Lymphatic filariasis is a vector-borne neglected tropical disease that causes damage of the lymphatic system and can lead to lymphoedema (elephantiasis) and hydrocele in infected individuals. The global baseline estimate of persons affected by lymphatic filariasis is 25 million men with hydrocele and over 15 million people with lymphoedema. At least 36 million persons remain with these chronic disease manifestations. The disease is endemic in 72 countries. In 2016, an estimated total population of 856 million were living in areas with ongoing transmission of the causative filarial parasites and requiring mass drug administration (MDA).² Lymphatic filariasis disfigures and disables, and often leads to stigmatization and poverty. Hundreds of millions of dollars are lost annually due to reduced productivity of affected patients. WHO has ranked the disease as one of the world’s leading causes of permanent and long-term disability.

In 1997, the Fiftieth World Health Assembly resolved to eliminate lymphatic filariasis as a public health problem. The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched by WHO in 2000 with the goal to achieve global elimination of the disease as a public health problem by 2020. The comprehensive elimination strategy promoted by GPELF comprises annual MDA to achieve interruption of transmission, and morbidity management and disability prevention to prevent and alleviate the suffering of affected individuals.

Since 2000, annual coverage of MDA has expanded from 3 million people in 12 countries to 6.7 billion cumulative treatments delivered to over 850 million persons in 66 of the 72 countries where the disease is known to be endemic. At least 20 (28%) endemic countries are now under post-MDA surveillance to demonstrate that elimination has been achieved. Despite progress, 22 of 52 (42%) endemic countries requiring MDA have not started MDA in all of their endemic implementation units. Additionally, some countries that have completed five effective MDA rounds are now grappling with suboptimal assessment results. Clearly, global elimination by 2020 will not be achieved using the existing regimens. This guideline therefore serves as a response to countries that have requested WHO to devise alternative regimens to realign their national programmes towards elimination by 2020.

The guideline was developed in accordance with the procedures established by the WHO Guidelines Review Committee and the WHO handbook for guideline development published in 2014. A WHO steering committee was formed to develop the PICO (population, intervention, comparator and outcome) questions and the scope of the guideline. A guideline development group reflecting diverse areas of expertise, multiple geographical regions and gender balance was formed and contributed to the refinement of the PICO questions. A systematic review team was externally commissioned to conduct a systematic review, meta-analysis and critical appraisal of the evidence.

At a meeting of the guideline development group (Geneva, May 2017) the available evidence was carefully reviewed and recommendations were formulated based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Two alternative regimens for MDA to eliminate lymphatic filariasis were considered: (i) a three-drug regimen (ivermectin, diethylcarbamazine and albendazole) instead of the current two-drug regimens (diethylcarbamazine and albendazole or ivermectin and albendazole); and (ii) biannual MDA with the current two-drug regimens, and albendazole instead of annual MDA with the same regimens. The assessment of the evidence included the priority of the problem, benefits and harms, certainty and quality of the evidence, resource implications, equity, acceptability and feasibility.¹ Based on the evidence appraised during the meeting, recommendations for alternative regimens were formulated for different epidemiological and technical situations (Table 1). The final guideline was reviewed by the WHO steering committee, the guideline methodologist, the guideline development group and the peer reviewers before submission to the WHO Guidelines Review Committee.

Table 1

WHO recommendations on alternative MDA regimens to eliminate lymphatic filariasis.

Chapters 1 and 2 provide the context for the justification of alternative regimens and the methodology and process for developing the guideline using the GRADE approach. Chapters 3 and 4 outline the recommendations of the guideline development group, the details of the GRADE approach and the evidence to decision process employed in the formulation of the recommendations. Chapter 5 details WHO’s plan to disseminate, implement, and monitor and evaluate the guideline.

Footnotes

2

Global programme to eliminate lymphatic filariasis: progress report, 2016. Wkly Epidemiol Rec. 2017;92:594–607. [PubMed: 28984121]

1

The recommendations contained in this guideline were made independently of the donation potential of the various antifilarial medicines.