intelligencer chats

How Bad Could the Delta Variant Get in the U.S.?

A makeshift COVID facility at a sports stadium in New Delhi, where the Delta variant ran rampant. Photo: Getty Images

The COVID picture in America has vastly improved from where it was a short time ago. But there are two troubling trends to reckon with: a marked slowdown in vaccinations and the rise of the Delta variant. I spoke with New York editor-at-large David Wallace-Wells about what to expect in the near future.

Ben: The Delta variant of COVID-19 that swamped India is picking up steam in the U.S., as predicted: It accounts for about one in five cases now, could be the dominant strain in a matter of two or three weeks. And experts have said that it is significantly more transmissible than previous variants. With about two-thirds of American adults having received at least one vaccine shot — but with new vaccinations slowing — how much havoc do you think this could wreak in the coming months?

David: Certainly some. But in two profound ways, the variant, while scary, isn’t quite the nightmare development it may sound like. The first is that vaccines — especially the two-dose mRNA vaccines — remain very effective against it, essentially as effective as they are against the earliest strains of the disease. And the second is that, while Delta does appear significantly more transmissible, it is much less clear that it is any more dangerous to those who do get infected. The picture there is a bit murky, since some studies have shown perhaps a doubling of hospitalization risk, but hospitalization rates are complicated by other factors (availability of beds, for instance).

But the crudest metric of severity, case-fatality rate, appears notably lower than for earlier variants — at least in the U.K., where Delta is now not just the dominant strain but has in fact crowded out all the others, accounting for 99 percent of new cases. The low fatality rate there may reflect the country’s vaccination patterns, where the older and more vulnerable are much likelier to have been vaccinated, but it is nevertheless modestly reassuring.

Ben: So basically, for vaccinated people, there’s no real reason to worry at this juncture? (I myself got the Johnson & Johnson vaxx and have been wondering whether I might need a second mRNA dose to protect me from Delta.)

David: The single-shot vaccines do appear to be somewhat less effective against Delta than the other variants, but still pretty effective by conventional standards. Much more worrying are those who haven’t been vaccinated at all — of whom there are still really quite a lot, probably 40 percent or more of American adults.

Ben: Isn’t it at 66 percent?

David: Different databases count in different ways, but according to the CDC, 56 percent of Americans over the age of 18 are fully vaccinated; 66 percent have had one shot.

And the differences between those categories are real. According to the U.K. data we have, a single shot is only 31 percent effective against symptomatic disease from Delta (compared with 49 percent effective against other variants). A second shot elevates that effectiveness to 80 percent (against other strains, two shots offer 88 percent protection against symptomatic disease).

In terms of hospitalizations, a single shot offers 75 percent protection (versus 78 percent against other strains), and two shots offer 94 percent protection (actually higher than the 92 percent estimated for other strains).

Ben: I was just looking at this AP story out of Missouri, which notes that hospitals are seeing a notably younger cohort in intensive-care units than in previous COVID surges. This was a common observation in India, too. Does that tell us anything much about the virulence of Delta, or is it more a function of the simple fact that fewer older people are being hospitalized because they’re more likely to be vaccinated?

David: I think much more the second. You’re seeing a similar pattern in parts of the country (and the world) where Delta hasn’t really taken hold, but vaccines have — leading to a fair number of alarming headlines about hospitalization rates rising among the young, when what is really meant is that hospitalization ratios are rising.

Ben: Most of the rest of the world is not nearly as vaccinated as the United States. Is Delta the biggest threat facing, say, African countries that are now seeing the beginning of the kind of surges people have been fearing?

David: It’s the most transmissible strain we’ve seen so far, for sure, which means any place without large-scale immunity, from either infection or vaccination, should absolutely worry. At the moment, though, the biggest outbreaks are concentrated not in Africa but in South America, it seems, where the pandemic has been raging for almost the full year.

Just in Colombia, for instance, 50 percent more people have died in the last week than in all of Africa. To some degree, that may be a reflection of data collection, testing, and measurement. But it’s hard to believe those account for all the difference, or even close to it.

Ben: How worried are you that the sluggish pace of vaccination in many countries where the pandemic is still raging leaves time and space for the pandemic to mutate into variants that may be better at evading the vaccines we have? Is there any kind of scientific consensus on the likelihood of that happening?

David: My own sense is that hardly anyone feels comfortable putting anything like real numbers on that risk. Most experts believe it is possible, and obviously a concern, and a strong argument for a faster vaccine rollout — perhaps, most especially, for extending much more support from countries like the U.S. to those much earlier on in their rollouts. But most seem much more worried about the humanitarian toll in unvaccinated places from current variants, at least for the time being. And personally, I’ve been encouraged at how well the vaccines have worked against the variants so far. It’s not something you want to have to count on, but things are holding up pretty well so far.

How Bad Could the Delta Variant Get in the U.S.?