Categories
Delta variant

Will the Delta Variant Peak and Then Burn Out?

Aug. 4, 2021 — When the Delta variant of the coronavirus was first identified in India in December 2020, the threat may have seemed too remote to trigger worry in the United States, although the horror of it ripping through the country was soon hard to ignore. Within months, the Delta variant had spread to…

Aug. 4, 2021 — When the Delta variant of the coronavirus was first identified in India in December 2020, the threat may have seemed too remote to trigger worry in the United States, although the horror of it ripping through the country was soon hard to ignore.

Within months, the Delta variant had spread to more than 98 countries, including Scotland, the U.K., Israel, and now, of course, the U.S. The CDC said this week the Delta variant now accounts for 93% of all COVID cases.

Fueled by Delta, COVID-19 cases, hospitalizations, and deaths are increasing in nearly all states, according to the latest CDC data. After the 7-day average number of cases dipped by June 22 to about 11,000, it rose by Aug. 3 to more than 85,000.

Some experts are heartened by the recent decrease in COVID-19 cases in the U.K. and India, both hard-hit with the Delta variant. COVID-19 cases in India peaked at more than 400,000 a day in May; by Aug. 2, that had dropped to about 30,500 daily.

Andy Slavitt, former Biden White House senior adviser for COVID-19 response, tweeted July 26 that if the Delta variant acted the same in the U.K. as in India, it would have a quick rise and a quick drop.

The prediction seems to have come true. As of Aug. 3, U.K. cases have dropped to 7,467, compared to more than 46,800 July 19.

So the question of the summer has become: “When will Delta burn out here?”

Like other pandemic predictions, these are all over the board. Here are five predictions about when COVID cases will peak, then fall. They range from less than 2 weeks to more than 2 months:

  • Mid-August: Among the most optimistic predictions of when the Delta-driven COVID-19 cases will decline is from Scott Gottlieb, MD, former FDA director. He told CNBC on July 28 that he would expect cases to decline in 2-3 weeks — so by August 11.
  • Mid-August to mid-September: Ali Mokdad, PhD, chief strategy officer for population health at the University of Washington, says that, “Right now for the U.S. as a country, cases will peak mid-August” and then decline. He is citing projections by the university’s Institute for Health Metrics and Evaluation. In its “most likely” scenario, it predicts COVID deaths will peak at about 1,000 daily by mid-September, then decline. (As of Aug. 3, daily deaths averaged 371.)
  • September: “I am hoping we get over this Delta hump [by then],” says Eric Topol, MD, founder and director of the Scripps Research Translational Institute in La Jolla, CA, and editor-in-chief of Medscape. “But sometimes, I am too much of an optimist.”
  • Mid-October: Experts at the COVID-19 Scenario Modeling Hub, a consortium of researchers from leading institutions who consult with the CDC, say the Delta-fueled pandemic will steadily increase through summer and fall, with a mid-October peak.
  • Unclear: Because cases are underestimated, “I think it is unclear when we will see a peak of Delta,” says Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security. He predicts a decline in cases as “more people get infected and develop natural immunity.”

The predictions are based on different scenarios, such as most likely or worst-case. Factors such as personal behaviors, public mandates, and vaccination rates could all alter the projections.

What a Difference Vaccination May Make

An uptick in vaccinations could change all the models and predictions, experts agree. As of Aug. 3, almost half (49.7%) of the total U.S. population was fully vaccinated, the CDC says. (And 80.1% of those 65 and over were.)

But that’s a long way from the 70% or 80% figure often cited to reach herd immunity. Recently, Ricardo Franco, MD, of the University of Alabama at Birmingham, said at a briefing by the Infectious Diseases Society of America that the infectiousness of the Delta variant may mean the herd immunity threshold is actually closer to 90%.

Mokdad of the University of Washington estimates that by Nov. 1, based on the current rate of infections, 64% of people in the U.S. will be immune to a variant like Delta, taking into account those already infected and those vaccinated against COVID-19.

Justin Lessler, PhD, a University of North Carolina epidemiologist involved in the modeling hub, says if enough people get vaccinated, it could stop the Delta variant in its tracks. But that percentage is high.

“I am relatively confident that if we could get 90% or more of the eligible population vaccinated that we would see the epidemic begin to recede,” he says.

It’s a huge leap from 50%, or even 64%, to 90%. Could the Delta surge really motivate that many people to head to a vaccination site?

That’s hard to predict, Topol says. Some unvaccinated people may feel like soldiers in a foxhole, he says, especially if t

Read More

Leave a Reply

Your email address will not be published. Required fields are marked *