Sick parents and relatives around newborn

My wife and I had our first son born on the 19th and our parents visited us in the hospital. My dad was sick and my mom had the flu and neither bothered to tell us before coming to the hospital. My parents want to come bring us presents for Christmas now. How do I ask/tell them nicely about the sickness and that they can't come around him if they are sick?My 8 year old niece was diagnosed with RSV & an upper respiratory and I know my dad and step mom were around her for Christmas. I'd like to ask them to wait to see the baby if they were around her. Is that necessary or if I ask them to wash their hands..is that enough?Thanks... via /r/Parenting http://ift.tt/2CfuQ3L