Deaths from COVID-19 used to peak three weeks after cases, although University of NSW mathematician and pandemic modeler Associate Professor James Wood said this had been closer to two weeks with the Omicron variant, which has been dominant in Australia throughout 2022.
After cases peaked in mid-to-late July, Wood said the current wave “should have passed [its] peak mortality”.
However, with more deaths from COVID-19 outside of public hospitals and thus counted by other agencies such as births, deaths and marriages, the timing of when state health departments report a death from the virus is less uniform than in previous waves of infection.
“The level of case reporting is also not as high as it used to be, so the level of known cases relative to the number of deaths that we see may not necessarily match,” Lang said.
In February, the task force warned that Australia would experience excess annual mortality, or more overall deaths from all causes than expected, by 2022 unless there was a significant reduction in cases. Lang said excess mortality was now expected.
David Muscatello, associate professor of infectious disease epidemiology at the University of NSW, agreed that this was a foregone conclusion, mainly because of the high death toll from COVID-19.
The recent wave has been driven by the Omicron BA.4 and BA.5 subvariants, which are known to evade immunity gained by previous infections or vaccinations. A higher proportion of elderly people have also been seen to contract the virus, which has affected the death toll.
Of the 164 NSW virus deaths reported in the week ending July 30, 124 were aged 80 or over, according to data from NSW Health’s latest surveillance report. Sixty-five were in their 90s and 79 lived in aged care facilities.
Old age is a risk factor for severe COVID-19.
However, the return to school has changed the demographics of the outbreak, with NSW data showing cases are now increasing among 10-19 year olds.
Aged care cases also appear to have peaked: The number of homes with an active outbreak fell from 1,064 to 952 last week, according to weekly reports from the federal government.
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“The age profile of people who get infected seems to change a bit as each one [virus] comes the lineage,” Muscatello said. However, he believed the volume of cases was what was driving Australia’s death toll.