Yes, the COVID vaccine came out super-quickly—but here’s why it’s safe

“One cell can make a million copies of a virus,” says Luis Villarreal, UC Irvine professor emeritus and co-founder of The Center for Virus Research. In the case of COVID-19, the virus takes hold inside a respiratory cell, where it makes millions and millions of copies of itself, before moving on to replicate in other cells in our body.