CMV vaccine (Cytomegalovirus) a herpes like virus that is latent in a lot of people and can cause neurological problems in newborn infants if they get it from their mothers during birth, which this vaccine aims to prevent that transmission, as I understand it.
I used to give blood every couple of months. I have donated over 6 gallons of the stuff. I am CMV negative. I did not even know just what CMV was. I do not think there was a CMV vaccine in those days. Even if there were, you would hive to give it to the mother to be soon enough.
One day I went into the blood bank and there was a man extremely upset walking around like a chicken with his head cut off. I asked my my technician what his problem was. It seems his wife had just given birth to twins and their blood was incompatible with the kids (maybe it had CMV in it). To oversimplify, they had to have all their blood removed and replaced with blood they were compatible with. They surely do not remove the bad blood and replace it. I happen to be a universal donor (O-negative). When donating to newborns, you must be CMV negative because the newborns’ immune system cannot deal with CMV.
I will never know if his kids got any of my blood or not, but they very well might have.