KNCV Tuberculosis Foundation

The Hague, Netherlands

KNCV Tuberculosis Foundation

The Hague, Netherlands
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Machingaidze S.,University of Cape Town | Verver S.,KNCV Tuberculosis Foundation | Mulenga H.,University of Cape Town | Abrahams D.-A.,University of Cape Town | And 4 more authors.
American Journal of Respiratory and Critical Care Medicine | Year: 2012

Rationale: Conversions and reversions occur with IFN-γ release assay (IGRA) serial testing, as with the tuberculin skin test (TST). Recent TST conversion is associated with an established risk of developing tuberculosis (TB) disease, but the risk associated with recent IGRA conversions is unknown. Objectives: To compare the incidence rate of TB disease after recent QuantiFERON TB Gold In-Tube (QFT) conversion compared with nonconverters. Methods: Adolescents with converted IGRA status (QFT converters [n = 534]) and randomly chosen adolescents whose IGRA status had remained negative over a period of 2 years (QFT nonconverters [n = 629]) were identified in a cohort study of TB infection and disease. Subsequent TB disease incidence was compared between the two groups. Measurements and Main Results: For QFT converters, the TB incidence rate (all cases) was 1.46 cases per 100 person-years (95% confidence interval [CI], 0.82-2.39), and the cumulative incidence was 2.8% (95% CI, 1.58-4.59). A significantly lower TB incidence rate (0.17 casesper100person-yr [95%CI,0.02-0.62])andcumulativeincidence (0.32% [95% CI, 0.03-1.14]) was observed for QFT nonconverters. The incidence rate ratio was 8.54 (95% CI, 2.51-29.13) for all cases of TB and 9.1 (95% CI, 1.65-50.36) for protocol-defined TB. Conclusions: Recent QFT conversion was indicative of an approximately eight fold higher risk of progression to TB disease (compared with nonconverters) within 2 years of conversion in a cohort of adolescents in a high-TB burden population. Copyright © 2012 by the American Thoracic Society.


Langendam M.W.,University of Amsterdam | Van Der Werf M.J.,University of Amsterdam | Van Der Werf M.J.,KNCV Tuberculosis Foundation | Huitri E.,Centers for Disease Control and Prevention | Manissero D.,Centers for Disease Control and Prevention
European Respiratory Journal | Year: 2012

A potential threat to the success of new tuberculosis (TB) drugs is the development of resistance. Using drugs in appropriate regimens, such as those recommended in the World Health Organization (WHO) treatment guidelines, prevents the development of resistance. We performed a systematic review to assess the prevalence of inappropriate prescription of TB drugs for the treatment of TB. MEDLINE, EMBASE and other databases were searched for relevant articles in January 2011. Observational studies published from 2000 that included TB patients receiving treatment were selected. A treatment regimen was considered inappropriate if the regimen was not a WHO recommended regimen. 37 studies were included. Inappropriate treatment regimens were prescribed in 67% of studies. The percentage of patients receiving inappropriate regimens varied between 0.4% and 100%. In 19 studies the quality of treatment regimen reporting was low. Despite the fact that assessment of inappropriate treatment was hampered by low quality of reporting, our data indicate a reasonable amount of inappropriate prescription of TB treatment regimens. Thus, there is a risk that new drugs will be used in inappropriate treatment regimens, even with WHO guidelines in place, introducing the risk of resistance development. This article highlights the need to improve implementation of the WHO treatment of TB guidelines. Copyright©ERS 2012.


