Prospective cohort studies of pregnant women and their infants

Overview 

We conducted prospective observational cohort studies of pregnant women and their infants in arbovirus-endemic settings in Jamaica and Haiti in order to: 

• Assess the association between ZIKV, DENV and CHIKV infection in pregnancy and adverse pregnancy and fetal/infant outcomes 

• Estimate the risk of vertical transmission of ZIKV, DENV and CHIKV by gestational age at different time points during pregnancy and by maternal, infant and viral factors 

• Estimate incidence of ZIKV infection in pregnancy and to describe risk factors and clinical presentation 

In brief, the approach was to enrol and follow up pregnant women at risk of these arbovirus infections in order to identify those with markers of recent infection (with or without symptoms) prospectively, to describe maternal and pregnancy outcomes and to follow up their infants to 18-24 months of age in order to assess outcomes including growth and neurodevelopment. Slightly different approaches to infant follow-up were taken in the two studies – in Jamaica, the design was to follow-up all infants, whilst in Haiti follow-up was restricted to “high risk“ infants whose mothers who had evidence of recent infection, plus a control group whose mothers had no markers of arbovirus infection whilst pregnant.  

Jamaica cohort 

The cohort study was led by Prof Celia D C Christie at the University of the West Indies, Mona Campus, Kingston. ZIKAction team members working in five antenatal clinics in the Greater Kingston Metropolitan Region participated in the recruitment and follow-up of pregnant women, with the first women enrolled in June 2017. These five clinics acted as feeder clinics to three hospitals – Spanish Town Hospital, Victoria Jubilee Maternity Hospital and the University Hospital of the West Indies – where the enrolled women delivered. Overall, a total of 605 pregnant woman were enrolled in the cohort, with enrolment completed in April 2019. 

Haiti cohort 

In Haiti, the study was led by Prof J Glenn Morris from the Emerging Pathogens Institute at the University of Florida. Pregnant women were recruited from clinics starting in April 2018. The study stopped recruitment in August 2019 with a total of 542 women enrolled.

Cohort study results  

Analyses from the cohort studies are currently being completed. Preliminary results from the Jamaica cohort have been presented at two international scientific conferences.