Why cruises are not to blame for fourth Covid wave as national cases hit 74,000 in a week

An expert explains why the arrival of a cruise ship laden with 800 Covid-positive passengers is unlikely to make a difference to the fast-growing fourth wave of the pandemic. Take our poll.

The arrival of 800 Covid-19 positive passengers from a cruise ship that docked in Sydney on the weekend is unlikely to impact Australia’s mushrooming fourth Covid wave, says an expert.

Epidemiologist Professor Adrian Esterman, chair of biostatistics at the University of South Australia, told News Corp that Australian cases were already in the tens of thousands – and these were only the reported cases.

Cases are also growing rapidly all over Australia, leading public health leaders to appeal for increased vigilance, mask-wearing on public transport and other crowded settings, and isolation when infection occurs.

According to the Australian Department of Health and Aged Care, 54,661 cases of Covid were reported across Australia in the seven days to November 8 – an average of 7809 per day.

This latest tally represents a 47 per cent rise in cases on the previous week. The number of hospitalised Covid-19 cases has increased by an average of 12 per cent compared to the previous week.

“There is so much Covid around now and it’s increasing so rapidly that an extra 800 of people is not going to make any difference at all,” said Professor Esterman.

“There were 20,000 diagnosed cases in NSW last week, and that’s the tip of the iceberg, there’s probably at least two or three times more actual cases because reporting is no longer mandatory.”

The Majestic Princess docked at Sydney’s Circular Quay early Saturday morning, and while healthy travellers disembarked from 12-day cruise from New Zealand fully masked and equipped with testing kits and instructions to monitor for symptoms, infected passengers remained quarantined in their rooms before being allowed to leave.

The Majestic Princess cruise ship prepares to depart for Melbourne from the International Terminal on Circular Quay in Sydney. Picture: Muhammad Farooq/AFP

Cruise staff then undertook a deep clean of the vessel, delaying boarding for the next crowd of cruisers taking an eight-day trip to Tasmania.

The outbreak follows a surge in Covid cases across Australia this month that has been described as an inevitable fourth wave of the pandemic.

While the Australian Government has scrapped the requirement for inbound and outbound international travellers to provide evidence of Covid vaccination status, travellers are still encouraged to be vaccinated for their own protection.

And cruise operators are responsible for ensuring measures are in place to protect passengers and crews from Covid and other infectious diseases. This includes the testing protocols in place for passengers and crew before joining the cruise and prior to disembarkation.

NSW Health released a statement on Saturday confirming its assessment that the Covid-19 risk level for the Majestic Princess was now Tier 3, which indicates a high level of transmission.

“In any enclosed space, including cruise ships, there is always a risk that Covid-19 will spread. Cruise ships must inform passengers of this risk,” the statement read.

“Prompt testing and isolation of cases, along with prevention through wearing masks and good hand hygiene, is important.”

The Majestic Princess cruise ship docked at the International Terminal on Circular Quay in Sydney on November 12. Picture: Muhammad Farooq / AFP

Australia is now in its fourth wave of Omicron infections, however unlike the previous waves caused by Omicron BA. 1, BA. 2, and BA.4/5, this wave has several causes, Professor Esterman explained.

“The first is waning immunity. Many people have had their last dose of vaccine over six months ago, and by now have comparatively little protection against symptomatic disease,” he said.

“At the same time, we have little or no public health measures in place to put a brake on transmission. The removal of mandatory isolation for infectious people just as new subvariants were on the horizon really was a poor decision. These new subvariants are more transmissible than BA.5.

“They include BA. 2.75, BQ. 1 and XBB. They are better than BA. 5 at getting around our immune systems, and this means that even fully vaccinated people or those who have recovered from an infection are at higher risk of infection.”

Professor Adrian Esterman.

Professor Esterman said cruise ships were well-known to be environments where viruses could easily spread, including Covid, influenza and gastrointestinal infections like norovirus.

“There are a lot of enclosed areas and there might not be air filtration with HEPA filters,” he said.

“So they can try to make it as safe as possible, but nonetheless they tend to be moving Petri dishes.”

Professor Esterman said the Australian Technical Advisory Group on Immunisation (ATAGI) was coming under increasing pressure to allow a fifth dose to vulnerable people.

He said the onus was on the states and territories to upgrade health advice, and if necessary, reimpose some public health measures, like face mask advice.

“Surely, mandating face masks on public transport is not that difficult,” he said.