Newborn Congenital Cytomegalovirus Screening Based on Clinical Manifestations and Evaluation of DNA-based Assays for In Vitro Diagnostics

Droplet Digital PCR (ddPCR) Does Not Enhance the Sensitivity of Detection of Cytomegalovirus (CMV) DNA in Newborn Dried Blood Spots Evaluated in the Context of Newborn Congenital CMV (cCMV) Screening

Congenital cytomegalovirus (cCMV) infection is a leading cause of sensorineural hearing loss (SNHL) and neurodevelopmental disabilities in children worldwide. Some regions in the United States and Canada have implemented universal newborn screening for cCMV, which requires molecular diagnostic technologies for identifying cCMV, such as PCR testing of newborn dried blood spots (DBS). This study aimed to evaluate the sensitivity of droplet digital PCR (ddPCR) compared to quantitative real-time PCR to detect CMV DNA in newborn DBS. The limit of detection of various ddPCR primer/probe combinations (singleplex UL55-HEX, singleplex UL83-FAM, and multiplex UL55-HEX/UL83-FAM) was evaluated using the National Institute of Standards and Technology's (NIST) CMV quantitative standard. Singleplex UL55-HEX ddPCR exhibited the lowest limit of detection among the primer/probe combinations tested for ddPCR. UL55 ddPCR was then compared to real-time PCR in 49 infants with confirmed cCMV identified through newborn screening for CMV in saliva swabs and confirmed by a urine test. The results showed that ddPCR was only positive for 59% (29 out of 49) of the cCMV infants, while real-time PCR was positive for 80% (39 out of 49). Due to its lower sensitivity and throughput, ddPCR may not be suitable for cCMV newborn screening.

Clinical Factors Associated With Congenital Cytomegalovirus Infection: A Cohort Study of Pregnant Women and Newborns

BACKGROUND

The aim of this prospective cohort study was to determine clinical factors associated with the occurrence of congenital cytomegalovirus infection (cCMV) in pregnant women.

METHODS

Between March 2009 and November 2017, newborns born at a primary maternity hospital received polymerase chain reaction (PCR) analyses for CMV DNA in their urine with informed consent of the mothers at a low risk. Clinical data, including age, gravidity, parity, body mass index, occupation, maternal fever/flulike symptoms, pregnancy complications, gestational weeks at delivery, birth weight, and automated auditory brainstem response, were collected. Logistic regression analyses were performed to determine clinical factors associated with cCMV.

RESULTS

cCMV was diagnosed by positive PCR results of neonatal urine in 9 of 4125 pregnancies. Univariate and multivariable analyses revealed that the presence of fever/flulike symptoms (odds ratio [OR], 17.9; 95% confidence interval [CI], 3.7-86.7; P < .001) and threatened miscarriage/premature labor in the second trimester (OR, 6.0; 95% CI, 1.6-22.8; P < .01) were independent clinical factors associated with cCMV. Maternal fever/flulike symptoms or threatened miscarriage/premature labor in the second trimester had 100% sensitivity, 53.2% specificity, and a maximum Youden index of .85.

CONCLUSIONS

This cohort study for the first time demonstrated that these clinical factors of pregnant women and newborns were associated with the occurrence of cCMV. This is useful information for targeted screening to assess risks of cCMV in low-risk mothers, irrespective of primary or nonprimary CMV infection.

Clinical Diagnostic Testing for Human Cytomegalovirus Infections

Human cytomegalovirus (HCMV) infections are among the most common complications arising in transplant patients, elevating the risk of various complications including loss of graft and death. HCMV infections are also responsible for more congenital infections worldwide than any other agent. Congenital HCMV (cCMV) infections are the leading nongenetic cause of sensorineural hearing loss and a source of significant neurological disabilities in children. While there is overlap in the clinical and laboratory approaches to diagnosis of HCMV infections in these settings, the management, follow-up, treatment, and diagnostic strategies differ considerably. As yet, no country has implemented a universal screening program for cCMV. Here, we summarize the issues, limitations, and application of diagnostic strategies for transplant recipients and congenital infection, including examples of screening programs for congenital HCMV that have been implemented at several centers in Japan, Italy, and the United States.