<em>The Atlantic </em>Daily: The Delta Whiplash Is Here

Every weekday evening, our editors guide you through the biggest stories of the day, help you discover new ideas, and surprise you with moments of delight. Subscribe to get this delivered to your inbox.

The Delta whiplash is here. A leaked CDC report, along with some new data released by the agency, put this week’s updated mask rules in context: This variant is more worrisome than previously thought.

America is not back to square one. But Delta is forcing us to reopen our toolkit and reconsider our approach to this virus. Here are four important things to know.

Delta appears to be extremely transmissible—and responsible for more breakthroughs.

The variant is more transmissible than previous strains of the coronavirus and maybe as transmissible as the chicken pox, the leaked CDC report suggested.

Breakthrough cases also appear more common. At the center of discussion is an outbreak in Massachusetts, where nearly three-fourths of those infected were vaccinated (but only four out of hundreds were hospitalized).

Vaccinated people may be able to transmit the virus more easily than hoped.

When studying the Massachusetts outbreak, researchers found unvaccinated and vaccinated people might carry similar amounts of the virus in their airways, a measure called viral load.

One key word here is might. Finding virus genetic material in the airway doesn’t guarantee a person is transmitting it (by, say, spitting or sneezing). But it does open up the possibility.

“People need to understand [that] infectiousness is multidimensional,” Müge Çevik, a virologist and infectious-disease expert at the University of St. Andrews, told my colleague Katherine J. Wu. “Viral load is only one piece of the puzzle.”

Fully vaccinated individuals are less likely to get infected, develop symptoms, go to the hospital, or die. They’re still not spreading the virus as often as unvaccinated people. But this is a particularly troubling development for those who are immunocompromised or elderly or live with people who are, as well as the parents of unvaccinated children.

We don’t know what this means for the fall and winter just yet.

Experts are divided on what the coming seasons will look like. “We unfortunately just have to get a little more comfortable with uncertainty and try to be flexible,” Katie, who is constantly covering the shifting science about the virus, told me.

“Things did just get more complicated,” she said.

“It’s definitely going to be bleak, but I don’t think it’s going to be quite as bad as last winter,” the infectious-disease doctor Gary Simon predicted.

So what does it mean for you?

Again, it depends on who you are and where you live. As Katie’s recommended in the past, you can check local virus conditions like the weather. The CDC advises those in transmission hot spots to mask up—although you’d be justified in wearing one anywhere.

Soon we may all be in the same boat. “If you’re not in high or substantial transmission today, you probably will be tomorrow or the next day, given the rate of spread of this Delta variant,” one physician told Katie.

Revisit the week that was. See photos from Tokyo and other places around the world in this collection assembled by our senior editor Alan Taylor.

Read. Pick a book off our summer reading guide.

Watch. The Green Knight, a King Arthur tale led by Dev Patel, is one of the best movies of the year. Woodstock 99, meanwhile, tells the story of a concert gone wrong—and reminds us of the dark side of social gatherings.

There’s always the Olympics.

Listen. Podcast people, we didn’t forget about you! This week’s episode of The Experiment is about the myth of the “student athlete.”

Also, this weekend could be a good time to revisit our episode on the 1905 Supreme Court tussle over government-mandated vaccines.

Thank a good dog near you. And while you’re still tingling with pride for your canine, read about why Millennials in particular are so obsessed with their pooches.

Every weekday evening, our editors guide you through the biggest stories of the day, help you discover new ideas, and surprise you with moments of delight. Subscribe to get this delivered to your inbox.