INT J TUBERC LUNG DIS 21(1):73–78 Q 2017 The Union http://dx.doi.org/10.5588/ijtld.16.0653
Do active case-finding projects increase the number of tuberculosis cases notified at national level? ´ K. G. Koura,*†‡ A. Trebucq,* V. Schwoebel* *
´ International Union Against Tuberculosis and Lung Disease, Paris, †Institut de Recherche pour le Developpement, ´ Universite´ Paris Descartes, Faculte´ des Sciences Pharmaceutiques et UMR216, Paris, ‡COMUE Sorbonne Paris Cite, Biologiques, Paris, France SUMMARY O B J E C T I V E : To analyse the impact of active tuberculosis case finding (ACF) projects on the number of sputum smear-positive (SSþ) tuberculosis (TB) cases notified at national level. M E T H O D S : Case-finding results of the 16 countries that participated in the first wave of the TB REACH project were analysed. Information on the number of SSþ TB cases at national level were taken from the 2014 World Health Organization global tuberculosis report. A segmented linear regression model was used to analyse trends in notification. R E S U LT S : An increase in SSþ TB cases from 3% to 334% was observed in the areas of intervention of the TB REACH project in almost all countries. There were
no significant increases in the number of SSþ TB cases notified at the national level in most countries, except in two countries during the intervention period (Benin and Kenya), and in one country after the intervention period (Somalia). C O N C L U S I O N S : The TB REACH project had no impact on SSþ TB cases notified at national level in almost all countries during and after the intervention. ACF projects are pilot studies that are often difficult to reproduce at national level due to their high cost and the lack of human resources. K E Y W O R D S : active case finding; TB REACH; number of cases notified; sputum smear-positive
ACCORDING TO the World Health Organization (WHO) annual global tuberculosis reports, many people with tuberculosis (TB) remain undiagnosed. In 2014, among the 9.6 million people estimated to have fallen ill with TB, 6 million new TB cases were notified (63%),1 which means that 37% of new cases were undiagnosed or were not reported.1 To increase the number of TB cases detected, reduce the burden of TB and cut the chain of transmission, one of the multiple interventions developed over the last two decades by the Global TB Programme has been to intensify TB case finding through systematic screening of active TB.2–4 This intervention remains an essential part of the new End TB Strategy (2015–2035) adopted by the World Health Assembly in 2014, which includes in the first component of its first pillar the early diagnosis of TB and systematic screening of high-risk groups such as household contacts and other close contacts of people with TB, especially children aged ,5 years, people living with the human immunodeficiency virus (HIV) or workers exposed to silica dust.2,5 Active TB case finding (ACF) is defined by the WHO as ‘the systematic identification of people with
suspected active TB, in a predetermined target group, using tests, examinations or other procedures that can be applied rapidly’.2 In the last few years, considerable efforts have been made to conduct ACF projects to complement the yield of passive case finding. Two major international ACF projects have been performed. The first is the FIDELIS Initiative, in which 51 projects were implemented between 2003 and 2007 in 18 countries. Researchers reported 85 267 additional cases compared to the number reported in the previous year, representing an average increase of 31%, from 187 972 to 273 239.6 The second was the TB REACH project.7 Authors analysed the results of 28 projects implemented from October 2010 to March 2012 in 17 countries. They found that the notification of sputum smear-positive (SSþ) cases increased by 25%, from 69 305 to 86 541.7 Increases in notified cases of all forms and SSþ TB have been described in areas where ACF projects were implemented.8–11 However, these projects were often implemented locally, and whether they had an impact on the number of TB cases notified at national level has not yet been documented. The present study aimed to analyse the impact of ACF projects on the
Correspondence to: Kobto Ghislain Koura, International Union Against Tuberculosis and Lung Disease, 68 Boulevard Saint Michel, 75006 Paris, France. e-mail:
[email protected] Article submitted 28 August 2016. Final version accepted 28 September 2016. [A version in French of this article is available from the Editorial Office in Paris and from the Union website www.theunion.org]
74
The International Journal of Tuberculosis and Lung Disease
number of SSþ TB cases notified at national level. Our hypothesis was that the TB REACH project had increased the number of SSþ TB cases notified at the national level during and after the intervention.
