Outbreaks of novel virus infections among people are always of public health concern. The risk from these outbreaks depends on characteristics of the virus, including whether and how well it spreads between people, the severity of resulting illness, and the medical or other measures available to control the impact of the virus (for example, vaccine or treatment medications).
Investigations are ongoing to learn more, but person-to-person spread of 2019-nCoV is occurring. It’s important to note that person-to-person spread can happen on a continuum. Some viruses are highly contagious (like measles), while other viruses are less so. It’s not clear yet how easily 2019-nCoV spreads from person-to-person. It’s important to know this in order to better assess the risk posed by this virus. While CDC considers this is a very serious public health threat, based on current information, the immediate health risk from 2019-nCoV to the general American public is considered low at this time. Nevertheless, CDC is taking proactive preparedness precautions.