The United States began Phase 3, one of the last steps in developing a vaccine, on July 27, 2020. See how vaccines are developed, and how close experts think we are to getting a coronavirus vaccine. Subscribe to The Washington Post on YouTube: https://wapo.st/2QOdcqK Follow us: Twitter: https://twitter.com/washingtonpost Instagram: https://www.instagram.com/washingtonpost/ Facebook: https://www.facebook.com/washingtonpost/