METHODS Study setting TB REACH is an international ACF project funded by the Canadian International Development Agency (Gatineau, QC, Canada), and administered by the Stop TB Partnership. TB REACH comprised four completed waves. We selected those countries that had participated in the first wave of the TB REACH project, which involved 30 projects implemented from October 2010 to March 2012 in 19 countries.7 Several risk groups, such as contacts of people with TB, migrants, internally displaced persons, miners, people with HIV, prisoners, sex workers, drug users, and women or people with difficulty in accessing diagnosis and treatment (rural and urban poor), were screened in these projects. Several case-finding strategies, such as the use of community health workers, private sector providers, mobile outreach teams, improved diagnostics using light-emitting diode microscopes, Xpertw MTB/RIF (Cepheid, Sunnyvale, CA, USA) and digital X-ray, were implemented.7 The results of 28 projects implemented in 17 countries were published in 2014 by the Stop TB Partnership.7 Two projects implemented in Burkina Faso and Yemen were not included either in the report or in the present study: Burkina Faso did not start on time, and data from Yemen could not be verified by the authors. We also excluded results from Sudan, as the country was divided into North and South Sudan in 2010. We therefore focused our analysis on 16 countries: Afghanistan, Benin, Democratic Republic of Congo (DRC), Ethiopia, Kenya, Lao People’s Democratic Republic (Lao), Lesotho, Nepal, Nigeria, Pakistan, Rwanda, Somalia, Tanzania, Uganda, Zambia and Zimbabwe. Data collection Information on the number of SSþ TB cases at baseline and during the intervention periods was collected from the results of the TB REACH project published in 2014 by the Stop TB Partnership.7 Information on the number of SSþ TB cases at the national level from 2005 to 2013 in the 16 study countries was obtained from the 2014 WHO global tuberculosis report.12 Statistical analysis We describe the results of TB REACH projects for SSþ TB cases in 16 countries from October 2010 to March 2012. If the project was implemented in several areas of a single country, cases reported in each area were added together. We then classified the 16 countries into two groups according to the percentage increase in the area of the intervention
(,10%, 710%). A semi-logarithmic scale was used to illustrate the trend in SSþ TB case notifications at the national level from 2005 to 2013 in the 16 countries, depending on the reference group. From 2005 to 2013, SSþ TB cases notified were reported annually to the WHO by country; however, these notifications cannot be considered independent from one year to the next. Because of the secular trends and potential serial correlation of data, we used segmented linear regression to analyse the trends in the number of SSþ TB cases notified at the national level from 2005 to 2013 using the following equation:13,14 Yt ¼ b0 þ b1 *Year þ b2 *intervention þ b3 *postslope þ et ; where Yt is the outcome variable at Year t, here the number of SSþ TB cases notified at the national level. In our model, b0 represents the baseline level of our outcome variable at the beginning of the period; b1 estimates the secular trend, independently of the intervention, here the TB REACH project; b2 estimates the immediate impact of the intervention; b3 reflects the change in trend after the intervention and et the residual variation. A Prais-Winsten estimator was used to correct data autocorrelation. The coefficient b1 is used to describe the secular trend before the TB REACH project. The coefficients b2 (immediate impact of the intervention) and b3 (the change in trend after the intervention) were used to analyse the impact of the TB REACH project on the annual case notification rate at the national level during and after the intervention. Statistical significance was set at P , 0.05. All statistical analyses were performed using Stata, version 12.1 (Stata Corp, College Station, TX, USA). Ethics Approval from an institutional review board was not required, as the study did not involve human subjects.
RESULTS Results of the TB REACH project in the intervention areas The results of the TB REACH project are summarised in Table 1. An increase in SSþ TB cases from 3% to 334% was observed in project areas in 14 countries. A decrease was observed in two countries: in Nepal from 4373 to 4338 cases, and in Rwanda from 845 to 805 cases, representing a decrease of respectively 1% and 5%. Group 1 (,10% change) comprised six countries: Kenya, Laos, Lesotho, Nepal, Rwanda and Zimbabwe. Group 2 (710% change) comprised 10 countries: Afghanistan, Benin, DRC, Ethiopia, Nigeria, Pakistan, Somalia, Tanzania, Uganda and Zambia. The trend in the number of SSþ TB cases notified at the national level between 2005 and 2013 are shown in Figures 1 and 2, respectively, for Groups 1 and 2.
