"[w]e have taken every precaution that we know and that our colleagues at the C.D.C. know to ensure that there is no spread of Ebola,” he said.
The director of the Centers for Disease Control, Dr. Thomas R. Frieden, agreed that the patients posed little risk to others. And he added: “These are American citizens. American citizens have a right of return. I certainly hope people’s fear doesn’t trump their compassion.”
"[I]n one episode last month, at least 62 Center for Disease Control employees may have been exposed to live anthrax bacteria after potentially infectious samples were sent to laboratories unequipped to handle them. Employees not wearing protective gear worked with bacteria that were supposed to have been killed but may not have been. All were offered a vaccine and antibiotics, and the agency said it believed no one was in danger.
In a second accident, disclosed Friday, a C.D.C. lab accidentally contaminated a relatively benign flu sample with a dangerous H5N1 bird flu strain that has killed 386 people since 2003. Fortunately, a United States Agriculture Department laboratory realized that the strain was more dangerous than expected and alerted the C.D.C.
In addition to those mistakes, Dr. Frieden also announced Friday that two of six vials of smallpox recently found stored in a National Institutes of Health laboratory since 1954 contained live virus capable of infecting people.
All the samples will be destroyed as soon as the genomes of the virus in them can be sequenced. The N.I.H. will scour its freezers and storerooms for other dangerous material, he said.
“These events revealed totally unacceptable behavior,” Dr. Frieden said. “They should never have happened. I’m upset, I’m angry, I’ve lost sleep over this, and I’m working on it until the issue is resolved.”
The anthrax and flu labs will remain closed until new procedures are imposed, Dr. Frieden said. For the flu lab, that will be finished in time for vaccine preparation for next winter’s flu season, he said.