I can't find the article I read a month or so ago that indicated a low protection of around 20% compared to vaccinated.

Here's a much older article about the original omicron (quite distinct from the BA.2 descendants we have now): https://www.cdc.gov/mmwr/volumes/71/wr/mm7109e1.htm

> The ARs among household contacts of index patients who had received a COVID-19 booster dose, of fully vaccinated index patients who completed their COVID-19 primary series within the previous 5 months, and of unvaccinated index patients were 42.7% (47 of 110), 43.6% (17 of 39), and 63.9% (69 of 108), respectively.