WASHINGTON - Health officials were trying to determine yesterday whether West Nile virus can be spread through blood transfusions. But any test to screen donated blood for the sometimes deadly disease is at least months, maybe years, away, they said.
Still, they emphasized that the blood supply is very safe and the risk of contracting West Nile from blood is far lower than the risk of forgoing any procedure that requires a transfusion.
West Nile, which emerged in the United States three years ago, has exploded across the country this summer, with 673 cases and 32 deaths.
But concern increased Tuesday when officials confirmed that at least three of four people who had received organs from a Georgia woman had contracted the disease. One died.
Officials said they are convinced that these patients got the disease through their transplants, though they do not yet know whether the virus can be spread through blood as well.
Dozens of epidemiologists at the Centers for Disease Control and Prevention in Atlanta and the CDC lab in Fort Collins, Colo., were trying to figure out how the organ donor, a Georgia woman who died in a car crash, got West Nile.
She had received blood from more than 60 donors before she died, and scientists were tracing those blood donors to see whether any of them have the virus. They are also tracking down about a dozen other people who received transfusions from the same donors.
It is possible the organ donor might have contracted West Nile from a mosquito bite, as others have. It also is possible that the virus can be spread through organ transplants but not through blood. Still, health officials suspect that blood can carry the virus, at least in some cases.
For now, they are reminding blood banks to be sure that no one with a fever or who appears ill donates blood, which could eliminate those with mild West Nile symptoms. They are also alerting organ procurement organizations to the issue.
Ultimately, a screening test is probably needed, said Dr. Lester Crawford, acting commissioner of the Food and Drug Administration. He said government would work with industry to speed development of a test.
Even so, testing for the virus is complicated. Some of the tests that are used to diagnose West Nile in sick people will not pick up the virus in donated blood. Other, more promising tests would require significant improvements to be practical on a mass scale, enabling blood banks to screen millions of pints each year.
"I'm reasonably optimistic that if needed, it could be done," said Dr. Jesse Goodman, deputy director of the Center for Biologics, Evaluation and Research at the FDA.
He suggested that an early test could be used to screen blood going to patients who are particularly susceptible to West Nile. The FDA could allow use of the test as an experimental product before it is officially licensed. That, he said, could give the blood supply some quick added protection.
Others are less confident.
"It's going to take several years to have a test suitable for blood donors," said Dr. Harvey G. Klein, chief of the Department of Transfusion Medicine at the National Institutes of Health and past president of the American Association of Blood Banks.
The tests, he said, are very early in their development.
He said tests available today would produce some false positives, where healthy blood appears to be infected. Using these tests could mean throwing away many pints of good blood at a time when the blood supply barely keeps up with demand.
Officials are worried about people who donate blood before they know they are sick.
Still, they emphasized that the blood supply is very safe and the risk of contracting West Nile from blood is far lower than the risk of forgoing any procedure that requires a transfusion.
West Nile, which emerged in the United States three years ago, has exploded across the country this summer, with 673 cases and 32 deaths.
But concern increased Tuesday when officials confirmed that at least three of four people who had received organs from a Georgia woman had contracted the disease. One died.
Officials said they are convinced that these patients got the disease through their transplants, though they do not yet know whether the virus can be spread through blood as well.
Dozens of epidemiologists at the Centers for Disease Control and Prevention in Atlanta and the CDC lab in Fort Collins, Colo., were trying to figure out how the organ donor, a Georgia woman who died in a car crash, got West Nile.
She had received blood from more than 60 donors before she died, and scientists were tracing those blood donors to see whether any of them have the virus. They are also tracking down about a dozen other people who received transfusions from the same donors.
It is possible the organ donor might have contracted West Nile from a mosquito bite, as others have. It also is possible that the virus can be spread through organ transplants but not through blood. Still, health officials suspect that blood can carry the virus, at least in some cases.
For now, they are reminding blood banks to be sure that no one with a fever or who appears ill donates blood, which could eliminate those with mild West Nile symptoms. They are also alerting organ procurement organizations to the issue.
Ultimately, a screening test is probably needed, said Dr. Lester Crawford, acting commissioner of the Food and Drug Administration. He said government would work with industry to speed development of a test.
Even so, testing for the virus is complicated. Some of the tests that are used to diagnose West Nile in sick people will not pick up the virus in donated blood. Other, more promising tests would require significant improvements to be practical on a mass scale, enabling blood banks to screen millions of pints each year.
"I'm reasonably optimistic that if needed, it could be done," said Dr. Jesse Goodman, deputy director of the Center for Biologics, Evaluation and Research at the FDA.
He suggested that an early test could be used to screen blood going to patients who are particularly susceptible to West Nile. The FDA could allow use of the test as an experimental product before it is officially licensed. That, he said, could give the blood supply some quick added protection.
Others are less confident.
"It's going to take several years to have a test suitable for blood donors," said Dr. Harvey G. Klein, chief of the Department of Transfusion Medicine at the National Institutes of Health and past president of the American Association of Blood Banks.
The tests, he said, are very early in their development.
He said tests available today would produce some false positives, where healthy blood appears to be infected. Using these tests could mean throwing away many pints of good blood at a time when the blood supply barely keeps up with demand.
Officials are worried about people who donate blood before they know they are sick.