The United States must remain on alert as the new coronavirus spreads globally, public health officials said Tuesday, though the risk of its spreading in the country still remains low.
"This is a very fast moving, constantly changing situation," Health and Human Services Secretary Alex Azar said during a news conference. "But at this point, Americans should not worry for their own safety."
Dozens of people have been tested for the coronavirus in the U.S., but only five cases have been confirmed so far. All are travelers from Wuhan, China — where most cases have been reported by far — and all are hospitalized in isolation.
The Centers for Disease Control and Prevention is now monitoring people who have come into close contact with those patients for any signs of illness. Even though cases have spread between people in China, Japan and Germany, there have been no signs of human-to-human transmission in the U.S. so far.
As the epidemic continues, the U.S. government has issued travel advisories, saying Americans should not travel to Hubei province in China, where the new coronavirus is believed to have originated, and where cases are concentrated.
For travel elsewhere in China, the Department of State cautions that Americans should reconsider or postpone trips.
The U.S. is also stepping up efforts to screen passengers arriving from China. The CDC will begin screening for sick passengers at quarantine stations at 20 airports across the nation, including the five airports already screening passengers from Wuhan.
Questions remain about the spread
Because the virus is so new, scientists are still learning the basics of how it acts, how it spreads, and how deadly it is. Additional information may be forthcoming, as Chinese authorities Tuesday agreed to allow outside experts in to help with the growing outbreak.
Most respiratory illnesses are spread when an infected person has symptoms, such as coughing or sneezing.
There have been some early reports that suggested this illness might be spread by people who are asymptomatic, that is, people who've been infected but aren't yet showing any symptoms. (This is similar to how influenza spreads, for example.)
In all the history of respiratory-borne viruses of any type, asymptomatic transmission has never been the driver of outbreaks.
U.S. health officials say they haven't seen this virus act like that, and want to see the data from China that suggests it does.
"The driver of outbreaks is always a symptomatic person," said Dr. Anthony Fauci, director of the National Institutes of Health's National Institute of Allergy and Infectious Diseases. "Even if there is some asymptomatic transmission, in all the history of respiratory-borne viruses of any type, asymptomatic transmission has never been the driver of outbreaks."
Treatments under development
There is no specific medication or treatment for the new coronavirus; patients are only helped by what's called supportive care, for example, to help them breathe.
But treatments are under development, and some existing drugs, such an experimental Ebola treatment called remdesivir, are being studied for their potential role in treating the new coronavirus.
Additionally, early work on a vaccine has begun at the NIH.
It's work that Fauci attributes to Chinese researchers publicly releasing the genetic sequence of the virus, so scientists worldwide can use it for vaccine development.
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Phase I of a clinical trial could begin within three months. That doesn't mean the U.S. will be immediately supplied with a vaccine, however. It would take many more months to determine whether that vaccine is safe and effective.
By then, the global outbreak could be over, and researchers would then reassess vaccine efforts.
"We are proceeding as if we will have to deploy a vaccine," Fauci said during the news conference. "We're looking at the worst scenario if this becomes a bigger outbreak."
Cases in China are rising daily. As of late Tuesday, there were at least 5,974 confirmed cases in that country, and at least 132 deaths, Chinese health officials said.
And health officials from around the world are confirming a rising number of cases. In addition to the five U.S. cases, others have been diagnosed in Australia, Cambodia, Canada, France, Germany, Hong Kong, Japan, Nepal, Singapore, South Korea, Thailand and Vietnam.
While all of those cases are associated with travelers from the epicenter of the outbreak — Wuhan, China — there has been evidence of person-to-person transmission in Germany and Japan. No close contacts of the U.S. patients have fallen ill, but they remain under close observation.
Meanwhile on Monday, the World Health Organization quietly raised its global risk assessment for coronavirus from "moderate" to "high," admitting the previous assessment was "incorrect."
The change does not mean, however, that the WHO has declared the outbreak an international health emergency. The WHO emergency committee has convened twice and has twice declined make such a declaration.