In early March, Deepta Bhattacharya, an immunologist at the University of Arizona, celebrated a milestone: the point of full vaccination, two weeks after his second Pfizer shot. Since then, he has watched the number of coronavirus antibodies in his blood slowly but surely decrease.
The decline wasn’t steep, but it definitely happens – regular checkups have shown his antibody levels, also known as titers, tick down, down, down from spring to summer, now to fall. The break-in fits the narrative that has been raising the alarm for countless reports for some time: In the months after the vaccination, our antibodies are out relax yourself, a trend that is often described as “decreasing” from immunity, and evidence that we all desperately need boosters to restore our defenses.
To be honest, it all sounds like a tragedy. But, as Bhattacharya and others assured me, it really, really isn’t. “We only hear about titers,” says Stephanie Langel, an immunologist at Duke University. This fixation “overlooks a whole nuance”.“Antibodies are allegedly leak; that’s why they always do it. But even if our antibodies are absolutely dwindling number, these scratchy molecules improve yours quality, keep replacing with new versions that last Improve their skills to get the virus under control. Months after the vaccination, the average antibody in the blood simply has a higher level of resistance. “That’s why I hate the word decreasing“Said Jennifer Gommerman, an immunologist at the University of Toronto. “Antibody levels are falling, but something good also happens: the immune response continues to develop.”
Just focusing on the number of antibodies harms our understanding of immunity, experts told me. Like a block of wood carved into a sharper blade, vaccinated immune systems can improve their capabilities over time. Part of losing weight certainly means fewer. But it can also mean better.
A few weeks after the vaccination, a group of immune defenses called B cells begins to pump out antibodies in droves. But a lot of those early antibodies, Bhattacharya told me, are “really crappy” at their job. Their raison d’etre is to be clingy – the Y-shaped molecules hook their tips onto a specific piece of SARS-CoV-2’s anatomy and hang for their lives. The better you are in the dark, the better your chance of ambushing the threat. Sometimes it’s a solo act: antibodies alone can grip so tightly that they prevent the virus from entering a cell, a process called neutralization. Or they use the stems of their Y to suppress other members of the immune system in a destructive aid.
But that’s the best case scenario. Most of our B cells, or the antibodies they produce, do not respond at all to SARS-CoV-2 or any similar vaccine. This is because our body continues to randomly produce B cells confuse them with their genetics so that they make a variety of antibodies –Billions or trillions in total– who collectively can recognize just about any microbe they could ever see. However, this process is arbitrary and imprecise: when B cells are born, “they don’t have a specific pathogen in mind,” said Gabriel Victora, an immunologist at Rockefeller University. Instead of clinging firmly to the surface of the virus, many antibodies could simply “jump back and forth” and give the pathogen enough time to break free, Bhattacharya said. It is the best defense the body can beat up in the short term as it has never met the beetle before. Early antibodies are, so to speak, the best of the immune system assumptions in defense – the immunological equivalent of throwing spaghetti against a wall to see what sticks – which usually means we need a lot of it to really implant the pathogen. They’re fragile too. Most antibodies don’t hang around for more than a few weeks before they break down.
Such flimsy fighters aren’t a particularly good investment in the long run. So while the below-average antibodies are fighting on the front line, the immune system will bring a contingent of young B cells into a boot camp. Called the germination center, where you can find out more about the coronavirus. What happens in these training camps is a miniature battle royal: the cells huddle together and fight desperately for access to the resources they need to survive. Their weapons are their antibodies, which they frantically wave around and try to cling to chunks of the dead coronavirus while a panel of other immune cells judges them from afar. Only the most combat-ready among them – those whose antibodies hold the coronavirus the strongest – advance to the next round. and the losers die of defeat. As Gommerman put it, “When they suck, they die.”
The harrowing cycle repeats itself over and over and only gets darker. Surviving B cells will xerox themselves by deliberately introducing errors in their genetic code in the hopes that some of the mutations will increase the chances of their antibodies to bind to the virus. The whole process is downright “Darwinian,” like a super-fast form of natural selection, said Victora. The weaker ones are sorted out, only the sharpest and strongest are left behind. It is also very extended. Researchers like Ali Ellebedy of Washington University in St. Louis have found that these cull tournaments at least last 12 to 15 weeks after receiving the COVID-19 vaccination, maybe longer.
If that all turns out to be a little too Squid game, consider the much rosier outcome: at the end of this process, some really top-notch antibodies are left in our bodies, well equipped to take over the protective mantle when the first waves of mediocre defenders begin to fade. In the immune systems of those who were vaccinated months ago, the following happens: An initial burst of antibody activity, followed by a gentle taper as the body returns to normal. “Immune reactions cannot stay in the blood forever,” Langel told me. If they didn’t wane, we would have no room or resources for the body to build another defense against another threat – and our blood would be nothing more than useless antibody sludge.
There is another way to think about the decline in antibodies after vaccination: take out the trash. Early-acting B cells are, in some cases, so shabby that they are not worth keeping. Evolution has also pointed out the advantages of this pattern, which is why the B-cell winners are not only of higher quality, but also much more durable. While the first B cells to collect after vaccination may only live for a few days, the cohort that defeated their peers in training can stay in the bone marrow or blood for months or years. Some will continue to express antibodies over the long term, while others will drift quietly, ready to resume their defensive duties when called upon again. “What is seen as a ‘loss’ of antibodies is actually the slow release of the less good, short-lived response,” Victora told me. And when antibodies are needed – say, when the actual virus infects us – experienced B cells will produce them again, in gigantic quantities. Antibodies themselves don’t always persist. But the ability to create them usually does.
There is definitely a limit to how much quality can compensate for quantity – one antibody, no matter how badass, can’t do the job of hundreds. Experts do not yet know how many antibodies (good, meh or “crappy”) people need to have in tow to be considered well protected against COVID. Rishi Goel, an immunologist at the University of Pennsylvania, told me that his work showed that six months after vaccination the number the neutralizing antibody found in human blood tends to decrease noticeably from its peak. But he and others have found it too little difference in how much neutralization the body is capable– a strong indication that superior antibodies have now reached the plate. Here too are the antibody levels always drop. That doesn’t mean that immune protection (which, by the way, is more than just antibodies) disappears.
The slow step toward self-improvement could also be a reason not to snap a booster shot in a rush. Boosting reminds the immune system of a threat it saw before. But offering this refresher too often or too early could be pointless, even slightly counterproductive, if active germinal centers are still doing their thing. Waiting a little longer could help get the best possible B cells back into action to make antibodies again. So immunity has a lot less to do with what’s around now, and more about what’s near when it is necessary; It’s no big deal if these defenses aren’t always visible as long as they get back on their feet when they are brought to the fore.
All of this means slowing down antibody production in some way as a beneficial. It’s a sign of an immune system that is managing its resources wisely rather than constantly panicking itself. Bhattacharya, for example, was not at all impressed by what happens to his antibodies, which after nearly eight months still look pretty good despite the decline in numbers – because they still seem to be fighting the virus when he tests them in his lab. Langel says that’s standard. When she sees that the antibodies are “waning”, she shrugs her shoulders. “I say ‘look’,” she told me, “‘that’s the immune system that does what it does.'”
Thank You For Reading!