Expert warns of higher death rate than China as Sydney outbreak investigated
Kate Aubusson & Rachel Clun
The Age
March 10, 2020
Australia must prepare for a higher coronavirus death rate than China, a biosecurity expert says, as health authorities investigate a growing cluster of cases in north-west Sydney.
The cluster of at least 15 people has now spread to two schools, a hospital, a nursing home and Defence Force personnel, NSW Health confirmed on Monday.
By Monday afternoon, the total number of cases in NSW was 47, including two year 10 students from St Patrick's Marist College in Dundas, a 12-year-old girl from Willoughby Girls High School, and three parents.
But it's not the young who are most at risk. Leading biosecurity expert Raina MacIntyre said Australia's relatively older population meant this group could have a significantly higher mortality rate than in China.
In China, about 9 per cent of the population are over the age of 65, compared with Australia where it is about 16 per cent.
Over the past two weeks, international case mortality rate estimates for COVID-19 have oscillated between 1.4 per cent and 3.4 per cent. Rolling death rates are unstable, and the true mortality rate won't be known until after the contagion subsides.
So far three elderly Australians have died from COVID-19.
Professor MacIntyre urged the government to enforce travel restrictions and containment measures for as long as possible.
"Epidemics grow exponentially over days and weeks, not years … time is critical," she said. "Every week we are going to see this get bigger and bigger unless we can contain it. This is the time to do it."
As locally acquired infections rise, Professor MacIntyre said Australia may have already entered a period of sustained community transmission.
Schools, universities and sports and entertainment venues could be sites of "intense transmission", she said. The Royal Easter Show, which attracts an average of 850,000 visitors, posed an unnecessary and dangerous risk.
"Having an event like the Easter Show that attracts tens of thousands of people makes control so much harder. It just sets us back and is going to cause unnecessary infections and potentially death," she said.
Travel bans were not sustainable indefinitely and Australia would need to make a choice between economic and public health consequences, Professor MacIntyre said.
Once the travel bans are inevitably lifted, Australia must prepare for a surge of cases and the impact they will have on the healthcare system.
"There is still a sliver of hope [that the virus can be contained in Australia] but just a sliver fades every day," she said.
"An individual will have nine to ten close contacts each day," she explained. "If we have 50 cases that’s 500 people who need to be traced and monitored … when that number gets to 500 or 10,000, the task will be impossible."
She commended NSW Health for continuing their rapid identification and isolation of confirmed cases, contact tracing and isolation measures to prevent and slow the contagion.
The state's Chief Health Officer Dr Kerry Chant said containment and contact tracing was a proven strategy to prevent and slow outbreaks even amid sustained community transmissions.
Addressing the cluster of cases in north-west Sydney, Dr Chant said NSW Health was "doing the detective work" to trace the "links and threads" between the two students at St Patrick's Marist College, a 16-year-old Epping Boys High School student diagnosed last week, Ryde Hospital, BaptistCare's Dorothy Henderson Lodge in Macquarie Park, and Australian Defence Force personnel.
The fathers of the two teenagers at St Patrick's Marist College - a 14-year-old boy and a 15-year-old girl - also tested positive for the virus. Both men work for the Defence Force, Dr Chant said.
"Our main aim now is to make sure we’ve tracked down any chain of ongoing transmission and any that may have been missed, to slow any community spread of COVID-19," she said.
"We know the greatest risk of transmission is within a family setting. So we have to plot who got sick when and do detective work to map it out and look at the connections."
NSW accounts for more than half of the 92 coronavirus cases in Australia confirmed by Monday evening. Victoria accounted for 15 cases and Western Australia had six.