Van Der Werf M.J.,KNCV Tuberculosis Foundation | Van Der Werf M.J.,University of Amsterdam | Van Der Werf M.J.,Centers for Disease Control and Prevention | Langendam M.W.,University of Amsterdam | And 2 more authors.
European Respiratory Journal | Year: 2012

Treating tuberculosis (TB) patients with inappropriate treatment regimens can lead to treatment failure and, thus, patients who have not been cured and/or to the development of (multi)-drug resistance. A systematic review was performed to assess the knowledge of appropriate TB drug regimens among all categories of healthcare workers (HCWs). In January 2011, MEDLINE, EMBASE and other databases were searched for relevant articles. Observational studies published as of the year 2000 that assessed HCW knowledge of TB treatment were selected. A treatment regimen, drug dosage or treatment duration was considered inappropriate if it was not recommended by national guidelines or by the World Health Organization (WHO). Of 1,896 studies, 31 were included from 14 different countries. No study was performed in Europe. In all studies, HCWs with inappropriate knowledge of treatment regimens (8-100%) or treatment duration (5-99%) were observed. The few studies providing detailed data showed that HCWs mainly reported giving treatment regimens with too many drugs and for too long. Knowledge of appropriate doses was also insufficient in most studies. The available studies show that there is a lack of knowledge of national or international TB treatment guidelines and recommendations. Generalisation of the findings to other settings and countries should be done with caution. Copyright©ERS 2012.


Van Der Werf M.J.,KNCV Tuberculosis Foundation | Van Der Werf M.J.,University of Amsterdam | Langendam M.W.,University of Amsterdam | Sandgren A.,Centers for Disease Control and Prevention | Manissero D.,Centers for Disease Control and Prevention
International Journal of Tuberculosis and Lung Disease | Year: 2012

BACKGROUND: Existing international guidelines provide different recommendations for the management of contacts of multidrug-resistant tuberculosis (MDR-TB) patients. OBJECTIVE: To conduct two systematic reviews with the aim of identifying chemoprophylactic approaches that are effective in contacts of MDR-TB patients to assist in policy making. DESIGN: We systematically searched the Medline, Embase, Central, LILACS, TRIP and BIOSIS Preview databases for studies on the effectiveness of anti-tuberculosis drugs in preventing active TB in persons at risk of developing MDR-TB. This was done as an update of a systematic review from 2006 using the same methodology. In addition, we searched for studies including persons at risk of developing TB after exposure to non-MDR-TB patients who were treated with anti-tuberculosis drugs other than isoniazid or rifampicin. RESULTS: Of 1195 references assessed in the update, one additional study could be included. As the initial review included two studies, the total number of included studies equals three. One study reported no contacts who developed TB, whether or not they received prophylaxis. The other two studies showed non-significant risk differences of 4% (95%CI -3 to 12), and 5% (95%CI -2 to 11), both in favour of chemoprophylaxis. For the additional review, 2480 references were assessed, but none could be included. CONCLUSION: The attention given to MDR-TB in recent years has not resulted in publications on preventive treatment for contacts of MDR-TB patients. The available evidence is not sufficient to support or reject preventive treatment. Furthermore, the combined available evidence is of very low quality. © 2012 The Union.


Van Der Werf M.J.,KNCV Tuberculosis Foundation | Van Der Werf M.J.,University of Amsterdam | Van Der Werf M.J.,Centers for Disease Control and Prevention | Langendam M.W.,University of Amsterdam | And 2 more authors.
European Respiratory Journal | Year: 2012

We conducted a systematic review and meta-analysis to assess the evidence for the postulation that inappropriate tuberculosis (TB) regimens are a risk for development of multidrug-resistant (MDR)-TB. MEDLINE, EMBASE and other databases were searched for relevant articles in January 2011. Cohort studies including TB patients who received treatment were selected and data on treatment regimen, drug susceptibility testing results and genotyping results before treatment and at failure or relapse were abstracted from the articles. Four studies were included in the systematic review and two were included in the meta-analysis. In these two studies the risk of developing MDR-TB in patients who failed treatment and used an inappropriate treatment regimen was increased 27-fold (RR 26.7, 95% CI 5.0-141.7) when compared with individuals who received an appropriate treatment regimen. This review provides evidence that supports the general opinion that the development of MDR-TB can be caused by inadequate treatment, given the drug susceptibility pattern of the Mycobacterium tuberculosis bacilli. It should be noted that only two studies provided data for the meta-analysis. The information can be used to advocate for adequate treatment for patients based on drug resistance profiles. Copyright©ERS 2012.


