https://www.wired.com/story/why-creating-a-covid-19-vaccine-is-taking-so-long/

The race is on for a Covid-19 vaccine, but the pace is less hare and more tortoise. And necessarily so: Developing a vaccine that’s both effective and safe is grueling, methodical work.

“When experts optimistically say that they expect a Covid-19 vaccine by the end of 2020, they’re talking about an emergency use authorized vaccine, not a fully-approved one,” says Dr. Seema Yasmin, director of the Stanford Health Communication Initiative.