Why the Vaccine Boosters Now?

Immune system function, antibodies, and our way out

The current US administration is poised to recommend vaccine boosters for everyone eight months after their first shot. This article from Politico states that it’s based on decreased efficacy for the vaccine against the Delta variant. This data should be made public later this week, so this early take may get revised.

But I suspect that a lot of this may be due to the misstated expectations that the vaccine is a sterilizing vaccine. As I stated in my first proper piece, this vaccine is designed to prime your immune system with the blueprints for the proteins it will encounter upon exposure, so that you’ll be able to mount a more effective response and avoid serious illness.

What I’ve learned since writing that piece is why. It has to do with how and, more importantly, where the virus replicates. And it puts into some context the issues with asymptomatic positive PCR tests.

First, a caveat: I’m beginning to get severe Imposter Syndrome about all of this, encapsulated by Socrates:

This is all incredibly complex, and the available information seems to change daily. But I wanted to at least put a marker on what I know as of today.

How a COVID Infection Starts

When you’re exposed to SARS-CoV-2, it lodges in your nasopharynx, that space that’s between your nose and your throat. That’s where it starts its replication, and where the virus is dislodged from while you breathe, causing the aerosolized spread. Once the replication reaches a high-enough threshold and appears in your blood stream, THAT’S when your immune system goes to work creating antibodies and begins to fight it off more vigorously. More on this in a second.

Note that this means that even a person with natural immunity, with the full gamut of antibodies, would be contagious during those early stages of the infection. This is why even a fully-immunized population, such as Iceland, Gibraltar, or Israel, still sees case rates ebb and flow with typical coronavirus seasonality. This is why Duke University just reported a case outbreak of 100+ people, despite a vaccination mandate and an indoor mask mandate.

This also puts into context the idea of the asymptomatic positive. If a swab is taken in your nasopharynx during this early replication phase, it will show as a positive test, even if it hasn’t — or more importantly, won’t ever — advance to cause any symptoms. The immune system may mount a response before it even gets to the blood stream, utilizing the mucosal immunity. Note that this would never read as measurable antibodies, so even though the person has had and successfully fought off the infection.

• Only about 15% of partners of infected individuals ever test positive for COVID. My theory is that these individuals were clearly exposed to it, but fought it off at the mucosal stage so they never test positive.

So Why Boosters Now?

What I think the CDC and other administration officials are responding to is the decreased serum levels of live antibodies in your blood. As time goes past after getting the vaccine, and your body doesn’t encounter any live virus, the live circulating antibodies will diminish. Your memory immune cells will retain the blueprint and be able to spool up once you encounter the virus, but it doesn’t need to maintain circulating antibodies to successfully combat an infection. Just as you don’t need circulating measles antibodies to be able to fight off a measles or chicken pox infection — the memory cells will pull up the plans and go into production.

So if you get another vaccine shot, the circulating antibodies will once again return to their previously high level. I believe there’s some epidemiological data that a high level of circulating antibodies could reduce the chance of contagion, which would dovetail with the trial data. But the further away we get from those initial injections, the greater a chance that a vaccinated person could be contagious.

This video is a great explanation of this process.

Getting Out of This

The upshot of all of this is that as long as we are single-mindedly focused on case counts, we will be in COVID Pandemic Mode for forever. This is heading towards being an endemic virus, taking its place amongst the other coronaviruses that give us colds every year. Case counts don’t matter, any more than it matters how many people get a cold every year. What matters is how many people end up in the hospital or die from it.

Vaccines are important to get us to that point, but as long as the framing is that high circulating antibodies will help case counts go down, we will all be getting booster shots periodically for the rest of our lives. Once those in charge are willing to publicly accept that everyone will get it, and that it’s a GOOD THING to get it and build your own natural immunity, only then will be begin to live our lives as normal.

Setting benchmarks like a set number of cases per capita in a population or a set positive test percentage are counterproductive to this goal. Setting benchmarks around hospitalizations doesn’t work because those are lagging indicators, about two weeks behind case waves, so responding to those would be like filling your car’s gas tank two weeks after it showed it was empty.

The vaccines have already uncoupled the death counts from the case counts, particularly by vaccinating the most vulnerable population — the elderly. This was Sweden’s approach — protect the elderly, vaccinate them early, and let everyone else live their lives and build their own natural immunity. And their 7-day average for COVID deaths has been at zero for a month.

So, let’s get back to normal. Let’s start ignoring the stories about cases surging in particular states, or outbreaks among vaccinated individuals with minimal to no hospitalizations among them. This virus is now here to stay, and the sooner we can accept that the better.