Behind the daily death figures, there is a more complicated picture of the impact of Covid-19 in Australia that raises questions about whether Covid could be causing more deaths from ischaemic heart disease, cerebrovascular disease and dementia.
As cases exploded after the emergence of the Omicron variant, the number of Covid deaths similarly rose, with more than 80% of Australia’s total Covid deaths occurring in 2022.
There has also been an increase in the proportion of people who died with Covid as a contributing cause of death, rather than as the primary cause of death:
The difference between these groups is important – due to some previous misinterpretation of the figures – and so is the contribution of pre-existing chronic conditions.
The Australian Bureau of Statistics (ABS) tracks Covid mortality in a monthly report, and divides Covid deaths into “deaths due to Covid” and “Covid-related deaths”.
Deaths due to Covid accounts for the vast majority of deaths during the pandemic, and includes any death where Covid was considered to be the underlying cause of death. This includes deaths that had other associated conditions listed on the death certificate, such as pneumonia due to Covid or pre-existing chronic conditions.
Covid-related deaths includes deaths where the person either died with Covid, or had complications from a previous Covid infection but the virus was not the underlying cause of death. Importantly, the ABS said that while Covid did not directly cause the death of these people, it was still considered to have contributed to the death.
Prof Roger Byard, a forensic pathologist from the University of Adelaide, said it’s very difficult to know how much Covid contributed to death in these instances without knowing the full details of each case
“You’ve got the whole spectrum of Covid causing the disease [listed as the cause of death], Covid contributing to the disease, and Covid not being related to the disease, and there’s grey zones in all of those areas,” he said.
Gideon Meyerowitz-Katz, an epidemiologist at the University of Wollongong, said interpreting the increasing proportion of deaths with Covid was complicated.
“It is possible that the increasing number of deaths where Covid-19 is listed as a co-morbidity rather than a contributing factor to death is simply because the prevalence of Covid is so high, so there are more people who are already dying who are categorised as having Covid-19,” he said.
“It’s also possible that this indicates a reduction in the overall severity, perhaps due to vaccination, and that what’s happening is that Covid-19 is then less fatal than before.”
Another way to measure the impact of Covid is to look at excess deaths – that is, how the number of deaths in a given time period compares with how many deaths we might have expected in that time period based on a model using deaths from previous years without Covid.
In Australia, the Actuaries Institute has been estimating excess deaths using data published by the ABS. This chart shows their latest analysis on excess deaths throughout the pandemic: