Five people in the U.S. have been hospitalized with confirmed cases of the coronavirus: one in Washington, one in Illinois, one in Arizona and two in California.
All of those patients had traveled to Wuhan, China, the epicenter of the outbreak. Cases in China have now surpassed 2,700, and at least 80 deaths have been reported. People most severely affected have generally been older adults with underlying health conditions.
"Our thoughts are with the people on the front lines of this emerging public health threat in China," Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases, said during a call with journalists.
"This is a rapidly changing situation, both here and abroad," she added.
A handful of cases have been reported in other countries as well, including Australia, Japan, Thailand, France, South Korea, Vietnam and Canada.
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Of the 110 people in the U.S. undergoing testing, the five cases in Arizona, California, Illinois and Washington are the only ones to come back positive. Thirty-two have tested negative. The rest of the results are pending at the CDC.
The 110 samples for testing have come from 26 states, though the CDC declined to say which states.
Right now, blood and respiratory samples from suspected patients are all sent to the CDC to test for the new virus. The CDC is working to make test kits available to state health departments, but it’s going to be at least another week or two before those are ready, Messonnier said.
The U.S. government is working to help evacuate some of the American citizens in Wuhan, as early as Tuesday. The flight is scheduled to make two stops: in Anchorage, Alaska and in Ontario, California, which is east of Los Angeles.
The CDC is "intricately involved in coordinating the planning" of the flight, Dr. Martin Cetron, the director of CDC's Division of Global Migration and Quarantine, said Sunday during a call with reporters.
He added that the passengers' health will be screened multiple times, including during the flight.
Health officials have been screening passengers traveling from Wuhan and arriving at five major airports: New York's John F. Kennedy International, San Francisco International, Los Angeles' LAX, Hartsfield-Jackson in Atlanta, and O'Hare in Chicago.
So far, around 2,400 passengers have been screened.
The purpose of the screenings is not just to identify ill passengers; they're also an opportunity for health officials to provide information about what symptoms to watch for, as well as what people should do if they start developing a fever or a cough.
That education is key, as at least two of the confirmed patients in the U.S. weren't ill when they flew home from China. They developed symptoms after getting home.
Health officials are also monitoring dozens of people who've had close contact with the five patients in the U.S. The incubation period, that is, the time from when a person is exposed to the virus to the time they become ill, is anywhere from two to 14 days, according to the CDC.
Officials said the health risk to the general American public remains low. "We're being aggressive and cautious in tracking those close contacts," Messonnier said. "So far, we have not seen any human-to-human transmission in the U.S."
The agency suggests people avoid all nonessential travel to Hubei Province in China, where Wuhan is located. Messonnier suggested talks are ongoing about changing that travel guidance, but declined to elaborate.