The UnCruise Wilderness Explorer is seen docked at Ketchikan’s downtown Berth 4 on Sunday. UnCruise says seven people aboard the 74-passenger vessel have tested positive for COVID-19. (Eric Stone/KRBD)

Seven fully vaccinated people aboard a small cruise ship that docked in Ketchikan over the weekend have tested positive for COVID-19. The ship’s operator UnCruise canceled a sailing due to depart this past weekend in response.

The 74-passenger Wilderness Explorer sailed to Juneau from Ketchikan Monday evening.

UnCruise spokesperson Liz Galloway said in a statement Monday evening that the four positive passengers would isolate in a Juneau hotel. Three positive crew members would isolate aboard the Wilderness Explorer, she said.

Assistant city manager Robert Barr said city officials have been coordinating with the operator.

“We’ve been working with UnCruise to make sure all that isolation is happening per public health guidance to make sure that the case activities stays contained to those individuals until they’re done with their isolation period,” he said.

Juneau officials say the risk to the community is minimal.

Ketchikan’s port director, Mark Hilson, said in a statement Monday evening that to his knowledge, the COVID-19 positive individuals stayed aboard while the ship docked in Ketchikan.

“My understanding is that none of the positives disembarked as they were not able to get hotel reservations,” Hilson said in an email. “The rest of the passengers disembarked as was originally planned.”

Galloway, the UnCruise spokesperson, said Tuesday that 28 crew and 9 passengers were identified as close contacts.

“Those who were not considered an issue were cleared to go following all protocols and guidelines while in Ketchikan. All guests and crew are fully vaccinated, wear masks, and provided a negative PCR (polymerase chain reaction) test prior to boarding to cruise,” she said.

She said UnCruise’s safety and compliance manager noticed symptoms on July 19, which prompted testing. The first positive test result came back July 23, she said.

UnCruise says it’s the first time a fully vaccinated guest has tested positive for COVID-19 on its ships.

Barr, the Juneau official, says that despite the positive tests, the three authorized COVID-19 vaccines are thought to be highly effective at preventing severe cases of the disease.

“The vaccine is very, very good at keeping people out of the hospital and keeping people from dying and getting seriously sick,” he said. “It’s not an iron-clad shield, it won’t necessarily completely prevent you from getting any version of the illness. But it does a very good job at keeping you from getting seriously sick.”

In a statement, UnCruise owner and CEO Dan Blanchard says the seven positive individuals had mild, cold-like symptoms. The company says it’s testing all symptomatic passengers and crew and working with local and state health officials to respond to COVID-19 cases, noting that its decision to cancel this weekend’s cruise was voluntary and not prompted by Coast Guard or health agency requirements. Small cruise vessels, including the entire UnCruise fleet, are not required to comply with federal pandemic rules that apply to larger ships.

UnCruise speculates that the delta variant is behind the cases. Barr says it’s a fair assumption, but lab testing has not confirmed the variant’s presence on the Explorer.

Juneau officials reported one case each on two additional cruise ships Monday: one aboard a large ship, the Celebrity Millennium, and the other on another small ship, the American Constellation. That ship already had an outbreak of 16 passengers on an earlier sailing this season.

This story has been updated with comments from Ketchikan’s port director and additional comments from UnCruise.