Dr. Julie Gerberding, head of the Centers for Disease Control and Prevention in Atlanta, said the agency has already recommended that change — a step not previously taken because flu virus has never been considered a possible bioterrorism weapon.
Gerberding statements came less than 24 hours after the World Health Organization began urging the world's labs to destroy an almost 50-year-old pandemic flu virus.
The germ was sent in kits as part of proficiency testing to nearly 5,000 labs — mostly in the United States.
A Canadian lab alerted the WHO that the sample was from the 1957 flu pandemic, which killed between 1 million and 4 million people. It has not been included in flu vaccines since 1968, and anyone born after that date has little or no immunity to it.
The WHO said Canada, South Korea, Hong Kong and Singapore had already destroyed their samples, while Japan was doing the same. Taiwan and Germany also announced that they had destroyed all their vials.
"It's very important these samples be destroyed very, very rapidly," the WHO's flu chief Dr. Klaus Stohr told CBS Radio News.
Stohr said he was "relatively confident" most of the samples outside the United States would all be destroyed by Friday.
Gerberding noted that there had been no sign of the strain circulating anywhere.
Health and Human Services Secretary Michael Leavitt also is reviewing all procedures regarding handling flu viruses to prevent future incidents of this nature, Gerberding said.
A spokesman said earlier the agency was in touch with an estimated 3,000 to 4,000 labs around the country to verify they had destroyed the pandemic virus.
The agency said it didn't know why such a dangerous strain was included as part of the testing process.
"There's a lot of questions right now we don't have answers to," said spokesman Tom Skinner. "I think what people need to understand is the very labs that receive these strains of influenza all have people trained to work safely and effectively with these viruses...."
Countries were urged by the World Health Organization to destroy samples of the dangerous virus because of the slight but real risk it could trigger a global outbreak.
"I think this is a theoretical risk. There is no outbreak at the moment CBS News Health Correspondent Dr. Emily Senay told Early Show co-anchor René Sylver.
"The concern is that it would escape from one of these laboratories, possibly infect one of the workers, and go from there. But this has not happened yet, and these laboratories ... are accustomed to working with virulent pathogens."