By Pesach Benson • September 27, 2026
Jerusalem, 27 September, 2026 (TPS-IL) — A new saliva-testing method could make it easier for hospitals to screen every newborn for a common virus that can cause hearing loss and developmental problems without overburdening laboratories, Israeli researchers found.
The method allows saliva from several babies to be tested together rather than requiring a separate laboratory test for every newborn. In the study, the approach cut the number of laboratory tests required by 83%.
More than half of the babies diagnosed with congenital cytomegalovirus (CMV) in the study would have been missed by standard targeted screening because they appeared healthy and had no obvious reason to be tested.
CMV is a very common virus that usually causes no symptoms in healthy people. It can become a serious concern during pregnancy because the virus can cross the placenta and infect the developing fetus. In some cases, congenital CMV can affect the developing brain and auditory system, causing lasting hearing, developmental or other health problems.
The study, published in the peer-reviewed journal The Lancet Infectious Diseases, was conducted by researchers from the Hebrew University of Jerusalem and Hadassah Medical Center. It was led by Prof. Dana Wolf of Hadassah and the Hebrew University, Prof. Smadar Eventov Friedman of Hadassah and Prof. Moran Yassour of the Hebrew University.
The researchers screened 48,556 newborns between April 2022 and March 2025, representing nearly 95% of babies born at Hadassah Medical Center’s two Jerusalem hospitals during the study period. They identified 176 babies with congenital CMV, or about 3.6 cases per 1,000 newborns.
Under targeted screening, babies are typically tested if they fail a newborn hearing test, show signs that could indicate CMV or have another known risk factor.
That approach would have missed 100 of the 176 babies diagnosed in the study. Although those babies initially appeared healthy, eight later developed moderate to severe signs of congenital CMV during follow-up. Three were found to have hearing loss despite being otherwise asymptomatic, and 11 ultimately received antiviral treatment.
The findings also highlight why passing a routine newborn hearing test does not rule out CMV-related hearing problems. Some babies identified only through universal screening later developed sensorineural hearing loss, caused by damage to the inner ear or auditory nerve, despite initially passing their hearing tests.
Testing More Efficiently
The pooled saliva method was designed to make universal screening more practical for hospital laboratories. Researchers combined saliva samples from several newborns and tested them together. When a pool tested positive, the babies’ samples were tested individually, with positive saliva results confirmed through urine testing.
The approach was adapted from a system the researchers developed to expand COVID-19 polymerase chain reaction (PCR) testing during the pandemic. By pooling samples, the team reduced the number of laboratory tests required by 83% compared with testing every newborn separately.
The study also found that congenital CMV can occur after a mother has previously been infected with the virus. Among 158 cases with known maternal infection histories, 53% followed a non-primary infection, meaning the mother had previously been exposed to CMV, while 47% followed a first infection. The two groups had similar rates of significant symptoms, hearing loss and complications at one year.
Among babies who were completely asymptomatic after their initial evaluation and were followed for one year, hearing and development remained normal during that follow-up period. The researchers noted that longer-term follow-up remains important because some effects of CMV can emerge later.
The study was conducted at Hadassah Medical Center’s two Jerusalem hospitals and did not determine whether universal screening improves long-term outcomes or is cost-effective. It therefore provides evidence that universal screening can detect infections that targeted screening would miss and that pooled testing can reduce laboratory workload. It does not, however, establish whether universal CMV screening should be adopted more broadly.
