Is malaria elimination within reach?

Lancet Infectious Diseases
May 2017 Volume 17 Number 5 p461-562 e128-e165

Is malaria elimination within reach?
The Lancet Infectious Diseases
Published: May 2017

Released on March 24, in ample time for World Malaria Day on April 25, WHO’s A Framework for Malaria Elimination is the first time WHO returns to this significant topic since 2007. Given the launch of this update to the framework it is fitting that the theme for World Malaria Day will ambitiously be “End Malaria for Good”. Within the theme of ending malaria for good there will be particular focus on prevention through the use of insecticide-treated nets and indoor spraying. Prevention has been a significant factor in the reduction of infections and deaths over the past 17 years.

Crucially, WHO has avoided a rigid approach to its framework, acknowledging the need for ongoing revision should new tools and strategies emerge. Pedro Alonso, Director of the Global Malaria Programme, emphasises that the framework does not offer a one size fits all approach; each country is to tailor the interventions to suit local needs. This flexibility is refreshingly pragmatic and stands a greater chance of success.

One tangible gap in the framework is its focus on only two species of the human malaria parasite: Plasmodium falciparum and Plasmodium vivax. The other species (Plasmodium malariae, Plasmodium ovale, and the zoonotic Plasmodium knowlesi) get scant mention. When some species are not factored into the equation it becomes difficult to understand how the ultimate aim of elimination can be achieved. However, taking such a critical view might allow the best to become the enemy of the good. The opening paragraph of the framework lays out why the focus is on P falciparum and P vivax: they pose the greatest threat. And the inclusion of P vivax is a notable advance given this was once considered a neglected parasite.

Nonetheless, the promotion of a strategy that is not comprehensive does risk saving up problems for the future.

To reach the milestones of WHO’s Global Technical Strategy 2016–2030, the pace of progress must be rapidly accelerated. Progress has been particularly difficult in low-income countries. It does not take an inspired leap of imagination to grasp that funding is a limiting factor—in 2015, requirements to support malaria programmes were forecast at US$6·4 billion by 2020, $7·7 billion by 2025, and $8·7 billion by 2030. Thankfully, as noted in the January Editorial in this journal, despite early concerns about the incoming US administration, crucial investment from the USA is likely to be forthcoming, which sends a powerful signal to other partners.

In 2015, when the millennium development goal for malaria was declared met, many stakeholders were at pains to express that this achievement was only the end of the beginning and too soon for any sort of victory celebration. That the framework still focuses on the low-hanging fruit of “areas of low transmission that are progressing to zero” highlights how much there is still to do. Adding to the complexity of the task ahead is the emergence of antimalarial resistance. In this issue, Mallika Imwong and colleagues chronicle the spread of artemisinin-resistant P falciparum in the Greater Mekong subregion. Their worrying conclusion is that elimination of P falciparum malaria from this region should be accelerated while available antimalarial drugs still remain effective. Although not part of the new framework, WHO did release a strategy specific to this region in November, 2016.

A section on innovation and research rounds out the framework, providing a very brief outline of ongoing work. Substantial advances have been made. For example, in this issue Mahamadou Sissoko, Sara Healy, and colleagues report for the first time on the safety and efficacy of a P falciparum sporozoite vaccine in the field. Also, progress is being made in the development of new treatments. Recently online in The Lancet Infectious Diseases, James McCarthy and colleagues and Mihály Sulyok and colleagues reported early trials of a new, long-lasting antimalarial, DSM265. Although clearly at an early stage of development, a new treatment offers some hope that it might be possible to keep pace with the emergence of antimalarial resistance.

A notable addition to the framework is the outlining of the requirements for achieving and maintaining malaria elimination. Included among these requirements is a greater emphasis on health systems. If applied with care, this focus on health systems could have broader benefits than on malaria alone. As with any document aimed at policymakers, the aims (ie, elimination) can seem very ambitious; however, as evident from progress so far, ambition is a strategy that has served the malaria community well.