ACF projects and TB cases at national level
Table 1 TB REACH project wave 1: additional cases and percentage change in SSþ TB in intervention areas, 16 countries, October 2010–March 20127
Country
Baseline cases n
Intervention period cases n
Group 1 (,10% change in intervention area) Rwanda 845 805 Nepal 4373 4338 Kenya 15454 15 911 Lesotho 1084 1124 Zimbabwe 2201 2346 Lao People’s Democratic Republic 3076 3328 Group 2 (.10% change in intervention area) Benin 3178 3593 Uganda 3560 4300 Afghanistan 5729 7159 Somalia 1801 2253 DRC 13218 18 324 Nigeria 2184 3038 Tanzania 629 885 Ethiopia 2909 5777 Pakistan 3226 6830 Zambia 38 165
Additional SSþ cases* n (% change) 40 35 457 40 145
(5) (1) (3) (4) (7)
252 (8) 415 740 1430 452 5106 854 256 2868 3604 127
(13) (21) (25) (25) (39) (39) (41) (99) (112) (334)
* In the report, the number of additional cases of SSþ TB was calculated as the difference between the numbers of cases notified during the project implementation period and the number of cases notified during the corresponding quarters of the previous year (baseline cases). SSþ TB ¼ sputum smear-positive tuberculosis; DRC ¼ Democratic Republic of Congo.
Impact of TB REACH project on the number of SSþ TB cases notified at national level The trends in numbers of SSþ TB cases notified at national level in the 16 countries before, during and after the ACF project are shown in Table 2. Trend in the number of SSþ TB cases notified at national level before the ACF project There was a secular increase in the number of cases notified at the national level in 9 countries: this increase was significant in 7 (Benin, DRC, Ethiopia, Nepal, Nigeria, Pakistan and Uganda) and non-
75
significant in 2 (Afghanistan and Laos). There was a secular decrease in the number of cases notified at the national level in 7 countries; it was significant in 3 (Kenya, Somalia, and Zambia) and non-significant in 4 (Lesotho, Rwanda, Tanzania and Zimbabwe). Impact on number of SSþ TB cases notified at national level during the intervention by group In Group 1, there was no significant increase in the number of SSþ TB cases notified at the national level in five countries: Laos, Lesotho, Nepal, Rwanda and Zimbabwe (Table 2). The number of SSþ TB cases notified at the national level significantly increased in only one country, Kenya (b2 ¼ 2654.86, P ¼ 0.03). In Group 2, there was no significant increase in the number of SSþ TB cases notified at the national level in nine countries: Afghanistan, DRC, Ethiopia, Nigeria, Pakistan, Somalia, Tanzania, Uganda and Zambia (Table 2). The number of SSþ TB cases notified at the national level significantly increased in only one country, Benin (b2 ¼ 415.28, P ¼ 0.001). Impact on number of SSþ TB cases notified at national level after the intervention by group Regardless of the group to which the countries belonged, there were no significant increases in the number of SSþ TB cases notified at national level in 15 countries (Table 2). The number of TB cases notified at national level increased significantly in only one country, Somalia (b3 ¼ 697.54, P ¼ 0.01).
DISCUSSION Evaluations of the TB REACH project reported increases in SSþ TB cases in project areas in all countries expect two (Rwanda and Nepal).7 Many other ACF projects led to an increase in the number of notified cases in project areas (South Africa,10 Malawi,11 and Cambodia8,9). It is almost certain
Figure 1 Number of sputum smear-positive TB cases notified at national level between 2005 and 2013 in Group 1.
76
The International Journal of Tuberculosis and Lung Disease
Figure 2 Number of sputum smear-positive TB cases notified at national level between 2005 and 2013 in Group 2.
that this local increase is directly related to ACF activity. To our knowledge, this is the first study to explore the impact of the ACF project on the number of TB cases notified at the national level, and not only in the intervention area. At the national level, our analysis shows no significant increase in notified cases during the intervention period, except in Benin and Kenya. In Kenya, given the low proportion of additional cases in the intervention area (3%), the increase at the national level cannot be attributed to the ACF. In Benin, as the intervention was performed in each of the 12 administrative divisions of the country, the increase at the national level can probably be attributed to the ACF. During the year following the intervention, no country except Somalia observed any significant increase in case notification. It is not clear whether the increase can be attributed to the ACF because of the war in this country that has lasted for more than three decades. The change during the intervention was not significant, and security problems led to irregular diagnostic and reporting activities. In Benin, where the increase during the intervention was probably due to ACF, the number of notified cases decreased in the year following the intervention, which shows that it was not possible to maintain the increase due to the intervention. We focused our analysis in this paper on SSþ TB cases only; however, the analysis was also performed on all forms TB case notifications, which gave similar results (data not shown). None of the published studies discuss the impact of the project at national level.8–11 The use of a segmented linear regression model allows adjustment for serial correlation of the data. This method provides a better interpretation of the trends in SSþ TB cases notified before, during and after the intervention.
