Serologic testing for Zika virus has been recommended in asymptomatic pregnant women, who have traveled to, or reside in, areas of ongoing transmission. This recommendation is included in the Centers for Disease Control and Prevention (CDC)’s updated interim guidelines on the Zika virus, which have been released today.

The update details guidance for pregnant women with clinical illness consistent with Zika virus disease, and recommends they be tested during the first week of illness. A negative RT-PCR result from serum collected 5–7 days after onset of symptoms does not rule out Zika virus infection because viremia decreases over time, and serologic testing is recommended.

For asymptomatic pregnant women living in areas with ongoing Zika virus transmission, testing should occur at the initiation of prenatal care with follow-up testing mid-second trimester.

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Testing pregnant women who have a clinical illness consistent with Zika virus disease during or within 2 weeks of travel to areas with ongoing viral transmission is still recommended, as stated in the CDC’s recommendations from January 19, 2016. They also recommend that health officials should decide when to implement testing of asymptomatic pregnant women based on information about levels of Zika virus transmission and laboratory capacity.

Discussions of pregnancy intention and timing should be initiated by health care providers with women of reproductive age (15 to 44 years) in the context of risks related to Zika virus infection. Due to the potential risks of maternal Zika virus infection, pregnant women whose male partners have or are at risk for Zika virus infection should consider using condoms or be abstinent.

The guidelines further reiterate how pregnant women, who live in areas of ongoing transmission, are at risk for infection throughout their pregnancy. With no vaccine or medication currently available to prevent the infection, the CDC advises health care providers and residents to strictly follow steps to avoid mosquito bites. Preventive efforts include wearing long-sleeved shirts, pants, permethrin-treated clothing, and using U.S. Environmental Protection Agency (EPA)-registered insect repellents.

Zika virus infection is associated with an increased risk for congenital microcephaly and other abnormalities of the brain and eye in newborns. On February 1, the World Health Organization (WHO) declared the virus a Public Health Emergency of International Concern. Recommendations will continue to be updated as more information becomes avaiable.

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