VACCINES: POSSIBLE SOURCES OF "MAD COW"
KATHERINE WORTON, MD, asks: "Vaccines in the U.S. aren't made using bovine serum from countries where bovine spongiform encephalopathy (BSE or "mad cow disease") has been found anymore, but vaccines already made from these materials are still in circulation. Have any cases of variant Creutzfeld-Jacob disease (vCJD) been linked to vaccine contamination?"
It's been shown that whole blood, serum or buffy coats derived from humans and animals can contain low levels of infectivity from prior associated diseases -- but only occasionally. Although there have been anecdotal reports, there aren't any clearly proven cases of CJD arising from the transfusion of blood products. Epidemiologic studies also haven't been able to identify transfusion as a risk factor for developing CJD. A potential link between BSE and CJD mainly applies to the newly described vCJD, which is characterized by a longer duration of illness and a preponderance of sensory and psychiatric manifestations. Epidemiologically, vCJD was first described after an outbreak of BSE in the United Kingdom. In addition, vCJD and BSE are very similar from a neuropathologic perspective. I'm not aware of any purported link between vaccines and CJD. In addition, there aren't any vaccines derived from bovine serum per se, though fetal calf serum is used in preparing and maintaining some in vitro cell lines. These, I suppose, might be used to raise viruses for vaccine preparation. DM