Factors other than ACF, which could help to explain the trends in national case notifications, were not analysed, as this was beyond the scope of the present study; however, before the start of intervention, there were significant secular trends (decrease and increase) in the number of SSþ TB cases notified at the national level. It is therefore not always easy to attribute an increase in notifications at the national level to a single action such as ACF. Whereas ACF had a very positive effect in intervention areas, it did not lead to changes in the figures reported at the national level, either during or after the intervention. This is a matter of serious concern, as international guidelines recommend future development of ACF to detect the estimated 30% of TB cases that remain undiagnosed. Even in countries where up to four waves of TB REACH have been performed (Pakistan, Ethiopia, Nepal, Nigeria, Uganda and Zimbabwe),15 there have been no significant increases in the number of SSþ TB notified at the national level during or after the intervention. There are several possible reasons why the TB REACH project has had no impact on the number of cases notified at the national level. As ACF projects are usually pilot projects, implemented in limited areas of a country, their impact is thus limited to these areas. Although it is expected that the experience gained at the local level will benefit the entire country, this does not seem to be the case. The problem of pilot projects is often structural: to show the possible impact of a new strategy, more money and more human resources are invested, but the activities are rarely extended to full coverage of a country because the costs are often too high. For example, in Benin, the only country with a significant increase in the number of TB cases notified at the local and national levels during the intervention, it was estimated that
ACF projects and TB cases at national level
Table 2 Impact of the TB REACH project on the number of SSþ TB cases notified at the national level Coefficient Afghanistan Constant b0 Secular trend b1 Change in level b2 Change in trend b3 Benin Constant b0 Secular trend b1 Change in level b2 Change in trend b3
10 869.28 428.41 133.70 184.13 2768.78 37.11 415.28 139.32
Standard error 896.50 230.22 1628.93 719.12 26.17 6.80 60.67 25.96
3
,10 0.12 0.94 0.81
3
,10 0.003 0.001 0.003
60 629.85 2 239.04 3 052.17 2 099.11
1190.39 308.63 2397.87 1 024.25
,10 ,103 0.26 0.1
Ethiopia Constant b0 Secular trend b1 Change in level b2 Change in trend b3
34 344.78 1874.52 6890.30 4 691.76
1628.84 415.38 2775.57 1257.60
,103 0.01 0.06 0.014
374.50 97.60 837.81 353.94
,103 ,103 0.03 0.3
Lao People’s Democratic Republic 2885.47 Constant b0 Secular trend b1 41.36 240.63 Change in level b2 174.01 Change in trend b3
68.81 17.83 137.80 58.95
,103 0.07 0.141 0.03
Lesotho Constant b0 Secular trend b1 Change in level b2 Change in trend b3
4233.51 92.85 533.97 409.66
140.02 36.23 275.28 118.35
,103 0.05 0.11 0.018
Nepal Constant b0 Secular trend b1 Change in level b2 Change in trend b3
13 818.17 271.14 479.21 226.53
312.82 80.69 594.73 258.36
,103 0.02 0.46 0.42
Nigeria Constant b0 Secular trend b1 Change in level b2 Change in trend b3
35 372.84 2010.50 1 390.30 504.35
2458.41 621.39 3 888.51 1 821.76
,103 0.023 0.73 0.79
Pakistan Constant b0 Secular trend b1 Change in level b2 Change in trend b3
43 395 11 347.53 4089.83 9623.39
9450.58 2 305.97 11 790.51 6 203.19
,103 0.004 0.74 0.18
Rwanda Constant b0 Secular trend b1 Change in level b2 Change in trend b3
4267.02 43.86 222.66 38.33
75.29 19.62 170.69 72.29
,103 0.08 0.25 0.62
Somalia Constant b0 Secular trend b1 Change in level b2 Change in trend b3
7391.12 304.16 203.49 697.54
185.20 48.26 408.13 172.23
,103 0.001 0.64 0.01
United Republic of Tanzania 24 903.93 Constant b0 Secular trend b1 64.83 207.06 Change in level b2 275.07 Change in trend b3
309.69 80.70 683.02 288.24
,103 0.46 0.77 0.38
40 746.91 780.993 2 654.86 407.21
(continued) Coefficient
Standard error
P value
Uganda Constant b0 Secular trend b1 Change in level b2 Change in trend b3
19 315.26 745.24 1 551.17 788.66
292.97 76.35 646.99 273.05
,103 ,103 0.06 0.034
Zambia Constant b0 Secular trend b1 Change in level b2 Change in trend b3
14 913.56 406.05 292.77 487.58
223.24 58.05 469.12 198.67
,103 0.001 0.56 0.06
Zimbabwe Constant b0 Secular trend b1 Change in level b2 Change in trend b3
12 887.55 392.82 2169.45 32.96
1211.49 300.79 1680.99 839.15
,103 0.25 0.25 0.97
P value
DRC Constant b0 Secular trend b1 Change in level b2 Change in trend b3
Kenya Constant b0 Secular trend b1 Change in level b2 Change in trend b3
Table 2
77
3
SSþ TB ¼ sputum smear-positive tuberculosis; b0 ¼ baseline level of study outcome variable at the beginning of the period; b1 ¼ the secular trend, independent of the intervention; b2 ¼ the immediate impact of the intervention; b3 ¼ the change in trend after the intervention; DRC ¼ Democratic Republic of Congo.
