Estimates of congenital cytomegalovirus-attributable infant mortality in high-income countries: A review.

As many as 5%-10% of infants with symptomatic congenital cytomegalovirus (cCMV) disease, or 0.4%-0.8% of all liveborn infants with cCMV infection, die in early infancy in high-income countries. However, estimates are uncertain due to several potential biases that can result from data limitations and study designs. First, infants with cCMV infections who die prior to diagnosis, which usually occurs at 1-4 weeks after birth, may be excluded from both the count of deaths and the denominator of cCMV births, resulting in left truncation and immortal time biases. These 'biases' are features of the data and do not reflect bias on the part of researchers, but understanding the potential existence of threats to validity can help with interpretation of findings. Left truncation of infant deaths occurring prior to diagnosis of cCMV can result in understatement of the burden of infant deaths due to cCMV. Conversely, overestimation of infant deaths associated with symptomatic cCMV may occur in clinical case series owing to greater representation of relatively severely affected infants owing to ascertainment and referral biases. In this review, we summarise the characteristics of 26 studies that reported estimates of cCMV-associated infant deaths, including potential biases or limitations to which those estimates may have been subject. We discuss study designs whose implementation might generate improved estimates of infant deaths attributable to cCMV. More complete estimates of the overall public health impact of cCMV could inform current and future screening, prevention, and vaccine research.

Newborn congenital cytomegalovirus screening and hearing outcomes: a systematic review of current literature.

PURPOSE OF REVIEW: The purpose of this review is to summarize the very recent literature surrounding hearing outcomes of children with congenital cytomegalovirus (cCMV) detected through systematic screening programs. RECENT FINDINGS: There are several different approaches to cCMV screening including forms of targeted vs. universal screening of newborns as well as maternally-derived prenatal testing. However, many studies fail to document hearing-related outcomes both in the newborn period and further into childhood when late-onset sensorineural hearing loss (SNHL) can occur. This systematic review included studies of neonates screened for cCMV reporting hearing outcomes for at least one point in time. Hearing targeted screening appeared the most widely reported for detection of unilateral and bilateral SNHL in those with cCMV. A few studies examined these clinical findings in relation to antiviral treatment. SUMMARY: Congenital CMV is an important and common cause of childhood hearing loss. Newborn screening programs may expand opportunities for early diagnosis and treatment of the infection and its sequelae.

Autism Spectrum Disorder Diagnoses and Congenital Cytomegalovirus.

OBJECTIVE: To examine the association between congenital cytomegalovirus (cCMV) and autism spectrum disorder (ASD) administrative diagnoses in US children. METHODS: Cohort study using 2014 to 2020 Medicaid claims data. We used diagnosis codes to identify cCMV (exposure), ASD (outcome), and covariates among children enrolled from birth through ≥4 to <7 years. Covariates include central nervous system (CNS) anomaly or injury diagnosis codes, including brain anomaly, microcephaly within 45 days of birth, cerebral palsy, epilepsy, or chorioretinitis. We used Cox proportional hazards regression models to estimate hazard ratios and 95% confidence intervals, overall and stratified by sex, birth weight and gestational age outcome (low birth weight or preterm birth), and presence of CNS anomaly or injury. RESULTS: Among 2 989 659 children, we identified 1044 (3.5 per 10 000) children with cCMV and 74 872 (25.0 per 1000) children with ASD. Of those with cCMV, 49% also had CNS anomaly or injury diagnosis codes. Children with cCMV were more likely to have ASD diagnoses (hazard ratio: 2.5; 95% confidence interval: 2.0-3.2, adjusting for birth year, sex, and region). This association differed by sex and absence of CNS anomaly or injury but not birth outcome. CONCLUSIONS: Children with (versus without) cCMV diagnoses in Medicaid claims data, most of whom likely had symptomatic cCMV, were more likely to have ASD diagnoses. Future research investigating ASD risk among cohorts identified through universal cCMV screening may help elucidate these observed associations.