Note the word “protection” in the headline, which is different from “antibodies.” Antibodies always fade in time; it takes around four months after a third COVID shot, according to the best data we have. But there’s more to immunity than just antibodies. There are also T cells and B cells, which work together to help the immune system form a “memory” of a particular virus. (Or the spike protein of a particular virus, which is how the vaccines work.) Once you have that “memory,” you can generate new antibodies rapidly to neutralize that virus if you’re infected with it.

And here’s the important part: The clearer the “memory” the immune system has, the more sophisticated the antibodies it can produce. According to new research, someone who’s had three exposures to the spike protein on the Wuhan virus via three doses of vaccine is capable of developing antibodies that can neutralize variants that didn’t exist when they were vaccinated, like Omicron. Just as the virus evolves in the wild as it passes from host to host, the T cells and B cells of someone who’s been boosted will generate more “evolved” antibodies.

And those T cells and B cells don’t fade in a matter of months like antibodies do. The latest data points to them lasting years, which means a person who’s had three doses might be equipped to avoid severe illness from the next serious variant to come down the pike even if that variant doesn’t arrive until 2025 or whatever.

None of which is to say that we’ll never be asked to get a fourth shot. Presumably the CDC will recommend it every fall like they do the flu shot, asking people to prep their immune systems for an expected surge of the virus over the winter by preemptively generating new antibodies. But the era of a new shot every four months or whatever is probably over, per the Times:

Three doses of a Covid vaccine — or even just two — are enough to protect most people from serious illness and death for a long time, the studies suggest…

Antibodies recognize two or three key parts of the spike protein, a protrusion on the outside of the coronavirus that allows it to latch on to human cells. But T cells detect many more parts of the spike, and so are less likely to fail when the virus gains mutations in some of them…

Researchers showed last year that the elite school inside of lymph nodes where the B cells train, called the germinal center, remains active for at least 15 weeks after the second dose of a Covid vaccine. In an updated study published in the journal Nature, the same team showed that six months after vaccination, memory B cells continue to mature, and the antibodies they produce keep gaining the ability to recognize new variants…

In the newest study, another team showed that a third shot creates an even richer pool of B cells than the second shot did, and the antibodies they produce recognize a broader range of variants. In laboratory experiments, these antibodies were able to fend off the Beta, Delta and Omicron variants. In fact, more than half of the antibodies seen one month after a third dose were able to neutralize Omicron, even though the vaccine was not designed for that variant, the study found.

That reminds me of the study from last year about people with “super immunity,” those who’d caught COVID initially and later got vaccinated. The same adaptive effect was seen in their immune systems: Because their T cells and B cells had gotten a look at the full virus and then were further exposed to the spike protein via the shots, they were able to produce antibodies so versatile that they managed to neutralize all six major strains plus a Frankenstein variant of the virus developed in a lab that doesn’t exist in nature. Today’s new data on boosters suggests that the triple-vaxxed are developing a similar ability to anticipate and defeat as-yet-unknown strains.

Six months after a third dose, said one scientist to the Times, the antibodies a vaccinated person produces are “better binders and more potent neutralizers than the ones that are produced one month after immunization.” Essentially, then, the future of COVID is an evolutionary race between the virus, which aims to transmit more and more efficiently, and our immune systems, which aim to produce antibodies versatile enough to counteract them. Hopefully future iterations of SARS-CoV-2 will be less virulent — but there’s no guarantee of that. “In these new hosts, the virus could possibly evolve to a new, more deleterious version that attaches better and infects other organs, like the heart or gastrointestinal tract, instead of the lungs,” writes Eric Topol today. “We have already seen people with simultaneous co-infections of two different variants, which enables the swapping of RNA between them and generating a hybrid, potentially worse version of the virus.”

If we do eventually see something worse, it’s a cinch that people who’ve had three looks at the spike will enjoy more sophisticated defenses than those who haven’t. And don’t count on natural immunity to fill the gap, one scientist told the NYT. While it’s true that some people generate strong immune responses after infection, it’s hit-or-miss, varying “quite a lot, while the vaccine response is much more consistently good.”

As for whether four doses are better than three, we already know from Israel’s data that a fourth dose doesn’t seem to add much near-term against Omicron. Conceivably it adds more long-term by providing even more information about the spike protein to the T cells and B cells but it’s too soon to know that, as Israel’s only been dosing out fourth shots for a few months. There must be some point at which even the long-term components of the immune system understand the virus as well as they’re capable of understanding it, making further shots superfluous.

Bottom line: It’s a cinch that senior citizens will be encouraged to get fourth doses at some point, as their immune systems are slower off the block than younger people’s are, but it may be awhile before the rest of us are asked to line up again. I’ll leave you with this guy, who hasn’t been seen on TV lately for a very good reason, it turns out. Neil Cavuto is extremely high risk from COVID due to preexisting conditions (he recovered from cancer, then developed multiple sclerosis) but he’s still here and kicking after two bouts with the disease.

Fox News/Business host Neil Cavuto explains on air that he was out for a while because he was hospitalized with Covid, adds, "doctors say that had I not been vaccinated at all, I wouldn't be here."

"I'm not here to debate vaccinations for you. Just offer an explanation for me." pic.twitter.com/DwI5dKZAL3

— Aaron Rupar (@atrupar) February 21, 2022