One in 7 Babies Exposed to Zika Have Health Problems, CDC Says

Megan Brooks

August 07, 2018

About 1 in 7 babies (14%) currently aged 1 year or older who were exposed to Zika virus before birth have one or more health problems possibly related to Zika, including some serious health problems that were not apparent at birth, federal health officials with the Centers for Disease Control and Prevention (CDC) said today.

"We are still learning about the effects of Zika, and it might be years before we fully understand the full spectrum of the health outcomes related to Zika infection during pregnancy," CDC Director Robert Redfield, MD, said during a media briefing.

"We do know that some babies may appear healthy at birth but can develop long-term health problems as they grow. That is why continued monitoring and follow-up evaluations are so crucial," said Redfield.

The findings were reported in an article published online August 7 in Vital Signs.

About 4800 pregnancies occurred between 2016 and 2018 in US territories (Puerto Rico, American Samoa, US Virgin Islands, Federated States of Micronesia, and the Republic of the Marshall Islands) for which there is laboratory evidence of confirmed or possible Zika virus infection, as reported in the US Zika Pregnancy and Infant Registry. From these pregnancies, the CDC team analyzed health outcomes and follow-up care for 1450 babies who were at least 1 year old by February 2018.

Among these 1450 babies, 6% had at least one Zika-associated brain or eye birth defect, a rate "which is over 30 times higher than the baseline for these brain and eye defects in the absence of Zika during pregnancy," Peggy Honein, PhD, director of the CDC's Division of Congenital and Developmental Disorders, said during the briefing.

About 9% of these children had at least one neurodevelopmental abnormality possibly associated with congenital Zika virus infection, such as seizures, problems with swallowing and moving, hearing loss, or developmental delay, as determined on the basis of standardized testing.

"We know that these health problems can lead to long-term functional challenges. Based on what we've learned about other congenital infections, we suspect that health issues will continue to emerge as these children age," said Honein.

The analysis also identified "opportunities for improvement" in follow-up care, said Honein.

Encouragingly, she said, 95% of babies had undergone at least one physical examination when they were older than 2 weeks, about 76% had undergone developmental screening or evaluation, and 60% had received the recommended neuroimaging after birth. However, fewer than half (48%) had undergone the recommended hearing evaluation, and only about one third (36%) had undergone the recommended eye examination by an eye specialist.

Updated Guidance

Today's Vital Signs report also includes updated guidance for couples who have possibly been exposed to Zika virus and who are planning for pregnancy.

The CDC now recommends that men who have possibly been exposed to Zika virus or are known to have been infected with Zika and who are planning to conceive with their partner wait at least 3 months after symptoms or after the last possible Zika exposure (travel to or residence in an area with risk for Zika) before trying to conceive.

The previous guidance was that men wait at least 6 months before trying to conceive. "These updated recommendations are based on emerging data that the risk of infectious Zika virus in semen declines substantially during the 3 months after onset of symptoms," Honein reported.

All other Zika guidance remains unchanged, she said, including the recommendation that men who have possibly been exposed to Zika virus and whose partner is pregnant should use condoms or the couple should not have sex during the entire pregnancy to reduce the risk for transmission. The CDC also continues to urge pregnant women not to travel to areas where there is risk for Zika infection.

Zika virus can be transmitted via the bite of an infected mosquito, from a pregnant woman to her developing baby, through sex, and through blood transfusion. Most of the cases in US states resulted from mosquito bites during travel to areas where there was risk for Zika. According to the CDC, there are currently no areas in the continental United States where local mosquito-borne Zika virus transmission is occurring.

But Zika "has not gone away," Redfield said. "Zika virus continues to spread at low levels in many areas or the world. Nearly 100 countries and territories have a risk of Zika, and we must remain cautious."

Vital Signs. Published online August 7, 2018. Full text

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