With no new Ebola cases in five days, US authorities were cautious but hopeful Monday that the virus has been contained in the United States after a flawed response revealed shortcomings in the system.
The fiancee of a Liberian man who died of Ebola earlier this month in Dallas, Texas, was among nearly 50 people who emerged from three weeks of quarantine without any signs of illness from exposure to the virus that has killed more than 4,500 in West Africa since the beginning of this year.
About 100 more people, most of them health care workers, are being tracked in Texas after coming in contact with the first patient diagnosed in the United States in late September.
Still, officials said it was reassuring that no new infections had emerged in recent days.
"We are breathing a little bit easier, but we are still holding our breath," said Dallas Mayor Mike Rawlings.
Those who are no longer in danger include a group of health care workers and community members who may have had contact with Liberian Thomas Eric Duncan between September 24, when he began showing symptoms, and September 28 when he was isolated in a Dallas hospital.
"This is a crucial milestone for the city of Dallas and for concerned persons across the United States," said Mark Rupp, an infectious disease specialist at Nebraska Medical Center, which has treated two US Ebola patients after they were infected in Liberia this year.
"I hope this reinforces the message that the public is safe and that Ebola is not very infectious in its early stages."
Two nurses in the intensive care unit at Texas Health Presbyterian Hospital Dallas were infected during the care of Duncan, who died October 8.
Nina Pham's infection was announced October 12, and her colleague Amber Vinson's was three days later.
Ebola is spread though close contact with vomit, blood, diarrhea or other bodily fluids. Most people get sick within eight to 10 days of exposure, and health care workers are particularly at risk.
Word of the nurses' infections sowed panic across the United States, leading to a rash of suspected cases that turned out to be nothing more than common illnesses.
"In the United States, two people have gotten infected with Ebola. Two. Both of them were taking care of a desperately ill patient in a risky situation," said Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, during a forum at Washington's Newseum.
"You have to distinguish the two nurses... from the risk to the general public who aren't anywhere near an Ebola patient, much less a very sick Ebola patient."
Pham is in fair condition at a specialized government hospital near the US capital, and Fauci declined to speculate on whether she would make a full recovery.
"She still is a bit knocked out," Fauci said.
"When you get an infection as serious as Ebola it is very, very draining on you."
Vinson's family said in a statement Sunday they "remain intensely prayerful and optimistic about Amber's condition and of the treatment she is currently receiving" at Emory University Healthcare, in Atlanta Georgia, but gave no details on the state of her health.
Another US man, who has kept his identity secret after being infected with Ebola in West Africa in September, has recovered and was released from the same hospital over the weekend, it was confirmed Monday.
The Dallas hospital which initially sent Duncan away when he sought care for pain and a fever, apologized Sunday for its handling of the case.
"As an institution, we made mistakes in handling this very difficult challenge," Texas Health CEO Barclay Berdan said in a statement.
Jesse Goodman, a doctor and public health expert at Georgetown University, said the United States was learning from the intially flawed response.
"I do think events indicate how important it is to probably be over cautious rather than over confident," said Goodman at the Newseum event.
Fauci added that the epidemic was far from ending in West Africa, and said all nations need to pour resources into ending the spread of the disease there.
"Right now I don't think we can predict when this epidemic is going to be over. When you look at it, it is still escalating rather than declining."