As the U.S. hits the half-million death mark from COVID-19 -- a grim milestone that is equal to roughly the entire population of Atlanta and more than that of Miami -- a new weapon is being added to the COVID-19 vaccine arsenal. Johnson & Johnson is seeking emergency use authorization for what would become the U.S.'s first one-dose and non-mRNA COVID vaccine. It employs adenovirus vectors, a technology that has been used in labs for decades and was approved for the Ebola vaccine by the FDA in December 2019. It's the same technology that AstraZeneca/Oxford and Sputnik V use. Still, questions remain on how these vaccines may be different than mRNA or similar enough to other existing shots to encourage vaccine uptake. To explain how adenovirus vectors work and what to expect from the new products, Daniel Griffin, MD, PhD, chief of infectious disease at ProHEALTH Care, an Optum unit, joins us on this week's episode.