Democratic U.S. presidential nominee and former Vice President Joe Biden has picked Senator Kamala Harris of California to be his running mate in the November election against Republican incumbent Donald Trump. —David E. Rovella

Here are today’s top stories

The recovery has stalled in major advanced economies, with some countries hitting a ceiling on activity that is below their pre-crisis levels, according to Bloomberg Economics gauges that integrate high-frequency data such as credit-card use, travel and location information. Euro-area economies such as Germany, France and Italy, along with Norway and Japan, are closest to their pre-pandemic readings, with Spain falling behind slightly. The U.K., U.S. and Canada are still far below their levels of activity at the start of the year.

The story of the war against Covid-19 begins half a billion years ago. That’s when jawed fish—our scaly forebears—evolved an immune system capable of learning, adapting and defeating invaders. This system was such an improvement over the slow-learning innate version of the day that some scientists now describe it as the Big Bang of immunology. But as awesome as our immune system is, it doesn’t win every time. Right now it’s faces a foe it doesn’t always know how to fight. While some countries have managed to control the novel coronavirus through social measures such as mask-wearing, others have manifestly failed. In a special issue of Bloomberg Businessweek, we look at the biggest challenges, promising solutions and weirdest science along the winding path to a Covid-19 vaccine.

Russia has conditionally registered a vaccine for the coroanavirus before clinical trials are complete, a move medical experts and pharmaceutical companies warn could put its recipients at risk. Less than 100 people had officially received the unproven inoculation by early August and its widespread use could be dangerous, the Association of Clinical Trials Organizations said. “Why are all corporations following the rules, but Russian ones aren’t?” said ACTO Executive Director Svetlana Zavidova, who deemed the announcement a “political decision by [Vladimir] Putin so he can claim that Russia was the first.” The rules for conducting clinical trials, Zavidova said, “are written in blood.” Most Americans, meanwhile, will not be able to get a vaccine until well into 2021. Worldwide, confirmed infections now exceed 20 million, though the true number is thought to be much higher. About one-quarter of all known infections globally are in America. New Zealand’s world-beating run of being Covid-19 free has come to an end, with the detection of new cases prompting the government to quickly put its largest city into lockdown. Here is the latest on the global pandemic.

The number of European Union citizens working in the U.K. shrank to the lowest since 2015 as the hospitality industry buckled. Employment of EU nationals dropped by 284,000 in the second quarter as Covid-19 prompted the U.K.’s biggest slump since the 2008 financial meltdown.

One demand by U.S. Senate Majority Leader Mitch McConnell is a key obstacle to passage of a second pandemic bailout package.

Trump is mulling two locations for his acceptance of the Republican nomination, both on federal property, which has been historically off-limits to political events.

More than one million homes and businesses were without power across the U.S. Midwest after a wall of lightning, hail and deadly winds ripped through Chicago and elsewhere, tearing apart trees and homes.

What you’ll need to know tomorrow

• As U.S. schools open, Israel’s mistakes offer a cautionary tale.
• An 1,100% stock gain is Hong Kong’s new protest rallying cry.
• How Singapore helped these three men become billionaires.
• Jamie Dimon and Jeff Bezos pledge to hire 100,000 New Yorkers.
• To escape Covid-19, grandma is now living in the backyard.
• QuickTake: How coronavirus and race collide in America.
• Stranded international students are keep U.S. college towns alive.

What you’ll want to read in Bloomberg Screentime

Amazon Ties Video Games Deeper Into Prime

The world’s largest e-commerce company has given its more than 150 million Prime members access to free video-game content, eliminating a step that required them to link their Amazon account with one on Twitch, the company’s live-streaming subsidiary. The service, once known as Prime Twitch, is now called Prime Gaming and offers special in-game perks and free downloadable PC games.

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