The doctor on a cruise ship stricken by COVID-19 and gastro has declared the outbreak over, but concern remains over an uptick in cases in the broader community.
Passengers began disembarking the Grand Princess cruise ship after it docked in Adelaide on Monday morning following an 18-day round trip to Queensland and back.
Three passengers and two crew members had gastro while eight guests were suffering from COVID-like symptoms, SA Chief Public Health Officer Nicola Spurrier said.
She said the case numbers were relatively small compared to the ship's population of more than 2500 guests and 1000 crew.
"I commend the company," she told reporters on Monday.
"They have very good infection prevention and control mechanisms in place and protocols to deal with outbreaks. And those outbreaks came down very, very quickly as the staff instituted those measures."
One passenger was transferred to the Royal Adelaide Hospital for treatment but their case was unrelated to the gastro or COVID outbreaks.
South Australian Premier Peter Malinauskas said the government had been monitoring the situation closely over the preceding 48 hours and the majority of cases had occurred before the ship's last stop in Melbourne.
"The good news is reports that we've got from the cruise operators that the number of cases presenting has actually dramatically decreased over the course of the last couple of days," Mr Malinauskas told Nine's Today show.
Passengers who had tested positive were not allowed to take part in shore excursions and had to remain on the boat in line with commonwealth health protocols, the premier said.
Cruise operator Princess Cruises said it launched a "comprehensive disinfection program" while the vessel was docked in Melbourne.
"In an abundance of caution, there will be another disinfection program carried out on board the ship in Adelaide today before Grand Princess returns to Melbourne on Wednesday," a spokesperson for Princess Cruises said.
SA Health said it had been in contact with the ship's doctor on Monday who confirmed the outbreaks were declared over.
"The few remaining cases are consistent with numbers you would expect on any cruise," a spokesperson for SA Health said in a statement.
Mr Malinauskas said the broader community was in the midst of one of the biggest COVID waves in recent months, so the caseload on the cruise ship was largely consistent with the situation in metropolitan Adelaide.
COVID cases in South Australia have increased 47 per cent in the past week and 150 per cent in two weeks amid a nationwide resurgence in the virus.
Dr Spurrier said 2493 cases were reported in South Australia last week, but given reduced reporting levels the actual figure was likely to be higher.
"We are in quite a different place now with the pandemic." she said.
"So it's good to be alert, but definitely not to be alarmed."
Dr Spurrier said only half of aged care residents across Australia had received a second booster this year. She urged people with elderly relatives to keep them up to date given they are more susceptible to the virus.
While the spike was concerning, Australian Medical Association SA branch president John Williams said the community has the tools to deal with a rise in infection.
"What has been said is that possibly there will be a peak around Christmas time," he told ABC Radio.
"We certainly hope that isn't the case but it is something we have to be aware of in the community."
