Health officials have yet to label the coronavirus outbreak a pandemic -- but they could be close to calling it one.
"We're on the knife's edge," said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center and a longtime adviser to the US Centers for Disease Control and Prevention.
"We're really on the brink," says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes for Health.
Not there yet
On Monday, the World Health Organization's director general Dr. Tedros Adhanom Ghebreyesus said coronavirus has pandemic potential -- but it’s not there yet.
Tedros said the decision to use the word pandemic is based on ongoing assessments of the geographic spread of the virus, severity and impact of the society and for the moment they are not witnessing the uncontained global spread of this virus.
He said the virus is affecting countries across the world in different ways and requires a tailored response, adding it’s not a one-size-fits-all response.
Remember: There is no precise, mathematical definition of a pandemic.
Outbreaks get characterized as pandemics by epidemiologists -- who are not yet using the term.
That's because they've yet to see sustained transmission among people who have not recently traveled to China or had close contact with someone who recently traveled to China.
It's not enough for a cluster of disease in a country to exist and even spread -- it has to spread in a sustained way, from person to person, time and time again, through many generations of transmission.
Right now, certain countries may still be able to contain the clusters of disease they are experiencing, and if they snuff out the outbreaks before they progress and achieve sustained transmission, they will have avoided a pandemic.