Dear Jeff,
Since your cat has all his shots and the outside cat did not touch him, I really do not think you have anything to worry about.
It would be next to impossible for your kitty to catch anything from the outside cat.
So your boy should be fine.
Sincerest best wishes,
Terri
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri