This book had a few arcs there.
Firstly, a government lab is experimenting with creating viruses that use a type of xeno-nucleic acid that contains some iron compound as its genetic code instead of DNA. This organism proves to be lethal to any form of life. There is a release of it in the lab, and a safety measure is activated that floods it and the surrounding area with nerve agent to kill any potential carriers, but it will not stop the virus itself from spreading by air. One of the characters needs to find out how to stop it.
Another arc had a scientist who was forced by a terrorist group to engineer a virus based on the XNA that produces a modified prion in humans that results in severe brain damage, but not death. I think the terrorists were a primitivist group that desired the end of human civilization.
Another arc involved an expedition to Antarctica, which turns out to house life that is based on the XNA. The reason this life is not present anywhere else is because Earth's magnetic field would normally prove lethal to these organisms, but it is weakest near geothermal hotspots, which Antarctica apparently has.
There's a few chapters where a character is infected with this prion virus (But is eventually cured). Eventually, the characters figure out that both the prion virus and the virus released from the government lab can be stopped by creating a strong magnetic field. The scientist destroys all samples of the prion virus by putting them in an MRI machine. The virus from the beginning is destroyed by nuking the area; the EMP from the detonation is enough to destroy it.
At the end, the big bad ends up injected with a sample of the prion virus left over in the syringe used to inject the other character and is confined to a mental institution after his mind is destroyed.
My guess, although I am not sure, would be that it was published sometime after 2000, maybe even after 2010. It made references to CRISPR as the gene-engineering technique and there is an appendix at the end describing real-life advances in synthetic biology, including how scientists added new "letters" to the genetic alphabet and also created the first synthetic cell.