I don't know who they got to write this press release, but it sounds like a public relations announcement not a scientific article. Anyhow, the first study boils down to this-
The scientists found that more diversity in the human gut microbiota may enable more robust immune responses to the Typhoid vaccine.In the second study-
The scientists found that those macaques that showed high diversity in their gut microbiota were more resistant to Shigella infection than those with lower diversity.And their conclusion:
These studies find that higher diversity in the gut microbiota, i.e., more types of bacteria in the gut, affect the characteristics and magnitude of immune responses to vaccines and infections.They don't say this, but I'm assuming this means antibiotics contribute to this adverse effect, and there is quite a bit of evidence for that.
Their solutions to acute disease causes chronic disease.