Pooled Saliva Testing Accurately Detects CMV in Newborns
Saliva-based screening detected congenital cytomegalovirus infection with almost 99 percent sensitivity, per previous research in newborns
Swathi Kodaikal, MSc, holds a master’s degree in biotechnology and has worked in places where actual science and research happen. Blending her love for writing with science, Swathi enjoys demystifying complex research findings for readers from all walks of life. On the days she doesn’t write, she learns and performs Kathak, sings, makes plans to travel, and obsesses over cleanliness.
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A new study recently published in Nature Medicine assessed the implementation of pooled saliva tests for universal screening of congenital cytomegalovirus (cCMV) infection in newborns. According to the findings/results, researchers have successfully introduced pooled saliva PCR tests to screen infants for cCMV infection, demonstrating its potential and feasibility.
The interdisciplinary team included Dana G. Wolf, MD, professor of virology and infectious diseases at the Hebrew University, Jerusalem, and a senior infectious diseases physician at the Hadassah University Hospital; Moran Yassour, PhD, principal investigator in the Department of Microbiology and Molecular Genetics, Faculty of Medicine at the Hebrew University; and Smadar Eventov-Friedman, MD, PhD, director of the Hadassah Department of Neonatology
CMV infection in infants
The most common intrauterine infection, cCMV can lead to neurodevelopmental disabilities, with an average worldwide birth prevalence of 6.4–7 per 1,000 live births. About 20 percent of congenitally infected infants combat neurodevelopmental disabilities, which can be apparent at birth or develop later during childhood. However, almost 90 percent of them are asymptomatic at birth, adding to the significant global cCMV burden.
Current screening methods focus on high-risk cases or those with clinically suspected cCMV but miss many asymptomatic infants with cCMV. Though considered one of the more sensitive techniques, screening dried blood spots using PCR also missed about one-quarter of newborns with cCMV.
Wolf, Yassour, Eventov-Friedman, and their teams explored pooled saliva-based screening in a study conducted in the two Hadassah Medical Center hospitals in Jerusalem, Israel, from April 2022 through April 2023. The study screened 15,805 infants for cCMV infection by pooling their saliva samples and testing them together for 13 months.
Screening pooled saliva samples
Leveraging cCMV’s characteristic high viral load in saliva, the researchers applied the Dorfman pooling method to segregate and assess eight pools of saliva samples using RT-PCR. If the pooled sample was cCMV-negative, all individual samples were considered negative; if cCMV-positive, that pool’s samples were retested individually.
The pooled saliva testing strategy helped screen nearly 94 percent of the newborns in the 13-month period, achieving an empirical efficiency of six and sparing about 83 percent of saliva tests.
cCMV was identified in 54 of the 15,000 infants screened using this method. About 55.6 percent of cCMV-positive infants would have been missed by the current targeted screening methods. The study, therefore, highlights the role and impact of early detection and intervention in mitigating cCMV-associated sequelae and mortality in newborns.
"Congenital cytomegalovirus is the most common intrauterine infection. We were driven by the unmet clinical need to identify all infants with cCMV, including those who are asymptomatic at birth, so that early treatment and monitoring could be delivered to a large proportion of infants who are otherwise not diagnosed,” said Wolf in a recent press release. “Our findings project the wide feasibility and benefits of saliva sample pooling to enhance universal neonatal screening for cCMV. Data derived from the implemented universal screening will serve to define the true burden of cCMV and assess future vaccines.”