Courting the common cold
In 1926, the last wolves disappeared from Yellowstone.
Wolves once roamed from Mexico to the Arctic, but a push to eradicate predators starting in the 1870s decimated the wolf population in the American West. Livestock owners wanted to protect their animals, and ranchers and settlers mythologized wolves as a menace to humans that had to be destroyed.
Once the last of the wolves were killed in Yellowstone, the elk population began to rise. The park’s aspen, willow, and cottonwood trees suffered from overgrazing. Without the trees, songbird populations declined. Beavers didn’t have enough wood to build their dams, and riverbanks eroded. Rising water temperatures from the lack of dams and tree shade killed off cold-water fish. The coyote population surged, and the coyotes killed too many antelope.
The whole ecosystem fell out of balance in a collapse known as a trophic cascade.
As biologist Merlin Sheldrake writes in his book Entangled Life, “Collaboration is always a blend of cooperation and competition... Symbiosis is a ubiquitous feature of life.” When we tug on a string over here, we can’t predict how it will affect the elaborate tangle over there.
But the cascade works in the other direction too.
In 1995, wolves were reintroduced to Yellowstone. Elk numbers dropped, and beaver colonies grew. Insects, songbirds, amphibians, and fish began to thrive. Antelope, rodent, and fox populations increased as coyotes were kept in check.
The ecosystem was restored to balance.
There’s a new sentiment I’m seeing everywhere — that many people want to continue wearing masks to avoid getting colds or the flu. I want to unpack this a bit, not from a moral or tribal standpoint (because God knows masks have become loaded from both these perspectives), but from an immunological one.
First of all, it’s far from clear that masks were the predominant factor keeping colds and the flu at bay over the past year. As we know, mask use around the country was spotty, but rhinoviruses, influenza, and other common cold-causing coronaviruses were strangely absent everywhere. Other factors probably had much more to do with your lack of a cold. These include:
Viral competition, in which a dominant virus out-competes others to become the main thing going in any given season. It’s just as likely that other viruses are now resurging because SARS-CoV-2 is receding.
We also stopped almost all international travel, closed schools in many places, and halted the majority of cross-household interaction — things that inflicted a huge opportunity cost in other measures of wellbeing and which we’re not likely to repeat, barring another pandemic (knock on wood).
But let’s leapfrog over all of that and say that masks are a terrific defense against cold and flu viruses, and wearing one in public as a healthy, asymptomatic person is an effective way to avoid the hassle of getting a minor illness — ever, at all.
Is this desirable? Is it wise? I’m not so sure.
Soon after we’re born, autoimmune (or self-directed) white blood cells populate our bodies. These help defend against cancer and repair tissue. We also develop peacekeeping cells, whose job is to restrain the autoimmune cells, so they don’t go around attacking the body’s own tissues willy-nilly.
Some of these regulator cells only emerge after contact with the outside world — specifically, parasites and microbes.
“This dependence is truly weird,” writes Moises Valasquez-Manoff in An Epidemic of Absence. “It means that our ability to self-regulate, to maintain homeostasis, is oddly reliant on external stimuli.”
Our immune system is designed to interact with the world. We are complex ecosystems of mutually dependent microbes and molecules — superorganisms — embedded in a larger ecosystem of diverse life-forms. As Sheldrake writes, “Our selves emerge from a complex tangle of relationships only now becoming known.”
As our relationship to the external stimuli with which we evolved has changed, so has our immune function. And it’s happening fast. Estimates are that up to 20 percent of the population now suffers from autoimmunity.
Interestingly, scientists have observed that autoimmunity rates are highest in societies with the least amount of contact with microbes and parasites. The “hygiene hypothesis” says that the decreasing incidence of infections in western countries is at the root of the increase in autoimmune and allergic diseases.
Kids who grow up on farms have way lower rates of allergies than urban kids. “The same way a musician’s brain can distinguish between notes and tempos inaudible to a nonmusician, the farming immune system appears to have a heightened ability to sense the microbial world,” writes Valasquez-Manoff.
