Risk of death more than 130% higher with delta variant than original COVID virus, research suggests

A new study using Canadian data suggests the delta variant of the COVID-19 virus causes more serious disease and is associated with an increased risk of death compared to previous strains — dangers that are drastically reduced with vaccination.

The study, conducted by researchers at the University of Toronto and published Tuesday in the Canadian Medical Association Journal, analyzed more than 212,000 cases of COVID-19 reported in Ontario between Feb. 7 and June 27.

They found that those infected with the alpha variant, which drove the province's third wave in the early spring, or the beta or gamma variants were 52 per cent more likely to be hospitalized, 89 per cent more likely to need intensive care and 51 per cent more likely to die of the infection than those who caught the early 2020 version of the virus.

Among delta cases, they found a 108 per cent increased risk for hospitalization, 235 per cent increased risk for ICU admission and 133 per cent increased risk for death compared to the original virus strain.

Some of the findings echo results from previous research papers published across the globe, but co-author David Fisman believes the study is the first large-scale analysis to include Canadian data.

The University of Toronto epidemiology professor said that could be an important factor for some to more strongly consider the risk that delta carries and get vaccinated.

"[The finding] jives with what the intensivists are telling us, which is that people come into hospital much sicker now than they did a year ago, but to see it in the numbers was initially pretty startling," Fisman said.