Valganciclovir treatment in a 6-month-old infant with asymptomatic congenital cytomegalovirus infection and late hearing loss

Role of Valganciclovir in Children with Congenital CMV Infection: A Review of the Literature

BACKGROUND

Cytomegalovirus (CMV) is the most common agent of congenital infection in humans. It is a main cause of neurodevelopmental delay and sensorineural hearing loss in infancy. Since the 2000s, a number of studies have used Valganciclovir as a therapy for children with congenital CMV infection.

METHODS

In order to evaluate the efficacy of Valganciclovir in preventing clinical sequelae and its possible side effects, we performed a review of the published literature. This search was completed via PubMed for manuscripts published from January 2007 to December 2021, combining the MeSH words "Valganciclovir", "Congenital", and "Cytomegalovirus".

RESULTS

A total of 27 articles were included (12 retrospective studies, 4 prospective studies, 1 randomized controlled trial, and 10 case reports). The clinical features were similar to those already described in the literature. The therapeutic protocols used were very different between the various studies included and neonatal antiviral treatments were only moderately effective. The therapy proved to be well-tolerated.

CONCLUSIONS

The quality of the included studies and the sample size were limited due to the rarity of the disease. The use of different therapeutic protocols in terms of starting dates, doses, and durations made it impossible to compare and correctly evaluate the efficacy of the treatments. Randomized controlled trials are needed to establish the correct effective dose with the fewest side effects and the most efficient duration of therapy.

Cytomegalovirus infection during pregnancy: state of the science

Cytomegalovirus is the most common congenital infection, affecting 0.5-2% of all live births and the main nongenetic cause of congenital sensorineural hearing loss and neurological damage. Congenital cytomegalovirus can follow maternal primary infection or nonprimary infection. Sensorineurological morbidity is confined to the first trimester with up to 40-50% of infected neonates developing sequelae after first-trimester primary infection. Serological testing before 14 weeks is critical to identify primary infection within 3 months around conception but is not informative in women already immune before pregnancy. In Europe and the United States, primary infection in the first trimester are mainly seen in young parous women with a previous child younger than 3 years. Congenital cytomegalovirus should be evoked on prenatal ultrasound when the fetus is small for gestation and shows echogenic bowel, effusions, or any cerebral anomaly. Although the sensitivity of routine ultrasound in predicting neonatal symptoms is around 25%, serial targeted ultrasound and magnetic resonance imaging of known infected fetuses show greater than 95% sensitivity for brain anomalies. Fetal diagnosis is done by amniocentesis from 17 weeks. Prevention consists of both parents avoiding contact with body fluids from infected individuals, especially toddlers, from before conception until 14 weeks. Candidate vaccines failed to provide more than 75% protection for >2 years in preventing cytomegalovirus infection. Medical therapies such as cytomegalovirus hyperimmune globulins aim to reduce the risk of vertical transmission but 2 randomized controlled trials have not found any benefit. Valaciclovir given from the diagnosis of primary infection up to amniocentesis decreased vertical transmission rates from 29.8% to 11.1% in the treatment group in a randomized controlled trial of 90 pregnant women. In a phase II open-label trial, oral valaciclovir (8 g/d) given to pregnant women with a mildly symptomatic fetus was associated with a higher chance of delivering an asymptomatic neonate (82%), compared with an untreated historical cohort (43%). Valganciclovir given to symptomatic neonates is likely to improve hearing and neurological symptoms, the extent of which and the duration of treatment are still debated. In conclusion, congenital cytomegalovirus infection is a public health challenge. In view of recent knowledge on diagnosis and pre- and postnatal management, health care providers should reevaluate screening programs in early pregnancy and at birth.

Treatment of late-onset hearing loss in infants with congenital cytomegalovirus infection

OBJECTIVE

To evaluate the effect of antiviral treatment on late-onset hearing loss in infants with congenital cytomegalovirus infection.

DESIGN

The database of all infants who had normal hearing at birth, and treated for late-onset hearing loss was collected. The primary study endpoint was the need for a cochlear implant at the last follow-up visit.

RESULTS

Twenty-one infants met the inclusion criteria. Brain stem-evoked response audiometry testing revealed hearing loss in 35 of 42 ears (83%). Mean age at diagnosis of hearing loss was 7.4 ± 3.7 months and onset of antiviral therapy 10.3 ± 7.8 months. None of the ears showed further deterioration as referred to pretreatment values. Hearing thresholds improved in 29 ears (69%). None of the patients needed a cochlear implant.

CONCLUSIONS

In children with late-onset hearing loss due to cytomegalovirus infection, antiviral treatment appears to prevent further deterioration and produce improvement. Controlled studies are needed to verify this observation.