One thing that parents often forget, is that the parents are the ones bringing the viruses home to their children and daycare providers in the first place. All these illnesses walk into my house with the families I work for. None of us can live in a bubble. And I bet that you kiss your child as much and as often as you can. It's just a fact of life. I do understand your concerns though.
In interest of limiting the exposures... Does your daycare have air purifiers? Do you run air purifiers at home? Are you using only purified water for bottles? Is the daycare? Maybe you can suggest to the daycare workers that they take the vitamin and herb supplements that are meant to strengthen their immune systems.
I take cleanliness, air purification and nutrition extremely serious in my daycare. I only care for 4 children on each shift 7 days per week/24 hours per day. Even with all my kiddos on all shifts, it's still a lot less than a daycare center. But we do get the viruses and pass them around. I never kiss my daycare kiddos for cleanliness issues. But it doesn't help. I'm always frustrated too. But it doesn't change anything. I use bleach in my dishes and wash out the cribs and blankets constantly.
Suzi