Cranial US in Infants Exposed to Zika Virus: The NATZIG Cohort.

Background Studies addressing neuroimaging findings as primary outcomes of congenital Zika virus infection are variable regarding inclusion criteria and confirmatory laboratory testing. Purpose To investigate cranial US signs of prenatal Zika virus exposure and to describe frequencies of cranial US findings in infants exposed to Zika virus compared to those in control infants. Materials and Methods In this single-center prospective cohort study, participants were enrolled during the December 2015-July 2016 outbreak of Zika virus infection in southeast Brazil (Natural History of Zika Virus Infection in Gestation cohort). Eligibility criteria were available cranial US and laboratory findings of maternal Zika virus infection during pregnancy confirmed with RNA polymerase chain reaction testing (ie, Zika virus-exposed infants). The control group was derived from the Zika in Infants and Pregnancy cohort and consisted of infants born to asymptomatic pregnant women who tested negative for Zika virus infection during pregnancy. Two radiologists who were blinded to the maternal Zika virus infection status independently reviewed cranial US scans from both groups and categorized them as normal findings, Zika virus-like pattern, or mild findings. Associations between cranial US findings and prenatal Zika virus exposure were assessed with univariable analysis. Results Two hundred twenty Zika virus-exposed infants (mean age, 53.3 days ± 71.1 [standard deviation]; 113 boys) and born to 219 mothers infected with Zika virus were included in this study and compared with 170 control infants (mean age, 45.6 days ± 45.8; 102 boys). Eleven of the 220 Zika virus-exposed infants (5%), but no control infants, had a Zika virus-like pattern at cranial US. No difference in frequency of mild findings was observed between the groups (50 of 220 infants [23%] vs 44 of 170 infants [26%], respectively; P = .35). The mild finding of lenticulostriate vasculopathy, however, was nine times more frequent in Zika virus-exposed infants (12 of 220 infants, 6%) than in control infants (one of 170 infants, 1%) (P = .01). Conclusion Lenticulostriate vasculopathy was more common after prenatal exposure to Zika virus, even in infants with normal head size, despite otherwise overall similar frequency of mild cranial US findings in Zika virus-exposed infants and in control infants. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Benson in this issue.

Risk of adverse outcomes in offspring with RT-PCR confirmed prenatal Zika virus exposure: An individual participant data meta-analysis of 13 cohorts in the Zika Brazilian Cohorts Consortium.

Background: Knowledge regarding the risks associated with Zika virus (ZIKV) infections in pregnancy has relied on individual studies with relatively small sample sizes and variable risk estimates of adverse outcomes, or on surveillance or routinely collected data. Using data from the Zika Brazilian Cohorts Consortium, this study aims, to estimate the risk of adverse outcomes among offspring of women with RT-PCR-confirmed ZIKV infection during pregnancy and to explore heterogeneity between studies. Methods: We performed an individual participant data meta-analysis of the offspring of 1548 pregnant women from 13 studies, using one and two-stage meta-analyses to estimate the absolute risks. Findings: Of the 1548 ZIKV-exposed pregnancies, the risk of miscarriage was 0.9%, while the risk of stillbirth was 0.3%. Among the pregnancies with liveborn children, the risk of prematurity was 10,5%, the risk of low birth weight was 7.7, and the risk of small for gestational age (SGA) was 16.2%. For other abnormalities, the absolute risks were: 2.6% for microcephaly at birth or first evaluation, 4.0% for microcephaly at any time during follow-up, 7.9% for neuroimaging abnormalities, 18.7% for functional neurological abnormalities, 4.0% for ophthalmic abnormalities, 6.4% for auditory abnormalities, 0.6% for arthrogryposis, and 1.5% for dysphagia. This risk was similar in all sites studied and in different socioeconomic conditions, indicating that there are not likely to be other factors modifying this association. Interpretation: This study based on prospectively collected data generates the most robust evidence to date on the risks of congenital ZIKV infections over the early life course. Overall, approximately one-third of liveborn children with prenatal ZIKV exposure presented with at least one abnormality compatible with congenital infection, while the risk to present with at least two abnormalities in combination was less than 1.0%.