But this exposure doesn’t translate into a more revved-up inflammatory response to allergens. Quite the opposite. In farming kids, constant contact with microbes seems to teach their immune systems a certain serenity.
“External stimuli help us learn tolerance,” writes Valasquez-Manoff. “Without it, the immune system spirals into dysfunction.”
The Princess and the Pea fairy tale tells the story of a prince who’s determined to marry a princess. He keeps discarding women who don’t live up to his exacting standards, not sure that they’re real princesses.
One rainy night, a poorly dressed woman comes to his door, needing a place to spend the night. She claims she’s a princess, so the prince’s mother devises a test, placing a pea beneath 20 mattresses.
In the morning, the guest says she endured a sleepless night, kept awake by something hard in the bed. She displays her back, badly bruised. The prince is delighted — only a real princess would have the sensitivity to feel a pea through all that bedding! The two are married, and the story ends.
Here’s my question: Would you want to be so sensitive that a pea under 20 mattresses could keep you up all night and leave you covered in bruises? Would you want such a person for a spouse?
The prince sounds like a real piece of work. Maybe the unspoken moral of the story is that, in the end, he got exactly what he deserved.
I worry that we’re creating the immune system equivalent of the hyper-sensitive princess, unable to tolerate a pea.
I worry that in our desire to kill all the microbial wolves with hand sanitizer and masks and an ever-escalating war on the virome and biome, we’re unleashing a trophic cascade whose consequences we haven’t thought through.
I worry that the more comfortable we get, the less we’re able to tolerate discomfort, until every minor twinge is amplified, destroying our equilibrium.
The immune system learns by encountering pathogens, like a muscle grows by being torn, experiencing micro-injuries that grow back stronger.
“Even if you just get exposed [to a virus] and there’s not much replication and you don’t get sick, there’s a restimulation of T-cells,” said Florian Krammer, a vaccinologist at Mount Sinai School of Medicine, in a recent article in Stat.
A year and a half without these boosts to our adaptive immunity — the part of the immune system that relies on the memory of previous exposures to activate defenses — could mean many of us are that much more susceptible to these bugs, Krammer said. “There’s just lower levels of adaptive immunity in the population for them.”
I say, let’s get out there and get that adaptive immunity going again. Immunity to bugs, to discomfort, to the minor challenges and provocations of interaction with the world. Let’s let the borders we guarded so fiercely for the past year start to soften again, become more porous. This is how our being breathes.
We need challenges to grow stronger. We need allies in the biome and virome that we haven’t even begun to identify or name. There’s a wisdom in nature and ecological balance that we can’t match in our myopic engineering of reality.
We need to stay in conversation with the world — the visible, the invisible, the ineffable. We can’t seal ourselves away, kill all the wolves, hide from all the viruses, scrub our guts clean of every bug. Complex life is formed by relationships.
Rather than ridding the world of peas, maybe we need more adaptive backs.
Odds and Ends
Every time I send one of these babies, I have to spend a day or two reassuring myself it's OK to have a point of view and to say it out loud, even if it may be different than others around me. So I really appreciated this essay in Aeon: Dare to Speak Your Mind and Together We Flourish. If you've ever stopped yourself from saying what you think, or wished you could stop others from saying what they think, this is a good and important read.
I recently joined Braver Angels, a national organization that aims to nurture civility, empathy, and goodwill among Americans across the political divide. I just did my first online workshop last night, with 8 "reds" and 8 "blues," plus a couple of moderators. It was really interesting, and much more fruitful than any of your standard online discourse with the "other side" on social media. It's free to participate. Maybe you want to check it out.
I'm about halfway into a new book called The Scout Mindset: Why Some People See Things Clearly and Others Don't by Julia Galef. It's full of guidance on how to be a more careful and nuanced thinker, the value of seeking the truth instead of seeking to be right, and how to avoid confusing your beliefs for your identity. I'm loving it.
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Have a glorious weekend, friends!
