Photo courtesy of NHS
The US Food and Drug Administration (FDA) has issued a guidance document intended to help reduce the risk of Zika virus transmission via human cells, tissues, and cellular and tissue-based products (HCT/Ps).
The guidance addresses donation of HCT/Ps from both living and deceased donors, including donors of umbilical cord blood and hematopoietic stem/progenitor cells.
In this document, the FDA recommends a 6-month deferral period for most HCT/P donors who may have been exposed to the Zika virus.
The exception is donors of gestational tissues, who should be considered ineligible if they were at risk of contracting the virus at any time during their pregnancy.
The new guidance is a part of the FDA’s ongoing efforts to protect HCT/Ps and blood products from Zika virus transmission. Last month, the agency issued recommendations for reducing the risk of Zika virus transmission via blood transfusion.
There is a potential risk that Zika virus can be transmitted by HCT/Ps used as part of a medical, surgical, or reproductive procedure. HCT/Ps include products such as corneas, bone, skin, heart valves, hematopoietic stem/progenitor cells, 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, there have been several cases of sexual transmission in the US.
Current information about Zika virus detection in semen suggests the period of deferral for HCT/P donors should be longer than the period recommended for donors of whole blood and blood components.
Therefore, the FDA has recommended that living donors of HCT/Ps 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 6 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.
Deceased donors should be considered ineligible if they were diagnosed with Zika virus infection in the past 6 months.
A deferral period of 6 months was chosen 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.
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 said it will continue to monitor the situation and evaluate new information regarding the associated risks as it becomes available.
In addition, the FDA said it is prioritizing the development of blood donor screening and diagnostic tests that may be useful for identifying the presence of or recent infection with the Zika virus. The agency is prepared to evaluate investigational vaccines and therapeutics that might be developed and review technology that may help suppress populations of the mosquitoes that can spread the virus.
