A series of studies released Wednesday shed a preliminary light on the Zika virus’ consequences for children infected in the womb. But, experts said, the findings also highlight additional challenges: identifying affected babies and making sure they receive needed follow-up care as they grow.
That task could prove complicated, especially as new data emphasizes the virus may cause more damage than previously thought.
Two studies track how many women infected with the mosquito-borne virus have had babies with identifiable evidence of birth defects, with one providing the first lens into how the virus has so far affected American children. A third paper suggests the disease stays active in those infants’ brains days beyond birth.
One paper, published in JAMA by researchers from the Centers for Disease Control and Prevention, tracked the 442 American pregnant women exposed to the virus who completed pregnancies between Jan. 15 and Sept. 22. The researchers found that about 6 percent of those children were born with Zika-related birth abnormalities — including but not limited to the brain disorder known as microcephaly. Another study, published in the New England Journal of Medicine, tracked outcomes for pregnant women in Brazil and suggested a higher rate of birth defects — 42 percent. Some experts say that higher figure may result from many of the Brazilian women having more severe infections, or from the prior exposure many had to dengue fever. The third study, also conducted by the CDC, found that the Zika virus was still active and replicating in children’s brains days after they were born. That builds on previous findings suggesting Zika remained a threat post-utero.
This study underscores the need for pediatricians to test babies who may have been exposed in utero to Zika, even if they don’t show obvious signs of infection at birth. The CDC has been urging aggressive screening. A clinical guidance released in August supports the approach, too.
The findings also underscore the need for thorough monitoring of how the disease develops and the importance of ensuring affected children access helpful treatments and therapies.
Zika has no cure or vaccine, but identifying children early on who have been affected can help. Doctors can undermine some of the infection’s consequences, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston and an expert on the virus.
“Early intervention, Head Start — all those things could make a difference” for children with neurological conditions, he said. “Occupational and physical therapy. All that needs to be done.”
But making sure those infants do get tested and treated remains difficult.
“We’re certainly hearing, from some of our state and local health department partners, that it’s challenging — making sure the mom’s testing information, and the fact that mom was documented to have Zika infection, is passed on to the pediatric health provider,” said Dr. Margaret Honein, an epidemiologist who co-chairs the CDC’s birth defects branch and was the lead author on the JAMA paper.
The JAMA paper, for instance, notes that 41 percent of infants who may have been exposed to Zika in the womb didn’t get tested for the virus. “What it suggests to me is that OB/GYNS are incorporating the [CDC’s recommendations] into their practice, but potentially, the pediatricians are not as aware,” said Julie Fischer, who co-directs the Center for Global Health Science and Security at Georgetown University. “The focus has been so much on pregnancy and treating pregnant women and identifying pregnant women. … Pediatricians are not as sensitized to these issues.”
That speaks to a need for greater communication about who may be at risk, and for how long, said Martha Rac, a maternal-fetal medicine specialist at Texas Children’s Pavilion for Women and Baylor College.
“That is a big area where there can be a push for broader screenings,” Rac said, referring to infants born to women who were exposed to the virus, regardless of what symptoms they have at their first physical examinations.
That said, coordinating this kind of testing and long-term follow-up won’t be easy.
Some public health experts argue low-income people are at greater risk of Zika exposure. They are more likely to live in conditions in which the mosquitoes carrying the disease thrive.
And those families are generally less likely to consistently access health care. Reports have suggested low-income children are less likely to receive regular preventive screenings and check-ups. Data published in 2016 by the U.S. Department of Health and Human Services found that, in the previous year, about 40 percent of children covered by Medicaid received fewer than six wellness visits in their first 15 months of life. Doctors advise they receive nine in that timeframe.
“Children who are born in families where exposure risk is higher may also be at risk of not having the kind of close monitoring of development through early childhood” that’s needed, Fischer said.
That could have consequences, since public health experts said tracking babies over time is crucial to understanding how the virus affects brain development and how widespread its consequences may be. The percentages found so far could be “the tip of the iceberg,” Hotez.
And, to be sure, more research is needed to determine what kind of subtle consequences the virus could have on a child’s long-term brain development, Fischer noted.
“If the findings do end up supporting the idea that children exposed to Zika virus in utero — particularly early in pregnancy — are at a higher risk of developmental disabilities, then clearly there’s the possibility there will be missed chances to intervene early, with therapies that might help.”