"Immunity Debt"

Why licking lamposts in Winter is a bad idea

There have been a few attempts to explain aberrations and unexpected severity of RSV and other viruses among young populations of late. One of the hypotheses includes “immunity debt,” which, in short, refers to postponed infections with pathogens the youth are typically exposed to which are ‘hitting harder’ due to transmission avoidance from masking and other health behaviors. An opposing hypothesis describes SARS Cov 2 as altering the response to other infections. We will search for the evidence of both.

Dall-E

First, imagine we travel back to the time when smallpox was endemic among the European populations but was not among the American populations in the 1750s. During the French and Indian Wars, the commanders used smallpox-ridden blankets to infect the native populations. Did they have an ‘immunity debt’ to smallpox? No. It was an epidemic among the exposed tribes and smallpox was able to spread as it was not encountered previously. Implying there is an ‘immunity debt’ to smallpox is absurd. However, what about from the perspective of the europeans, where smallpox was near ubiquitous and outbreaks occurred every 2-4 years. Would they have considered the tribes as having a relative susceptibility or ‘immunity debt’ to smallpox? Perhaps. But to an observer of the modern day, ‘immunity debt’ to smallpox simply does not exist.

Now let us turn our focus to RSV. As covered before, RSV is capable of causing long term respiratory harm like wheeze in those infected, among other things. Is there a collective ‘rsv immunity debt?’ There were 10,280 fewer RSV cases in winter 2020-2021 in England. The following summer there were around 11,500 lab confirmed RSV cases.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00525-4/fulltext

The concept of “immunity debt” to an illness is interesting, because we must accept that it is a ubiquitous and inevitable thing in order to have a debt to it. But what is really happening? In my opinion, what is happening is a combination of disequilibria and expansion of the naive pool of individuals. Therefore when the means to transmit among these populations is reinstated, more individuals will be opted in to make a synchronous ‘wave.’ The phrase, ‘immunity debt’ is more of a social term rather than a scientific one.

Now, for the suggestion of changed immunity due to SARS Cov 2. It’s not completely ‘out there,’ no matter how many pop-culture virologists will clutch their pearls about the suggestion, and it has been well-published upon as a phenomenon. You may have even seen myself drumming up the possibility of “T-cell exhaustion” to great opposition, which has now been proven true, of course, despite vested interests determined to show the contrary. In one example, scientists found that there was a degree of T cell exhaustion to pathogens other than SARS Cov 2 following SARS Cov 2 infection. To be most clear, it was slightly attenuated t cell function ex vivo, or in a dish. We do not know the real-life dynamics or change one would have in a response to influenza or another pathogen with and without sars cov 2 infection previously, it is difficult to control for that and ascertain the truth. However, there is another study also showing a relative B cell immunodeficiency following SARS Cov 2 infection.

Let’s go back to an example of another poxvirus. Somehow, Monkeypox was able to exploit it’s frequent forays into human populations and turn itself into an endemic virus in the United States. Some argued Monkeypox is filling a niche, some have argued there was depressed immune function from frequent sars cov 2 infections. What is the answer? I would not be surprised if it is filling a niche AND exploiting dampened immunity from frequent SARS Cov 2. A few took offense to the notion that SARS Cov 2 could be altering immunity on a population level, and claimed we would see a rise in AIDS-defining illnesses, not things like monkeypox, but I think they are incorrect. If you take a pathogen with R=.99 in a population, then slightly attenuate T cell function via exhaustion and B cell function from cd19 downregulation, I posit you would move R to 1.02 if there is potential in a niche. Kind of like in the pox virus niche in humans. Am I suggesting Molluscum contagiosum, chickenpox, or other pox virus parties to crowd out the niche? Absolutely not, because these illnesses are harmful to health. You can see the results of the sars cov 2 parties people are throwing.

So what is the solution? Vaccines, of course, and greater cleanliness and public health sanitation of things like the air. Not opting into infections like brutes. However, I realize this is a nascent field with nascent technologies. We musn’t delude ourselves into thinking infections actually confer a benefit or are a debt that must be paid. They are more like a tax we make the children pay for our civilization not being developed enough to prevent viral illnesses that hospitalize thousands of children per year.

Stay safe out there,

AJ