Credit: Vera Kratochvil
New research confirms that transfusing leukoreduced, cytomegalovirus (CMV)-seronegative blood products prevents CMV transmission in very-low-birth-weight (VLBW) infants.
The study showed that, with this approach, maternal breast milk becomes the primary source of postnatal CMV infection.
“Previously, the risk of CMV infection from blood transfusion of seronegative or leukoreduced transfusions was estimated to be 1% to 3%,” said Cassandra Josephson, MD, of Emory University School of Medicine in Atlanta, Georgia.
“We showed that, using blood components that are both CMV-seronegative and leukoreduced, we can effectively prevent the transfusion-transmission of CMV. Therefore, we believe that this is the safest approach to reduce the risk of CMV infection when giving transfusions to VLBW infants.”
Dr Josephson and her colleagues described this research in JAMA Pediatrics.
The researchers evaluated 462 mothers and 539 VLBW infants who were admitted to 3 neonatal intensive care units between January 2010 and June 2013.
A majority of mothers had a history of CMV infection prior to delivery (CMV sero-prevalence of 76.2%). The infants were enrolled in the study within 5 days of birth and had not received a blood transfusion at that time.
The infants were tested for congenital infection at birth and again at 5 additional intervals between birth and 90 days, discharge, or death.
Twenty-nine of the infants had CMV infection (cumulative incidence of 6.9% at 12 weeks). Five infants with CMV infection developed severe disease or died.
Although 2061 transfusions were administered to 310 of the infants (57.5%), the blood products were CMV-seronegative and leukoreduced, and none of the CMV infections was linked to transfusion.
Twenty-seven of 28 infections acquired after birth occurred among infants fed CMV-positive breast milk.
Dr Josephson and her colleagues estimate that between 1 in 5 and 1 in 10 VLBW infants who are fed CMV-positive breast milk from mothers with a history of CMV infection will develop postnatal CMV infection.
The American Academy of Pediatrics currently states that the value of routinely feeding breast milk from CMV-seropositive mothers to preterm infants outweighs the risks of clinical disease from CMV.
But the researchers noted that new strategies to prevent breast milk transmission of CMV are needed because freezing and thawing breast milk did not completely prevent transmission in this study.
The team said alternative approaches to prevent breast milk transmission of CMV could include routine CMV-serologic testing of pregnant mothers to enable counseling regarding the risk of infection, closer surveillance of infants with CMV-positive mothers, and pasteurization of breast milk until a corrected gestational age of 34 weeks (as recommended by the Austrian Society of Pediatrics).
In addition, routine screening for postnatal CMV infection may help identify infants who are likely to develop symptomatic disease.
The researchers also said the frequency of CMV infection in this study raises significant concern about the potential consequences of CMV infection among VLBW infants and points to the need for large, long-term follow-up studies of neurological outcomes in infants with postnatal CMV infection.
