What Happens When Vaccinated People Get COVID-19?

A brand-new dichotomy has actually started dogging the pandemic discourse. With the increase of the über-transmissible Delta version, professionals are stating you’re either going to get immunized, or going to get the coronavirus.

For some individuals—a good variety of us, really—it’s going to be both.

Coronavirus infections are taking place amongst immunized individuals. They’re going to keep taking place as long as the infection is with us, and we’re no place near beating it. When an infection has so completely penetrated the human population, post-vaccination infections end up being a math inevitability. As much as we’d like to believe otherwise, being immunized does not indicate being done with SARS-CoV-2.

Post-vaccination infections, or developments, may periodically turn symptomatic, however they aren’t outrageous or aberrant. They likewise aren’t evidence that the shots are stopping working. These cases are, usually, gentler and less symptomatic; faster-resolving, with less infection remaining—and, it appears, less most likely to pass the pathogen on. The resistance provided by vaccines operates in versions and gradations, not absolutes. It does not make an individual totally invulnerable to infection. It likewise does not vaporize when a couple of microorganisms breach a body’s barriers. A development, regardless of what it may appear, does not trigger our defenses to collapse or perhaps break; it does not eliminate the security that’s currently been constructed. Instead of establishing vulnerable and penetrable guards, vaccines strengthen the defenses we currently have, so that we can come across the infection securely and possibly construct even more upon that security.

To comprehend the anatomy of an advancement case, it’s handy to consider the body as a castle. Deepta Bhattacharya, an immunologist at the University of Arizona, compares immunization to strengthening such a fortress versus attack.

Without vaccination, the castle’s protectors have no concept an attack is coming. They may have stationed a couple of aggressive watchdog outside, however these dogs aren’t extremely critical: They’re the system’s natural protectors, fast-acting and harsh, however temporary and woefully inaccurate. They’ll sink their teeth into anything they don’t acknowledge, and are quickly fooled by stealthier intruders. If just quarrelsome dogs stand in between the infection and the castle’s treasures, that’s a quite lightweight very first line of defense. However it’s basically the circumstance that lots of uninoculated individuals remain in. Other fighters, who operate with more precision and punch—the body’s adaptive cells—will eventually be roused. Without prior warning, though, they’ll come out in full force only after a weeks-long delay, by which time the virus may have run roughshod over everything it can. At that point, the fight may, quite literally, be at a fever pitch, fueling worsening symptoms.

Vaccination completely rewrites the beginning, middle, and end of this story. COVID-19 shots act as confidential informants, who pass around intel on the pathogen within the castle walls. With that info, defensive cells can patrol the building’s borders, keeping an eye out for a now-familiar foe. When the virus attempts to force its way in, it will hit “backup layer after backup layer” of defense, Bhattacharya told me.

Prepped by a vaccine, immune reinforcements will be marshaled to the fore much faster—within days of an invasion, sometimes much less. Adaptive cells called B cells, which produce antibodies, and T cells, which kill virus-infected cells, will have had time to study the pathogen’s features, and sharpen their weapons against it. While the guard dogs are pouncing, archers trained to recognize the virus will be shooting it down; the few microbes that make their way deeper inside will be gutted by sword-wielding assassins lurking in the shadows. “Each stage it has to get past takes a bigger chunk out” of the virus, Bhattacharya said. Even if a couple particles eke past every hurdle, their ranks are fewer, weaker, and less damaging.

In the best-case scenario, the virus might even be instantly sniped at by immune cells and antibodies, still amped up from the vaccine’s recent visit, preventing any infection from being established at all. But expecting this of our shots every time isn’t reasonable (and, in fact, wasn’t the goal set for any COVID-19 vaccine). Some people’s immune cells might have slow reflexes and keep their weapons holstered for too long; that will be especially true among the elderly and immunocompromised—their fighters will still rally, just to a lesser extent.

Changes on the virus side could tip the scales as well. Like invaders in disguise, wily variants might evade detection by certain antibodies. Even readily recognizable versions of the coronavirus can overwhelm the immune system’s early cavalcade if they raid the premises in high-enough numbers—via, for instance, an intense and prolonged exposure event.

With so lots of factors at play, it’s not hard to see how a few viral particles might still hit their mark. But a body under siege isn’t going to throw its hands up in defeat. “People tend to think of this as yes or no—if I got vaccinated, I should not get any symptoms; I should be completely protected,” Laura Su, an immunologist at the University of Pennsylvania, told me. “But there’s way more nuance than that.” Even as the virus is raising a ruckus, immune cells and molecules will be attempting to hold their ground, regain their edge, and knock the pathogen back down. Those late-arriving efforts might not halt an infection entirely, but they will still curb the pathogen’s opportunities to move throughout the body, cause symptoms, and spread to someone else. The inhospitality of the vaccinated body to SARS-CoV-2 is what’s given many researchers hope that long COVID, too, will be rarer among the immunized, though that connection is still being explored.

Breakthroughs, especially symptomatic ones, are still uncommon, as a proportion of immunized individuals. But by sheer number, “the more people get vaccinated, the more you will see these breakthrough infections,” Juliet Morrison, a virologist at UC Riverside, told me. (Don’t forget that a small fraction of millions of people is still a lot of people—and in communities where a majority of people are vaccinated, most of the positive tests could be for shot recipients.) Reports of these cases shouldn’t be alarming, especially when we drill down on what’s happening qualitatively. A castle raid is worse if its inhabitants are slaughtered and all its jewels stolen; with vaccines in place, those cases are rare—many of them are getting replaced with lighter thefts, wherein the virus has time only to land a couple of punches before it’s booted out the door. Sure, vaccines would be “better” if they erected impenetrable force fields around every fortress. They don’t, however. Nothing does. And our shots shouldn’t be faulted for failing to live up to an impossible standard—one that obscures what they are able to accomplish. A breached stronghold is not necessarily a defeated stronghold; any castle that arms itself in advance will be in a better position than it was before.

There’s a potential silver lining to breakthroughs as well. By definition, these infections occur in immune systems that already recognize the infection and can learn from it again. Each subsequent encounter with SARS-CoV-2 might effectively remind the body that the pathogen’s threat still looms, coaxing cells into reinvigorating their defenses and sharpening their coronavirus-detecting skills, and prolonging the duration of protection. Some of that familiarity might ebb with certain variants. But in broad strokes, a post-inoculation infection can be “like a booster for the vaccine,” Su, of the University of Pennsylvania, told me. It’s not unlike keeping veteran fighters on retainer: After the dust has settled, the battle’s survivors will be on a sharper lookout for the next assault. That’s certainly no reason to seek out infection. But should such a mishap occur, there’s a good chance that “continuously training immune cells can be a really good thing,” Nicole Baumgarth, an immunologist at UC Davis, told me. (Vaccination, by the way, might mobilize stronger protection than natural infection, and it’s less dangerous to boot.)

We can’t control how SARS-CoV-2 evolves. But how disease manifests depends on both host and pathogen; vaccination hands a lot of the control over that narrative back to us. Understanding breakthroughs requires some intimacy with immunology, but also familiarity with the realities of a virus that will be with us long-term, one that we will probably all encounter at some point. The choice isn’t about getting vaccinated or getting infected. It’s about bolstering our defenses so that we are ready to battle an infection from the best position possible—with our protective wits about us, and well-armored bodies in tow.

Jobber Wiki author Frank Long contributed to this report.