I don't give it to either Sophie or Ivan. I don't board them at all and even when they go to the groomers I have it arranged that they are the last appt. of the day and are never in a kennel. My dogs stay in my arms until I hand one over to the groomer. The groomer calls me 10 min. before she's done so I get there just as she finishes! It pays to tip your groomer well.
It's similar to like our flu shot. Sometimes they can get sick from it. I figure one less chance of a reaction, especially if they don't need it. PS: This is my PERSONAL choice. My Vet recommends it. I decline.