From the CDC
This is a rapidly evolving situation and CDC’s risk assessment will be updated as needed.
Current risk assessment:
    For most people, the immediate risk of being exposed to the virus that causes COVID-19 is thought to be low. This virus is not currently widespread in the United States.
    People in places where ongoing community spread of the virus that causes COVID-19 has been reported are at elevated risk of exposure, with increase in risk dependent on the location.
    Healthcare workers caring for patients with COVID-19 are at elevated risk of exposure.
    Close contacts of persons with COVID-19 also are at elevated risk of exposure.
    Travelers returning from affected international locations where community spread is occurring also are at elevated risk of exposure, with increase in risk dependent on the location.