The authors sequenced the microbial content of wastewater treatment plant samples and related it to SARS-CoV-2 gene copies and community case rates. Genera depleted in infected people, such as Blautia, Dorea and Akkermansia, and expanding pathobionts such as the Ruminococcus gnavus group, tracked case rates, as did bacteria of non-human origin. Bacteria combined with viral gene copies best estimated current cases, while bacteria alone were modestly better at predicting future ones, in a single setting.
Why it is interesting: Wastewater may carry a leading signal beyond viral load, though the evidence is associational and from one setting.