Asher D M
Laboratory of Method Development, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20852-1448, USA.
Dev Biol Stand. 1999;99:41-4.
Since 1993, consistent with its statutory responsibility to ensure that regulated products are safe, pure, and free of << extraneous organisms, >> the United States Food and Drug Administration (FDA) has requested that, with certain exceptions, bovine-derived materials from animals born in or residing in countries where bovine spongiform encephalopathy has occurred, should not be used to manufacture products intended for humans. FDA's Center for Biologics Evaluation and Research (CBER) has specifically recommended that serum used to produce biologicals be obtained from sources << certified to be free from contaminants and adventitious agents, such as the agent responsible for the production of Bovine Spongiform Encephalopathy. >> The United States Department of Agriculture (USDA) has prohibited importation of such serum for use in products. FDA staff are aware that bovine blood, including foetal blood, and placental tissues and fluids that might contaminate foetal serum have not been found to contain the infectious agent of BSE, and that those tissues are considered by most authorities to have little risk for transmitting disease to humans or animals. However, studies of BSE have been limited in size and sensitivity, and several experimental studies of scrapie and CJD in rodents found their blood to be infectious. In addition, a recent unpublished study of BSE (requiring confirmation) reported finding infectivity in the bone marrow of cattle. Possible transmission of BSE from cows to calves, although unlikely to constitute a major mode for maintaining the BSE outbreak, has also not been rigorously ruled out. Considering the special nature of biological products, especially of vaccines intended for widespread use in children, it seems prudent for U.S. regulatory authorities to continue current conservative policies that discourage or prohibit the use of bovine serum from countries with BSE.
自1993年以来，美国食品药品监督管理局（FDA）依据其法定职责，即确保受监管产品安全、纯净且无<<外来生物体>>，要求除某些例外情况外，不得使用来自曾发生牛海绵状脑病国家出生或居住的动物的牛源材料来制造供人类使用的产品。FDA生物制品评估和研究中心（CBER）特别建议，用于生产生物制品的血清应从<<经认证无污染物和外来因子的来源获取，例如导致牛海绵状脑病的因子。>>美国农业部（USDA）已禁止进口此类血清用于产品。FDA工作人员知晓，尚未发现牛血（包括胎血）以及可能污染胎血清的胎盘组织和液体含有疯牛病感染因子，并且大多数权威机构认为这些组织向人类或动物传播疾病的风险极小。然而，疯牛病的研究在规模和敏感性方面有限，对啮齿动物进行的一些羊瘙痒病和克雅氏病实验研究发现其血液具有传染性。此外，最近一项关于疯牛病的未发表研究（有待确认）报告称在牛的骨髓中发现了传染性。疯牛病从母牛传播至小牛的可能性虽然不太可能构成维持疯牛病疫情的主要传播方式，但也尚未被严格排除。考虑到生物制品的特殊性质，尤其是打算广泛用于儿童的疫苗，美国监管当局继续推行当前保守政策，即不鼓励或禁止使用来自有疯牛病国家的牛血清，似乎是审慎之举。
