With cases of the B.1.617.2 variant, or the Delta variant, of COVID-19 still of significant number, it remains critical for both experts and the public both to stay afloat of all the news, and know all the details about this persistent and deadly variant of the coronavirus. (To help you, Modern Sciences has explored the scale and impact of the now-dominant Delta variant of the COVID-19 pandemic before, and how the different strains of the coronavirus actually enter our body’s cells.)
Now, new research published in the Canadian Medical Association Journal sheds even more light onto the true virulence and deadly impact of the Delta variant, especially compared to the other variants of the virus. The study was led by researchers from the University of Toronto David Fisman and Ashleigh Tuite.
In the study, Fisman and Tuite analyzed some 200,000 records of COVID-19 cases in Canada, and checked for rates of hospitalization, admissions into an intensive care unit (ICU), and death rates. The two actually paid attention to the differences in metrics the Delta variants produced compared to the previous variants of COVID-19 (e.g. Alpha, Beta, Gamma).
Compared to the original strain, the Alpha, Beta, and Gamma variants of COVID-19 caused a 52% increase in hospitalization rates compared to the original SARS-CoV-2 strain. The three variants also increased ICU admission rates by 89% and deaths by 51% compared to the original. By themselves, these values already appear alarming; however, it’s the values obtained for the Delta variant that show just how dangerous this variant is.
Fisman and Tuite found out that compared to the original strain of SARS-CoV-2, the Delta variant increased rates of hospitalization by as much as 108%, ICU admission by as much as 235%, and death by 133%—more than twice as much as the three previous variants of COVID-19.
These results correspond with data obtained from earlier studies like those published in the journal Nature just a month ago, which showed that the Delta variant exhibits six times (6×) less sensitivity to antibodies from people who had already been infected with the SARS-CoV-2 virus beforehand.
Luckily, it’s not all bad news; the two researchers also found that vaccination really did decrease the chances of serious illness and death across all variants of the coronavirus—even the Delta variant. According to their paper, vaccinations imparted a “substantial degree of protection” to patients against death, and by as much as 90%. This, they say, is crucial in the fight against the coronavirus, even if the vaccine didn’t necessarily prevent infection.
The authors continued: “The emergence of novel SARS-CoV-2 [variants of concern, like the Alpha and Delta variants,] has slowed progress against the pandemic in 3 distinct ways, namely: by increasing transmissibility and the virus’ reproduction number; by increasing immune escape and diminishing vaccine effectiveness; and by increasing the virulence of SARS-CoV-2 infection.”
At this point, we must understand all that we can about these variants in order to know how to slow or stop them for good. And, while the results from the two researchers apply mostly to the locality of Canada, their study proves useful to the rest of the world, too, as it helps inform health professionals the world over of what to expect as this Delta-dominant pandemic continues on.
References
- Fisman, D. N., & Tuite, A. R. (2021). Evaluation of the relative virulence of novel SARS-CoV-2 variants: A retrospective cohort study in Ontario, Canada. CMAJ. https://doi.org/10.1503/cmaj.211248
- Haridy, R. (2021, October 11). Delta more than doubles risk of death compared to original coronavirus. New Atlas. https://newatlas.com/health-wellbeing/delta-variant-increased-hospitalization-disease-compare-original-strain/
- Mlcochova, P., Kemp, S., Dhar, M. S., Papa, G., Meng, B., Ferreira, I. A. T. M., Datir, R., Collier, D. A., Albecka, A., Singh, S., Pandey, R., Brown, J., Zhou, J., Goonawardane, N., Mishra, S., Whittaker, C., Mellan, T., Marwal, R., Datta, M., … Gupta, R. K. (2021). SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion. Nature, 1–8. https://doi.org/10.1038/s41586-021-03944-y
