To be considered vaccinated you will need to remain in the US for 14 days after you get vaccinated. The issue is most people don't have a legitimate quarantine plan. Are you alone in your home or only with the people you have travelled with or do you have your own basement suite which will allow you to not have contact with anyone you have not travelled with?
I am travelling with my wife, and yes, we will be alone where we are staying. It's a small guest house on her dad's property. We are also going to be in a rural area where our closest neighbours are a kilometre down the road. We are lucky to have access to an ideal quarantine location.