A COVID-19 outbreak on a sister ship to the Ruby Princess has been called "inevitable" but did not impact the liner's scheduled stop in Sydney today.
The Coral Princess, which arrived in the Harbour City today as part of a 12-day cruise, is battling a COVID-19 outbreak of 115 crew members and 14 passengers, according to Carnival Australia.
Carnival Australia confirmed 10 more passengers had tested positive for COVID-19.
President Marguerite Fitzgerald said 10 passengers who returned positive rapid antigen test (RAT) results before disembarking in Sydney today are isolating on the ship.
"We believe and the health authorities have also said that most of those guests probably brought COVID with them onto the ship when they embarked in Brisbane," she said.
"We knew this was going to happen...no one expected that we'd keep COVID off ships, it was just about managing it."
NSW Health said it was likely the passengers acquired the virus prior to boarding, and all infected travellers and crew were isolating.
Brisbane passenger Liz Bolton and her partner Clive Bolton, who departed the ship this morning, said the health measures in place had been smooth.
"It's not as bad as people are making it out. We are loving it. We feel really safe," Ms Bolton said.
Regular cruise passengers Richard and Robin Cooper said they were fully vaccinated and not worried.
"You're letting people in the country who aren't vaccinated. Everyone on the ship is at least double vaccinated with boosters," Ms Cooper said.
"We did an anniversary cruise prior to this one...we had no trouble then either."
Despite the strict COVID protocols now enforced on cruises, the virus is still too hard to stop in such settings, says professor of infectious diseases Peter White.
"SARS-CoV-2 is probably the major risk to cruises now … I think we're going to see more of these [outbreaks] unfortunately," Professor White, from the University of NSW, told the ABC.
He said coronavirus would become the new norovirus of cruise ships.
Norovirus is a type of virus that causes gastroenteritis and can spread easily in close quarters, including on cruise ships.
"Around one in 20 cruises would have a norovirus outbreak on them [before the pandemic] but we know that SARS-CoV-2 is probably more transmissible and infectious," he said.
Ms Fitzgerald said the low number of passengers infected proved the health measures implemented on board were actually working.
"This is the protocols working. It shows we actually are able to very successfully operate cruises in a COVID environment," she said.
The Coral Princess is in the same family as the Ruby Princess cruise liner which was responsible for Australia's first COVID super-spreader event in March 2020.
However, it is likely this outbreak, which is mostly contained to the crew, will be a drop in the ocean in relation to wider community transmission.
NSW is expecting a COVID-19 peak in the coming weeks as the new Omicron subvariants BA.4 and BA.5 circulate widely.
Professor White said the Coral Princess outbreak was simply foreshadowing what would be seen on land soon.
"We often consider a cruise ship as sentinel surveillance because we start seeing the outbreaks first on the ships," he said.
"That would be playing on my mind if I was going on a cruise and I might try to delay until there's not a wave of outbreaks set to roll in."
NSW Health has assessed the risk level for the Coral Princess outbreak as "amber", which is the second-highest level.
Carnival Australia, which owns Princess Cruises, says the ship is managing "quite well" in the circumstances but there will be some service impacts due to the number of staff isolating.
NSW Health said the crew were not allowed to get off this morning in Sydney and passengers had to take a RAT before disembarking.
Professor White said this outbreak was "particularly interesting" because the virus was most prevalent in the crew.
"I think there is a warning here that extra precautions for crew-based outbreaks … are something the cruise companies should focus on," he said.
