Is deployement of diagnostic test alone enough? Comprehensive package of interventions to strengthen TB laboratory network: three years of experience in Burkina Faso

The laboratory plays a critical role in tuberculosis (TB) control by providing testing for diagnosis, treatment monitoring, and surveillance at each level of the health care system. Despite representing an integral part of a continuum of care by providing evidence for decision making in clinical practice, diagnostic servicses are the weakest link in the cascade of care influencing only 60–70% of the healthcare decisions [1]. The diagnostic gap is a common thread of many infectious diseases, but it is much higher for TB [2].

Globally in 2019, there was a gap of about 2.9 millions between the number of incident and notified TB cases in the same year [3]. The missed cases were either not diagnosed or diagnosed but not reported. Despite the development of diagnostic tests able to provide rapid and accurate detection of TB and drug-resistant TB, poor accessibility to the health care system is still a big concern in many settings [4, 5]. In addition, on-field implementation studies have shown that diagnostic tests alone may fail to meet the expected impact on the TB care cascade if not implemented within the context of a strengthened health system [6].

Development of new TB diagnostic, treatment, and prevention tools has increased substantially over the last decades, leading to more than 20 new or updated World Health Organization (WHO) guidelines on different aspects of TB care [3, 7‐9].

As a result of these rapid changes, National TB Programmes (NTP) have experienced difficulties in the prompt adoption and full implementation of TB laboratory policies and strategies [6, 10]. In this context, the WHO plays a crucial role in directing the international public health efforts through the coordination of technical assistance programmes to countries, partnerships, and initiativesaimed at facilitating the translation of policies into practice. The TB Supranational Reference Laboratory Network (SRLN) is a key WHO technical resource in supporting the strengthening of laboratory capacity in high TB burden countries [11].

The Emerging Bacterial Pathogens Unit (EBPU) of the Fondazione Centro San Raffaele part of San Raffaele Scientific Institute of Milan, Italy, was appointed as SRL and as WHO Collaborating Centre for TB laboratory strengthening (ITA-98) in 2006 and 2013, respectively. From 2016 to 2018, the EBPU-SRL Milan, thanks to the United States Agency for International Development (USAID) financial support, has served as a technical partner to the WHO Global TB Program to strengthen the TB diagnostic capacities and to support the Drug-Resistance Surveillance (DRS) activities in selected countries, including Burkina Faso..

The objective of the present study is to determine the impact of implementing a comprehensive package of interventionson the TB laboratory capacity and accessibility in Burkina Faso.

To assess the impact of the development and implementation of TB diagnostic guidelines and the effectiveness of the TA provided by the SRL Milan, we monitored the following five indicators over a three-years timeframe, from 2016 to 20/20:

A total of 5918 and 5839 new and relapse TB cases were notified in 2016 and 2017, respectively. Of them, 3993 (67%) and 4044 (69%) were bacteriologically confirmed through smear microscopy and/or Xpert MTB/RIF (Fig. 2). In 2018, out of the 6166 new and relapse TB cases notified, 4288 (71%) were bacteriologically confirmed through smear microscopy and/or Xpert MTB/RIF (Fig. 2).

The number of new and relapse TB cases notified tested with Xpert MTB/RIF remained stable in 2016 and 2017 with a totale of 1094/5918 (18%) and 1147/5839 (20%) in 2016 and 2017 respectively. Only in 2018, we observed a much higher increase in the number of notified TB cases that received an Xpert MTB/RIF test, up to 2826/6166 (46%) (Fig. 2).

The number of bacteriologically confirmed TB cases with an available DST result for rifampicin increased from 27% in 2016 (1094/3993) to 28% in 2017 (1147/4044) (Fig. 3). Notably, the number of bacteriologically confirmed cases with an available DST result for rifampicin increased up to 66% (2826/4288) in 2018 (Fig. 3).

The number of notified MDR-TB cases (confirmed by Genotype MTBDRplus VER 2.0) over the number of estimated MDR-TB cases increased from 43% (58/136) in 2016 to 47% (63/134) in 2017. In 2018, we observed a much higher increase in the ratio between notified and estimated MDR-TB cases, upt to 78% (102/131).

