The study -- from the COVID-19 forecasting team at the University of Washington's Institute for Health Metrics and Evaluation -- notes that, as of September 21, only about 49% of US residents reported that they "always" wear a mask in public.
If mask-wearing remains 49% through February and states continue with removing social distancing mandates, the COVID-19 death toll across the United States could reach about 1 million deaths by February 28, according to the study, published in the journal Nature Medicine on Friday.
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Yet under the assumption that states shut down when their daily death rate exceeds 8 deaths per 1 million people in the population but mask-wearing doesn't change, the study's model projections forecast the death toll could reach 511,373 deaths by February 28.
The scenario that 95% of people in each state wear masks -- in addition to states reinstating social distancing mandates if their daily death rates exceed 8 deaths per 1 million people -- resulted in the lowest death toll projection, with 381,798 deaths by February 28, according to the study.
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For the study, the researchers analyzed data on COVID-19 cases and deaths in the United States from February 1 through September 21. That analysis -- along with other factors, such as pneumonia seasonality, testing rates and mask use -- helped inform model projections for the course of the pandemic through February 28.
The study had some limitations, including that the findings are only forecast projections from models and not definitive about what the future holds.
IHME Director Dr. Chris Murray emphasized during a virtual press briefing on Friday that the institute's weekly modeling projections provide more updated data than what is provided in the study. However, the study still helps offer insight into how mask-wearing can make a difference.
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