Could the delta variant lead to a COVID summer wave in the U.S.?

dr bob wachter covid summer wave warning delta variant twitter thread
Photo via Christopher Michel/Flickr (CC BY 2.0)
  • This story is regularly updated for relevance. Last updated: July 12, 2021

Dr. Robert Wachter, the chair of the University of California, San Francisco’s department of medicine, has taken to Twitter to express concerns about the delta variant of COVID-19 and whether it could produce another U.S. wave in the summer.

The Twitter thread expanded on what he discussed on a June 15 PBS Newshour interview with Judy Woodruff. Commenting on how the delta variant compares to prior known versions of COVID-19, he said that it “appears to be more infectious than the alpha variant, which was more infectious than the original. So it’s substantially better at its job in infecting people. It appears to be more serious. The data on that is a little bit less clear. But I think that the consensus is, it probably is more serious.”

“And it has some ability to evade the vaccine,” he said. “The great news is, when you’re fully vaccinated, the vaccines work spectacularly well, as they do against the original. But you can tell that it has some superpowers because the first dose of your vaccine, which was 80% effective for Pfizer and Moderna with the original virus, now appears to be only 30-35% effective.”

In that interview, Wachter also observed that even though only 6-10% of new infections in the U.S. are the result of the delta variant, the fact that it’s overwhelming the U.K. leads him to believe the same could happen in America within the next month or two. It could potentially lead to a summer wave of new COVID infections.

By early July, the delta variant had reportedly become the most dominant strain in the U.S., making up about 52% of new cases, and former Biden administration official called it “COVID-19 on steroids.”

Wachter was featured in a May 2020 Wall Street Journal article about health experts going online to make COVID-19 information go viral because “they feel a moral obligation to provide credible information online and steer the conversation away from dubious claims, such as those in Plandemic, a video espousing COVID-19 conspiracy theories that [has drawn] millions of views.”

Wachter’s 25-tweet thread began with the remark, “I know everybody’s sick of playing 3-dimensional Covid chess. Sorry, but the Delta variant forces us back to the chess board.” He also prefaced his comments saying that, “If you’re fully vaxxed, I wouldn’t be too worried, especially if you’re in a highly vaxxed region.”

But as he observed, those who refuse to become vaccinated have reasons for concern about a potential summer COVID wave. As he bluntly assessed, “If you’re not vaccinated: I’d be afraid. Maybe even very afraid.”

The thread expanded on the point he made about the delta variant and first doses, noting that the delta variant “does appear to be somewhat immune resistant.”

“The efficacy of 2-doses of Pfizer is 88%, only a smidge lower than the 95% we’re used to, and still great,” he wrote. “But the first dose data is concerning. Normally, a few weeks after dose 1, you’re about 80% protected.”

He went on to say that the lower efficacy from just one dose of the Pfizer vaccine creates two issues: “People stay vulnerable until after shot 2 (& many let guard down earlier),” and “Loss in efficacy for dose 1 points to some degree of vaccine/immune escape.”

He concluded, “I’ll now bet we’ll see significant (incl. many hospitalizations/deaths) surges this fall in low-vaccine populations due to combo of seasonality, Delta’s nastiness, & ‘back to normal’ behavior.”

He added, “If you’re unvaxxed, you’ve made a bet that Covid is yesterday’s news, & that now seems like an awful bet. Moreover, I worry that a right-leaning Governor who opened up early & proudly (& has gotten away with it so far) will be stubbornly unwilling to reverse course, even in the face of surging cases & deaths.”

He also advised, “We need [the U.S. Food and Drug Administration] to fully authorize our vaccines, to step up research on boosters, and faster approvals for kids.”

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Sources: Wall Street Journal, Newshour

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