Yep, but then they go on to make the credulous woo-woo argument. None of us know what the actual results are here (since this is a conference talk, translated by a reporter), so I can only work with what they say.
In any well-done study with an effective treatment, you'd expect, a priori, that a reduction in intervention produces a reduction in effect. In other words, you don't benefit if you don't get the drug.
The article is actually silent on whether the mortality effect was reduced, or whether the study was powerful enough to reliably detect that the mortality effect was reduced in lower-vaccinated communities. It just says the effect "was documented" in those communities, not whether it was exactly as strong.
In any well-done study with an effective treatment, you'd expect, a priori, that a reduction in intervention produces a reduction in effect. In other words, you don't benefit if you don't get the drug.