CDC Updates Healthcare Guidance for Infants of Mothers Exposed to Zika

Brenda Fitzgerald, MD

New guidance from the Centers for Disease Control and Prevention (CDC) on diagnosing, evaluating and managing infants of mothers with possible exposure to Zika virus departs from guidelines issued in 2016 in several areas, including reliance on previously recommended screening procedures and possible clinical presentations.

CDC Director Brenda Fitzgerald, MD, said there’s still a lot of unknown information on the Zika virus, making it important for clinicians to keep a close eye on developing infants.

“Learning how best to support them will require a team approach between healthcare providers and families,” Fitzgerald said.

The new guidelines were informed by an August 2017 meeting convened by the CDC in collaboration with the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. The meeting was held 1 month after Fitzgerald was appointed as the 17th Director of the CDC and the Administrator of the Agency for Toxic Substances and Disease Registry.

The August meeting focused on the diagnosis, evaluation and management of 3 groups of infants: those with clinical findings consistent with congenital Zika syndrome, regardless of maternal testing results; those without the clinical findings but who were born to mothers with laboratory evidence of possible Zika virus infection; and those without clinical findings born to mothers without laboratory evidence but with history of possible exposure.

The new guidance no longer recommends some screenings such as thyroid screening or hearing screening at 4 to 6 months of age, as there have not been sufficient data on whether these are useful.

In addition, Zika testing and clinical evaluation beyond the standard evaluation and routine preventive care are no longer routinely recommended for infants without birth defects consistent with congenital Zika syndrome born to mothers with potential exposure but no laboratory evidence.

Infants without birth defects consistent with Zika should still receive an eye examination by an ophthalmologist, however, if born to mothers who have laboratory evidence of possible Zika infection during pregnancy. For infants with birth defects consistent with congenital Zika syndrome, the guidance expands the list of potential problems that healthcare providers should anticipate, including difficulty breathing and swallowing, and hydrocephaly after birth. The guidance emphasizes that care and follow-up of these infants no longer depends on the infants' Zika virus testing results.

The lessening of reliance on Zika virus testing reflects limitations which have been found with the testing process. The virus RNA is only transiently present in body fluids, so a negative finding in nucleic acid testing does not rule out infection.

Serologic testing is also affected by timing of the sample collection, and can produce a false negative if it is collected before the development of the target immunogloulin M (IgM), or after antibody levels have waned. Even if serologic testing is positive, it is difficult to determine if exposure occurred before or during pregnancy.

"Given the limitations in the available screening modalities and the absence of effective interventions to prevent and treat congenital Zika virus infections, a shared decision-making model is essential to ensure that pregnant women and their families understand the risks and benefits of screening in the context of the patient's preferences and values," the new guidance note.

The guidance, "Update: Interim Guidance for the Diagnosis, Evaluation, and Management of Infants with Possible Congenital Zika Virus Infection," was published online in an issue of the Morbidity Mortality Weekly Report in October.

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