We keep our three fat cats inside. If they go out, they get a harness put on and are on a leash.
A lot less cats in the area than there use to be - coyotes take way more cats IMHO. Neighbor down the street was feeding the coyotes a few winters back: her cat was fighting it for the piecs of ham ...... LOL. Suggested it wasn't a good idea to encourage them to come close to her home (she is an animal lover). I was sort of shocked her dad hadn't taken the coyotes - he's an avid shooter.
.22 HP short will do the job. If you have enough of a distance buffer to the nearby homes then shoot the fox. Otherwise you don't want your neighbor calling the police on you.

Do you see the fox consistantly or now and then?
Send me a pm if you need more aid.