The incidence rate ratios of COVID-19 are impacted by vaccination status.
Published January 28, 2022:
[0] https://www.cdc.gov/mmwr/volumes/71/wr/mm7105e1.htm
> All incidence and hospitalization rate ratios exceeded 1, regardless of predominant variant, indicating that the risks were consistently highest for unvaccinated persons and that COVID-19 vaccines were protective against SARS-CoV-2 infection and COVID-19–associated hospitalization among fully vaccinated persons, and most protective among those with a booster.
Published 2/2/2022
[1] https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/...
This one shows a nice breakdown of the incidence rate ratio among age groups and similar.
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What does this have to do with community transmission?
[1] If you aren't infected, you aren't spreading the disease
[2] A lower transmission rate equates to lower community spread all else equal (as someone identified earlier, Jevon's paradox could come to head)
[3] The lower IRR is a lower propensity (or, if you prefer, a lower R_t) between the two groups.
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This matches what I see in my regional reporting; the IRR is significantly different between the two groups. In my area (a red state in the US) behaviors are mostly back to pre-pandemic levels of behavior, so it is reasonable to conclude that the IRR in my area is representative of life following any COVID-19 protocols being relaxed.