Former FDA Commissioner Scott Gottlieb told CNBC on Friday the fast-spreading coronavirus outbreak in China is likely more contagious but less severe than the SARS epidemic that rattled markets in 2003 and slowed global economic growth.
"We probably will have some isolated outbreaks [of coronavirus in the U.S.], but that doesn't mean it'll translate to an epidemic," said Gottlieb, a physician, health advocate and Pfizer board member. He left the Food and Drug Administration in April.
The total number of coronavirus cases in China rose to over 900, with 26 deaths. The flu-like virus, which was first identified less than a month ago in the Chinese city of Wuhan in Hubei province, has also infected at least 15 people around the world, mostly in Asia. The U.S. reported one case on Tuesday, a Snohomish County, Washington, resident who was returning from China.
Gottlieb told CNBC that in comparison with SARS, this appears to be more contagious and less severe.
"But the question is, has it achieved sort of that golden point where it's contagious enough to spread rapidly but still severe enough to cause a lot of harm?" he said a "Squawk Box" interview. "We don't know that yet."
Gottlieb said there could be thousands of mild cases that will likely go undiagnosed and clear up on their own.
Physicians have compared coronavirus to the 2003 outbreak of severe acute respiratory syndrome, which had a short incubation period of two to seven days. At the time, World Health Organization officials said it was less infectious than the flu. While there were just eight confirmed cases in the U.S., it infected 8,098 people worldwide and killed 774.
SARS, however, didn't spread as fast in its first few weeks as the coronavirus, according to WHO data. It took almost two months for SARS to spread to 456 people. By comparison, the 2019 coronavirus has already infected more than 900 people in less than a month.
Some experts have also said that higher stats could be due to health officials learning from the SARS outbreak and can now confirm cases much more quickly.
National Institutes of Health disease expert Dr. Anthony Fauci told CNBC earlier Friday that China is "doing much better this time" than with SARS.
"From the feedback we're getting, in a real time basis, it's an enormous difference, in a positive way," said the director of the NIH's National Institute of Allergy and Infectious Diseases.
The fast-spreading infection prompted local authorities to quarantine several major cities and cancel Lunar New Year's events. More than a dozen Chinese cities, impacting more than 30 million people, were placed on lockdown.
Several companies, including Walt Disney's Shanghai Disney, are suspending operations until further notice to prevent the outbreak from spreading. McDonald's suspended business in five cities in Hubei province.
Fauci said there's still much to be learned about the outbreak.
"We don't have definitive information now about shedding a virus and we're going to get that information pretty soon as these patients are starting to be studied," he said. "But if they were shedding the virus before showing symptoms, it would not be surprising."
— CNBC's Berkeley Lovelace Jr. and Dawn Kopecki contributed to this report.