The question is how hard is to pick good control communities. During the pandemic I've read a lot of preprints about cures for covid-19 (like Ivermectin) and many of them used a similar aproach. It looks very hard. I've seen too many bad results with this kind of controls. Double blind randomized controled trial or it didn't happen.
We already did the RCT and saw that the incidence of severe malaria was reduced.
Now we've done an actual rollout, and have seen in observational data a bigger reduction in all-cause mortality than we expected. It's relatively high quality observational data, but of course the risk of confounds is larger than the RCT.
