US beefs up screening of travellers for new virus from China

US health officials offered a reality check about the scary new virus from China: They're expanding screenings of international travellers and taking other precautions but for now, they insist the risk to Americans is very low.

"At this point Americans should not worry for their own safety," Health and Human Services Secretary Alex Azar told reporters on Tuesday.

China has confirmed more than 4,500 people with the respiratory illness, which in severe cases can cause pneumonia, with dozens more counted in other countries.

In the US so far, there are five confirmed patients, all of whom had travelled to the hardest-hit part of China and no sign that they have spread the illness to anyone around them.

Still, "this is a very fast-moving, constantly changing situation", Azar added.

Flanked by the government's top infection specialists, Azar listed the biggest unanswered questions of the outbreak and tried to tamp down some of the fear and speculation provoked by China's rising toll: How deadly is this new virus?
How easily does it spread?
What about silent carriers?