The utilization of Xpert MTB/RIF test in routine practice has been assessed by calculating the ratio between the number of smear-microscopy and Xpert MTB/RIF tests performed annually. This ratio decreased from 53% (58,510/1105) to 51% (61,755/1200) in 2016 and 2017 respectively. In 2018, the ratio between the number of smear microscopy and Xpert MTB/RIF test substantially decreased down to 21% (59,714/2826).

In this paper, we demonstrated that broader access to diagnostic services requires a comprehensive package of interventions that address multiple needs. This evidence is clearly supported by the improvement of all five indicators we monitored over the three-years timeframe. By the end of 2016, Burkina Faso experienced a 5-time increase in the number of 4-module GeneXpert instruments. This expansion was crucial to decentralize the diagnostic capacity of the country, but still not sufficient to drastically improve the evaluated indicators over a 1 year timeframe (2016–2017). We instead observed a strong improvement of the five indicators by the end of 2018, after the implementation of laboratory guidelines and strategies. Nonetheless, while all of evaluated indicators showed a substantial increase over time, the overall number of new and relapse TB cases that were bacteriologically confirmed showed a smaller change over the two-years timeframe (2016 to 2018). This can be explained by the fact that access to Xpert MTB/RIF testing was initially limited to smear positive patients at high-risk of MDR-TB, to avoid the rapid overload of the network and to promote a more gradual move toward universal DST.

Also the provision of technical assistance played an important role in speeding up the process of increasing diagnostic accessibility. This is shown by the change in the ratio between the number of smear microscopy and Xpert MTB/RIF tests performed. This indicator can be used to monitor how a country moves with regard to Xpert usage when compared to other settings [10, 14]. Between 2017 and 2018, Burkina Faso substantially increased the utilization of GeneXpert over microscopy, which resulted in a 30% decrease of the smear/Xpert ratio. Notably, this process was much faster as compared to other African countries with more experience on Xpert implementation such as Mozambique, Uganda, DR Congo, and Zimbabwe [10].

It is undoubtedly that interventions had a positive effect on the evaluated indicators and external assistance has played a fundamental role in speeding up the TB laboratory system improvement process. However, we acknowledge that additional programmatic factors, other than those evaluated in this work, such as community engagement to promote health seeking behaviours, improved TB communication strategies and support to TB advocacy groups, could have contributed to the improvement of the TB indicators.

The experience of Burkina Faso shows that the country-wise implementation of laboratory guidelines is a requirement to rapidly advance the provision of TB laboratory services. We believe that, the lessons learnt over this three-years timeframe will be useful to other NTPs that aim to achieve concrete goals in strengthening their national TB laboratory networks. One of the key lessons learnt is the need for country commitment. These results could have not been achieved without a strong national commitment as this represents a sine qua non condition to ensure that the planned activities have a continuum on national TB control strategy. Another key lesson learnt is related to the need of building a roadmap of priority interventions guided by a comprehensive analysis that include the country’s epidemic situation, as well as the assessment of financial and, human resources and available network infrastructure. In ou specific context, timing played a crucial role, as Burkina Faso was able to achieve most of its results by conducting this comprehensive analysis and development of key operational plans the year before the Global Fund grant development. This was critical to secure the necessary funding to implement priority activities. Together with this clear activity plan, technical assistance played a key role in boosting the achievement of the obtained outcomes. Importantly, TA needs to be planned in advance with the country and must be provided over an adequate period of time rather than being delivered on-demand or through a single interaction. Supporting countries with a comprehensive package of technical assistance interventions that cover the entire donor’s grant cycle is preferable over a fragmented TA since this helps ensuring continuity while at the same time increasing the pace of change. Estimating TA financial needs is complex. Technical partners must work togehter with the NTP in identifying upfront the country needs for the implementation of the priority activities during the donor’s grant cycle. In this context, TA acts as an intermediary to best align and leverage donor’s and recipient’s needs. Security of funds for external technical assistance has multiple benefits as it allows to work with the same TA provider over a prolonged period of time and, therefore, to build a strong relationship between the partners and facilitate the systematic transfer of skills. Besides the TA plan and secured funding, also the consultant individual capacity and skills in assisting the country is a key factor, as it should promote the establishment of an environment fostering the autonomous development of the country staff rather than a dependency culture.

The experience from Burkina Faso can help outlining some recommendations which may inform countries with similar challenges on future technical assistance interventions to strengthen laboratory system: