Children with "bubble boy" disease are believed to have the best chance of survival if they undergo a hematopoietic stem cell transplant as soon after birth as possible.

The findings suggest newborn screening for severe combined immune deficiency (SCID) should be expanded, the Dana-Farber Cancer Institute reported. The disorder leaves infants so vulnerable to infection they usually die within the first year of life if left untreated.

The study, published today in the New England Journal of Medicine, looked at 240 children who received SCID transplants before newborn screening was recommended by the U.S. Department of Health and Human Services in 2010.

The researchers found patient age and status of infection at time of transplant had the strongest effects on outcomes.

"Survival is much, much better if infants undergo transplant before they turn 3 [and a half] months old and before they contract any SCID-related infections," said study first author Sung-Yun Pai, MD, of Dana-Farber/Boston Children's. "The best way to identify patients that early when there is no family history of SCID is through newborn screening."

Data acquired through newborn screenings suggest SCID is twice as common as once believed, although it is still really rare. Many newborns who died from "unexplained infections" in the past most likely suffered from SCID. The disorder is believed to occur in one in every 50,000 births; this is up from a previous estimate of one in 10,000.

"Time is not the ally of children with SCID," said Luigi Notarangelo, MD, of Boston Children's Hospital, one of the study's senior authors, who was among those who lobbied successfully to establish SCID newborn screening in Massachusetts in 2009. "Because they do not have a functional immune system, the longer the wait before a transplant the greater the risk they will contract a potentially devastating infection."