Mothers of children with SCID should be tested for a virus called Cytomegalovirus, or CMV. Most people have contracted CMV and carry it in their bodies, but it doesn’t affect their health. However, a person with a compromised immune system can get sick from CMV.

CMV is transmitted through breast milk, and other body fluids. If a birth mother wishes to breastfeed the infant, doctors will advise that she not breastfeed until she has been tested for past exposure to CMV. The test checks for CMV antibodies that will be created if the mother was exposed to CMV. The test results require only a few days to come back, and if they are negative, the mother may breastfeed.