In this article, Bloomberg claims that undisclosed manufacturing changes at one of the largest producers of anti-malaria bednets have led to distribution of hundreds of millions of ineffective (or less-effective) bednets, and that this problem is linked to an increase in malaria incidence in the places where these nets were distributed.
The manufacturer is Vestergaard and the Against Malaria Foundation is among their clients.
Bloomberg has a steep paywall but the link here gives free access until March 2.
Hi Ian, thanks for sharing this article – our team wrote up some notes on how this topic intersects with our work, and I (Isabel Arjmand writing on behalf of GiveWell) thought it might be useful to share here.
Like the Bloomberg editorial board, we're concerned about stalling progress in the fight against malaria, but we're skeptical that quality issues with PermaNet 2.0s have influenced this progress as much as the article suggests.
All things considered, we believe that malaria nets are, and have been, highly effective in reducing malaria burden. The Against Malaria Foundation had first shared the studies highlighted above with us in 2020, and the claims in the Bloomberg article have prompted us to do some additional research.
Based on the work we've done so far, we aren't convinced that decreased net quality is primarily responsible for malaria resurging in Papua New Guinea. So far, we see this as a milder negative update on nets than the article would indicate, in part because we think these tests of net quality may not be a perfect proxy for effectiveness in reducing cases and in part because we no longer fund PermaNet 2.0s (for unrelated reasons). At the same time, renewed interest in the evidence around PermaNet 2.0 quality is a nudge for us to prioritize further work to understand net quality control in general.
More detail on the implications of this research for GiveWell's work
While we no longer fund PermaNet 2.0s because we now fund newer types of nets instead, they make up roughly 20% of nets we've funded historically. The studies referenced in the Bloomberg article looked at nets distributed in Papua New Guinea and indicate that the post-2012 PermaNet 2.0s perform worse on certain efficacy tests. We aren't sure how well those efficacy tests serve as a proxy for malaria transmission (e.g. mosquitoes in these tests could be impaired from the exposure to insecticides even if it isn't sufficient to kill them). We're also skeptical that changes to the formulation of PermaNet 2.0s were the key driver of increased malaria cases in Papua New Guinea. During this time, we think other factors like insecticide resistance and shifts in biting patterns likely played a meaningful role (as highlighted in this paper). That said, we see these studies as a negative update on the effectiveness of those nets.
We did a quick back-of-the-envelope calculation (so this is more illustrative than fully baked, at this point):
While concerns specific to PermaNet 2.0s don't directly affect our future allocation decisions, this issue does raise more general concerns about quality control for nets. Ideally, we would have prioritized more work in this area in the past. We're planning to learn more about quality control processes and we also want to better understand how others in the malaria field are thinking about this.