Ah, bacteriophages, not general viruses.

Still makes me wonder how dangerous it is and how high the danger of a virus, developed with this technique, not being a phage is.

Depends a lot on the proofreading the scientists did before "deploying" it:

Radical Numerics’ research is really more like a blog post — not only was the study self-published, rather than being vetted by a scientific journal, but it hasn’t even been peer reviewed. Making matters even murkier, the company declined to share clinical information about the patient or the doctors involved with the NYT, citing the proprietary nature of a treatment it hopes to monetize.

Say no more. Is Elizabeth Holmes out of prison now?