Health experts: Human-to-human spread of new virus worrying

A saleswoman takes out face masks from a box as people queue up waiting to purchase face masks outside a shop in Hong Kong, Wednesday, Jan. 29, 2020. A viral outbreak that began in China has infected more than 6,000 people in the mainland and more than a dozen other countries. (AP Photo/Vincent Yu)

FILE - In this Thursday, Jan. 23, 2020, file photo, Chinese paramilitary police wear face masks as they stand guard at Beijing Capital International Airport in Beijing. British Airways and Asian budget carriers Lion Air and Seoul Air are suspending all flights to China as fears spread about the outbreak of a new virus that has killed more than 130 people. British Airways said Wednesday it is immediately suspending all flights to and from mainland China after the U.K. government warned against unnecessary travel to the country. (AP Photo/Mark Schiefelbein, File)

A Japanese chartered plane carrying evacuees from Wuhan, China, landed at Haneda international airport in Tokyo Wednesday, Jan. 29, 2020. Countries on Wednesday began evacuating their citizens from the Chinese city hardest-hit by an outbreak of a new virus. (AP Photo/Eugene Hoshiko)

A Japanese chartered plane carrying evacuees from Wuhan, China, landed at Haneda international airport in Tokyo Wednesday, Jan. 29, 2020, in Tokyo. (AP Photo/Eugene Hoshiko)

A woman holds a box of face mask as people queue up waiting to purchase face masks outside a shop in Hong Kong, Wednesday, Jan. 29, 2020. A viral outbreak that began in China has infected more than 6,000 people in the mainland and more than a dozen other countries. (AP Photo/Vincent Yu)

BEIJING — World health officials, back from a visit to Beijing, expressed great concern Wednesday that a dangerous new virus is spreading between people outside of China, even as the number of illnesses continue to grow dramatically inside that Asian nation.