After weeks of discouraging news about COVID-19 — U.S. hospitalizations hitting 100,000 for the first time since February; more people dying in Florida than before vaccinations became available — a rare glimmer of hope seems to have punctured the gloom: America’s summer wave, which has torn through undervaccinated communities across the South, may finally be peaking.

The question now is whether the hypercontagious Delta variant will trigger similar surges in northern states next — or whether the worst of it is behind us.

Some politicians subscribe to the first theory. Chief among them is Florida’s Republican Gov. Ron DeSantis, who recently sought to minimize the role his own laissez-faire approach may have played in his state’s horrific summer surge by claiming that all those deaths and hospitalizations — more than occurred last summer — were simply part of a predictable “seasonal pattern.”

And so “you’re going to start to see winter and fall waves in the Northern states,” DeSantis argued last month in Jacksonville. “We have a summer season, but you’re going to see that, and so I think that that’s something that should be stressed more and more.”

Many experts disagree. “I don’t think COVID is going to be epidemic all through the fall and the winter,” former Food and Drug Administration Commissioner Scott Gottlieb told CNBC last month. “I think that this is the final wave, the final act, assuming we don’t have a variant emerge that pierces the immunity offered by prior infection or vaccination.”

Who’s right? At the moment, it’s impossible to say; overconfident prognosticators have gotten the pandemic wrong plenty of times already, and they’ll probably get it wrong again.

But the latest numbers offer some early hints about what to expect from the virus as summer turns to fall.

For one thing, Sun Belt hot spots are starting to show improvement. In Florida, new cases appear to have topped out two weeks ago; since then, they have fallen 20 percent to about 20,000 per day, according to the New York Times database. The seven-day average of hospitalizations is down, too, from a high of more than 17,000 on Aug. 24 to less than 16,500 five days later. There are still more Floridians hospitalized today than during any previous wave; tragically, deaths will continue to climb. But it is a tentative sign of progress.

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Other hard-hit states are following a similar arc. Over the last two weeks, cases and hospitalizations are either falling or flattening in Louisiana (-43 percent and -14 percent, respectively); Missouri (-12 percent and -5 percent); Arkansas (-1 percent and -5 percent); Mississippi (-21 percent and +2 percent); and Nevada (+6 percent and -4 percent). And across much of the rest of the Sun Belt — California, Texas, Arizona, Alabama — growth rates are beginning to slow.

As a result of this regional deceleration, national cases and hospitalizations appear to be approaching a peak, too.

Yet will they actually turn the corner and start to decline — and will the U.S. start to put Delta in its collective rearview mirror? Or is the country in for another rough holiday season? That depends on what happens next, especially up North.

DeSantis isn’t wrong when he points out that COVID has some seasonal tendencies. Last summer, the virus slammed Southern and Southwestern states harder than their Northern and Midwestern counterparts, perhaps because hotter temperatures drove more people inside. Then the North and Midwest were clobbered over the winter.

But to claim that only the North and Midwest suffered last winter is wrong. In fact, pretty much every state that was hit last summer wound up struggling even more a few short months later: California, Arizona, Texas, Nevada, Georgia, South Carolina, Tennessee, Mississippi, Louisiana — the list goes on. Florida’s winter wave may have been milder than those of many other states, but it was still bigger than the summer surge it followed. Colder temperatures, lower humidity, pandemic fatigue, holiday travel and indoor gathering probably all conspired to make the first winter of the pandemic much worse than any season that preceded it.

This should raise alarm bells for the fall and winter ahead. What’s more, Delta is roughly twice as contagious as last year’s strain of the virus (and could be twice as likely to send unvaccinated people to the hospital). Compliance with masking and distancing recommendations is lower than ever. And unlike last fall, when nearly all schooling was remote, kids across the North and Midwest are about to stream back into crowded indoor classrooms.

Yet experts insist there are four reasons for cautious optimism.

The first is that the “seasonal pattern” of the U.S. pandemic is about to shift from states with some of America’s lowest vaccination rates to states with some of the highest. While about 53 percent of Floridians are fully vaccinated, in line with the nationwide figure, every other state where Delta has taken off so far is well below that threshold: Mississippi (38 percent), Alabama (38 percent), Louisiana (41 percent), Georgia (41 percent), Arkansas (41 percent), Tennessee (41 percent), South Carolina (43 percent), Missouri (45 percent), Texas (47 percent), Nevada (48 percent) and so on.

In contrast, Northeastern states such as Connecticut (66 percent fully vaccinated), Massachusetts (66 percent), Maryland (61 percent), New Jersey (61 percent) and New York (60 percent) have significantly higher levels of protection — as do Western states such as New Mexico (60 percent), Colorado (57 percent) and California (56 percent), and Upper Midwestern states such as Minnesota (56 percent) and Wisconsin (54 percent).

To be sure, vaccinated people can still test positive for Delta and transmit it to others, but not as frequently or as easily as unvaccinated people. And the higher the community-wide vaccination rate in one’s area, the lower those chances tend to be.

Then there’s so-called natural immunity to consider. Some earlier research suggested that vaccination provided “more durable and more consistent protection than recovery,” as former Baltimore Health Commissioner Leana Wen recently explained, while “a new study from Israel, not yet peer reviewed, found there was a lower risk of infection with the Delta variant among those with immunity from recovery compared with vaccination.”

