The Atlanta Journal-Constitution
■ Do we have an idea of when the delta surge might end?
The United States has entered the fourth wave of the pandemic — or fifth, depending on which expert you ask. As the vaccination campaign lags and the contagious delta variant spreads, cases and hospitalizations are at their highest since last winter. COVI
What happened
After every other peak has come a trough, however, often for reasons that were not immediately obvious. In Britain, where the variant is also the dominant form of the coronavirus, daily cases fell from a peak of 60,000 in mid-july to half that within two weeks, though they have since been climbing again.
In India, the numbers spiked to more than 400,000 daily cases this spring; experts estimated that the true figure could be more than 20 times greater. The unimaginable toll shocked many who had declared that the country had successfully eluded the virus. But then, in June, infections fell drastically.
Why it matters
Scientists are struggling to understand why delta outbreaks in those countries dissipated, even if temporarily, and what that may mean for similar surges, including the one in the U.S.
In the U.S., the variant’s pace has slowed, and new infections are falling in some states, like Missouri, that delta struck hard. The number of infections over the past week is now 14% higher than it was two weeks ago, a fraction of the rate during much of July and early August.
Is the delta surge beginning to slow in the U.S.? Or is the variant putting the country on course for months of bumps
and valleys?
What it means
Expert opinion varies widely on the direction of the virus in the coming months. A number of national forecasts being tracked by the Centers for Disease Control and Prevention predict that cases will rise in the early weeks of September — but many foresee the opposite.
“Whatever downturn we have, I think, will be fairly mild,” said Dr. Celine Gounder, an epidemiologist and infectious disease specialist at Bellevue Hospital Center in New York. “We’re right at that tipping point where backto-school will tip us back into growth at some point.”
Gounder predicted that cases in the U.S. would climb again in September before subsiding in October. The virus may have burned through unvaccinated segments of the population this summer, Gounder said, but other people remained vulnerable.
Other epidemiologists said that they were encouraged by trends in Southern states where schools had already opened, noting that while infections were growing among children, they were also falling off among adults.
It is important “not to overly extrapolate” from delta’s course through Britain and India, Gounder added. The three countries vary greatly in the percentage of population vaccinated, the ages of the vaccinated, the embrace of large gatherings and open schools, and the prevalence of mask-wearing and other precautions.
Delta’s path across the U.S. has depended heavily upon vaccination rates, social behaviors, the weather and various levels of precautions, epidemiologists said. Week on week, cases are now falling in a number of Southeastern states and California, but rising across much of the Midwest and Northeast.
The variant is thought to be more contagious than previous versions of the coronavirus because the infected carry it in substantially greater amounts in their airways.
This makes the variant particularly adept at exploiting opportunities for transmission: the crowded nightclub, the classroom with an unmasked teacher. But it also means that even modest restrictions, like masking and distancing, can bring numbers back down.
Gounder said Americans should expect to see surges over Thanksgiving, Christmas and New Year’s, as they did last year, she added — though none as bad as they were last winter.
“I don’t think we’re really going to turn the corner until next spring,” she said.