the cost per new patient diagnosed through the ACF was more than US$4000 and a dedicated team with a medical doctor and nurses was hired. In other countries, the cost per TB case detected was estimated at around US$800.16 Many strategies to implement ACF have been proposed.17 Regardless of the strategy chosen, all have a cost. According to the WHO, 3 million TB cases are missing; if an ACF strategy is used to reach them, the cost would be more than two billion US dollars. This exceeds by far the capabilities of national and international funders: in comparison, the Global Fund, the world’s primary funder of TB activities, allocated 411 million USD for TB control in 2014, 17% of the funding needed to reach the 3 million missing cases using ACF. In conclusion, ACF projects have had no impact on the number of cases notified at the national level in almost all countries during and after the interventions conducted. ACF projects are pilot studies and are usually difficult to reproduce at the national level due to their high cost and lack of human resources. Acknowledgements This work was presented in part at the 47th Union World Conference on Lung Health, 26–29 October 2016, Liverpool, UK. The authors acknowledge the Agence Fran c¸ aise de D´eveloppement (AFD), which provided funding for open access. Conflicts of interest: none declared.
References 1 World Health Organization. Global tuberculosis report, 2015. WHO/HTM/TB/2015.22. Geneva, Switzerland: WHO, 2015. 2 World Health Organization. Systematic screening for active tuberculosis: principles and recommendations. WHO/HTM/ TB/2013.04. Geneva, Switzerland: WHO, 2013. 3 Raviglione M C, Uplekar M W. WHO’s new Stop TB Strategy. Lancet 2006; 367: 952–955.
78
The International Journal of Tuberculosis and Lung Disease
4 World Health Organization. The Stop TB Strategy. WHO/ HTM/STB/2006.37. Geneva, Switzerland: WHO, 2006. 5 World Health Organization. Implementing the new End TB strategy: the essentials. WHO/HTM/TB/2015.31. Geneva, Switzerland: WHO, 2015. 6 Hinderaker S G, Rusen I D, Chiang C-Y, Yan L, Heldal E, Enarson D A. The FIDELIS initiative: innovative strategies for increased case finding. Int J Tuberc Lung Dis 2011; 15: 71–76. 7 Creswell J, Sahu S, Blok L, Bakker M I, Stevens R, Ditiu L. A multi-site evaluation of innovative approaches to increase tuberculosis case notification: summary results. PLOS ONE 2014; 9: e94465. 8 Eang M T, Satha P, Yadav R P, et al. Early detection of tuberculosis through community-based active case finding in Cambodia. BMC Public Health 2012; 12: 469. 9 Morishita F, Eang M T, Nishikiori N, Yadav R P. Increased case notification through active case finding of tuberculosis among household and neighbourhood contacts in Cambodia. PLOS ONE 2016; 11: e0150405. 10 Pronyk P M, Joshi B, Hargreaves J R, et al. Active case finding: understanding the burden of tuberculosis in rural South Africa. Int J Tuberc Lung Dis 2001; 5: 611–618.
