A Chicago woman who traveled to Wuhan, China, in December has been diagnosed with the deadly coronavirus, making her the second case in the United States, officials announced Friday.

The Centers for Disease Control and Prevention (CDC) said is it monitoring 63 people across 22 states for possible signs of the killer virus.

“CDC believes the immediate risk to the U.S. public is low at this time, but the situation is evolving rapidly,” Dr. Nancy Messonnier, the director of the National Center for Immunization and Respiratory Diseases, said in a conference call with reporters.

“We have our best people working on this problem,” Messonnier added.

The federal public health agency confirmed the U.S.’s first case on Tuesday — an unidentified man who was hospitalized and quarantined near Seattle after returning from Wuhan.

Chinese health officials said Friday at least 26 people have now died from the outbreak of a coronavirus, which has led authorities to lock down a number of cities in a desperate bid to keep it from spreading.

Beijing’s National Health Commission said there are more than 900 documented cases and more than 1,000 suspected cases of the virus worldwide. Most are in mainland China, with a smattering of cases in Thailand, Singapore, Hong Kong, South Korea, Japan, Vietnam, Taiwan and the United States. The virus in all confirmed cases are believed to have originated in Wuhan, China.

Officials said most of the deaths have occurred in the outbreak’s epicenter of Hubei province in central China. One was recorded in Hebei province.

Chinese officials said they have tracked down 9,500 close contacts of the carriers — of which some 8,400 were under medical observation. Hundreds of others have since been discharged.

The UPI contributed to this report.

Editor’s Note: The photo on this story was taken in Beijing. The individuals captured in this photo are not involved in this medical case; the picture choice is illustrative rather than literal.