UPDATE: 8:54 p.m., Feb. 6, 2020:
A second plane traveling from Wuhan, China will land at Marine Corps Air Station Miramar Friday morning, the station announced Thursday night. The passengers will be quarantined for two weeks under as federally mandated, according to MCAS Miramar.
@MCASMiramarCA can now confirm the planned arrival of a second inbound flight originating from China. The flight will land in the mid-morning hours of 7 Feb. HHS and CDC personnel will receive these travelers as they begin the federally mandated quarantine.
— MCAS Miramar (@MCASMiramarCA) February 7, 2020
KPBS will continue to follow the latest developments and provide more information as it becomes available.
UPDATE: 4:25 p.m., Feb. 6, 2020:
A fifth person who was evacuated from the Wuhan region of China and brought to Marine Corps Air Station Miramar was hospitalized Thursday after developing symptoms that warranted further observation for possible exposure to the deadly coronavirus.
According to the U.S. Centers for Disease Control and Prevention, the patient -- described only as an adult -- "developed a fever or a cough" that prompted the precautionary hospitalization. The person was taken to UC San Diego Health.
Four other people, including a 4-year-old girl, were hospitalized Wednesday afternoon, hours after a plane carrying 167 Americans landed at the northern San Diego military base. All of the passengers underwent medical screening upon landing.
Doctors from UC San Diego Health and Rady Children's Hospital told reporters Thursday morning that the four initial patients were all considered stable. Two unrelated adults were being treated at UCSD Health, and one father and his daughter were at Rady Children's Hospital, according to the federal agency.
Doctors said they were awaiting test results from the CDC to determine if any of the four patients are infected with coronavirus. Those results are expected as early as Saturday morning.
Dr. John Bradley, medical director of infectious diseases at Rady, said there was no threat to the public at large or to other patients in either facility.
"Nobody who comes to Rady or UCSD has to worry at all, even if the patients test positive — which is unlikely," he said. "We have really good isolation policies and they are in special rooms designed for Ebola, which is far worse than coronavirus."
RELATED: 4 American Coronavirus Evacuees At MCAS Miramar With Symptoms Transported To Hospitals
Coronavirus is a respiratory illness with similar symptoms to a cold or influenza in most patients, including a fever and difficulty breathing. Both hospitals are following CDC protocol and treatment guidelines.
Dr. Francesca Torriani, the program director of infection prevention at UCSD Health, reminded the public to have compassion and patience.
"Remember, these are American citizens who have already gone through a lot," she said. "We are going to welcome them and make life as good as possible."
She also said that according to estimates, coronavirus has a lower mortality rate than the strain of influenza which has killed 7,000 Americans this season.
"If we are looking at worst-case scenario, the mortality for the flu is something like 2.5%, with that number going up if there are underlying medical problems," she said. "The estimates for coronavirus (are) less than 2%."
Even so, both physicians expressed shock at media reports that one of the first doctors to express alarm over the outbreak in China was seriously ill. They said the virulence of coronavirus was not fully understood, but said best knowledge was that it was spread by large water droplets within 3-6 feet of a person suffering symptoms such as coughing or sneezing. Such a transmission method means it's unlikely any of the people on the flight to Miramar had developed symptoms of the illness, they said.
"If anyone on that flight had symptoms, after 11 hours of flying, the whole flight would have been sick," Bradley said.
Bradley said that while the coronavirus is indeed "novel" in that its exact strain has not been seen before, SARS was a similar coronavirus with much higher mortality rates, so world health officials have some research on treating similar viruses. He said antiviral medications had already shown some efficacy in treating the illness.
The hospitals and county health officials were pressing the CDC to offer test kits to identify the strain of virus without the need to send biological samples to the federal headquarters in Atlanta.
The 167 people who arrived from China on Wednesday are under a government-mandated two-week quarantine due to possible exposure to the potentially deadly disease. Medical personnel with the CDC met the arriving flight at the northern San Diego military base after it touched down shortly before 9:30 a.m., officials said.
Nearly 200 Americans arrived at March Air Reserve Base in Riverside on Jan. 29 and are quarantined there after being evacuated from Wuhan.
A child among the group was taken to Riverside University Medical Center on Monday night after developing a fever, but the child was later cleared and allowed to return. A second child from the group was taken to a hospital Wednesday for observation.
The coronavirus epidemic has claimed at least 560 lives, with more than 28,000 infections, mostly in China. The respiratory illness is treatable, and many patients are recovering, according to reports.
There have been 12 confirmed cases of coronavirus in the United States, with six of those in California, including one case each in Los Angeles and Orange counties. Temporary quarantine and processing sites have been established at major airports, including LAX.
The virus was first identified by the Chinese government on Dec. 31, when authorities indicated an unknown pneumonia variant was infecting residents of Hubei province.
