Breast Milk and Saliva for Postnatal Cyto†megalovirus Screening among Very Low Birth Weight Infants.

Background: The optimal approach to managing postnatal cytomegalovirus disease (pCMV) among very low birth weight (VLBW) infants remains unknown. Methods to facilitate screening are needed.

Objective: Determine whether mother's milk and infant saliva can be used to reliably identify maternal cytomegalovirus (CMV) serostatus and detect infant pCMV acquisition.

Methods: This was a single-center, prospective cohort study of VLBW infants, and their mothers, born between 2017 and 2020. Maternal milk samples were tested for CMV immunoglobulin G (IgG) using a CMV glycoprotein B binding enzyme-linked immunosorbent assay and the results were compared with maternal serum CMV IgG results. Biweekly paired saliva and urine samples were collected from infants born to mothers with positive or unknown CMV serostatus. Saliva samples were tested for CMV DNA by quantitative real-time polymerase chain reaction (PCR) and compared with urine CMV qualitative PCR results obtained from a clinical laboratory.

Results: Among 108 infants without congenital CMV included in the study, 10 (9%) acquired pCMV. Both milk and blood CMV serology results were available for 70 mothers. Maternal milk antibody testing had a sensitivity of 97.2% (95% CI: 85.5-99.9%) and specificity of 91.2% (95% CI: 76.3-98.1%) in establishing CMV serostatus. Paired serially collected saliva and urine samples (n = 203) were available for 66 infants. Saliva PCR had a sensitivity of 30.0% (95% CI: 6.7-65.2%) and specificity of 92.7% (95% CI: 88.1-96.0%) in detecting pCMV acquisition.

Conclusions: Maternal breast milk is a reliable alternative sample to determine CMV serostatus. Serial testing of infant saliva was not adequately sensitive for identifying pCMV acquisition in preterm infants.