Are COVID Vaccines Not as Socially Protective As They Could Be?
As far as I can tell — the data isn’t freely available — the extant approved COVID vaccines can protect you from serious clinical disease. They’re disease-protective or disease-preventive, but may not be not sterilizing. That is, they might not guarantee that you’ll be virus free. That you won’t still be able to infect others after you’re vaccinated.
In a theoretical sense, this could be a good thing, but in the practical world of current vaccine distribution ineptitude, it could turn into something far less salubrious for some unlucky folks.
The Different Flavors (Classes) of Antibodies
To get just a little technical, we’ll consider just two of these (five) antibody flavors: known as “G” and A”, full names, antibody classes IgG and IgA. G-antibodies are produced such that their main protective venue is your blood. From blood, G-antibodies can slip out into your tissues, the deeper parts of your lungs, for example, through the walls of inflamed blood vessels (capillaries). It’s one benefit of acute inflammation, which the G-antibodies themselves participate in promoting.
On the other hand, A antibodies are made locally at our mucosal surfaces — in the membranes lining the cavities of our nose and throat, for example. Their function is to protect those surfaces from infection by pathogenic organisms that enter our bodies through these surfaces. This means most common viruses and many bacteria.
A-Antibodies and COVID
So far, the data tells us that the immune systems of folks who’ve recovered from COVID produce both the G and the A flavors of antibodies. This is a fairly common finding for viruses transmitted through aerosols. The combination of G and A can offer what can be called “sterilizing immunity”, in which we become not only individually protected from the ravages of COVID, but also become far less likely to still infect others with shed coronavirus. Starting with our noses and mouths, the A-antibodies in the surface regions of our respiratory and digestive systems can clamp down and eliminate any residual viruses at those surfaces, preventing us from expelling them into our surroundings.
In other words, if the current vaccines don’t induce our bodies to make A-antibodies against the virus, it’s still possible to infect others even after we ourselves have gained personal disease protection.
A-Antibodies and COVID Vaccines
The initiatives to rapidly develop vaccines, whether they used mRNA technology (Pfizer and Moderna) or more traditional approaches (Oxford/Astrazeneca and Sputnik) were focused on quickly coming up with an injectable that would induce our bodies to form protective antibodies. But the clinical trials using those vaccines generally assessed vaccine success by measuring G-antibodies in blood.
Do these vaccines also induce A-antibodies? It’s difficult to find any data supporting a significant A-antibody response, my searches failing to find any clear information. As the February 5, 2021 NY Times informs us: “Not all the details or raw data for trials of the Pfizer-BioNTech and Moderna vaccines have been made available, not even to researchers. The fact is that no Covid-19 vaccine has been developed or released as transparently as it should have been.” So, the measure of this question may have to be experience with other viruses like polio.
For example, while the situation with injected and oral polio vaccines is a bit complicated, the data tell us that the oral polio vaccine is a great inducer of A-antibodies. Which therefore means that recipients of at least one oral dose among the multiple doses of polio vaccine, are better protected — as both individuals and as social beings. They are more likely to achieve sterilizing immunity, where they’re far less likely to transmit poliovirus. This makes perfect sense, if we realize that vaccinating via the normal route by which a virus enters our bodies presents it to the immune system as it would be presented during actual viral infection. (How so-called antigens are presented to the immune system forms an entire sub-discipline of immunology.)
There are, in fact, several initiatives by smaller biotech companies to develop an oral COVID vaccine, one by a San Francisco company, Vaxart, is even advertised as being in Phase 1 clinical trials (first and easiest of three phases, so don’t get your hopes up too high).
Since there has been more experience at developing injectable vaccines, that injectable route was likely to be faster to the finish line for vaccine developers. But beware the PR that it’d be great to have an oral vaccine mostly for folks that refuse to be injected — the needle-fear argument. Because, right at this moment, having A-Antibodies from an oral COVID vaccine would be quite useful at reducing transmission.
Herd Immunity’s Great — IF We Vaccinate
The upside of shedding virus even after you yourself are protected has something to do with herd immunity. If I’m immune after injection with two doses of a vaccine, but still can shed virus, then my interaction with other fully vaccinated folks can be mutually reinforcing to the strength and duration of our immunity. There have been many concerns expressed about the duration of strong anti-COVID immunity after vaccination. So our exchange of shed virus should re-kick our immune systems, via so-called immunological memory, to induce a reinforcing response. Everyone in the herd benefits. Except the un-vaccinated.
But herd immunity only works if ~70+ % of us are well-vaccinated (estimates range from 65 % to 80%). And with the bureaucratic nightmares surrounding the rollout so far, that seems a bridge too far, unless vaccine manufacturers and federal and state governments suddenly get their acts together. Meanwhile, in this context of bureaucratic inefficiency, it would’ve been wise to have simultaneously developed an oral vaccine to give as a second or third dose after the initial injection. This is simply because, with our current under-10% vaccinated herd, there’s still a lot of transmission going around and around.
Perhaps a more coordinated international intergovernmental science agency or university coalition might have led to task-sharing and co-development of an oral vaccine along with the injectable ones. Or perhaps there was too much confidence in the vaccine manufacturing and distribution agencies. Misplaced apparently, given that manufacturers are wringing their hands about their output numbers and both domestic and international distribution seems chaotic at best. In any case, the entire PR horse-race narrative seemed, and still seems, inappropriate to an endeavor such as one this deathly serious. The collaboration crucial to scientific research surrendered to the competition implicit in private-enterprise biotechnology.
By the way, if you’re vaccinated, I’d still counsel you to wear a mask indoors in public. Just a nod to your un-vaccinated neighbors in case you might still be shedding virus. A positive socialization strategy. Unless an approved oral vaccine suddenly manifests.
Pace e salute a tutti. (Peace and health to everyone.)
Thanks to my PCP, Dana Ellen Brown PA-C, with whom I had an interesting vaccine conversation that stimulated this essay.
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NOTE ADDED
On Feb. 23, three weeks after I posted this piece, the NY Times published similar, but less-detailed information in an opinion column by Georgetown virologist, Dr. Angela L. Rasmussen. In short, this Times columnist says: “It is true that, according to the clinical trial data, both the Pfizer-BioNTech and Moderna vaccines are highly effective at preventing Covid-19, the disease, but it’s unknown how well they prevent infection with SARS-CoV-2, the virus. Although Covid-19 and SARS-CoV-2 are often used interchangeably, they are fundamentally different. You can’t have the disease without the virus, but you can have the virus without the disease — as many asymptomatic people already know. It’s possible that vaccinated people are protected against Covid-19 themselves, but still spread SARS-CoV-2 to others who are not vaccinated.”
https://www.nytimes.com/2021/02/23/opinion/covid-vaccines-transmission.html
Despite the fact that the Times finally allowed someone to write about this, it still bothers me that this MD defaults to the damned fool position that we should be OK w/ clinical data without the supporting raw biological data; especially coming from corporate criminals who — from thalidomide to Vioxx to oxycontin — have collectively given us so many example of lying for profit. The naiveté (or the denial) is astonishing. No wonder we’re in such disarray!
