Originally Posted by
Response Ability
Trump declares public health emergency and will quarantine U.S. citizens returning from China's Hubei Province. . . .
The repatriated 195 at MARB under federal quarantine order (1st quarantine in US in 50 years) (Distinguish between "isolation" means when patient is ill and "quarantine" for people exposed and not yet sick.)
Quarantines don't really work for diseases that are easily transmitted and have long-ish latency periods. There's never an effective way to identify the people who would need to be quarantined.
The CDC test shows 2019-nCoV negative or positive when the patient is ill. Test reliability unknown at this time for asymptomatic people.
If it is reliably accurate, that's good for informing treatment decisions and for determining when patients should be isolated (ignoring the problem of having sufficient facilities and staff for isolation of large numbers of sick people). It won't help with transmission control, because it's effectively impossible to test large populations of asymptomatic people.
CDC team to China to access "best data" at the epicenter especially concerning asymptomatic transmission. (important because the virus is new and its characteristics are being studied and learned even as we speak)
As indicated in one of RA's citations, it appears that transmission from an asymptomatic carrier has been confirmed.* If asymptomatic transmission is
common, and the rapid early spread of the virus suggests that is fairly likely, it will be very difficult to prevent a pandemic.
The good news is that, so far, it appears that only a minority (perhaps 20% per earliest estimates) of infections result in serious illness and the mortality rate seems, so far, to be <2%. We don't yet know what portion of that 2% received prompt and effective supportive care.
It's a good bet that 2019-ncov is going to be a significant factor in world affairs and travel, probably for some time. Serious impacts to aviation are nearly certain.
*
https://www.nejm.org/doi/full/10.1056/NEJMc2001468