Less than one year since the pandemic began, the FDA has granted Emergency Use Authorization (EUA) to two COVID-19 vaccines, the Pfizer and Moderna vaccines — both of which are mRNA vaccines.

This is the first time mRNA vaccines have been used in humans, but mRNA research and technology isn't as new as you may think.

"A lot of thought has gone into RNA vaccines, and they've actually been studied in clinical trials for many years now for cancer and other infectious diseases," says Dr. John Cooke, medical director of the RNA Therapeutics Program at Houston Methodist.

In the video above, Dr. Cooke takes you behind the scenes to explain how mRNA works, as well as what makes mRNA vaccines effective.