Regence Blue Cross,mariners Why Is Walgreen's Charging Insured People For The H1N1 Vaccine?

Why is Walgreen's charging insured people for the H1N1 Vaccine? - regence blue cross,mariners

I have insurance through my employer with Regence Blue Shield / Blue Cross. I recently went into business with my local Walgreen's to be vaccinated against the H1N1, but they said they would pay up to $ 18. They said they could not bill Medicare (the elderly, are not likely to need) the vaccine. I'm 27 and I'm obviously not old enough for Medicare. Why do places like the village are available to shoot if it your responsibility to bill insurance companies, especially large because Regence? Walgreen bills directly to insurance for prescription drugs, if it seems very strange that it is not bill insurance companies for vaccines against flu.