Babies born with Zika-related microcephaly continue to experience profound health complications, including seizures, motor impairments and hearing problems as they grow older, scientists say.

It’s been two years since Brazil declared the Zika virus outbreak to be a public health emergency. Thousands of babies were born to mothers who were infected with the mosquito-borne virus, and many have congenital defects like microcephaly — a birth complication characterized by an underdeveloped head.

In a new report released Thursday by the U.S. Centers for Disease Control and Prevention (CDC), researchers followed 19 babies born with microcephaly and lab-confirmed cases of congenital Zika infections as they aged. The children, between 19 months and two years old, continue to face significant developmental difficulties, according to the researchers.

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Among the infants, 11 had a possible seizure disorder, 10 had trouble sleeping, nine had trouble eating, 15 had motor impairments that included the inability to sit on their own, 13 had hearing problems and 11 had vision problems.

“As children born affected by Zika virus grow up, they will need specialized care from many types of healthcare providers and caregivers,” Dr. Georgina Peacock, director of CDC’s Division of Human Development and Disability, said in a statement about the findings.

Prior to this study, researchers had documented the health complications of babies born with microcephaly but only speculated about what their development would look like. In the United States and U.S. territories, there have been 240 cases of babies born with Zika-related birth defects.

This is the first study to follow babies born with microcephaly from Zika infections over time. The study used children partaking in the Zika Outcomes and Development in Infants and Children (ZODIAC) trial, which is run by the CDC in partnership with the Ministry of Health of Brazil.

The researchers say that studying these children will allow countries and health providers to anticipate what kinds of needs, both medical and social, that affected families will need.

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