As an additional safety measure against the emerging Zika virus outbreak, the FDA has issued new guidance to reduce the potential risk of Zika virus transmission from human cells, tissues, and cellular and tissue-based products (HCT/Ps). The guidance addresses the donation of HCT/Ps from both living and deceased donors, including donors of umbilical cord blood, placenta, or other gestational tissues.
On February 16, the FDA issued recommendations for reducing the risk of Zika virus transmission via blood transfusion in the U.S.
“Though there is more to be learned about the transmission of Zika virus, given what we know about the virus at this point, which also is informed by our understanding of similar viruses, we must address the potential risk of Zika virus transmission by human cells and tissues,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research. “Providing HCT/P establishments with donor eligibility recommendations will help reduce that potential risk.”
There is a potential risk that the Zika virus can be transmitted by HCT/Ps used as part of a medical, surgical, or reproductive procedure, according to the FDA. HCT/Ps include corneas, bone, skin, heart valves, hematopoietic stem/progenitor cells (HPCs), gestational tissues, such as amniotic membrane, and reproductive tissues, such as semen and oocytes.
According to the Centers for Disease Control and Prevention, Zika virus can be spread by a man to his sexual partners. To date, several cases of sexual transmission have been reported in the U.S. Current information about Zika virus detection in semen suggests that a period of ineligibility longer than the waiting period that has been recommended for donors of whole blood and blood components is necessary for HCT/P donors, the FDA says.
Recommendations for living donors of HCT/Ps: Donors should be considered ineligible if they were diagnosed with Zika virus infection, were in an area with active Zika virus transmission, or had sex with a male with either of those risk factors, within the past six months. Donors of umbilical cord blood, placenta, or other gestational tissues should be considered ineligible if they have had any of the above risk factors at any point during their pregnancy.
Recommendations for deceased (non–heart-beating) donors: Donors should be considered ineligible if they were diagnosed with Zika virus infection in the past six months.
The FDA chose a deferral period of six months because of the limited data available on the length of time the virus can persist in all tissues. Zika virus has been detected in tissues and body fluids after the virus is no longer detectable in the blood stream, and has been detected in semen possibly up to 10 weeks after the onset of symptoms. Given the uncertainty, six months was determined to provide the appropriate level of caution.
Less evidence exists regarding the potential for transmission of Zika virus by HCT/Ps typically recovered from deceased donors. As more information becomes available, the understanding of the risks to recipients of HCT/Ps, including HCT/Ps recovered from deceased donors, may evolve. The FDA will continue to monitor the situation, and will carefully evaluate new information regarding the associated risks as it becomes available.
In addition to the guidance documents addressing the nation’s blood supply and HCT/Ps, the FDA continues to prioritize the development of blood donor screening and diagnostic tests that may be useful for identifying the presence of or recent infection with the virus. The agency is also preparing to evaluate the safety and efficacy of investigational vaccines and therapeutics that might be developed, and is reviewing technology that may help suppress populations of the mosquitoes that can spread the virus.
Sources: FDA; March 1, 2016; and FDA; February 16, 2016.