNDING:
The Sullivan Family Foundation, Massachusetts General Hospital Executive Committee on Research, and US National Institutes of Health.
