Can I have the Covid vaccine while on the UTI maintenance antibiotic trimethoprim?

Hi, Gabe!
Probably yes. I used the Interactions Checker for the Moderna vaccine because that's the one I'm most familiar with. No interaction was found with trimethoprim.
If you getting a different vaccine you can use this link:
https://www.drugs.com/drug_interactions.html
You can also ask the doctor/nurse or your pharmacist to be sure.