Is This Ethical?

I live in PA, my stepchildren live with my husband and I. Their mother, who just became a licensed RN in December of 2008, lives in Maryland. When they came home this past Sunday, my stepdaughter complained of pain in her right arm. When we asked her what was wrong, she said that before leaving the house that morning, her mother gave her three shots, one for the flu, one for pneumonia, one for HPV. My step son, about 1/2 an hour later, came into the room, also complaining that his arm was sore from shots. I asked him if they'd gone to the doctor, he replied, "NO! My mom is an RN, she can buy the shots from the hospital and give them to us at home." My question to you is, IS THIS ETHICAL? Is it legal? Can you 'buy' your vaccinations at your place of work and give them at home without a doctor's orders? I have looked a bit on the internet, and especially with the HPV vaccination, it says that a doctor has to administer it, and it's a series of three shots. Something about this whole thing doesn't sit right with me. I thought I'd throw it out there to the professionals. Any advice?