Dr Robert Moss, a University of Melbourne epidemiologist within the Victorian government’s epidemic-tracking team, said: “It does look as though BA.5 may have peaked in a number of states. It’s a little earlier than we might have expected.”
However, I have added that the stress on hospitals “could remain uncomfortably high for a while yet”.
BA.5 is a subvariant of Omicron, which caused a huge spike in cases in January.
This version of the virus is particularly good at evading the antibody protection generated by vaccines or infection. At the same time, vaccine protection has been waning, with only 71.3 per cent of Australians over 16 having had a booster shot.
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While McCaw fears the worst may be to come for hospitals, other epidemiologists noted the number of people needing a bed was falling in several states.
Dr Romain Ragonnet, part of Monash University’s epidemiology team, said: “I am quite confident that our hospital system has now passed its most testing times. We seem to have passed the flu peak and we are approaching warmer days.”
Unlike earlier in the pandemic, authorities no longer have a firm grip on how much virus is in the community, as many people are either not getting tested or not reporting test results. Victorian authorities have said they suspect about half of new cases are being missed.
Rather than just looking at daily cases, some epidemiologists are now focusing on the total percentage of positive tests to track the virus.
In Victoria, that rate peaked in the first week of July and has since fallen slightly, while it has fluctuated in NSW.
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“New cases have flattened out and are now likely to decline in the majority of states, and we’re not seeing any rises in PCR-positive percentage,” said Associate Professor James Wood, a disease modeller at the University of NSW who provides data to state governments. “So that trend is realistic.”
University of Melbourne epidemiologist Professor Tony Blakely came to the same conclusion, pointing to falling hospitalization rates across the country as evidence that the surge is past its peak.
Blakely said BA.5 may continue to circulate, causing smaller waves as immunity from the vaccine wanes, or another variant may emerge and become dominant, leading to a new, larger wave.
“What happens beyond this wave? No one really knows,” he said.
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