With the rapid spread of COVID-19’s Delta variant, more than twice as contagious as prior variants, hospitalization and mortality rates are once again on the rise across the United States and around the world. According to the U.S. national public-health agency, the Centers for Disease Control and Prevention, newer victims are overwhelmingly among the unvaccinated, with less than 0.1 percent of fully vaccinated people having experienced a “breakthrough case” of the virus—and a smaller percentage still having experienced a case resulting in hospitalization or death. Yet less than 50 percent of the U.S. population is fully vaccinated. The reasons behind these numbers are complicated—and complexly related to a highly polarized political environment—but one of the ideas in high circulation among “anti-vaxx” skeptics is that the vaccines are “failing” against the Delta variant. Tucker Carlson, maybe the most influential voice on America’s contemporary cultural right is just one amplifier of the idea, which continues to replicate across mainstream and social media: “Weird how many vaccinated people seem to be spreading the virus at this point.” How has this idea managed to get traction?

According to James Hamblin—a physician specializing in preventative medicine and public health, a lecturer at the Yale School of Public Health, and the author of Clean—all the forms of political pressure and media manipulation that have become common drivers of misinformation in contemporary American life are part of the answer; but a significant part is how easily the appearances of evidence in health and medicine can be deceiving. Understanding the cognitive frameworks behind an idea like vaccine failure isn’t, as Hamblin illustrates, simply a matter of understanding ignorance or bad faith; it’s a way of understanding an important dynamic in vaccine skepticism—and how vaccination advocates can engage with it more effectively.


Eve Olivette: What do people mean when they talk about vaccine failure?

James Hamblin: During the rollout of the vaccines, public-health advocates and doctors used a lot of language to convey how effective vaccines are at stopping the virus and ending the pandemic—and that language was both true and potentially a bit oversimplified, in a way that could lead people to believe that there would be zero instances of post-vaccine infection and breakthrough cases.

People actually mean different things by vaccine failure. The technical definition would be when you actually become sick with the disease against which you were vaccinated, as opposed to, say, briefly carrying some of the virus in your nose. But some will use the expression “vaccine failure” more casually, to say that the vaccines aren’t working in the way that they were promised or that they expected—which they see as a sort of absolute protection, as if you were coated in a nonstick anti-virus armor.

Seatbelts are a better comparison. If your seatbelt breaks during an accident, and you go flying through the window, then that’s a seatbelt failure. But if you get rear-ended and the seatbelt works, yet you still have some injuries, that’s not a seatbelt failure. That’s actually the seatbelt doing its job. Which could seem confusing if you were thinking, “I was wearing a seatbelt, so there should be zero injuries whatsoever.”

Olivette: So, it’s not that there are simply no instances of infection or death that you could describe as vaccine failure; it’s that there’s no evidence of vaccine failure at scale?

Hamblin: It’s something that happens in medicine. You can point to single instances of people becoming very sick and use that as a framework to highlight individual cases, where, indeed, the vaccines failed—the person got very sick despite being vaccinated—then imply that it means the vaccines don’t work.

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