Florida Sees This Year's First Sexually Transmitted Case of Zika As CDC Changes Testing Guidance

Aug 7, 2017
Originally published on August 4, 2017 12:44 pm

Florida has confirmed its first sexually-transmitted case of the Zika virus of this year. That comes as the Centers for Disease Control and Prevention are changing their recommendations for testing pregnant women for the disease. The new guidance means more patients may go without screening.

Being pregnant is never easy. But the Zika virus can make the experience even more stressful, challenging and confusing. It’s not always clear what pregnant women should do. Rick Scott spoke with local officials and public health experts in Doral earlier this summer about the stress of Zika.

“I have a daughter that’s pregnant right now with twins. She’s very…of course, like most anybody that’s pregnant, wants to have a healthy child. And so she constantly asks me about how we’re doing on the state level with regard to Zika. I remind her of what we have to do personally," he said. "You don’t have any standing water around your house or business. You know to use bug repellant. Use protective clothing.”

Now some of the guidance for pregnant women is changing again. The CDC is discouraging the use of the antibody test when screening for the Zika virus, according to the agency's Zika Response Incident Manager Henry Walke.

“We are emphasizing the use of this nucleic acid test for pregnant women,” Walke said.

According to the organization, all pregnant women should talk to their doctors about Zika. But now the agency says those with symptoms, living in places with ongoing exposure, like Puerto Rico, should definitely get tested. Those in areas with outbreaks but no symptoms, should consider testing. Women who travel to a place with local transmission and don’t develop symptoms, don’t have to get tested. But, Walke says there is room for flexibility. 

“If the provider and the patient, the pregnant woman feels that they’ve had significant exposure or other reasons, certainly that testing could be performed. But both the provider and the patient need to understand the limitations of the testing in that context,” Walke said.

He says the reason the CDC is discouraging the use of the antibody test is because public health experts are increasingly worried about its accuracy.

“Our concern is that, especially in this very low incidence setting, a setting where the cases are very low, that a number of the tests that we’re conducting, especially on asymptomatic pregnant women might be false positives rather than true positives,” Walke said.

The problem is evidence of Zika exposure stays in the body longer than experts thought. The antibody or IGM test can’t reliably tell the difference between an inactive virus and an active one.

“And therefore it makes it more difficult to differentiate, for example in a territory like Puerto Rico, if a woman who is positive now was actually exposed last season. So we can’t tell if a woman is recently affected or potentially immune,” Walke said.

Those false positives can unintentionally put pregnant women in a really difficult situation, says chair of the Florida Chapter of the American Congress of Obstetricians and Gynecologists Karen Harris.

“And then we scare women and women unnecessarily intervene in their pregnancies unnecessarily, when they really haven’t had an exposure during the pregnancy,” Harris said.

The constantly evolving guidance can be hard to track. And Walke acknowledges the possibility that patients who really should get tested, may not. But he says that chance is vanishingly small, compared to the number of false positives.

“When the majority of the tests that we’re using to interpret or provide some guidance to pregnant women are actually false, we felt that it was important really to update our guidance,” Walke said.

The CDC is encouraging patients and their physicians to work together to decide any possible screenings and treatments. And Harris wants her colleagues to stay up to date on the newest information.

“Make sure your physician follows the latest CDC guidelines. What I’m telling you today could change next week,” Harris said.

Walke says the changes will likely shift more responsibility on to pediatricians. They’ll be the ones keeping tabs on babies who may develop symptoms of undiagnosed Zika exposure. 

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