At the recent Blood Products Advisory Committee (BPAC) meeting (ABC Newsletter #42), the U.S. Food and Drug Administration (FDA) heard the committee’s endorsement for moving from the current universal individual donation nucleic acid testing (ID-NAT) for Zika virus (ZIKV) to a model used for West Nile Virus (WNV) donor screening—screening using minipools (MP-NAT) to reduce operational burdens, with rapid conversion to ID-NAT based on prospectively determined “triggers” that demonstrate at the probability of local (autochthonous) vector-borne transmission(s). This strategy was recommended by ABC via a statement endorsed by the Scientific, Medical, and Technical Committee, reviewed by the ABC Board of Directors, and delivered as a joint statement from ABC, the American Red Cross, and the AABB. The current expectation for WNV is that ID-NAT triggering will occur in an appropriate geographic region based on a donor’s residential zip code within 24 hours or less of reaching a trigger—a fixed number of presumptively viremic donors (and/or the presence of other WNV activity in the area served by a collection facility). For WNV, accomplishing this rapid conversion to ID from MP-NAT required the evolution of an effective communication system among laboratories and center-to-center that includes blast e-mail communications to formally maintained address lists and entry of appropriate data on a website hosted by the AABB. A similar website was established to accommodate information on ZIKV testing of donors during IND testing and remains operable. Such data entry and e-mail messaging must occur as soon as possible (again, not to exceed 24 hours) since other collectors must assess their need to transition to ID-NAT.
Recent review of data from the AABB ZIKV website suggests that individual centers are not providing timely data entry (e.g., as of Jan. 5th, only 43 of 55 confirmed positive donors were listed). This has not yet had a safety or operational impact, since there is no switching to ID from MP-NAT. However, our adherence to timely conversion to ID-NAT will be critical for FDA to accept a more flexible testing model. The AABB Transfusion Transmitted Diseases (TTD) Committee (inclusive of centers, hospitals, the Centers for Disease Control and Prevention, and the military) and FDA are now considering the advice from BPAC, and what information is needed and useful for nimble triggering and detriggering. It is clear that waiting for public health surveillance data will not be timely in many, if not most, jurisdictions, so our responsibility for timely donor surveillance is critical. MP-NAT has the advantage of allowing the prediction of which donors will be confirmed with subsequent testing. That is, a reactive minipool that resolves to a single donation sample, has a very high positive predictive value, and can be used to initiate immediate donor interview regarding risk for infection and subsequent triggering decisions without waiting for reference supplemental testing. As we develop processes for this transition, please be sure your SOPs will support timely (i.e., immediate) communication and data entry. Let us know how we can assist in timely submission of data to the Zika hemovigilance website.
Jed Gorlin, MD, MBA, ABC Liaison to AABB Transfusion Transmitted Diseases Committee
Louis Katz, MD, Chief Medical Officer, ABC & AABB Transfusion Transmitted Diseases Committee