CMV is a common viral infection that causes flu-like or no symptoms in healthy people. However, it can cause additional problems for pregnant women, particularly if the infection occurs for the first time during pregnancy, potentially resulting in hearing loss and intellectual disability in newborn babies. The prevalence of CMV worldwide at birth is about 0.64 per cent with 10 to 15 per cent of infants displaying symptoms of the virus at birth.
In Australia, CMV is greatly under diagnosed, said Professor William Rawlinson of the University of New South Wales and South East Area Laboratory Services at the Randwick Hospitals Campus.
"Based on a live birth rate of 285,000 per year in Australia, and a CMV birth prevalence of around 0.64 per cent, the predicted incidence is about 1,800 infected infants per year, which is substantially more than the national rates of 5-25 cases per year we have collected through the Australian Paediatric Surveillance Unit," Prof Rawlinson said.
"Most infected babies will be well. However, about half of the infants who develop disease will be asymptomatic at birth and are unlikely to be identified without screening." About 13.5 per cent (240 per year), will go on to develop permanent problems. In the more severely affected babies who are identified at birth, CMV can be treated with an antiviral therapy if treatment starts before 30 days of age," Prof Rawlinson said.
"With an additional estimated 100 cases symptomatic at birth every year, over 400 children per year may be affected by this disease in Australia, with no routine newborn screening currently in place," Prof Rawlinson said. "With a vaccine having been trialled in the US and Europe, and treatments during pregnancy being further assessed, we need to continue approaching this problem in partnership with all the clinical and community stakeholders involved."
Prof Rawlinson and co-authors call for the cost effectiveness of incorporating congenital CMV screening into neonatal screening tests to be determined, and the potential benefits, including the opportunity for doctors to better diagnose pregnant women with the infection, and prescribe targeted antiviral therapy in infants with hearing loss weighed against issues of cost and availability of timely CMV testing.
The Medical Journal of Australia is a publication of the Australian Medical Association.