Importance: The sensitivity of dried blood spots (DBS) to identify newborns with congenital cytomegalovirus (cCMV) infection has not been evaluated in screening studies using the current, higher-sensitivity methods for DBS processing. Objective: To assess the sensitivity of DBS polymerase chain reaction (PCR) for newborn screening for cCMV infection using saliva as the reference standard for screening, followed by collection of a urine sample for confirmation of congenital infection. Design, Setting, and Participants: This population-based cohort study took place at 5 newborn nurseries and 3 neonatal intensive care units in the Minneapolis/Saint Paul area in Minnesota from April 2016 to June 2019. Newborns enrolled with parental consent were screened for cCMV using DBS obtained for routine newborn screening and saliva collected 1 to 2 days after birth. Dried blood spots were tested for CMV DNA by PCR at both the University of Minnesota (UMN) and the US Centers for Disease Control and Prevention (CDC). Saliva swabs were tested by CMV DNA PCR at the UMN laboratory only. Newborns who screened positive by saliva or DBS had a diagnostic urine sample obtained by primary care professionals, tested by PCR within 3 weeks of birth. Analysis began July 2019. Exposures: Detection of CMV from a saliva swab using a PCR assay. Main Outcomes and Measures: Number of children with urine-confirmed cCMV and the proportion of them who were CMV positive through DBS screening. Results: Of 12554 individuals enrolled through June 2019 (of 25000 projected enrollment), 56 newborns were confirmed to have cCMV (4.5 per 1000 [95% CI, 3.3-5.7]). Combined DBS results from either UMN or CDC had a sensitivity of 85.7% (48 of 56; 95% CI, 74.3%-92.6%), specificity of 100.0% (95% CI, 100.0%-100.0%), positive predictive value (PPV) of 98.0% (95% CI, 89.3%-99.6%), and negative predictive value (NPV) of 99.9% (95% CI, 99.9%-100.0%). Dried blood spot results from UMN had a sensitivity of 73.2% (95% CI, 60.4%-83.0%), specificity of 100.0% (100.0%-100.0%), PPV of 100.0% (95% CI, 91.4%-100.0%), and NPV of 99.9% (95% CI, 99.8%-99.9%). Dried blood spot results from CDC had a sensitivity of 76.8% (95% CI, 64.2%-85.9%), specificity of 100.0% (95% CI, 100.0%-100.0%), PPV of 97.7% (95% CI, 88.2%-99.6%), and NPV of 99.9% (95% CI, 99.8%-99.9%). Saliva swab results had a sensitivity of 92.9% (52 of 56; 95% CI, 83.0%-97.2%), specificity of 99.9% (95% CI, 99.9%-100.0%), PPV of 86.7% (95% CI, 75.8%-93.1%), and NPV of 100.0% (95% CI, 99.9%-100.0%). Conclusions and Relevance: This study demonstrates relatively high analytical sensitivity for DBS compared with previous studies that performed population-based screening. As more sensitive DNA extraction and PCR methods continue to emerge, DBS-based testing should remain under investigation as a potential low-cost, high-throughput option for cCMV screening..
Bibliographical noteFunding Information:
Ms Rosendahl, and Mr McCann reported grants from the US Centers for Disease Control and Prevention (CDC) during the conduct of the study. Dr Sidebottom reported grants from University of Minnesota during the conduct of the study. Dr Schleiss reported grants from CDC, National Institutes of Health, and University of South Carolina’s Disability Research and Dissemination Center (DRDC) during the conduct of the study; and personal fees from Moderna Vaccines, Sanofi Vaccines, GlaxoSmithKline Vaccines, and Merck Vaccines outside the submitted work. No other disclosures were reported.
Funding/Support: Funding for this study was provided by the US Centers for Disease Control and Prevention (CDC), the National Vaccine Program Office, the Minnesota Department of Health Newborn Screening Program, and the University of South Carolina Disability Research and Dissemination Center (DRDC) through its cooperative agreement (6U19DD001218) with CDC. Financial support for this study was provided by the CDC, Minnesota Department of Health, the National Vaccine Program Office (US federal government), and the University of South Carolina Disability Research and Dissemination Center.
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