Four coronavirus patients who had been passengers on the Diamond Princess cruise ship off the coast of Japan remain in satisfactory condition at Providence Sacred Heart Medical Center in Spokane.

Sacred Heart is one of 10 special pathogens units in the country, established as a part of the United States’ preparedness program during the ebola virus outbreak. Last week, four patients were flown from Travis Air Force Base outside Sacramento, California, to Spokane to be treated here. All four patients were asymptomatic during their transfer. Hospital officials reiterated that the patients, who are in a locked, secured unit separate from other patients, do not affect hospital operations.

The number of confirmed COVID-19 cases in the United States continued to grow over the weekend. There are now 53 confirmed cases, the latest Centers for Disease Control and Prevention count shows. The majority of those cases are repatriated Americans from the Wuhan region or were passengers on the Diamond Princess cruise ship. The number of confirmed cases of cruise ship passengers doubled in the last few days, from 18 to 36.

After an influx of Diamond Princess passengers returned to the United States, the Department of Health and Human Services stopped allowing those U.S. citizens on the cruise ship from returning unless they have been off the boat for two weeks without symptoms.

Cruise ship passengers who have returned to the United States are being monitored and quarantined at Travis Air Force Base and Joint Base San Antonio-Lackland. Some Americans were hospitalized in Japan with confirmed COVID-19 cases, CDC officials said last week.

“There are several Americans with COVID-19 who are hospitalized in Japan and who are seriously ill,” Nancy Messonnier, a CDC director, said last week in a news briefing. “Sadly, we may see poor outcomes in others, not just people who were on board the Diamond Princess, but among others who become sick with this virus.”

Americans who have traveled to mainland China or the Wuhan region and begin to experience flu-like symptoms like fever, cough or difficulty breathing are asked to contact their medical provider and avoid contact with others. Specifically, COVID-19 is believed to be spread through coughing and sneezing, so covering coughs and washing hands is important to preventing the spread of the virus.

Much is still not known about how coronavirus is spread, but symptoms of COVID-19 may appear in as few as two days or as long as 14 days after exposure, CDC guidelines say.

For Washingtonians who need to be quarantined outside of their home, the Washington Department of Health has created a quarantine site in Shoreline. Currently, there is one healthy traveler under quarantine there completing a voluntary two-week stay, Jessie Payne, public information officer with DOH, said Monday.

The Shoreline site has six trailers to be used for quarantine, and DOH is working on opening another site in Lewis County at the Maple Lane site where the Washington Department of Corrections has offices. No one is currently incarcerated at this location. The site will contain pods of RVs for people to be isolated if they cannot be quarantined at home.

Separately, the Washington State Legislature is preparing for the novel coronavirus outbreak. House and Senate budget proposals both set aside at least $5 million to cover potential state and local expenses that could result from the coronavirus outbreak.

The Senate proposes to spend $5 million of state funds and nearly $2 million in federal funds to prepare for a potential outbreak “and limit the spread of the contagion among the state’s population.” It would also set up a call center and help cover the costs of monitoring known cases in the state.

The House proposal also calls for spending $5 million in state funds out of the disaster response account, specifying only that it be spent on “costs associated to the response to the corona virus.”

House Appropriations Committee Vice Chairwoman June Robinson, D-Everett, said it would be used to help cover expenses the state Health Department is already incurring, testing by the department and local health districts to detect the virus, and reimbursement for some costs of quarantines.

Reporter Jim Camden contributed to this report from Olympia.