Either way, natural immunity is real — and it’s not just on the rise in the Sun Belt hot spots. The curves in highly vaccinated Northern states aren’t nearly as steep as they are in the South, but pretty much all of these states have been recording more COVID cases this summer than last. In other words, Delta is so transmissible that it’s not waiting for winter to head north; instead, it’s already finding unprotected hosts even in places where higher inoculation rates may ultimately keep it from spiking to Louisiana-like levels.

Vaccination is a far safer way to acquire immunity than infection, of course. But if more unvaccinated people get the virus now, fewer of them will be vulnerable over the winter. Even outside the Sun Belt, that wall of combined immunity — from both vaccination and infection — is growing every day. This may also mean that Upper Midwestern states such as Michigan and Minnesota, where the Alpha variant sent cases skyrocketing this spring, are approaching winter in better shape than last year.

School safety could help forestall a Delta comeback as well. A new CDC-funded simulation predicted that, absent masks and regular testing, more than 75 percent of susceptible children might be infected with the coronavirus during their first three months in elementary school. A number of recent studies have also shown that youth camps that have not embraced testing and masks for attendees — or contact tracing and isolation for the infected — have fared much worse than those that have adopted more stringent protocols.

Schools across the West and South are already back in session, and many Republican governors there — including those in Oklahoma, South Carolina, Tennessee, Utah, Florida, Texas and Arizona — have prohibited local districts from requiring masks for students and staff. Driven by out-of-control Delta transmission in the community — and the fact that kids under 12 are not yet eligible for vaccination — the nationwide rate of increase in infection among 5- to 11-year-olds outpaced almost every other demographic between July 1 and mid-August, rising 900 percent (compared with 500 percent among highly vaccinated 65- to 74-year-olds). These infections among kids have, in turn, spilled over into newly reopened schools that aren’t taking the necessary precautions, and tens of thousands of students and staff have already been sent home and forced to quarantine as a result.

Schools outside the Sun Belt will reopen soon for in-person instruction — mostly after Labor Day — and students there will undoubtedly test positive for COVID. But unlike many of their red-state peers, leaders in places such as California, Connecticut, New York, Delaware, Maryland, Massachusetts, New Jersey, Oregon and Washington have embraced universal indoor masking in K-12 schools; many districts also conduct surveillance testing.

“Wearing a mask in school is necessary to keep our children in the classroom, and to keep COVID out,” Pennsylvania Gov. Tom Wolf, a Democrat, said Tuesday while announcing his state’s new school mask mandate.

Such sensible precautions — along with higher vaccination rates and lower preexisting levels of community infection — will help minimize the impact of schools reopening on winter transmission in states that implement them. Likewise, polls have repeatedly shown that vaccinated Americans are more likely to exercise caution around Delta than unvaccinated Americans, which should help as well.

Finally, the fourth reason for cautious optimism this fall: booster shots. In recent months, evidence has emerged that while the vaccines are still highly effective in preventing serious illness, protection against infection diminishes over time. In response, the U.S. is set to start making third doses available nationwide by Sept. 20. These boosters will likely be popular in highly vaccinated states; according to the latest Yahoo News/YouGov poll, nearly three-quarters of vaccinated U.S. adults (74 percent) say they would get one if offered. They’re also likely to help slow the spread of the virus wherever uptake is high, with a new study out of Israel — the first nation to offer boosters to all residents 12 or older — showing an 11.4-fold reduction in the risk of a confirmed SARS-CoV-2 infection a dozen days after the third jab.

None of which is to say the U.S. is about to experience a steep and sudden drop in Delta cases. Many other countries have seen Delta soar, then peak, then seem to stutter on the way down instead of plummeting immediately back to earth; America is so heterogeneous, and so riddled with undervaccinated pockets, that this pattern seems more likely than not to repeat itself here. Both Washington and Oregon, for example, have high overall vaccination rates driven by population centers like Seattle and Portland, yet Delta is still ripping through their less protected communities. 

And even as Mississippi and Florida top out, other Southern states such as South Carolina and Kentucky are taking off. Meanwhile, colder weather and holiday gatherings are almost certain to keep cases higher this winter — both across the Sun Belt and beyond — than they would be at another time of year. A new, even more widespread wave could build. 

Still, there is reason to hope for the best. Last winter in Los Angeles was harrowing; at one point, more than 16,000 Angelenos were testing positive each day. But now more than two-thirds of adult residents are fully vaccinated; more than half of all residents have had prior infection; and the city has sent kids back to school while mandating masks indoors, requiring teacher inoculation and testing nearly all 600,000 students and staff each week. So far, cases have fallen 25 percent countywide since school reopened; test positivity is down to 2.5 percent.

Could this be a preview of things to come for other careful cities and states?

“Looking ahead to the fall, I’m optimistic,” Dr. Eric Topol, the head of Scripps Research Institute, recently told New York magazine. “Delta will … burn through. We’ll still have lots of COVID in this country, but it’ll be back to where it was before Delta came. It will be at a lower level. The only question is, is there something lurking that’s worse than Delta?

“There’s no sign of it yet,” Topol continued, “but there’s too much of this virus circulating to be confident — too many people in Indonesia and sub-Saharan Africa who are getting sick. But I hope not. I’m hoping that this is as bad as it gets.”

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