The child was transported by ambulance to Riverside University Health System-Medical Center Monday night after developing a fever, according to a spokesman for Riverside County.
Officials said the child was transported "out of an abundance of caution" and is with a parent.
Officials said the child is part of a group of 195 passengers who were flown to the reserve base from China last week and placed under a 14-day federal quarantine.
Officials also said a person who arrived at LAX Monday after a flight from China was placed under quarantine and transferred to March Air Reserve Base. This person does not have symptoms of coronavirus, but was moved as a precaution because of their travel history.
The U.S. currently has 11 patients who have tested positive for the new coronavirus and 167 patients who have tested negative. Eighty-two tests are still pending, according to the Centers for Disease Control and Prevention.
The coronavirus outbreak has now infected more than 20,000 people globally and has killed at least 425 of them, almost all in China.
No deaths have been reported in the United States.