We've all gotten a crash course in the pandemic about viruses and how they can kill us, and how they can be defeated by vaccines.
It turns out viruses can also help us in certain situations... for example, in defeating bacteria that antibiotics have no effect against.
It's combat at a microscope level, a story told by epidemiologist Steffanie Strathdee in The Perfect Predator: A Scientist's Race to Save Her Husband from a Deadly Superbug.
Yes, the husband is Steffanie's, and it took bacteriophages to save him. Hear how in this interview from 2019.