Diel R.,University of Kiel | Vandeputte J.,Trivarop SPRL | De Vries G.,KNCV Tuberculosis Foundation | De Vries G.,National Institute for Public Health and the Environment | And 3 more authors.
European Respiratory Journal | Year: 2014

Without better vaccines it is unlikely that tuberculosis (TB) will ever be eliminated. An investment of ,J560 million is considered necessary to develop a new, effective vaccine in the European Union (EU). However, less is known about the costs of TB disease in the EU. We performed a systematic review of literature and institutional websites addressing the 27 EU members to summarise cost data. We searched MEDLINE, EMBASE and Cochrane bibliographies for relevant articles. Combining direct and indirect costs, we arrived at an average per-TB case costs in the original EU-15 states plus Cyprus, Malta and Slovenia of €10 282 for drug-susceptible TB, €57 213 for multidrug resistant (MDR)-TB and €170 744 for extensively drug resistant (XDR)-TB. In the remaining new EU states, costs amounted to €3427 for drug-susceptible TB and €24 166 for MDR-TB/XDR-TB. For the 70 340 susceptible TB cases, 1488 MDR-TB and 136 XDR-TB cases notified in 2011 costs of €536 890 315 accumulated in 2012. In the same year, the 103 104 disability-adjusted life years caused by these cases, when stated in monetary terms, amounted to a total of €5 361 408 000. Thus, the resulting economic burden of TB in the EU clearly outweighs the cost of investing in more efficient vaccines against TB. Copyright © ERS 2014.


McNerney R.,London School of Hygiene and Tropical Medicine | Cunningham J.,University of Sheffield | Hepple P.,KNCV Tuberculosis Foundation | Zumla A.,University College London
International Journal of Infectious Diseases | Year: 2015

Early detection and effective treatment are crucial for tuberculosis control, but global case detection rates remain low. The diagnosis of paediatric and extrapulmonary disease is problematic and there are, as yet, no rapid screening tests to assist active case finding in the community. Progress has been made in clinic-based detection tools with the introduction of Xpert MTB/RIF, a nucleic acid amplification test that combines sample processing and analysis in a single instrument to provide a diagnostic result and detection of resistance to rifampicin in under 2. h. Enthusiasm for Xpert MTB/RIF has been high and global rollout has been facilitated by donor agencies. However, concerns remain about access and sustainability due to the high cost and infrastructure requirements. Although more sensitive than smear microscopy, early studies suggest the impact of the new test on case detection rates and patient survival has been limited. Alternative technologies are being developed, including non-sputum-based tests to assist the detection of extrapulmonary disease. Evaluation studies are needed to provide evidence of the impact of the new technologies on patient outcomes. This will enable appropriate placement of new diagnostic products in the healthcare system to support the control and eventual eradication of tuberculosis disease. © 2015 The Authors.


Zwerling A.,McGill University | Van Den Hof S.,KNCV Tuberculosis Foundation | Van Den Hof S.,Amsterdam Institute for Global Health and Development | Scholten J.,KNCV Tuberculosis Foundation | And 4 more authors.
Thorax | Year: 2012

Healthcare workers (HCWs) are at increased risk of exposure to tuberculosis (TB). Traditionally, screening for latent TB infection (LTBI) is done using the tuberculin skin test (TST). Interferon-gamma release assays (IGRAs) are now increasingly being used for diagnosis of LTBI, but their role in HCW screening is unclear. A systematic review was conducted of all IGRA studies in HCWs to summarise their performance in cross-sectional and serial testing settings. By searching four electronic databases and other sources, all available studies using any one of the commercial IGRA assays in HCWs were retrieved and screened. 50 unique studies were identified which met the inclusion criteria including five from high TB incidence settings. Among 24 cross-sectional studies in low TB incidence settings, the pooled prevalence of positive IGRA using either test was significantly lower than for a positive TST. However, in high-incidence settings (n=2) there were no consistent differences in the prevalence of positive tests. IGRAs showed good correlation with occupational risk factors for TB exposure in low-incidence settings. Only 10 studies assessed use of IGRA for serial testing and all showed large variation in the rates of conversions and reversions, with no data suggesting that IGRAs are better at identifying the incidence of new TB infection than the TST. The use of IGRAs instead of TST for one-time screening may result in a lower prevalence of positive tests and fewer HCWs who require LTBI treatment, particularly in low TB incidence settings. However, the use of IGRAs for serial testing is complicated by lack of data on optimum cut-offs for serial testing and unclear interpretation and prognosis of conversions and reversions. Further longitudinal research will be required to inform guidelines on serial testing using IGRAs.


