A new study conducted by Merck’s North Wales and New Jersey teams has found that survival rates of hospitalized COVID-19 patients increased in the early months as doctors gained more experience in dealing with the new disease, writes Stacey Burling for The Philadelphia Inquirer.

According to the study published in JAMA Network Open earlier this week, overall death rates dropped 19.7 percent for hospitalized patients last April to 9.3 percent in November.

The study analyzed data from over 503,000 patients at 209 hospitals. However, it stopped before the peak of the winter surge and before the vaccinations started.

Among the possible reasons for the trend is that hospitals had more experience treating coronavirus patient. They now had a better understanding of how and when to use ventilators in patients with the most severe breathing problems.

Lyn Finelli, executive director for new vaccines at Merck Research Labs in North Wales, said that the company runs epidemiological studies such as this one to “inform development programs” for its medicines and vaccines as well as to “identify groups of patients that would get the greatest benefit from our medicines.”

Read more about the study in The Philadelphia Inquirer.