I did a quick search and there are numerous studies that come up. I haven’t analyzed them myself, but it seems like there is a lot of evidence for this (example

I did a quick search and there are numerous studies that come up. I haven’t analyzed them myself, but it seems like there is a lot of evidence for this (example https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8956107/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8956107/). I also found various things written about covid living in the mouth and playing a role in transmission.