CDC looks to improve tracking of infant outcomes from Zika
Although the Centers for Disease Control and Prevention is working with state, local and territorial public health departments on following pregnant women who have laboratory evidence of Zika virus infection, the agency acknowledges that it needs to do a better job tracking infant outcomes.
“We gather data on evaluations that are done on the mother and fetus throughout pregnancy and, importantly, also on the condition of the fetus and medical consequences of infection following birth,” Lyle Petersen, MD, director of the Division of Vector-Borne Diseases in the CDC’s National Center for Emerging and Zoonotic Infectious Diseases, told a House subcommittee on Tuesday. “What we know now is that some of the babies that may appear completely normal actually aren’t.”
Last year, CDC established pregnancy registries to capture information about pregnant women with Zika and their babies. The agency has documented 3,795 pregnant women with laboratory evidence of Zika virus infection in U.S. territories, with another 1,845 identified in U.S. states and Washington, D.C.
The U.S. Zika Pregnancy Registry and the Zika Active Pregnancy Surveillance System in Puerto Rico are helping the agency better understand the range of adverse outcomes that occur in infants and when in pregnancy those risks are highest for microcephaly and other severe birth defects caused by the virus. However, gaps in care still exist, according to Petersen.
Despite the fact that the Zika pregnancy registries contain information on women who have been tested for the virus and are known to be infected, Petersen revealed that “not all pregnant women exposed to Zika will be tested during the relatively narrow time period when we can identify Zika infections.”
To address this shortcoming, he said the CDC has established rapid birth defects surveillance to identify the same Zika-associated birth defects in babies whose mothers might not have been tested for Zika in the time period when maternal infection could otherwise be identified.
“The combination of the pregnancy registries and rapid birth defects surveillance are providing critical data for public health officials and clinicians, and these combined systems are the only way to identify all the babies affected by congenital Zika virus infection,” added Petersen.
Another gap in care he cited to lawmakers was in the area of brain imaging, a critical medical procedure given that among pregnant women with confirmed Zika virus infection, about 10 percent of their fetuses and babies are affected by critical birth defects—primarily serious damage to their brains.
“Based on data reported to the registries, only about one in four babies born to women with Zika virus infection during pregnancy are receiving the recommended brain imaging after birth,” Petersen said. “Some brain abnormalities are only identified with brain imaging, suggesting that the impact of Zika on babies born to mothers infected with the virus may be underestimated.”
Of the nearly 1,000 births in 2016 recorded in the Zika pregnancy registries, 51 had a Zika-associated birth defect, mostly serious brain abnormalities and microcephaly, he noted.
Petersen recommends tracking infants born to mothers infected during pregnancy for five years or possibly longer to “determine what the full impact of the virus infection on the mother actually is on the fetus—that’s still an open question.”