Last winter, when vaccines were still incredibly scarce in the United States, Ashish Jha told The Atlantic that he was feeling optimistic about summer: By July 4, Jha, the dean of the Brown University School of Public Health, expected enough people to be vaccinated that he could host a backyard barbecue. Indeed, Jha confirmed to me this week, he will be grilling burgers and hot dogs for friends this Fourth of July. He had predicted back in the winter that guests would still need to mask up indoors, but even that feels unnecessary now. “Fifteen, 20 vaccinated people inside my house, if it starts raining, feels very safe,” he said.
This is because, he added, he lives in Massachusetts, which has one of the lowest COVID-19 case rates in the nation (fewer than one new case per 100,000 people a day) and one of the highest vaccination rates (82 percent of adults have had at least one dose). His town, Newton, is an outlier even among outliers: More than 95 percent of people older than 30 have gotten at least one dose. It’s one of the safest places in the world with respect to the coronavirus.
The outlook is dramatically different elsewhere in the country. COVID-19 cases are rising sharply in several states with low vaccine coverage, fueled by the spread of the coronavirus’s more transmissible Delta variant. In southwest Missouri, understaffed hospitals are already having to send COVID-19 patients hundreds of miles away. The same July 4 party that is very safe in Massachusetts is riskier in Missouri, where much more virus is circulating (15 new cases per 100,000 people a day) and many fewer adults are at least partially vaccinated (56 percent).
Earlier this year, the Biden administration set a goal of partially vaccinating at least 70 percent of adults by Independence Day. The U.S. will narrowly miss the mark; the number is currently hovering around 67 percent. When you zoom in closer, though, we’re doing both better and worse than that, depending on where you look. Our pandemic fates have diverged. The plateauing national case numbers obscure two simultaneous trends: an uptick in several sparsely vaccinated states and continued declines in well-vaccinated ones.
In this new reality, a single national strategy no longer makes sense. On Thursday, the White House announced that it would be sending “surge response” teams to hot spots with rising caseloads and low vaccination rates. The COVID-19 situation in different parts of the country has diverged so much now that Peter Hotez, a vaccine expert at Baylor College of Medicine, has suggested that the CDC issue two separate sets of guidelines.
Delta’s increased transmissibility only exacerbates the divide between the inoculated and the un-inoculated. As my colleague Ed Yong writes, “Vaccinated people are safer than ever despite the variants. But unvaccinated people are in more danger than ever because of the variants.” For people who are fully vaccinated, Delta poses very little direct threat. Its mutations do erode immunity slightly, but most breakthrough infections that result are mild or even asymptomatic. For entirely unvaccinated people, however, this means that Delta actually poses a double danger. They cannot rely on direct immunity from a vaccine, of course. But they also cannot rely as much on the herd immunity of vaccinated people around them if the variant is causing more breakthrough infections.
The U.S. was always going to struggle to vaccinate its way to the herd-immunity threshold for COVID-19—the point at which enough people have gained immunity that viral spread is limited. As I wrote in February, America’s vaccine reluctance and the evolution of new variants that can evade vaccines make herd immunity difficult to achieve and maintain. The upshot is that the coronavirus will keep circulating, looking for new bodies it can infect. For the unvaccinated, getting infected is probably a matter of time. “Everybody will end up getting immunity to this virus eventually,” Jha told me. “You’ll either get it through vaccination or infection.”
This time last year, vaccines were still a distant hope. It was hard to imagine, last July 4, that we would have this many different vaccines that are this effective. It was hard to imagine scaling up factories to manufacture this many doses so quickly—more than enough for every American. But we also did not imagine that variants would emerge and how quickly they would widen the divide between the vaccinated and the unvaccinated. Here we are a year later, with too many doses and too few willing arms, at a time when the advantages of vaccination are clearer than ever.