© Will Lester—MediaNews Group/Getty Images A team in white biohazard suits watch as some of the approximately 200 passengers walk to waiting buses upon arriving on a charter flight from Wuhan, China, after landing at March Air Reserve Base in Riverside, Calif. on Jan. 29, 2020.

A San Diego hospital says a U.S. citizen who was evacuated from Wuhan, China, the epicenter of the coronavirus outbreak, was temporarily discharged after initial testing determined they had not contracted the virus. However, further testing determined the patient was actually positive for coronavirus.



A similar incident has also occurred in Japan — two men tested negative on Jan. 30 after returning to Japan on a chartered flight from China, according to Bloomberg News, but were found to have the virus following tests undertaken a week later.

University of California San Diego Health released a statement Monday announcing that four patients were evaluated at its hospital and tested by the Centers for Disease Control and Prevention (CDC) for coronavirus. The CDC directed the discharge of the four patients on Sunday, and they were returned to the Marine Corps Air Station Miramar, where more than 200 people evacuated from China are spending a 14-day quarantine.

Read more: ‘Like I’m in a Bad Movie.’ Concerns Mount on Quarantined Ship as More Passengers Test Positive for Coronavirus

Two flights of evacuees from Wuhan have landed in the U.S. in recent weeks. In total, more than 800 people have been evacuated, according to the State Department. All have been in mandatory quarantine since their arrival, where they stay at military bases in hotel-sized rooms and share communal spaces.

The hospital said it was notified Monday morning, however, that further CDC testing had found one of the four patients was positive for coronavirus. The patient was returned back to UC San Diego Health for “observation and isolation until cleared by the CDC for release,” the hospital said in a Monday statement. An additional patient from the military base was also transported to UC San Diego Monday afternoon for evaluation for coronavirus.

“Both patients are doing well and have minimal symptoms,” the hospital said.

We currently have two patients at UC San Diego Health from Miramar. One has tested positive for #2019nCoV; the other is considered a person under investigation. Both patients are doing well and have minimal symptoms. For latest info, follow @CDCgov updates https://t.co/c43FtXW2Qm — UC San Diego Health (@UCSDHealth) February 11, 2020

There are now 13 cases of 2019 novel coronavirus in the U.S. Globally, more than 43,000 people have been diagnosed with the virus, resulting in more than 1,000 deaths. The vast majority of cases remain in China. The U.S. has established quarantine stations for hundreds of American evacuees at military bases in California, Texas and Nebraska, according to the Associated Press.

On Tuesday, about 200 people are expected to leave quarantine a the March Reserve Air Base in Southern California, according to the AP.