California reported a bump in coronavirus cases on Monday as community infections continue to spread, tests become more widely available and doctors catch up with a backlog in diagnosing.

There are two new cases in Santa Clara County, one in San Mateo County, one in Placer County and one in Sonoma County. The state of Washington also reported four new deaths, all in sick or older adults in a nursing home in the Seattle suburb of Kirkland. Of all U.S. locales, California and Washington are hardest hit: 29 of the 43 domestic cases are in those two states. There are now nearly 100 cases in the United States, six of them fatalities.

At a White House news conference, officials assured the nation that the risk remains low — but that the number of cases will climb as testing increases.

“We will continue to see these cases as a consequence of health departments doing their job,” said Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, at Monday’s press briefing.

But there still aren’t enough tests for everyone — so only people who meet the federal government’s strict criteria are being tested. If people with flu-like symptoms want to be tested, they won’t qualify — unless they’re hospitalized or have a history of exposure to the virus.

“This is frustrating for providers. It’s frustrating for the public. I absolutely understand that,” said Paul Biddinger of Harvard’s T. H. Chan School of Public Health at a campus briefing. “There’s a lot of anxiety out there, and fever and respiratory illness.

“Right now we have so few tests available that we have to prioritize testing for severe illness,” he said.

The California Department of Public Health did not respond to questions about the availability of tests. And the CDC has removed information on its website that lists how many people in the country have been tested for the virus. It now only displays the number of confirmed cases.

“There’s probably low-thousands of cases in this country that we now need to turn over the card on,” said Dr. Scott Gottlieb, former director of the U.S. Food and Drug Administration, on Twitter. “We are going to have a surge of cases before we actually catch up to the level of spread.”

At the White House press briefing, health officials said that 75,000 to 100,000 tests have been distributed. With about 4,750 acute care hospitals and 2,800 local health departments in the nation, that represents an average of 10 tests per agency. Some people need repeat tests.

“But we expect a substantial increase,” promised U.S. Food and Drug Administration Director Dr. Stephen Hahn at the White House briefing, referring to a policy change that enables more public and private labs to create their own diagnostic tests. He said that it’s possible that by the end of the week, “1 million tests (could ) be done.”

America’s exact case count is published only three times as week, when the CDC updates its web page. In contrast, China and Hong Kong update their case counts daily. South Korea issues three daily updates.

There’s a delay in a person’s progression to serious disease, so the new illnesses may reflect infections that occurred days ago. It takes 9.1 to 12.5 days, on average, between the onset of illness and hospitalization, according to new research published in the New England Journal of Medicine.

In other news, all Americans in Italy and South Korea will be screened before they can board U.S.-bound flights, Vice President Mike Pence said. There will be multiple ‘temperatures checks’ in airports before boarding back to the states.

As a precaution, organizers of major conferences and corporate events in the Bay Area are opting to cancel plans more than two months ahead of their event.

Cancellations include the tech research giant IDC’s conference in Santa Clara, Nvidia’s GTC 2020 conference in San Jose — the cancellation of which was just announced Monday — and Facebook’s F8 conference in San Jose. Smaller gatherings also are scrapped, such as Stanford’s Natural Capital Annual Symposium and an annual meeting of alumnae of the university’s online business program.

Palo Alto’s Stanford Theatre announced Monday it is suspending operations. The tech companies Salesforce, Twitter and Amazon are restricting all nonessential domestic travel. UC Berkeley has suspended its spring and summer programs in China.

Meanwhile, a quarantine was lifted Monday for about 140 passengers of the ill-fated Diamond Princess cruise ship, ensconced for two weeks At Travis Air Force Base. About a dozen more had to stay behind because their quarantine was extended a few days. Many of those allowed to leave boarded buses for San Francisco International Airport.

“Everyone is exhausted but excited that very very soon … we will be free to reclaim some pieces of normalcy,” wrote passenger Sarah Arana, of Paso Robles. “Lots of goodbyes and I’ll miss you’s,” she wrote. “It’s hard to convey exactly how deep the bonding is with the others who have gone through this together.”

On Sunday night — their last night together — the passengers watched a farewell video from Diamond Princess captain Gennaro Arma. The last to leave the ship, he walked down the gangplank in full uniform, still wearing his mask.

But more than 120 of their fellow passengers, quarantined at Lackland Air Force Base in San Antonio, Texas — also scheduled for release — must remain in place until they are re-tested for the virus. An asymptomatic woman who was released from the base by the CDC was sent back to the facility when a test showed she was, in fact, infected. San Antonio city officials have sued the federal government as a result.

Two passengers quarantined at the University of Nebraska Medical center were allowed to return home Monday, and another two were released on Sunday.

California is no longer pursuing a plan to send infected but healthy people to Costa Mesa’s Fairview Developmental Center after lawsuits and intense local opposition. Instead, it is hospitalizing them.

Health officials in Washington’s Seattle area are setting up modular units and purchasing a motel to house patients in isolation.

But Harvard epidemiologist Marc Lipsitch, director of the university’s Center for Communicable Disease Dynamics, predicted that our response to the outbreaks will change. Already, European nations, South Korea and Japan are transitioning “from the so-called ‘case-based’ response to the more ‘social distancing’ type of response,” he said on Monday.

“Frankly, I think we’re in a phase where quarantine and isolation of individual patients is going to be still an important piece of the response,” he said, “but it’s not going to be the main focus of the response as the number of cases grows.”