A lockdown affecting 56 million people could actually be making the situation worse, including by exacerbating shortages of medical supplies, some experts say — though they are divided. Hospital workers are calling for stricter border checks as holiday travelers return, and Chinese officials are racing to contain public anger at the government.

Stocks tumbled and oil prices fell on Monday as the virus’s spread worried investors around the globe. China’s currency also fell, while investors moved into safe havens like gold.

The scope: Most of the nearly 3,000 people who have contracted the virus live in China, but it has spread to 10 other countries. At least 110 people are being tested for it in the U.S.

Inside China: In addition to antiviral H.I.V. drugs, the authorities told doctors to prescribe traditional medicine. Hospitals are overwhelmed, as the country does not have a functioning primary care system and people flock to understaffed hospitals even on a normal day. The weaknesses are most pronounced in poorer areas.

Another angle: Many airlines are accommodating travelers who want to modify, delay or cancel China itineraries. Here’s what to know.