The US Food and Drug Administration (FDA) on Tuesday announced new measures to prevent transmission of Zika virus via human cell and tissue products (HCT/Ps) by recommending a six-month deferral for at-risk donors.
The virus, which has swept across Latin America and the Caribbean, is believed to be behind a spike in cases of microcephaly, a rare condition where an infant is born with an abnormally small head, and Guillain-Barré syndrome, a neurological disorder that can lead to paralysis or death.
According to the World Health Organization (WHO), local transmission of Zika has been reported in more than 50 countries and territories.
On Friday, Secretary of Health and Human Services (HHS) Sylvia Burwell declared that Zika poses a "significant potential for a public health emergency," clearing the way for FDA to approve the first diagnostic to detect Zika under its emergency use authorization (EUA) pathway.
The same day, the US Centers for Disease Control and Prevention (CDC) said it had confirmed nine cases of Zika in pregnant travelers: two that ended in losses; two that were terminated; and three that resulted in live births, of which one baby was born with what CDC called "severe microcephaly."
Similar to the guidance released last month to reduce the risk of Zika transmission by blood transfusion, FDA's new guidance goes into effect immediately, with the agency urging establishments to implement its recommendations within four weeks of its issuance.
For living HCT/P donors, FDA is recommending a six-month deferral period for donors who have been diagnosed with Zika, travelled to a region where Zika is being transmitted or who have had sex with a man with any of those risk factors.
Additionally, the agency says that "donors of umbilical cord blood, placenta or other gestational tissues should be considered ineligible if the birth mother who seeks to donate" has met any of the risk factors listed for HCT/P donors "at any point during that pregnancy."
FDA says that deceased donors who have been diagnosed with Zika in the past six months should be considered ineligible for donation.
The agency says it chose a deferral period of six months as a cautionary measure. And while the virus can be detected in tissues and bodily fluids after clearing the bloodstream, FDA says there is not enough data available to know for exactly how long the virus can remain present.
Researchers have detected the virus in a male patient's semen up to 10 weeks after experiencing Zika symptoms, and the CDC has reported more than a dozen suspected cases of sexual transmission of the disease. Zika has also been detected in the placenta of women diagnosed with the virus.
However, FDA says, there is little data on the potential for Zika transmission via HCT/Ps, and promises to update its recommendations as new information becomes available.
Donor Screening Recommendations to Reduce the Risk of Transmission of Zika Virus by Human Cells, Tissues and Cellular and Tissue-Based Products