Tiemersma E.W.,KNCV Tuberculosis Foundation | Tiemersma E.W.,University of Amsterdam | van der Werf M.J.,KNCV Tuberculosis Foundation | van der Werf M.J.,University of Amsterdam | And 3 more authors.
PLoS ONE | Year: 2011

Background: The prognosis, specifically the case fatality and duration, of untreated tuberculosis is important as many patients are not correctly diagnosed and therefore receive inadequate or no treatment. Furthermore, duration and case fatality of tuberculosis are key parameters in interpreting epidemiological data. Methodology and Principal Findings: To estimate the duration and case fatality of untreated pulmonary tuberculosis in HIV negative patients we reviewed studies from the pre-chemotherapy era. Untreated smear-positive tuberculosis among HIV negative individuals has a 10-year case fatality variously reported between 53% and 86%, with a weighted mean of 70%. Ten-year case fatality of culture-positive smear-negative tuberculosis was nowhere reported directly but can be indirectly estimated to be approximately 20%. The duration of tuberculosis from onset to cure or death is approximately 3 years and appears to be similar for smear-positive and smear-negative tuberculosis. Conclusions: Current models of untreated tuberculosis that assume a total duration of 2 years until self-cure or death underestimate the duration of disease by about one year, but their case fatality estimates of 70% for smear-positive and 20% for culture-positive smear-negative tuberculosis appear to be satisfactory. © 2011 Tiemersma et al.


Hoa N.B.,National Tuberculosis Programme Viet Nam | Sy D.N.,National Tuberculosis Programme Viet Nam | Nhung N.V.,National Tuberculosis Programme Viet Nam | Tiemersma E.W.,KNCV Tuberculosis Foundation | And 2 more authors.
Bulletin of the World Health Organization | Year: 2010

Objective To estimate the prevalence of tuberculosis in Viet Nam with data from a population-based survey, compare it with the prevalence estimated by the World Health Organization, and identify major demographic determinants of tuberculosis prevalence. Methods A cross-sectional survey with multistage cluster sampling, stratified by urban, rural and remote areas, was done in 2006-2007 in 70 communes. All inhabitants aged ≥ 15 years were invited for cough and chest X-ray examination. Participants with findings suggestive of tuberculosis provided sputum specimens for smear examination and culture. Point prevalence estimates, 95% confidence intervals and design effects were calculated. Confidence intervals and P-values were adjusted for the cluster design. Findings Of 114 389 adult inhabitants, 94 179 (82.3%) were screened. Of 87 314 (92.7%) screened by both questionnaire and chest X-ray, 3522 (4.0%) had productive cough, 518 (0.6%) had a recent history of tuberculosis and 2972 (3.4%) had chest X-ray abnormalities suggestive of tuberculosis. Sputum tests were done for 7648 participants. Sputum test, bacterial culture or both confirmed 269 tuberculosis cases, 174 of which were smear-positive. The prevalence rate of smear-positive tuberculosis was 145 per 100 000 (95% confidence interval: 110-180) assuming no tuberculosis in persons aged < 15 years. Prevalence was 5.1 times as high in men as in women, increased with age, was higher in rural than in urban or remote areas and showed a north-to-south gradient. Conclusion In Viet Nam, the tuberculosis prevalence rate based on positive sputum smear tests was 1.6 times as high as previously estimated. Age and sex patterns were consistent with notification data. Tuberculosis control should remain a high priority in Viet Nam.

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