Contributed by: Leslie Choi

Background

In 2016, the WHO commissioned the development of new guidelines for malaria vector control [56] in partnership with the Cochrane Infectious Diseases Group (CIDG) based at the Liverpool School of Tropical Medicine. CIDG contributed eight systematic reviews [[57], [58], [59], [60], [61], [62], [63], [64]] (five de novo, two updates, and one previously published review) that were used to inform the recommendations made in these guidelines.

Examples of challenges

Challenges 2 and 3: Vector control tools are typically public health interventions distributed at a community level. To evaluate efficacy at a community level, appropriate study designs with applicable outcomes are required. The main challenge encountered with these guidelines is how to tailor the guidelines for the correct target audience. Are they for individuals wanting to protect themselves from malaria or for national malaria program planners? Paradoxically, increased protection for some individuals may translate into increased risk for others in the community who are not as well protected. Leading on from this, it is difficult to assess whether the study evidence included in the systematic reviews demonstrates community protection. For example, the systematic review on topical repellents combined studies that distributed the intervention at an individual level and those that distributed at a community level. Therefore, it was unclear if the conclusions drawn from that review were applicable to both contexts.

Challenge 4: Some modelling studies have suggested that poor coverage of vector control tools leads to more harm than good in a community by protecting a few individuals at the expense of the majority. However, these findings were difficult to capture and reconcile with the evidence from RCTs within the Summary of Findings and by extension the Evidence to Decision (EtD) framework.