Thread by @KatherineJWu

If your antibody levels drop over time... it's not the end of the world. Actually, it's what happens naturally. It's expected. It's your body being economical with its resources. 1/

theatlantic.com/science/archiv…

There are so many other immune cells and molecules protecting you; antibodies aren't the whole story.

But if you're worried about antibodies specifically—which, yes, are powerful and important and do play a big role in protection— 2/

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Think of it this way. Antibodies are ephemeral proteins. Individual antibodies aren't built to last forever. They'll ebb after an infectious threat has passed. But the body retains the capacity to produce them. 3/

Fretting over a drop in antibody titers is like panicking over a restaurant that isn't grilling 400 steaks every hour of every single day.

Maybe sometimes they hit peak output—but it's based on NEED. More patrons, more cooking.

Grilling for an empty room is a waste. 4/

And yet, even when those topline chefs aren't cooking, they retain the capacity to do so. They remember the recipes. They still have the cookware and the raw meat. And they can whip what you need in a jiffy, because they're pros. 5/

For perspective - yes, there are viruses to which we keep churning out measurable levels of antibodies for a lifetime, even without them visiting us again.

But there are also some for which we *don't*, and we're still protected. 6/

If you take a hepatitis B antibody test years after you've been vaccinated and it's negative, for example, that's actually no cause for alarm. Studies have shown that the vast majority of these people are still protected. 7/

That's because B cells in the body—the cells that make antibodies—immediately leap into action if they see the actual virus, and make more antibodies. It's fast enough that these people are still considered protected. 8/

(Health care workers may get boosters if their HBV antibody tests are negative, but this is an intentionally overcautious approach. They are at high risk because of their job.) 9/

We can't yet reliably "measure immunity" to the coronavirus. When thinking about vaccine efficacy, look to data from real people, and whether they're getting sick for the best info—not tests done on molecules in labs. 10/10

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