The biggest vaccination effort in history has begun. This week, the U.K. was first to clear the use of a new shot from Pfizer Inc. and BioNTech SE. The U.S. will likely do the same, and a separate vaccine from Moderna Inc. is close behind. By the end of 2020, tens of millions of people could be inoculated. Next year: billions more. Bloomberg is tracking nine of the most promising vaccines around the globe, from national procurement deals to shots in patients’ arms. By our count, at least 7.85 billion doses have already been allotted. It’s enough to cover half the world’s population (most vaccines use two doses), if the shots were distributed evenly. That, however, isn’t likely. Rich countries have hedged their bets with extensive supply deals, and ultra-cold storage requirements make some vaccines difficult to deliver to far-flung places. Other countries have struck their own paths: China and Russia authorized their vaccines in July before they’d been fully tested. Including those, a total of five vaccines are now available in limited quantities, in three countries. Subscribe to our YouTube channel: https://bit.ly/2TwO8Gm Bloomberg Quicktake brings you live global news and original shows spanning business, technology, politics and culture. Make sense of the stories changing your business and your world. To watch complete coverage on Bloomberg Quicktake 24/7, visit http://www.bloomberg.com/qt/live, or watch on Apple TV, Roku, Samsung Smart TV, Fire TV and Android TV on the Bloomberg app. Have a story to tell? Fill out this survey for a chance to have it featured on Bloomberg Quicktake: https://cor.us/surveys/27AF30 Connect with us on… YouTube: https://www.youtube.com/user/Bloomberg Breaking News on YouTube: https://www.youtube.com/c/BloombergQuickTakeNews Twitter: https://twitter.com/quicktake Facebook: https://www.facebook.com/quicktake Instagram: https://www.instagram.com/quicktake