Worries of 'Mad cow' contamination lead panel to urge barring some blood donors

Worries of 'Mad cow' contamination lead panel to urge barring some blood donors

By LAURAN NEERGAARD

GAITHERSBURG, Md. (June 2, 1999 10:06 p.m. EDT http://www.nandotimes.com) - Some Americans who visited Britain frequently during the mad cow disease scare should be forbidden to donate blood back home, a federal panel recommended Wednesday.

The advisers to the Food and Drug Administration expressed concern about a theoretical risk that a similar human brain disease might be able to spread through blood.

Panel members stressed that their vote did not mean that frequent travelers to Britain are at risk of getting a fatal illness linked to mad cow disease - or of spreading it through their blood.

The problem is that scientists just don't know if the illness can be spread that way. There's never been a human case where that happened. But at issue is a new fatal disease that doctors don't yet understand - and some scientists have successfully transmitted similar illnesses to animals through blood.

"The day you find out there is (human) transmission, you're years too late" to protect the blood supply, warned Dr. Linda Detwiler of the U.S. Agriculture Department as the panel voted 12-9 that FDA should forbid some blood donations.

The FDA is not bound by its advisers' recommendations, but typically follows them.

If it does so in this case, it must decide how long someone had to stay in Britain to be deemed enough of a risk to refuse their blood.

That's crucial because an American Red Cross study found almost 23 percent of recent blood donors had traveled to Britain at least once between 1980 and 1996. If the FDA barred them all, the United States would face a critical blood shortage.

The advisory panel said the concern is not a typical week-long tourist trip. Instead, a majority said Americans must have spent a total of over six months in Britain between 1980 and 1996 before being blocked from donating blood. Some advisers wanted the time extended to over a year, excluding fewer people.

Blood donations are dropping every year even as demand for blood increases, and every summer and during holidays parts of the country experience serious shortages.

If the FDA blocks travelers who spent a total of six months in Britain, there will be a 2.2 percent drop in the U.S. blood supply, the Red Cross study said.

A majority of FDA's advisers said even though the risk is only theoretical, it makes sense to be conservative in protecting the public. Some noted that critics say the AIDS epidemic might have been mitigated had doctors taken a more aggressive stand to protect the blood supply in the early 1980s.

At issue this time is an infection that kills by literally eating holes in brain tissue. In cows, this condition is called mad cow disease - and from the late 1980s through 1996, British cows suffered an epidemic. Mad cow disease also has been found in cattle in certain other countries, but Britain was hardest hit.

About one in 1 million people around the world gets a similar brain disease called Creutzfeldt-Jakob disease, or CJD. Although CJD sometimes is hereditary, usually its cause is not known.

The worry about blood stems from Britain's discovery in the mid-1990s that some people caught a new variety of CJD apparently by eating beef infected with mad cow disease. Named "new variant CJD," it has claimed 39 British victims.

There is no known mad cow disease in U.S. cattle, the United States has not allowed importation of British beef for over a decade and no American has caught new variant CJD.

But because these brain diseases can incubate for years without causing symptoms, some scientists say the possibility exists that years from now they will discover a link between blood transfusions and infection. Indeed, doctors are closely watching Britain to see if that happens.

The British government now imports drugs made from blood plasma from other countries, although British researchers told the FDA panel Wednesday that they simply cannot predict the risk, if any.

Canadian health officials last month decided they, too, would determine how to block blood donations from certain Canadians who traveled to Britain.