Could this virus cause a pandemic?
In order for this virus, or any, to lead to a pandemic in humans, it needs to do three things: efficiently infect humans, replicate in humans and then spread
easily among humans,
Live Science previously reported. Right now, its unclear how easily the virus spreads from person to person.
To determine how easily the virus spreads, scientists will need to calculate what's known as the "basic reproduction number, or R0 (pronounced R-nought.) This is an estimate of the average number of people who catch the virus from a single infected person,
Live science previously reported. A study published Jan. 29 in the
New England Journal of Medicine (NEJM) estimated an R0 value for the new coronavirus to be 2.2, meaning each infected person has been spreading the virus to an average of 2.2 people. This is similar to previous estimates, which have placed the R0 value between 2 and 3. (For comparison, SARS initially had an R0 of around 3, before public health measures brought it down to less than 1.)
In general, a virus will continue to spread if it has an R value of greater than 1, and so public health measures to stem the outbreak should aim to reduce R0 to less than one, the authors of the NEJM paper said.
The CDC says outbreaks of new viruses are always concerning. However, the agency says the immediate risk to the American public remains low, given the small number of cases and limited spread of the virus here.
Still, an individual's risk of infection "depends on exposure," the CDC said. Some people, including health care workers and those with close contacts infected with 2019-nCoV, are at increased risk of infection, the agency said.
On Jan. 30, the World Health Organization (WHO) declared that the new coronavirus outbreak is a public health emergency of international concern. The main reason for the declaration is concern that the virus could spread to countries with weaker health systems, WHO said.