In its continuing attempt to assure the safety of all our vaccines, this year the Food and Drug Administration Center for Biologics Evaluation and Research (CBER) conducted a careful review of the science relating to risk of bovine spongiform encephalopathy (BSE) transmission through use of vaccines. The human disease that has been attributed to ingestion of products infected with BSE is variant Creutzfeldt-Jakob disease (vCJD).
CBER held a joint meeting of the two committees involved (the Transmissible Spongiform Encephalopathy Advisory Committee and the Vaccines and Related Biological Products Advisory Committee) on July 27, 2000.
At that session, FDA statisticians presented their calculations that the theoretical risk of any bacterial or viral vaccine contamination by the agent of BSE was remote, ranging from 1 in 2 billion to 1 in 200 billion doses1. Further reassurance stems from CDC's surveillance of neurologic disorders, which reveals no cases of vCJD in the USA2.
Moreover, a review by British scientists of the 52 vCJD cases reported in Britain (published in the October issue of Vaccine) shows that vaccine use appears to have no role in the development of the disease3. The authors conclude: 'If vCJD is the result of exposure to BSE-infected cattle material, the vaccines given before age 2 years appear to have no role in its etiology to date. Forty-nine of the 52 cases were born before 1980 and would therefore have received the vaccines before exposure was possible. The remaining three were born in the 1980s, but even so, given the long period between starting manufacture from the raw materials and the completion of the finished products, exposure would seem unlikely. The distribution of birth dates implies that exposure through booster doses and vaccines given at secondary school age is also unlikely.'
The Public Health Service Recommendations for the Use of Vaccines Manufactured with Bovine-Derived Materials are published in the December 21 issue of Morbidity and Mortality Weekly Report (MMWR), which is available at http://www.cdc.gov/mmwr/. These findings should reassure clinicians that the U.S. vaccine surveillance system is effectively working to ensure that the vaccines we use are safe, and that concerns about possible effects are being thoroughly researched.
1. http://www.fda.gov/ohrms/dockets/ac/00/transcripts/3635t1b.pdf Transcript of July 27, 2000, CBER meeting, p. 120.
2. Gibbons RV, Holman RC, Belay ED, Schonberger LB. Creutzfeldt-jakob Disease in the United States: 1979-1998. JAMA. 2000 Nov 8;284(18):2322-3.
3. Minor PD, Will RG, Salisbury D. Vaccines and variant CJD. Vaccine. 2000 Oct 15;19(4-5):409-10.
U.S. Food and Drug Administration
The Centers for Disease Control and Prevention National Immunization Program:
National Center for Infectious Diseases:
U.S. Department of Agriculture
United Kingdom Ministry of Health and Agriculture
World Health Organization