860: Neonatal surveillance among asymptomatic Zika-exposed infants through 6 months of life.

Abstract

While congenital Zika infection may lead to significant fetal neurologic abnormalities, little is known about the postnatal consequences of Zika exposure to apparently asymptomatic fetuses. Our aim was to examine the postnatal outcomes of infants exposed to maternal Zika infection during pregnancy. This is an ongoing prospective, observational cohort study from a large-scale, county hospital-based prenatal Zika screening program in a southern border state. All women reporting travel to an at-risk region during pregnancy were screened with serum Zika IgM or PCR as appropriate. Infants born to women with laboratory evidence of Zika infection during pregnancy underwent laboratory and comprehensive neurologic evaluation at birth, and were surveyed for developmental milestones and head circumference (HC) measurements at local pediatric clinics. HC measurements were compared using Z-scores to sex-specific reference standards from the World Health Organization (WHO) using a mixed effects repeated measures model. Among 26,789 women screened between March 2016 and July 2017, a total of 55 women with laboratory evidence of probable or confirmed Zika virus infection delivered neurologically intact infants at our hospital. One (1.8%) asymptomatic infant had serologic evidence of probable congenital flavivirus infection. No significant intracranial abnormalities were identified on prenatal or postnatal head imaging (n=55). All infants had normal hearing screens prior to hospital discharge (n=55), and those with dilated eye exams were unremarkable (n=29, 52%). Among 31 female and 24 male infants, there were no significant deviations in available head circumference Z-scores from respective WHO population means over 210 days of life (Figure). Developmental milestones were achieved for infants available for follow-up through 2 months (n=29/52) and 6 months (n=13/41) of life. Asymptomatic infants born to women with probable or confirmed Zika virus infection during pregnancy do not have significant head circumference deviations from population expectations through at least 6 months of life, and no adverse developmental outcomes have been identified in assessed infants to date. These data could be used to support future CDC guidance on evaluation of asymptomatic Zika-exposed infants.