In a conference call this morning, officials with the Centers for Disease Control and Prevention announced a more transparent system for reporting cases of Zika virus in pregnant women.
While the CDC previously only reported the number of pregnant women with visible Zika symptoms, its weekly figures will now also include the amount of women whose test results show evidence of Zika, even if there are no external indicators.
This new data shows that the vast majority of Zika cases in pregnant women are asymptomatic—279 women in the U.S. states and territories were reported to have laboratory evidence of Zika virus. In contrast, the previous report (the last under the old system) included only the 112 women who had visible symptoms. None of the women contracted Zika in the U.S.—all cases were travel related.
The new number includes all infected women who are still pregnant, along with those who have recently delivered or miscarried babies. There is no ongoing monitoring of women with Zika after their babies are delivered
This new distinction is important because women with lab evidence of Zika are still at risk of delivering babies with microcephaly or other birth defects, even if they show no visible symptoms. The CDC is not yet reporting specific data on pregnancy outcomes (mainly because many pregnancies are still ongoing) but said that less than a dozen children had been born with Zika-related birth defects in the U.S. thus far.
All infected women who are still pregnant, along with those who have recently delivered or miscarried babies, are included in the CDC’s new figures. There is no ongoing monitoring of women with Zika after their babies are delivered.
Nine women also caught Zika from their spouses who had traveled to affected countries. In light of this, the CDC recommends that both men and women wait eight weeks to conceive if they have traveled to Brazil, Puerto Rico or other affected areas.
Physicians are also advised to offer testing to pregnant women who have visited countries affected by Zika virus, at the onset of pregnancy and again during the second trimester.
The CDC clarified that they have been monitoring every symptomatic and asymptomatic case since the Zika outbreak began—this new reporting system is simply a way to be more transparent with the American people.
“We’ve learned a lot in the last four months,” Dr. Margaret Honein, chief of the Birth Defects Branch at the CDC, said on the conference call. “Our top priority is protecting pregnant women and their fetuses.”