A report into an outbreak of coronavirus at the North West Regional Hospital has found the majority of healthcare workers who tested positive for the disease worked while they were infectious.
The COVID-19 North West Regional Hospital Outbreak Interim Report, released on Thursday morning, found 20 per cent of staff worked for several days while experiencing symptoms of COVID-19.
It found the most likely cause of the outbreak was one or both inpatients admitted to the hospital after acquiring COVID-19 on the Ruby Princess cruise ship who then passed the infection on to healthcare staff and patients on the medical ward.
Public Health director Mark Veitch said the two cruise ship related cases of COVID-19 were admitted to the NWRH in late March and the first staff member tested positive on April 3.
"Our impression was the cruise ship related cases had given rise to infection in one or more health care workers and there was subsequent transmission to other healthcare workers," he said.
Dr Veitch said it was likely by the time cases were diagnosed there was already established person-to-person transmission of coronavirus within the hospital.
The report said factors which may have contributed to the spread were staff continuing to attend work while experiencing respiratory symptoms, workplace activities such as staff gatherings in confined spaces, any shortcomings in infection control practices, incomplete or delayed identification of confirmed COVID-19 cases for immediate isolation, high levels of staff mobility between different healthcare facilities and the transfer of undiagnosed infectious or incubating patients between healthcare facilities.
"Several distinct clusters and pathways of transmission were identified," it said.
"Cases linked with the outbreak were identified in most areas of the NWRH, including the medical, surgical and mental health wards, the emergency department and operating theatres."
"Cases also occurred in the North West Private Hospital.
"Affected staff worked in many areas, including facilities in the co-located medical precinct such as pathology collection and outpatient services, the Mersey Community Hospital in Latrobe, and in aged care facilities in the North-West region."
The report said as of April 21, 73 staff members had contracted COVID-19 of whom 77 per cent worked while they were infectious, being the period from 48 hours before the onset of symptoms until the date they were tested and required to isolate.
"About half (51 per cent) did not attend work while symptomatic, about a third (29 per cent) had symptoms on the same day as their last day at work, and a fifth (20 per cent) attended work on one or more days after the date of onset of their symptoms, with a range of one to seven days," the report said.
"Some staff with longer durations of continued attendance attributed their symptoms to other chronic respiratory conditions, not to COVID-19."
There were a number of instances where close contacts were not immediately identified following the diagnosis of a confirmed case of COVID-19, the report said.
Culture shift needed
Chief Medical Officer Tony Lawler said his recommendations in the report fell under the three main headings of structuring and resourcing, process and practice, and culture and behaviour.
Professor Lawler said there was a culture of not wanting to let people down which needed to be addressed.
"People come to work when they feel they must because they don't want to let their staff, their colleagues down or their patients down," Professor Lawler said.
"It's understandable that some staff members turn up to work with symptoms. Often as healthcare workers seeing patients in extreme states we underestimate our own symptoms.
"We also sometimes ascribe these symptoms to other underlying conditions such as asthma or long-standing respiratory disease.
"We need to work to address the issues that drive people to come to work with symptoms."
Professor Lawler said he had also recommended regular audits of infection control practices, a review of how information is shared on cases between staff and the roll-out of a staff wellbeing and resilience program in the North-West.
Dr Veitch recommended strengthening the culture of safety regarding infection control practices, ensuring governance arrangements for managing future outbreaks in healthcare settings, considering the underlying drivers of staff presenting to work while unwell with respiratory illness and implementing strategies to minimise this, enhancing screening of staff and visitors to hospitals, implementing structural and cultural changes to strengthen social distancing in healthcare workplaces, reducing the movement of staff between facilities, and reducing the transfer of patients between and within facilities.
He said the report was a descriptive epidemiological account of the outbreak comprised of information about each case related to the cluster.
"These sort of reports take a higher-level look at the event but nevertheless seek to prevent and address future outbreaks," Dr Veitch said.
"The focus is the who, where, when of cases ... and it looks to find things in common with cases to explain how the outbreak occurred."
No one to blame
Premier Peter Gutwein said the Ruby Princess was responsible for about one in 10 of Australia's coronavirus cases.
"Most likely the Ruby Princess is the root cause of our problems on the North-West Coast. In terms of how this disease has spread is frankly something we will never know," Mr Gutwein said.
The Premier said he wanted to make it clear no passenger or healthcare worker was to blame.
"Don't use this report to blame people. Use this report to learn and to go forward," Mr Gutwein said.
Health Minister Sarah Courtney said the report made it clear COVID-19 was a disease which had never been seen before.
"What this report makes clear is the government took strong action at key times," Ms Courtney said.
Ms Courtney said she had accepted all of the report's recommendations.
She said some recommendations could be implemented quickly and others had already been implemented.
Read the full report here.