How Nassim Taleb Says You Should Think About the Covid-19 Vaccine
By: Thomas Smith
Tags: Vaccine, Covid 19, Black Swan, Risk, Nassim Taleb

How Nassim Taleb Says You Should Think About the Covid-19 Vaccine

Photo by Markus Spiske on Unsplash

Despite very promising results in clinical trials — with many trials suggesting greater than 94% effectiveness — many people remain reluctant to get the new Covid-19 vaccines from Moderna, Pfizer and others.

Philosopher Nassim Nicholas Taleb often weighs in on questions of iatrogenics (harm caused by the healer, or the risks of unintended harm caused by medical treatments). For a while, he had remained relatively silent on questions about the Covid-19 vaccine, aside from a handful of press statements and an excellent YouTube video.

Yesterday, though, Taleb addressed the question directly in a Tweet:

Let’s unpack what Taleb is saying here — and what it means for your own personal decisions about getting the vaccine.

Linear vs. Non-Linear

Taleb’s core argument here is that virus risks scale, and vaccine risks do not. Put differently, the risks of a vaccine scale linearly with the number of people vaccinated. The risks from a virus, though, scale exponentially (nonlinear).

Imagine that each vaccination you give has some (low) level of risk to the person receiving it. If you give the vaccine to 1,000 people, the overall risk you’re taking goes up by 1,000. If you vaccinate 2,000 people, it goes up by 2,000, and so on.

Yes, the overall risk taken increases with each dose you give. But it increases linearly, since the risks incurred by one person who gets vaccinated don’t affect the risks incurred by another person. If you and I go in to get vaccinated (wouldn’t happen — I’m a 30-something) and I have a terrible allergic reaction, my reaction doesn’t increase the risk that you’re going to have a terrible allergic reaction, too.

With a virus, though, things are totally different. Suppose that 100 people get Covid-19. Each spreads the virus to 3 people (Taleb uses the range 2–5 in his Tweet, so let’s go with 3). In a week, you have 300 people infected. In two weeks, it’s 900. In three weeks, it’s 2,700. And in a month, it’s 8,100. And so on.

The spread of a virus (and thus the risk created by it) is non-linear. Each person who gets the virus increases the risk to other people — potentially thousands of them. A few cases can quickly balloon into a few thousand, or a few million.

In contrast, the risk from a vaccine are not. Vaccine risks aren’t zero, but they scale linearly with the number of people vaccinated. That makes vaccines a much smaller driver of systemic risk than viruses.

The Worst Black Swan

The difference dynamics of risk for the vaccine versus the virus (linear vs. non-linear) should make sense. But there’s still the question of who bears the risk.

If you get the vaccine, you bear the (low) risk of a serious complication. Whereas if you forego it, get sick, and infect thousands of others, they bear the risk from your actions (unless there are legal consequences for you — still a big question mark). The difference between personal and systemic risk is probably a stumbling block for a lot of people, who might prefer to protect themselves, even at the cost of creating huge risks for others.

To address this, let’s return to another one of Taleb’s concepts — that of a Black Swan (to be clear, Taleb says that the pandemic itself is not a Black Swan).

Black Swans are rare, consequential events which are impossible to predict in advance. In his book Antifragile, Taleb asks readers to consider what the worst possible Black Swan would be for them personally. Most people, Taleb says, assume that “their own death is the worst Black Swan scenario”.

But Taleb says that’s not correct. In his words, most people would “agree explicitly that their death plus the death of their loved ones plus the termination of humanity would be vastly worse outcome than their own death.” Taleb says that “We are a mere part of a large chain, and we are worried about both ourselves and the system.”

Taleb isn’t saying that Covid-19 will end humanity. But his argument here is that your death isn’t the worst case scenario — your death and/or the deaths of people and systems you care about is much worse.

Multiplicative risks like those from viruses tend to lead more easily to these absolute-worst-case scenarios. Linear risks like those from vaccines tend not to.

Consider that people who get Covid-19 infect, on average, half of their household members. Also consider that even a few cases of the virus can balloon massively (due to nonlinear dynamics describe above), and cause massive amounts of illness and death. A small number of infected individuals at a Biogen conference in Boston, for example, likely caused over 300,000 infections and scores of deaths.

Because of non-linear dynamics and multiplicative risks, getting a virus like Covid-19 puts you at risk of death, but it also puts your family members at risk of death (most immediately), as well as potentially tens of thousands of others.

In contrast, getting a vaccine puts you at (low) risk. But it doesn’t expand in this way, to threaten the people and systems you care most about.

Thus, as Taleb says in his September 20th, 2020 YouTube video:

“At the collective level, something tells me that vaccines have much, much lower risk than the disease. It’s hard to compare. But so for one person, they maybe break even. But for the collective, it would be a huge payoff because the vaccine effective de-multiplies whereas the other one [the virus] multiplies. At the societal level, it’s a no-brainer. Vaccines are better.”

What to Consider

In making your own decision about whether to get vaccinated, Taleb appears to be asking that you consider the following question:

How do you weigh the (low) risk to yourself from getting the vaccine against the (potentially much higher) risk to those around you that you create by foregoing it?

Consider that “those around you” (or “the collective”) doesn’t just mean society. It also (and much more likely) means the people directly in your sphere — your friends, family members, local community, etc. — since most people pass Covid-19 to those directly around them.

That’s a person question. But as Taleb suggests in his point about the worst Black Swan, most people would probably agree that putting their family members at risk and potentially causing hundreds of deaths of unknown others would be worse than putting themselves at (low) risk. And for that reason, most people would likely choose to get the vaccine.

The full risk picture is likely more complex than this. Vaccines can cause viruses to mutate and get worse over time, prioritizing vaccination economically could lead to de-prioritization of other things like general healthcare, and so on. Timing is another question, as some may choose to get the vaccine, but may want to wait to see more data before they do so. And there’s the tiny risk that some iatrogenic effect of the vaccine appears much later, once millions have already received it.

But overall, the question Taleb poses is this:

Would you take on a (low) personal risk which is non-linear, to prevent a potentially much larger, multiplicative risk to your loved ones and society as a whole?

If the answer is yes, then consider vaccination, when it’s available to you.