RNA is a less stable molecule than DNA — it can be single-stranded, form double strands, self-pair (form loops), react readily with proteins... just difficult to deal with. On top of that, as mentioned, RNAses (enzymes that destroy RNA) are everywhere. Your skin secretes them as an anti-pathogen defense against viral RNA [0]. So do a plethora of other living organisms including single-celled bacteria ubiquitous in the atmosphere and on surfaces.

I haven’t heard of any recent developments — it’s been a decade since I was in grad school and now I build software — but I briefly studied a subcategory of ribozyme called self-splicing group I introns which is where my interest comes from.

[0] https://en.m.wikipedia.org/wiki/Ribonuclease

[1] https://en.m.wikipedia.org/wiki/Group_I_catalytic_intron

> In addition, active RNA degradation systems are a first defense against RNA viruses, and provide the underlying machinery for more advanced cellular immune strategies such as RNAi.

Huh... today I learned. I didn't realise we have such "low-level" immune defences, I always just assumed that the simplest defence we had were antibodies.