Australia is experiencing its ninth wave of Covid-19 but immunity built up through vaccinations and previous infections is resulting in fewer hospitalisations and deaths, according to the government and health experts.
A spokesperson for the Department of Health and Aged Care said national surveillance indicators, including average daily case numbers, hospitalisations and ICU admissions, outbreaks in aged care facilities and the dispensing of oral antiviral treatments, suggest that Covid-19 transmission has been gradually increasing since mid to late-August.
“These increases have started from a low baseline, however in the past week the highest weekly increase since May 2023 has been observed,” the spokesperson said.
The government’s most recent national weekly figures show Australia is reporting an average of 936 cases a day – a 23.6% increase in the week ending 24 October compared with the previous week.
Cases have risen in every state and territory, with Victoria seeing the lowest increase, at 15.8%, while Northern Territory is reporting the highest, at 45.1%.
The spokesperson said a sixth Omicron wave was being driven by a combination of Omicron sub-variants (mainly XBB), which the department considers Australia’s ninth Covid wave.
This wave is Australia’s first since 20 October when chief medical officer Paul Kelly declared Covid-19 was no longer a communicable disease incident of national significance.
The government’s principal health protection committee said Australia had shifted to managing Covid-19 in a way consistent with other common communicable diseases.
Prof Catherine Bennett, the chair of epidemiology at Deakin University, says it is important that people know the risk of infection is increasing so they can take precautions – especially if they are vulnerable to severe illness.
Do you still need to report positive results?
The health department says reported case numbers are an underestimate because of the changes in testing and reporting requirements.
New South Wales, Western Australia, Tasmania, the Northern Territory and the ACT are no longer collecting information on Covid-19 self-reported Rapid Antigen Test results.
Prof Dominic Dwyer, a medical virologist and infectious diseases physician at NSW Health Pathology’s Institute of Clinical Pathology and Medical Research, said “activity is much harder to measure now than two years ago because less people getting a PCR test done”.
Bennett said reporting of cases has been gradually dwindling and she estimates it’s now about 5% of infections. However, while the government’s surveillance systems don’t capture every infection, they can predict trends.
When did cases start rising?
Southern states were hit by this most recent wave first, followed by northern states, Bennett said.
Cases first started rising slowly in Victoria, then New South Wales, then Queensland, she said.
The number of Covid-19 cases in hospital has increased by an average of 17.5% nationally compared with the previous week, according to the government’s most recent weekly figures. The seven-day rolling average is 1,245 hospitalisations, including 31 in intensive care.
But these are fewer than half those recorded during the June wave (2,776 at 6 June 2023), and under a quarter of the cases recorded in last year’s July wave (5,377 at 27 July 2022).
Bennett said case numbers in each subsequent Omicron wave haven’t been as high as the previous peak. Cases have also tended to be milder as the majority of people have a combination of prior infection and vaccine immunity.
What are the current rules around Covid?
State and federal health departments have moved away from mandatory rules on Covid – and that’s part of the transition to the disease being endemic, Bennett said. “You can’t keep putting rules in and out each time you have a wave – this could go on for a very long time.”
Instead, Bennett said the approach will become like flu season where warnings are issued by authorities during peaks.
Face masks are no longer mandatory in most places. While advice varies between state health departments, most recommend wearing them if you have Covid-19 and are in indoor settings outside your home, where you cannot maintain physical distance.
The Australian Health Protection Principal Committee also recommends staying home when unwell with Covid and wearing a mask both if you are at high risk of the disease or visiting places with people at higher risk of serious disease, such as aged care facilities.
Are we still talking about Covid waves?
The health department spokesperson said a new wave of transmission is considered to have started when multiple national surveillance indicators concurrently increase from relatively low levels.
Bennett said she doesn’t number Covid waves because before borders opened at the end of 2021 some states experienced waves while others didn’t. Once borders opened waves became more clearly defined but the progressive waves have been declining in impact, she said. “Waves are just identifying that increased risk of being exposed to the virus in the community.”
The director of infectious diseases at Mater Health Services in Brisbane, associate prof Paul Griffin, said “we need to move more towards people understanding that Covid is going to be in our community basically forever with fluctuations in case numbers from time to time”.
“It doesn’t go away between these so-called waves and perhaps we need to adapt our terminology accordingly,” Griffin said.
What’s the latest on vaccinations?
The health department spokesperson said 4.1m booster doses have been administered to all ages in 2023.
“Fewer people have received a Covid-19 booster this year than previously,” the spokesperson said.
“The number of people getting vaccinated each week is good, but we would like it to be higher.”
Dwyer said vaccinations and boosters are very important, but the messaging around a vaccination like influenza is easier because it occurs every winter.
The Australian technical advisory group on immunisation recommends that all adults aged 75 years and older should receive an additional Covid vaccine dose if it has been more than six months since their previous dose.
Atagi advises adults aged 56-74, as well as anyone aged 18 and older who is severely immunocompromised, should only consider a booster if more than six months has passed since their last dose, after discussion with their healthcare provider.
Atagi’s advice is in line with the latest update from the World Health Organization, which advised only high-risk groups should receive ongoing Covid-19 booster doses.
