"I don't want to be directly criticizing the decision that was made but we have to be careful that there are unintended consequences," Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said of the measures imposed by New York, New Jersey and Illinois.
"The best way to stop this epidemic is to help the people in West Africa, we do that by sending people over there, not only from the U.S.A. but from other places," Fauci told NBC's "Meet the Press," adding such quarantines were "a little bit draconian."
The three states imposed 21-day mandatory quarantines in the last two days for anyone arriving with a risk of having contracted Ebola in Sierra Leone, Liberia and Guinea. They are the three West African countries that have borne the brunt of an epidemic that has killed nearly 5,000 people.
The policies were abruptly imposed after a New York City doctor was diagnosed with the disease on Thursday after coming home from treating patients in Guinea.
A nurse who returned on Friday through New Jersey's Newark airport after working in Sierra Leone with Ebola patients, strongly criticized the quarantine policy on Saturday, describing hours of questioning and then transfer to a hospital isolation tent, calling her treatment a "frenzy of disorganization."
Fauci reiterated what the medical officials have been stressing as Americans worry about the spread of the disease: that it is spread only by contact with bodily fluids of people with symptoms. There have been four cases of the disease diagnosed in the United States.
"The science tells us that people who are not sick, if you do not come into contact with body fluid, if someone comes back from wherever, Liberia, and they're well, they are no danger to anyone," Fauci said.
But New Jersey Governor Chris Christie, asked to respond to Fauci's comment that it is not good science to quarantine people when they're not symptomatic, said, "I don't believe that when you're dealing with something as serious as this that we can count on a voluntary system."
"This is government's job. If anything else, the government's job is to protect the safety and health of our citizens," he told the "Fox News Sunday" program.
'CRIMINALS AND PRISONERS?'
Kaci Hickox, the nurse who came home from Sierra Leone on Friday said after her experience that she feared for what lies ahead for other U.S. health workers trying to help combat the epidemic.
"Will they be made to feel like criminals and prisoners?" she wrote in an article published on Saturday by The Dallas Morning News on its website. (http://bit.ly/1w4Vi4J)
"I am scared that, like me, they will arrive and see a frenzy of disorganization, fear and, most frightening, quarantine," wrote Hickox, who had been working with Doctors Without Borders.
The medical charity has also criticized her treatment.
Ebola has killed almost half of more than 10,000 people diagnosed with the disease - predominantly in Liberia, Sierra Leone and Guinea - although the true toll is far higher, according to the World Health Organization.
Samantha Power, the U.S. Ambassador to the United Nations, arrived in Guinea's capital Conakry on Sunday, and plans also to visit Liberia and Sierra Leone to see the global response to the Ebola spread first hand.