11 Zachariah R, Spielmann M P, Harries A D, et al. Passive versus active tuberculosis case finding and isoniazid preventive therapy among household contacts in a rural district of Malawi. Int J Tuberc Lung Dis 2003; 7: 1033–1039. 12 World Health Organization. Global tuberculosis report, 2014. WHO/HTM/TB/2014.08. Geneva, Switzerland: WHO, 2014. 13 Lagarde M. How to do (or not to do). . . Assessing the impact of a policy change with routine longitudinal data. Health Policy Plan 2012; 27: 76–83. 14 Wagner A K, Soumerai S B, Zhang F, Ross-Degnan D. Segmented regression analysis of interrupted time series studies in medication use research. J Clin Pharm Ther 2002; 27: 299–309. 15 Stop TB Partnership. Improving tuberculosis case detection. A compendium of TB REACH case studies, lessons learned and a monitoring and evaluation framework. Geneva, Switzerland: Stop TB Partnership, 2015. 16 Cambridge Economic Policy Associates. Mid-term evaluation of the TB REACH Initiative. London, UK: Cambridge Economic Policy Associates Ltd, 2013. 17 Golub J E, Mohan C I, Comstock G W, Chaisson R E. Active case finding of tuberculosis: historical perspective and future prospects. Int J Tuberc Lung Dis 2005; 9: 1183–1203.
ACF projects and TB cases at national level
i
RESUME O B J E C T I F : Analyser l’impact des projets de d´epistage actif de la tuberculose (TB) sur le nombre de cas de TB pulmonaire a` microscopie positive (SSþ) notifi´es au niveau national. M E´ T H O D E : Les r´esultats de d´epistage de 16 pays ayant particip´e a` la premi`ere vague du projet TB REACH ont e´ te´ revus. Le rapport mondial de l’Organisation Mondiale de la Sant´e sur la TB, publi´e en 2014, a e´ t´e utilis´e pour collecter les informations sur le nombre de cas de TB SSþ notifi´es au niveau national. Les tendances des notifications ont e´ t´e analys´ees en utilisant un mod`ele de r´egression segment´ee. R E´ S U LT A T S : Une augmentation du nombre de cas de
TB SSþ allant de 3% a` 334% a e´ t´e observ´ee dans les zones d’intervention du projet TB REACH. Il n’y avait pas d’augmentation significative du nombre de cas de SSþ notifi´es au niveau national sauf dans deux pays durant l’intervention (B´enin et Kenya) et dans un pays apr`es l’intervention (Somalie). C O N C L U S I O N : Le projet TB REACH n’a pas eu d’impact sur les cas de TB SSþ notifi´es au niveau national dans pratiquement tous les pays durant et apr`es l’intervention. Les projets de d´epistage actif sont des projets pilotes difficilement reproductibles au niveau national, probablement a` cause de leur cout ˆ e´ lev´e et du manque de ressources humaines. RESUMEN
O B J E T I V O: Analizar la repercusion ´ de los proyectos de busqueda ´ activa de casos de tuberculosis (TB) sobre el numero ´ de casos de TB con baciloscopia positiva (SSþ) que se notifican a escala nacional. M E T O D O S: Se analizaron los resultados de la busqueda ´ de casos en los 16 pa´ıses que participaron en la primera ronda de la iniciativa TB REACH. La informacion ´ sobre numero ´ de casos de TB SSþ a escala nacional se obtuvo del Informe Mundial de Tuberculosis de la Organizacion ´ Mundial de la Salud del 2014. Se aplico´ un modelo de regresion ´ lineal segmentada con el fin de analizar la evolucion ´ de la notificacion. ´ R E S U LT A D O S: Se observo ´ un aumento de los casos TB ´ de la SSþ de 3% a 334% en las zonas de intervencion
iniciativa TB REACH, en casi todos los pa´ıses. No ocurrio´ un aumento notable del numero ´ de casos de TB SSþ que se notifico´ a escala nacional en casi ningun ´ pa´ıs, con la excepcion ´ de dos pa´ıses durante el periodo de la intervencion ´ (Ben´ın y Kenia) y un pa´ıs despu´es de la misma (Somalia). C O N C L U S I O N: La iniciativa TB REACH no tuvo repercusion ´ sobre el numero ´ de casos de TB SSþ notificados a escala nacional en casi ningun ´ pa´ıs durante la intervencion ´ ni despu´es de la misma. Los proyectos de busqueda ´ activa de casos son estudios preliminares, cuya reproduccion ´ a escala nacional suele ser dif´ıcil, debido a los altos costos y la falta de recursos humanos.
