The ZIKA-VT prospective cohort studies enrolled a cumulative total of 1147 women. The dramatic decline in ZIKV incidence in 2017 meant that few incident ZIKV infections were identified, but incident DENV cases were documented and followed. Seroprevalence of ZIKV IgG and CHIKV IgG in pregnancy in Jamaica was 15.6% and 83.6% respectively. The pilot of the ZIKApp in Jamaica demonstrated its feasibility and acceptability among 173 pregnant women, with good participant retention (91%) and adherence to daily symptom diary completion up to delivery. An evidence synthesis using Bayesian Latent Class models to estimate the risk of vertical transmission of ZIKV by trimester of maternal infection using published data reported estimated average risks of transmission in the 1st, 2nd and 3rd trimesters to be 46%, 28% and 25%.
ZIKA-PED established a Paediatric Registry to characterize the features of children antenatally exposed to ZIKV and/or presenting with suspected Congenital Zika Syndrome, and including longitudinal data to assess longer-term sequelae and management. Overall 192 children were enrolled in Brazil, Jamaica and Argentina, with most children now aged 5-6 years. Most Registry participants have microcephaly (in Brazil 65% had severe microcephaly) and associated brain abnormalities, whilst prevalence of ocular abnormalities varied by country (62% in Brazil versus 28% in Jamaica). In the Spanish PEDZIKARED birth cohort study, 152 children have been followed to assess long-term effects of in utero ZIKV exposure. The ZIKA-HOST sub-study used a ZIKV vaccine and gene expression approach to explore ZIKV infection from the host perspective, utilising a host biobank of mother-child samples from Brazil and Spain to identify host genes regulated after ZIKV infection.
In ZIKA-PATHO, activities included investigation of ZIKV replication in human placental explants, including the role of antibody dependent enhancement and comparison of the replication profile and infectivity of African and Asian ZIKV lineages. Experiments were also conducted to assess how the viral lipid profile may impair the placental barrier in pregnant women . An ovine model of ZIKV infection was developed to explore the kinetics of placental infection and pathogenesis, and potential for sexual transmission, the first to do so in a large animal outbred host other than non-human primates. This has involved immunological, endocrinological and pathological characterization of a timed gestation model, as well as development of a model of in vitro placental infection which showed that cortisol and reproductive hormones enhance viral susceptibility of fetal cells.
A major activity in ZIKA-VID was a comprehensive comparative analysis of the accuracy of second generation ZIKV diagnostic assays for use in LAC populations, which informed a theoretical model to address uncertainty in diagnosis that could prove useful not only in ZIKV but also in future emerging infections. Other work included seroprevalence studies of ZIKV, DENV and CHIKV in adults, pregnant women and children in Brazil and Jamaica, plus a study of the metabolomic profiles of ZIKV-exposed infants, which showed significant changes in the plasma lipidome in exposed versus control newborns.
With the other EU-funded ZIKV consortia, joint work on harmonization and data sharing has included partcipation in the WHO individual patient data meta-analysis. REDe provides an online hub for knowledge sharing across the regions impacted by ZIKV.
