Appears there are at least two critical unknowns about #2019nCoV #coronavirus that, once we have more information on them, will help further focus response efforts.
These are: 1) whether (and how often) people can spread the virus preceding the development of symptoms (asymptomatic transmission), and 2) how often infection with the virus leads to severe disease.
Some conflicting information out there on asymptomatic transmission. China's health minister says yes it does occur with this virus, while one of CDC’s top experts says they haven’t seen any evidence of that yet, but are investigating. washingtonpost.com/world/asia_pac…
With no (or little) asymptomatic transmission, response can focus on infection control, identifying and isolating symptomatic cases, & tracing and monitoring their contacts. That tried and true public health approach helped interrupt many outbreaks, from SARS to Ebola.
If significant asymptomatic transmission is present, the tried and true method may identify some people who need care, but doesn’t identify all those infected and transmitting the virus. Therefore, chains of infection keep propagating.
That would be a more influenza-like scenario. Hard to contain such an outbreak without broader, potentially disruptive measures. In addition to isolation and infection control as above, authorities might institute social distancing measures (closing schools, public events, etc).
Another key effort in such a scenario would be to rapidly developing vaccines, and deploy them as widely as possible in the population at risk.
For point 2), the severity, we don’t really know how many people total have been infected so we can’t calculate an accurate case fatality ratio. Estimates from the modelers put the true number of cases at 50,000 or even 100,000 or more. theguardian.com/science/2020/j…
If those modeled estimates are close to true, the fact that relatively few deaths have been noted so far points to something less severe than, say, SARS.
But, it could be that the infected haven’t progressed to severe disease yet, and we might see a very sharp rise in the severe cases and deaths in the coming days. That indeed would be a very bad sign, and be cause for great concern.
Not trying to draw parallels, but early estimates of the severity of 2009-H1N1 influenza were fairly high and caused a lot of concern. Turned out severity was close to that of seasonal influenza (still caused a lot of deaths and severe disease because it spread so much, though).
