“Experts assume there are many more infections than what are officially documented. Some people with infections may have mild or no symptoms, and they may never realize they carried the virus.
One of the most urgent questions is whether and to what extent people can spread the disease if they are not symptomatic.”
That's March 3rd, less than two weeks ago.
“In just two months, the novel coronavirus spread from a cluster in Wuhan, China, to an impending global pandemic with cases in more than 60 countries. This is unprecedented. Never before has a new pathogen emerged and caused a global spread like this."
CDC briefing, 1/31/2020, Dr. Nancy Messonnier:
"...the emerging evidence this week of the growth and spread of this outbreak, the increase in deaths, and the incoming data...
And I think it’s really important to clarify, because I think our screening of people’s nose with this test has been misunderstood. This test was developed at CDC.
Essentially, the CDC was testing for the virus based on symptoms not knowing the virus could present and spread without symptoms. That testing had to stop.
As of 1/31, we did not have access to that critical data.
"There is also strong evidence that it can be transmitted by people who are just mildly ill or even presymptomatic. That means COVID-19 will be much harder to contain than the Middle East respiratory syndrome or severe acute respiratory syndrome (SARS),