Health officials confirmed a coronavirus case in northern California on Wednesday in a person with no known links to China, raising fears that the virus might be spreading in the United States.
The Centers for Disease Control and Prevention (CDC) said the person, who is a resident of Solano County, had no history of travel to China, where the deadly virus originated, and no close contact with anyone known to be infected.
The U.S. has 60 confirmed cases of the virus, officially called COVID-19. All of the other infected people had either traveled overseas or had been in close contact with those who traveled. The virus has transmitted from human-to-human in cases in Chicago and San Benito County, Calif., but in both cases, the infected person had close, prolonged contact with family members who had returned from Wuhan, China and had tested positive for the virus.
CDC spokesperson Richard Quartarone tells TIME the patients are either at hospitals in Sacramento, San Antonio or the Nebraska Medical Center.
More than 300 American evacuees were flown out of Japan to air bases in Texas and California.
“This was a high-risk situation,” Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases at the CDC, said at a Friday teleconference for reporters. “Based on what we know about the attack rates and the exposures, we should expect to see additional cases.”
The total number of confirmed COVID-19 cases in the U.S. is now 60, including the case in Northern California, the cruise evacuees, three people who were evacuated from the central Chinese city of Wuhan and 14 people who traveled back from other areas of China, or their spouses.
So far, cases have been diagnosed in California, Washington, Arizona, Illinois, Massachusetts, Wisconsin, Nebraska and Texas. Globally, more than 76,000 cases of COVID-19 have been diagnosed or clinically confirmed as of Feb. 21 and more than 2,200 people have died, according to a virus tracker from researchers at Johns Hopkins University.
The vast majority of confirmed and/or clinically diagnosed cases are in China, but diagnoses in the U.S. are expected to increase over the coming days and weeks, according to the CDC.
“We are proactively planning now to prevent further spread in the United States,” U.S. Department of Health and Human Services Secretary Alex Azar told CNN on Feb. 14. He added that the department is working with state and local governments and with the private sector to prepare. “So far we’re seeing very limited impact here in the United States, but that could change at any time.”
Here’s what to know about COVID-19 cases in the U.S.
Cruise ship evacuees
On Feb. 17, the U.S. State Department evacuated more than 300 American citizens from a quarantined cruise ship in Japan. The Diamond Princess has the largest outbreak of the novel coronavirus outside China with at least 621 confirmed cases so far.
During the evacuation process, American officials learned that 14 of the more than 300 Americans who were to be flown back were infected with COVID-19 after being tested two to three days earlier, according to a joint statement from the U.S. State Department and U.S. Department of Health and Human Services. After consulting with HHS, officials with the State Department decided to allow the 14 individuals, “who were in isolation, separated from other passengers, and continued to be asymptomatic, to remain on the aircraft to complete the evacuation process,” the statement said.
The evacuees who are not hospitalized were being held in quarantine for 14 days after departing planes at Travis Air Force Base in Sacramento, Calif. and Joint Base San Antonio-Fort Sam Houston in San Antonio, Texas, officials said.
The CDC said there are more than 100 American citizens who remained in Japan, including in hospitals. The CDC specified that these citizens will only be allowed to fly back to the U.S. if they test negative for and don’t show any symptoms of the virus during the 14-day period.
“If an individual from this cruise arrives in the United States before the 14-day period ends, they will still be subject to a mandatory quarantine until they have completed the 14-day period with no symptoms or positive coronavirus test results,” the CDC said.
The CDC also highlighted concerns with the quarantine process on board the ship, saying that it may have slowed the spread of the disease but that it “may not have been sufficient to prevent transmission among individuals on the ship.”
The first case of COVID-19 in the U.S. appeared in Washington on Jan. 21. A 35-year-old man presented himself to an urgent care clinic in Snohomish County, Wash., after four days of cough and fever, according to the New England Journal of Medicine, which reported that he had recently been visiting family in Wuhan.
“The patient should be recognized for his decision to voluntarily isolate himself, seek proper medical care, and allow the details of his private medical treatment to be made public so that the world may learn from his case, and advance our understanding of novel coronavirus,” the Washington State Department of Health said in a public statement on Jan. 31.
The man was released from a Washington hospital on Feb. 4, according to the Associated Press.
“I am at home and continuing to get better,” the man said in a statement to the AP. “I appreciate all of the concern expressed by members of the public, and I look forward to returning to my normal life.”
