Minimizing the incidence of hearing loss in children- the case for universal screening for newborns
The World hearing Day is held every year on the 3rd of March to help raise awareness about hearing problems and how best to prevent deafness, as well as encourage innovative treatment methods and technologies to help individuals deal with hearing impairment.
Studies have shown that many factors which contribute to hearing loss may start before birth and as high as ~ 60% of cases of hearing loss in children can be avoided. Therefore, with the right diagnosis and treatment, children with hearing impairment can have a better chance of growing up without a hearing disability.
A leading cause of hearing loss in new-borns is through an infection with a common virus, namely the congenital cytomegalovirus (cCMV) which can also cause neurodevelopmental delays, vision loss, and other symptoms. The majority of babies infected with cCMV are usually asymptomatic, while 10-15% of infected babies show symptoms at birth, and the remaining escape early diagnosis and intervention. However, as much as 5-25% of infected babies develop symptoms in subsequent years as they grow into adulthood.
Therefore, a universal cCMV screening of all neonates has been recommended by an international committee, but to date has not been implemented in any country.
Considering the lack of standardized procedures for the detection of congenital cytomegalovirus and the associated complications this infection can cause, a team of researchers led by Prof. Katrin Neumann from the University of Münster in Germany, and Dr. Khalid Shahada from Hamad Medical Corporation in Qatar, conducted a joint study funded under Qatar National Research Fund’s National Priorities Research Program titled, “Prevalence, determination and management of neonatal human cytomegalovirus infections and development of an identification, follow-up, and intervention program for associated hearing loss,”(NPRP7-1845-3-480).
The study examined the prevalence of cCMV infection in Qatar and Germany, and the feasibility of introducing a universal cCMV screening and follow-up program. Under this project, more than 12,000 newborns, half from Germany and half from Qatar, received the cCMV screening, in which saliva from mucosa swabs was tested for viral DNA (deoxyribonucleic acid). Newborns who failed the cCMV hearing screening, as confirmed by detection of cCMV DNA in saliva swabs blood or urine test, qualified for enrolment in a long-term follow-up program.
Among the tested infants, four were found to be symptomatic including one infant who was symptomatic at birth and would have been detected without any form of screening. Another child had congenital hearing loss, which was identified by the cCMV screening but also by newborn hearing screening, whereas one baby from Germany developed late-onset hearing loss and additional symptoms in the first year of life.
Based on the results, the first three children received prompt antiviral therapy, treatment with hearing aids, and rehabilitation to help them avoid developing hearing disabilities as they grow up. As for the fourth case, the child showed signs of brain abnormality in cerebral magnetic resonance imaging and continues to be monitored closely to provide the best follow-up care.
Moreover, the results also showed that 0.32 per 1000 infants in the sample showed symptoms typical of cCMV infection at birth or later. Screening and a three-year follow-up program to date have identified 0.24 of the 1000 newborns who developed hidden or late-onset symptoms, who were treated in a timely manner or required further surveillance due to hidden symptoms. Hence, based on the outcomes of this project, universal neonatal cCMV screening is advisable and a necessary step towards ensuring higher standards of infant care and health.
Moreover, the research team took a step further to minimize the concerns and worries of the parents whose children remain asymptomatic throughout life. They have successfully developed a screening algorithm that classifies infected infants according to low and high risk for late-onset cCMV symptoms. While the study was conducted in Qatar and Germany, its findings make a strong case for the implementation of universal cCMV screening to ensure all newborns are tested for the infection to help them avoid health complications including hearing loss as they grow up and live a healthy life.