< 5 years later, researchers assess how children exposed to Zika are developing

ARI SHAPIRO, HOST:

Before COVID-19, there was Zika. The virus swept through Latin America in 2016. Some babies were born with small heads. Scientists didn't understand why or how common it was. Since then, they've learned that most kids whose mothers had Zika during pregnancy were not born with any visible birth defects. In 2017, Selena Simmons-Duffin met one of those children named Yariel. At the time, he was a curly haired 1-year-old. She went with him to Children's National Hospital here in Washington, D.C.

YARITZA MARTINEZ: (Speaking Spanish). Up, up, up.

SELENA SIMMONS-DUFFIN, BYLINE: At this moment, he's gazing up at his mom, Yaritza Martinez, in an exam room chair, pondering a move to stand.

MARTINEZ: Up - good job. Bravo.

SHAPIRO: Well, now Yariel is 5 years old, and Selena went back to check in on him and bring us up to date on what scientists know about the long-term impact of Zika exposure.

SIMMONS-DUFFIN: Yariel has spent a lot of this pandemic year in his family's cozy apartment just north of Washington, D.C. He's a bit shy. His long, curly hair is pulled into a ponytail.

You don't remember me.

MARTINEZ: He was too little (laughter).

SIMMONS-DUFFIN: His mom, Yaritza Martinez, says he's doing great. His older brother and sister, Dylan and Angie (ph), clearly adore him, enough to turn up the volume of "My Little Pony: A New Generation," which they say they have watched a thousand times.

YARIEL: More. More. I can't hear it.

SIMMONS-DUFFIN: A few months ago, Yariel went back to Children's National Hospital for his five-year-assessment - no more baby stuff like standing up. This time, he showed off his vocabulary and threw bean bags and walked along a line of yellow tape. Yariel remembers putting coins through a slot.

MARTINEZ: The coins - do you remember?

YARIEL: The coins - I was doing it faster.

MARTINEZ: You had fun that day, right?

YARIEL: Yeah.

MARTINEZ: At Children's National, Dr. Sarah Mulkey says from her perspective, Yariel is doing very well.

SARAH MULKEY: He certainly knew a lot of words on his vocabulary test. We were quite impressed with him. He probably needs to work on some of his fine motor skills. When he was doing his drawing assessment, he went over the lines a couple times too much, so his score wasn't the best.

SIMMONS-DUFFIN: That's something he can work on before he goes to school next year, she says. Her analysis of the data from her assessment of Yariel and the other children in this group isn't complete yet. She says it's a challenge to tease apart the effects of Zika exposure from the effects of living through the coronavirus pandemic, which has meant fewer chances to play with other kids, for instance. But so far, it seems like Yariel isn't alone and that fine motor skills is an area that Zika-exposed children struggle with more than children who were not exposed.

MULKEY: That seems to be an area that they are having some more struggles with, whereas kind of the bigger motor functions of running and jumping seem to be doing a little bit better.

SIMMONS-DUFFIN: Drawing outside the lines might not sound like a serious problem, but it does matter. Dr. Karen Puopolo is a neonatologist at Pennsylvania Hospital in Philadelphia. She explains...

KAREN PUOPOLO: Say you're in third grade and you're really frustrated by not being able to do the recorder, and so you start misbehaving during music class. And so when we make the placement for you for fourth grade, maybe we're not going to put you in the advanced class because, you know, you seem like you're a fidgety, misbehaving child.

SIMMONS-DUFFIN: That's why it's so important to identify these subtle differences and intervene early, she says. This kind of research, following groups of children from before birth through school age, is unusual. Mulkey has images of Yariel's brain from before he was born, MRIs of Martinez's pregnant belly, and she'll have images of his brain again when he's 7 years old. This is expensive and time-consuming work that requires a lot from the participants, but it's also really important, Mulkey says.

MULKEY: A baby doesn't have to do a lot of things. They need to eat and make lots of diapers for their parents and all that kind of thing. But it's not until they get older and they're starting to go to school age that we can really assess executive function, language development, emotional development.

SIMMONS-DUFFIN: Things that may affect their success later in life. This isn't just about Zika. Getting sick during pregnancy with any virus can affect fetal development, says Puopolo, including perhaps coronavirus.

PUOPOLO: Currently, we do not have evidence that having COVID during pregnancy leads to any specific impact on the infant, other than the fact that there is an increased risk that the baby will be born preterm.

SIMMONS-DUFFIN: However, she says, COVID-19 has already affected a lot of pregnant people - more than 150,000 in the U.S., according to the CDC. That's more than 100 times the number affected by Zika in the U.S., and there's still a lot unknown about COVID-19's long-term effects.

PUOPOLO: I don't want to, like, scare the world and suggest that there's any reason to worry about that, but clearly it's a novel virus, and it's a novel situation. And so there is reason to be thoughtful about how we might approach understanding any potential impact that might come down the line.

SIMMONS-DUFFIN: Mulkey is following a group of children affected by COVID-19, and she hopes she can do long-term research with them as well.

For his part, Yariel will keep going in for assessments for several more years. That's OK with him and his mom, Yaritza.

MARTINEZ: Even now, they don't know everything about Zika, so they still investigate.

SIMMONS-DUFFIN: His older sister Angie, who's 16, has already started drawing with him so he can work on his fine motor skills.

YARIEL: Practice, writing and, you know, holding, like, a pencil. And, like, he's kind of getting the hang of it there, so...

SIMMONS-DUFFIN: He's working at it so next fall, when it's time to start kindergarten, he'll be ready. Selena Simmons-Duffin, NPR News.

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