Delta has changed pandemic endgame

Delta has changed pandemic endgame

Ed Yong writes:

In September 2020, just before COVID-19 began its wintry surge through the United States, I wrote that the country was trapped in a pandemic spiral, seemingly destined to repeat the same mistakes. But after vaccines arrived in midwinter, cases in the U.S. declined and, by summer’s edge, had reached their lowest levels since the pandemic’s start. Many Americans began to hope that the country had enough escape velocity to exit its cycle of missteps and sickness. And though experts looked anxiously to the fall, few predicted that the Delta variant would begin its ascent at the start of July. Now the fourth surge is under way and the U.S. is once again looping through the pandemic spiral. Arguably, it never stopped.

This new surge brings a jarring sense of déjà vu. America has fallen prey to many of the same self-destructive but alluring instincts that I identified last year. It went all in on one countermeasure—vaccines—and traded it off against masks and other protective measures. It succumbed to magical thinking by acting as if a variant that had ravaged India would spare a country where half the population still hadn’t been vaccinated. It stumbled into the normality trap, craving a return to the carefree days of 2019; in May, after the CDC ended indoor masking for vaccinated people, President Joe Biden gave a speech that felt like a declaration of victory. Three months later, cases and hospitalizations are rising, indoor masking is back, and schools and universities are opening uneasily—again. “It’s the eighth month of 2021, and I can’t believe we’re still having these conversations,” Jessica Malaty Rivera, an epidemiologist at Boston Children’s Hospital, told me.

But something is different now—the virus. “The models in late spring were pretty consistent that we were going to have a ‘normal’ summer,” Samuel Scarpino of the Rockefeller Foundation, who studies infectious-disease dynamics, told me. “Obviously, that’s not where we are.” In part, he says, people underestimated how transmissible Delta is, or what that would mean. The original SARS-CoV-2 virus had a basic reproduction number, or R0, of 2 to 3, meaning that each infected person spreads it to two or three people. Those are average figures: In practice, the virus spread in uneven bursts, with relatively few people infecting large clusters in super-spreading events. But the CDC estimates that Delta’s R0 lies between 5 and 9, which “is shockingly high,” Eleanor Murray, an epidemiologist at Boston University, told me. At that level, “its reliance on super-spreading events basically goes away,” Scarpino said.

In simple terms, many people who caught the original virus didn’t pass it to anyone, but most people who catch Delta create clusters of infection. That partly explains why cases have risen so explosively. It also means that the virus will almost certainly be a permanent part of our lives, even as vaccines blunt its ability to cause death and severe disease.

The U.S. now faces a dispiriting dilemma. Last year, many people were content to buy time for vaccines to be developed and deployed. But vaccines are now here, uptake has plateaued, and the first surge of the vaccine era is ongoing. What, now, is the point of masking, distancing, and other precautions?

The answer, as before, is to buy time—for protecting hospitals, keeping schools open, reaching unvaccinated people, and more. Most people will meet the virus eventually; we want to ensure that as many people as possible do so with two doses of vaccine in them, and that everyone else does so over as much time as possible. The pandemic isn’t over, but it will be: The goal is still to reach the endgame with as little damage, death, and disability as possible. COVID-19 sent the world into freefall, and although vaccines have slowed our descent, we’d still be wise to steer around the trees standing between us and solid ground. “Everyone’s got pandemic fatigue—I get it,” Rivera told me. “But victory is not you as an individual getting a vaccine. It’s making sure that SARS-CoV-2 doesn’t bring us to our knees again.” [Continue reading…]

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