Western Australian researchers have called for a national targeted newborn screening program to identify babies who may have a virus which can lead to permanent hearing loss.
Congenital cytomegalovirus (CMV), which can be acquired by mothers unknowingly during pregnancy, occurs in half to one per cent of the approximately 300,000 babies born in Australia every year – around 3,000 cases every year.
About 90 per cent of those who get congenital CMV will remain asymptomatic, but for the 10 per cent who are more seriously affected – around 300 babies a year – it can cause progressive and permanent hearing loss and, for some, intellectual disability, or cerebral palsy.
Associate Professor Asha Bowen, a paediatric infectious diseases researcher and specialist at The Kids Research Institute Australia and Perth Children’s Hospital, said congenital CMV was a leading cause of developmental disability and a common cause of permanent hearing loss in infants – yet few mums or maternity healthcare professionals were aware of it.
“This virus is having a profound impact on the lives of hundreds of Australian children every year, but most cases go undiagnosed because it’s simply not widely recognised and there’s no organised approach to testing within the ideal window to pick it up – the first three weeks of life,” Associate Professor Bowen said.
A handful of hospitals across Australia do routinely test for congenital CMV, but it is by no means uniform. A national approach is essential to make sure we’re getting in early enough to give these children the support they and their families need.
In a paper published in the Medical Journal of Australia, Associate Professor Bowen and a team of researchers – led by University of Western Australia Masters student and Perth Children’s Hospital ear nose and throat registrar Dr Allison Reid – have called for every baby who fails the newborn hearing test shortly after birth to be targeted for congenital CMV testing. This could be done via a simple and inexpensive polymerase chain reaction (PCR) test of saliva or urine.
“The sooner we can pick up congenital CMV the better – early diagnosis is crucial so we can get kids into routine follow-up, audiology, speech and language development support and on a pathway to a cochlear implant if appropriate,” Associate Professor Bowen said.
“Making an early diagnosis of congenital CMV means we can also assess and monitor them for other potential impacts that we otherwise may not go looking for.”
Associate Professor Bowen said while congenital CMV could be detected further down the track from the Guthrie heel prick tests undertaken on every baby soon after birth, not all states kept these tests long term – meaning many families may never know for sure what caused their child’s hearing loss or developmental disability.
There are kids out there who may have progressive hearing loss through their toddler and primary school years that is likely caused by congenital CMV – but if they live in a place where newborn cards aren’t kept for a long time, you can’t go back later and find whether that’s the cause.
A trial currently being undertaken at PCH, led by Dr Reid, is assessing the feasibility and cost-effectiveness of targeted congenital CMV testing for newborns. Any infant who does not pass the newborn hearing test will be offered testing for CMV with the saliva test.
The full paper, Congenital cytomegalovirus: the case for targeted infant screening in Australia, was published in the Medical Journal of Australia. A discussion of the paper’s findings can be read in MJA Insight+.
For more information on congenital CMV, see our article, A virus all pregnant women should know about, here.