Maternal breast milk is the primary source of postnatal cytomegalovirus infection among very low birth weight infants who undergo blood transfusion, according to study findings in JAMA Pediatrics.
Cassandra D. Josephson, MD, of Children’s Healthcare of Atlanta, and colleagues assessed the risk for postnatal cytomegalovirus (CMV) transmission from transfusion of CMV-seronegative and leukoreduced blood and maternal breast milk among 539 very low birth weight infants born to 462 mothers. Prevalence of CMV among mothers was determined via serologic testing, and nucleic acid testing determined CMV prevalence in transfused blood and breast milk. Infants were followed from birth to 90 days after birth.
Approximately 76% of mothers tested positive for CMV. Of these, 11 tested positive for CMV immunoglobulin M antibody. Two of the 27 mothers who developed postnatal CMV tested positive for CMV IgM. Of the 11 mothers who tested positive for CMV IgM antibody, only two had an infant with CMV.
Twenty-nine infants (5.4%) had CMV. The cumulative incidence of postnatal CMV infection at 12 weeks was 6.9%.
The percentage of longitudinal blood and urine samples with detectable CMV increased from 0.5% at 1 to 3 weeks to 3.2% at 4 to 6 weeks. Approximately 9% of samples had detectable CMV by 10 to 12 weeks.
Approximately 57% of infants received one or more blood transfusions. The overall incidence of transfusion-transmitted CMV among infants was 0% (95% CI, 0-0.9). No CMV infections were linked to transfusion, indicating a CMV incidence of 0% (95% CI, 0-0.3) per unit of CMV-seronegative and leukoreduced blood.
More than 80% of mothers breast-fed at least one of their children. The median duration of breast-feeding was 38 days.
All of the 28 infants with postnatal CMV received maternal breast milk from CMV-seropositive mothers. The mean time from first detection of CMV in maternal breast milk to first detection of postnatal CMV infection in infants was 36 days.
Incidence of CMV among infants fed CMV-positive breast milk was 15.3% at 12 weeks.
Twenty-six of the 189 mothers with CMV-positive breast milk were CMV transmitters; 163 were CMV nontransmitters.
The CMV transmission rate did not differ between infants who received fresh CMV-positive breast milk and those who received frozen or thawed CMV-positive breast milk. The 12-week incidence of infection was 17.6% vs. 11.6%, respectively.
A greater number of breast-feeding days, higher breast milk viral load, and premature rupture of membranes increased risk for CMV infection. Adjusted risk for CMV infection increased as breast milk viral load increased. Infants born to mothers with premature rupture of membranes before delivery had an adjusted risk for CMV infection three times higher than infants of mothers with other indications for preterm delivery.
Premature rupture of membranes was an independent predictor of mother-to-child CMV transmission among CMV-seropositive mothers. Mode of delivery was not associated with transmission.
"Previously, the risk of CMV infection from blood transfusion of seronegative or leukoreduced transfusions was estimated to be 1 to 3%. 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 [very low birth weight] infants," Josephson said in a press release.
Disclosure: Some of the researchers report financial ties with Qiagen and 3Ti.