Medical workers have learned how to better treat Covid-19 patients since earlier in the pandemic, likely leading to lower mortality rates, Atlantic Health System CEO Brian Gragnolati told CNBC. “We’ve seen tremendous progress in clinical innovation ... and you’ve got to remember, it’s only been about five months,” Gragnolati said on “Squawk on the Street.” Gragnolati referenced changes in ventilator use when patients are transferred to ICUs, as well as how to best use drugs such as remdesivir.