The International Cohort Study of Children Born to Women Infected with Zika Virus (ZIKV) During Pregnancy study is a prospective, observational, international cohort study of children previously enrolled in the ZIP study or other ZIP 2.0 Protocol Team approved ZIKV-cohort study that will continue the longitudinal follow-up of children born with documented confirmed or presumptive in-utero ZIKV exposure ("ZIKV-exposed" cohort) and children born without documented confirmed or presumptive in-utero ZIKV exposure, matched by site and birth sex ("ZIKV-unexposed" cohort).

Follow-up evaluations and assessments will allow for the determination and comparison of long-term neurodevelopmental outcomes among in utero ZIKV-exposed and ZIKV-unexposed children. Each participant will be followed for about 2 years, beginning at approximately 18 months through 42 months of age.

The International Prospective Observational Cohort Study of Zika in Infants and Pregnancy (ZIP) study has leveraged 10 international sites to follow mother-infant dyads prospectively in pregnancy and postpartum to determine the incidence and outcomes of Zika Virus (ZIKV) infection. The ZIP study has collected demographic, physical, environmental, laboratory, and delivery outcome data in relation to mother-infant pairs with and without ZIKV infection. Infants born to women enrolled in the ZIP study are followed for 1 year and undergo regular physical and neurological assessments to identify clinical or developmental outcomes.

The International Cohort Study of Children Born to Women Infected with Zika Virus During Pregnancy (ZIP 2.0) study will enroll children who themselves or whose biological mothers were previously enrolled in the ZIP study and other ZIP 2.0 Protocol Team-approved studies. Assessments include growth, neurodevelopmental, audiologic, ophthalmologic, and other clinical outcomes. Evaluations will occur about every 6 months over about a 2-year period beginning at approximately 18 months of age. Follow-up evaluations and assessments will allow for the determination and comparison of long-term neurodevelopmental outcomes among in utero ZIKV-exposed and ZIKV-unexposed children.

After parent(s)/legal guardian(s) permission is obtained for the child's participation in ZIP 2.0, several means to contact them will be requested. Parents will be asked whether or not messages can be left for each of the phone numbers provided and if messages can contain information regarding the nature of the study.

We expect to compare approximately 200 children with documented confirmed or presumptive in-utero ZIKV exposure and 200 controls matched by site and birth sex without documented confirmed or presumptive in-utero ZIKV exposure at age approximately 18 months, and at age 42 months.

The primary objective is to determine the long-term neurodevelopmental outcomes among children born with documented confirmed or presumptive in-utero ZIKV exposure. The secondary objectives are to compare the long-term effects (e.g., on growth, vision, hearing and neurodevelopment) of in-utero ZIKV-exposure compared to unexposed children.

Inclusion Criteria:

ZIKV- Exposed Inclusion Criteria:

• Parent(s)/legal guardian(s) provided written permission for his or her child to participate.
• Participant and/or participant's biological mother previously enrolled in the ZIP study or other ZIKV cohort study approved by the sponsors.
• Participant's biological mother has laboratory documentation of positive ZIKV RNA test results during pregnancy through delivery delivery or the participant has laboratory documentation of ZIKV RNA or serology positive/presumptive positive/equivocal ZIKV test within 5 days of birth according to the ZIKV-exposed definitions included in the ZIP 2.0 inclusion criteria.
• Minimum 74 weeks of age (approximately 17months) of age at enrollment

ZIKV-Unexposed Inclusion Criteria:

• Parent(s)/legal guardian(s) provided written permission for his or her child to participate.
• Previously enrolled in the ZIP study and identified as matching the same birth sex and followed at the same study site as an enrolled ZIKV-exposed participant.
• Laboratory documentation that the participant's biological mother has negative ZIKV RNA test results and no positive ZIKV RNA test results at any time during her pregnancy through delivery.
• Participant did not test ZIKV RNA and/or serology positive presumptive positive or equivocal at any time prior to ZIP 2.0 enrollment, if testing was performed prior to enrollment.
• Minimum 74 weeks of age (approximately 17months) of age at enrollment

Exclusion Criteria: Both Exposed and Unexposed Cohorts

• Enrolled in other clinical research (including other ZIKV research) requiring blood collection, which in combination with ZIP 2.0 evaluations, would exceed the lesser of 50 mL or 3 mL per kg in an 8-week period and/or blood collection would be required more frequently than two times per week.

Approximately 200 children with confirmed or presumptive in-utero exposure to Zika virus and approximately 200 children matched by site and birth sex without confirmed or presumptive in-utero exposed to Zika virus.