Answering in reverse order: Phages were used in the west prior to the advent of antibiotics. They had a repetitional issue then, because our purification metho

Answering in reverse order: Phages were used in the west prior to the advent of antibiotics. They had a repetitional issue then, because our purification methods weren't always great, so phage preparations had both phage and potentially bits of the cell wall of the bacteria they had killed. Bacterial cell walls contain endotoxins, which are potentially quite dangerous. They were largely abandoned in the West because with the advent of antibiotics, a wildly more effective solution to bacterial infections was present. The Cold War meant the Soviet Union had less access, and so needed to continue working on phage research more intensively. There's a lot of work on phages going on in academia - I don't know about the startup world, TBH. I think some of the most promising leads are in combination therapy. It appears that treating with phage can push bacteria back into susceptibility (basically, two selective pressures at the same time), which is a cool idea. But the gap phage has to jump from "Interesting bespoke one-time treatments" to a generalizable treatment is a pretty big one. My expectation at least in the medium term is they'll be supplemental treatments for a few well known conditions where you can maintain phage libraries for them.