Most of the samples of a dangerous flu virus sent to laboratories around the world have been destroyed, easing concerns that the specimens might trigger a deadly pandemic, health officials said yesterday.
At least 15 of the 19 countries that received the virus confirmed that they had eliminated all samples, and officials were hopeful the remainder would be accounted for soon.
"Based on this progress, we think the risk to human health from the distribution of these samples has been sharply decreased," said Klaus Stohr of the World Health Organization. "With the ongoing destruction, we are optimistic."
The problem occurred when Meridian Bioscience Inc. outside Cincinnati mailed the virus to more than 4,000 laboratories, mostly in the United States, as part of kits designed to certify the labs' performance. The company apparently believed the virus was safe.
The same virus caused the 1957-58 Asian pandemic, which killed 1 million to 4 million people, including about 70,000 in the United States. Because the virus has not circulated since 1968, anyone born after that time has little or no immunity, raising fears that a laboratory worker might become infected and spread it, triggering another deadly pandemic.
Canadian officials discovered the problem accidentally during routine testing and alerted WHO and the U.S. Centers for Disease Control and Prevention on April 8, setting off an urgent campaign to locate and destroy the samples.
Bermuda, Belgium, Brazil, Canada, Chile, France, Germany, Hong Kong, Italy, Lebanon, South Korea, Mexico, Singapore and Taiwan confirmed that they had neutralized all their samples, along with a newly identified U.S. military lab in Britain, WHO said. Officials also determined that samples sent to labs in Lebanon, Chile and Mexico that never arrived had either been secured or already destroyed.
Israel, Japan, Saudi Arabia and the United States were the only countries still tracing samples, Stohr said.
The College of American Pathologists, which requested most of the kits and is coordinating their destruction, said written confirmation had been received for 77 percent of all samples, and telephone conversations with recipients of the remaining 23 percent indicated most of those samples had been destroyed as well. The organization set up a 24-hour hotline that will be open over the weekend in the hope of confirming destruction of the remainder as quickly as possible, a spokesman said.
Ninety percent of samples shipped at the request of other organizations had also been destroyed, WHO said.
Health officials continued to monitor anyone who may have come in contact with the virus for signs of illness, but no cases were reported.
In response to the problem, the CDC announced this week that the agency would speed up plans to require tighter security for the handling of dangerous strains of flu virus. WHO is also drafting new procedures for handling the virus, Stohr said.
But officials remained concerned that there is no comprehensive inventory of exactly how many facilities had the virus and how it was being stored.