The Cleveland Clinic on Tuesday released a study showing that 99.75% of patients hospitalized with COVID-19 between Jan. 1 and April 13 were not fully vaccinated, according to data provided to Axios.

Why it matters: Real-world evidence continues to show coronavirus vaccines are effective at keeping people from dying and out of hospitals. The Pfizer-BioNTech and Moderna vaccines have been found to be 95% and 94% effective, respectively, at preventing symptomatic infections.

Details: The study also looked at 47,000 Cleveland Clinic employees who had received one shot, both shots or no shots at all.

• The Cleveland Clinic found that 99.7% of its employees who were infected with the coronavirus were not vaccinated, and 0.3% of infections occurred in those who were fully vaccinated.
• The study found that in this group, mRNA vaccines were more than 96% effective in protecting against coronavirus infections.

Go deeper: Vaccines: What you should know