The observational study, published Aug. 8 and yet to be peer-reviewed, included more than 50,000 patients in the Mayo Clinic Health System, which runs hospitals and clinics in Minnesota, Iowa and Wisconsin.
The study authors noted that the delta variant’s prevalence in Minnesota increased from 0.7% in May to over 70% in July, while the prevalence of the alpha strain decreased from 85% to 13% during the same timeframe.
Nationwide, the delta variant accounted for an estimated 83% of all U.S. COVID-19 cases by July 20, according to the U.S. Centers for Disease Control and Prevention.In a matched cohort across multiple states, the researchers found that those fully vaccinated with Moderna’s vaccine "were about half as likely to experience.