Yesterday we learned of the first case of coronavirus of unknown origin discovered in Northern California. What does this mean?
Well, before yesterday, there had been 14 confirmed cases of coronavirus in the US. Of this group, 12 had travelled to China recently and 2 were exposed to a confirmed case. With this latest case, neither of those two factors were in play. This suggests that coronavirus may have spread within the community. Although it is a bit early to say whether this is the case, there are also some characteristics of coronavirus which make it pretty much inevitable that the virus will develop community spread.
First off, most cases of the coronavirus result in mild illness. While this is a good thing in general, it also means that infected individuals could walk around thinking they just have a regular cold when in fact they have (and are spreading) the coronavirus. In addition, the incubation period for the coronavirus may last up to 14 days, meaning an infected person may not show any symptoms for the first 14 days after infection. Both of these factors mean that infected individuals are more likely to spread the disease, which is something that the CDC, NIH, and other government agencies are already planning for.