CNN is first to report that two airline passengers flew to the United States while actively sick with Wuhan coronavirus, but passengers who sat near them did not become ill, according to a spokesperson for the US Centers for Disease Control and Prevention.

The sick passengers are among the 11 confirmed cases of coronavirus in the US. It’s significant that they were ill on the flights, since health authorities say people who are actively ill are most likely to infect others.

The two sick passengers traveled from China to Los Angeles International Airport on January 20 and January 22. The 14-day incubation period for the virus has since passed, so it’s believed that other people who were on the flights are no longer at risk for contracting the illness.

Health authorities got in touch with passengers who flew in the same rows as the sick passengers as well those in the two rows in front and behind. Local health officials told those passengers to look out for the symptoms of the coronavirus, including fever, coughing and trouble breathing.

In addition to the nine travel-related cases of Wuhan coronavirus, two person-to-person cases have been confirmed in the United States, bringing the total number of confirmed cases to 11.