Seven of the 55 Marin residents who were exposed to the coronavirus on a cruise ship last month now have symptoms of the illness or were in close contact with a symptomatic person, and they are awaiting test results to determine whether they are infected, health officials said Friday.

On Wednesday, Princess Cruises contacted passengers who got off the Grand Princess cruise ship in San Francisco on Feb. 21 to let them know that they had been exposed to the novel coronavirus during the ship’s voyage to Mexico, according to the Marin County Public Health Department.

There were 55 Marin residents on that cruise, which began its passage from San Francisco on Feb. 10, officials said. The health department initially said that 50 passengers were from Marin, but clarified that the number was higher on Friday.

Before those passengers were notified by the company this week, they were unaware that they had been exposed to the virus and had not been quarantined, the health department said.

“They had been out in the community,” said Dr. Matt Willis, the county’s public health officer.

Health officials made contact with each of the Marin passengers this week to find out if any were symptomatic.

The seven passengers who were tested for the virus are of varying ages. All are adults and none have school-aged children, officials said. Two have been hospitalized due to severe symptoms and the other five are under orders to stay at home in isolation.

Officials also reached out to family members and others who had been in close contact with those seven passengers, but “we didn’t detect anyone who was having symptoms through our calls,” Willis said.

A 71-year-old infected man who had been on the cruise ship died this week after returning home to Placer County. It was the first death from the disease in California, where there are 69 confirmed cases statewide.

At least four more passengers, including two Sonoma County and two Contra Costa County residents, have tested positive for the disease.

After it returned to San Francisco on Feb. 21, the Grand Princess set out for a voyage to Hawaii. Since its return from that crossing, the ship has been idling off the coast of San Francisco while health providers test passengers. On Friday, Vice President Mike Pence announced in a news conference that 21 people on the ship are infected, including 19 crewmembers. The health department said it doesn’t know whether any of the 2,422 passengers stranded on the ship are Marin residents.

Six people died and 706 passengers were infected on another Princess Cruises ship, the Diamond Princess, which traveled to Japan last month. Some of the passengers on that ship were evacuated and quarantined at Travis Air Force Base in Solano County. One woman who tested positive for coronavirus while at the base was transferred to Kaiser Permanente hospital in San Rafael. She is asymptomatic, but will be isolated at the hospital until testing shows no sign of the infection, which could potentially take weeks, Willis said.

Awaiting test results

There have been no confirmed cases in Marin of COVID-19, the disease caused by the novel coronavirus. But 12 people in the county have been tested, including the seven who were on the cruise ship. Results are pending from 11 of those tests, which are being processed at a public health laboratory the East Bay.

“We are expecting to see cases in Marin County,” Willis said. “Every community in the Bay Area should expect to see cases.”

County health officials are limited in their ability to test for the coronavirus, Willis said. The federal Centers for Disease Control and Prevention is only providing tests for people with symptoms of the disease who meet certain criteria, he said. That includes people who have recently traveled in areas that have seen outbreaks — including China, Italy, Iran and South Korea — or people who have come into contact with an infected person. People who are hospitalized with severe respiratory illnesses are also being tested if doctors can’t drill down alternative diagnoses.

But Willis said it’s likely that the testing criteria will soon be expanded, allowing health providers to request tests for patients who they suspect have the disease.

Health officials reported Friday that the first conclusive test of a Marin patient had ruled out the coronavirus as the cause of that person’s respiratory illness. The patient, who had been hospitalized, is the parent of a student at Marin Catholic High School in Kentfield. The student had been asked to stay home in isolation, but is now able to return to school, officials said.

Four other Marin residents who were not on the cruise are awaiting test results because they met the testing criteria, Willis said.

There are some two dozen people under isolation orders in Marin due to possible exposure, but an exact number was unavailable, according to the health department.

“We’re doing our best to identify and isolate individuals who may have been exposed,” Willis said. “But one of the reasons we expect to see community spread at some point is the fact that individuals who have mild symptoms who are not aware they are infected are not in isolation and can be out in the community.”

Willis recommends that people experiencing symptoms of respiratory illness “stay calm and realize it’s very likely that it’s a common seasonal respiratory virus and not COVID-19.” He said people with symptoms who have recently traveled to areas with outbreaks should notify their health providers.

“To get COVID-19, it generally requires much closer contact with someone who is actively symptomatic,” he said. “Simply walking past someone with the illness, the CDC calls that zero risk.”