America’s Blood Centers
American Red Cross
Before the Blood Products Advisory Committee
October 21, 2004
Simian Foamy Virus
Presented by Steven Kleinman, MD, Chair
Transfusion-Transmitted Diseases Committee, AABB
Simian Foamy Virus (SFV) infection in humans has been recognized for a number of years. Newer studies have confirmed that humans working with primates in zoos or in research institutes in the U.S. may acquire this infection. It also appears that primate-to-human transmission has been occurring for many years in areas of Central Africa.
Because of the past experience with other simian retroviruses developing into human pathogens (e.g. HIV-1, HIV-2, and HTLV), AABB, ABC, and ARC believe that continued concern over, and study of, SFV as a potentially transfusion-transmitted pathogen is warranted.
Current knowledge indicates that SFV infects human peripheral blood leukocytes and establishes a persistent infection that can be detected for over 20 years. SFV does not appear to cause disease in humans, although the number of chronically infected persons undergoing follow-up is limited.
Data about human-to-human transmission of SFV are sparse. Sexual transmission has not occurred in six couples and transfusion transmission did not occur in four recipients of blood components from a single SFV chronically-infected donor.
There are many unknowns about potential transfusion transmission, if it occurs. As a highly cell-associated virus, it is possible that SFV will behave similarly to HTLV, such that a) storage of red cells beyond 10-14 days would eliminate transmission; b) leukoreduction would greatly reduce if not eliminate the transmission risk from chronic carriers; and c) there would be no transmission from FFP, cryoprecipitate or fractionated plasma derivatives. These possibilities could be tested in an animal transfusion-transmission model.
There have been no studies of the prevalence of SFV in the U.S. donor population. Based on a limited number of research studies, some broad risk factors can be defined, including close physical contact with primates in the wild in Central Africa or in zoos and research institutes outside Central Africa. It is unclear if increased risk extends further to persons with more limited primate contact. It should be noted that the current donor history questionnaire includes a question about residence in Central Africa, which appears to be a possible risk factor for SFV infection. It has been anticipated that this question may be discontinued as blood centers begin using laboratory tests capable of detecting HIV-1 Group O.
In summary, limited current data suggest that SFV does not appear to be pathogenic for humans, the prevalence of the agent in U.S. donors is unknown (but would be suspected to be very low), transfusion transmission in humans has not been demonstrated, and if it were to occur, the potential protective effect of leukoreduction and the risk from plasma products have not been assessed. With the exception of definitively assessing the potential for SFV to be a human pathogen, we believe that the answers to all the remaining questions can be obtained by performing well-defined research studies.
In its investigations, the CDC has adopted a policy of counseling SFV-infected subjects to not donate blood, tissue, or other biological material. We agree with this approach. However, the deferral of a known SFV-infected person is a very different issue than adopting a deferral policy based on an attempt to establish an epidemiologic risk profile.
Until further information is available, AABB, ABC, and ARC believe that no additional questions should be added to the donor health history questionnaire. This document is already extremely long and complex, and the addition of more questions with unknown benefit runs the risk of distracting donors from more important risk questions. At this point, it is unclear what criteria should be adopted to identify SFV risk and how a question could be worded to elicit accurate risk information from donors.
AABB is an international association dedicated to advancing transfusion and cellular therapies worldwide. Our members include more than 1,800 hospital and community blood centers and transfusion and transplantation services as well as approximately 8,000 individuals involved in activities related to transfusion, cellular therapies and transplantation medicine. For over 50 years, AABB has established voluntary standards for, and accredited institutions involved in, these activities. AABB is focused on improving health through the advancement of science and the practice of transfusion medicine and related biological therapies, developing and delivering programs and services to optimize patient and donor care and safety.
America’s Blood Centers is a national network of locally-controlled, non-profit community blood centers that provide nearly half of the U.S. blood supply from volunteer donors. Collectively, ABC total blood collections exceeded 7 million donations in 2003. ABC members provide blood services in 45 states and in Quebec, Canada, and serve more than half of the 6,000 hospitals in the U.S.
The American Red Cross, through its 36 Blood Services Regions and nine National Testing Laboratories, supplies approximately half of the nation's blood supply. Over six million units of Whole Blood were collected from more than four million Red Cross volunteer donors, separated into 12 million components, and supplied to over 3000 hospitals to meet the transfusion needs of patients last year. Over one million liters of plasma from volunteer blood donations are recovered annually by the American Red Cross, further processed into numerous plasma derivatives, and distributed to healthcare providers.