A single case of COVID-19 was confirmed in Arizona by the CDC on Jan. 26. The person had also recently returned to the U.S. after visiting Wuhan. The Arizona Department of Health Services said in a public statement that the person is “a member of the Arizona State University community who does not live in university housing,” and added that they were not severely ill but would be kept in isolation.
The case confirmed on Wednesday brings the total number of confirmed cases of COVID-19 to eleven in California, the highest number in any state so far.
The latest person to be confirmed to have the virus is receiving medical treatment in Sacramento County, according to the CDC.
The first confirmed cases in the state were announced by the CDC on Jan. 26; the two patients had recently returned to the U.S. from Wuhan.
On Jan. 29, the State Department announced a flight carrying 195 evacuees from Wuhan landed at the March Air Reserve Base in southern California. Later, on Feb. 5, the CDC announced 14-day quarantine sites at the Travis Air Force Base in Sacramento, Calif. and the Marine Corps Air Station Miramar in San Diego, Calif., where more evacuees from Wuhan would be placed.
Two people who were quarantined at Miramar have since been diagnosed with COVID-19 and are now in isolation at the University of San Diego Health. A third person has been placed under investigation after developing symptoms that warrant testing, the hospital announced on Feb. 12.
Orange County and San Francisco have both declared states of emergency over the virus.
The first case in Illinois was a woman in her 60s who had returned to the U.S. from Wuhan on Jan. 13, health officials said at a press briefing on Jan. 30. Her husband then contracted the virus, becoming the first confirmed case of person-to-person transfer of the virus in the U.S.
The Illinois Department of Public Health announced Feb. 12 that it became the first state in the U.S. to begin in-state testing for the virus.
On Feb. 1, the CDC announced that a man in his 20s who lives in Boston was diagnosed with COVID-19, making him the eighth confirmed case in the U.S. He had also recently traveled to Wuhan.
The Massachusetts Department of Public Health said the man sought medical care soon after his return to Boston. He has since been in isolation, and those who came in contact with him have been identified and are being monitored for symptoms, the agency said in a public statement.
“We are grateful that this young man is recovering and sought medical attention immediately,” said Monica Bharel, Massachusetts Public Health Commissioner, in the statement. “Massachusetts has been preparing for a possible case of this new coronavirus, and we were fortunate that astute clinicians took appropriate action quickly. Again, the risk to the public from the 2019 novel coronavirus remains low in Massachusetts.”
The Wisconsin Department of Health Services and the CDC announced the first case of COVID-19 in the state on Feb. 5. The person was only identified as “an adult with a history of travel to Beijing, China prior to becoming ill and was exposed to known cases while in China.”
Wisconsin health officials said in a public statement that the person is isolated at home, and is doing well.
The first person diagnosed with COVID-19 in Texas is currently in isolation. The name of the individual has also not been released, but Jennifer McQuiston, a CDC division deputy director and current team lead at the JBSA-Lackland quarantine, told reporters at a Feb. 13 press conference that the person was a solo traveler.
Two additional Diamond Princess passengers are also in isolation in Texas as of Feb. 21, after they were determined to have the virus. The patients are being held at the Texas Center for Infectious Disease hospital, according to a public statement by the City of San Antonio.
The City of San Antonio Metropolitan Health District and the CDC announced Feb. 13 that the first person diagnosed was one of the Americans evacuated from Wuhan and transported to the military base on Feb. 7, after leaving Wuhan the previous day. There are currently 91 evacuees in a 14-day quarantine at the JBSA-Lackland military base, one of four designated quarantine sites for the roughly 800 Americans who have been evacuated from Wuhan.
On the morning of Feb. 11, the patient exhibited signs of a fever, McQuiston said. The person was transported to a hospital that morning, where samples were gathered and sent to the CDC overnight. Officials received the positive diagnosis around 6 p.m. on Feb. 12. “[That patient is] receiving excellent medical care,” McQuiston said at the Feb. 13 press conference. “They were, of course, not happy to learn of their diagnosis last night, and they do have loved ones in the United States that they are in contact with by phone, and we wish this individual well.”
Dr. Anita Kurian, assistant director at the San Antonio Metropolitan Health District, also said at the press conference that “the risk for us at this time to the community here is still considered low.”
Of the estimated 400 Americans aboard the Diamond Princess, 151 landed at the Lackland Air Force Base on the morning of Feb. 17. Of those, 144 asymptomatic Americans were assessed and transported to Lackland quarantine, according to the City of San Antonio.
The individuals who remain in quarantine are being monitored for signs and symptoms of COVID-19.